Comparative Study on the Effects of Calcination Temperature of Kaolin Clay on the Fabrication and Properties of Ceramic Membranes

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A common challenge with tubular supports made from extruded raw kaolin is deformation during drying. To overcome this, kaolin calcination was investigated as a processing strategy. Pre-calcination prior to shaping significantly reduced shrinkage and deformation, thereby improving the structural integrity of the supports. The calcination temperature was found to be a key parameter, influencing support quality, enlarging the average pore size, and enhancing water flux—achieving up to a fivefold increase compared with uncalcined samples. Furthermore, the effect of sintering temperature on porosity, pore size distribution, and mechanical strength was systematically examined. The fabricated MF membranes exhibited an average pore size of ~ 0.5 µm. Filtration tests with distilled water demonstrated their suitability for tangential microfiltration applications. Membranes Supports Extrusion Drying Microfiltration Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 1. Introduction Separation processes are essential in industrial applications. Among these methods, membrane technology stands out for its cost-effectiveness and exceptional selectivity. Ceramic membranes, in particular, offer distinct advantages over their polymeric counterparts [ 1 – 9 ]. Their superior chemical, mechanical, and thermal stability make them a more reliable choice in demanding environments, far surpassing the performance of organic membranes. Microfiltration (MF) and ultrafiltration (UF) are highly effective techniques for removing particles, microorganisms, and colloidal substances from suspensions [ 10 – 13 ]. Consequently, there has been growing interest in the development of inorganic membranes, particularly ceramic ones, for these applications [ 14 ]. These membranes typically consist of a thin separation layer supported by a porous substrate with a larger average pore size (APS) than that of the separation layer. Commercial supports and membranes are generally manufactured from ceramic compounds such as alumina (Al₂O₃), cordierite (2MgO.2Al₂O₃.5SiO₂), silicon carbide (SiC), and mullite (3Al₂O₃.2SiO₂) [ 15 – 18 ]. While these materials exhibit excellent mechanical and thermal properties, they are relatively expensive. To reduce production costs and promote the use of locally available resources, various processing routes have been proposed for fabricating membrane supports from kaolin [ 19 – 23 ], a naturally abundant and inexpensive raw material [ 24 – 26 ]. These efforts also aim to valorize local natural materials. Accordingly, the present study investigates the preparation of both supports and membrane layers from locally sourced kaolin. Tubular ceramic supports for membranes can be prepared using various shaping techniques. Among these, extrusion is widely employed due to its simplicity and suitability for producing long tubular structures. The main steps of this process include paste preparation, extrusion, drying, and firing. Among these steps, drying plays a critical role in the overall process chain, as it significantly affects the final quality of the product. However, several challenges can arise during the drying stage [ 27 ]. One of the primary difficulties is maintaining the structural integrity of long extruded samples, particularly those made from kaolin clay, which are prone to deformation. Another common issue is the cracking or breakdown of specimens during drying. This is mainly caused by the removal of water from the samples, leading to substantial drying shrinkage and, consequently, mechanical stress. Despite the importance of the extrusion method for fabricating clay-based membrane supports, the calcination step of the starting powder is rarely addressed in the literature. While a few studies explicitly mention calcination, most omit this detail even though it is implicitly assumed as part of the process. In particular, the calcination of kaolin clay prior to extrusion is often overlooked, despite its critical role in shaping the final properties of the support. Calcining the starting powder can significantly influence the microstructure of the resulting supports, including their shape, porosity, and the formation of microcracks, all of which directly affect the mechanical and functional properties of the supports. Therefore, understanding the impact of calcination on the material’s behavior during drying and shaping is essential for optimizing the manufacturing process. The aim of the present study is to investigate the influence of calcination temperature and drying method on the shape and structural integrity of extruded samples, given the high technological relevance of these parameters. Specifically, this work examines the effects of calcined kaolin clay on drying shrinkage, weight loss, and the final form of the specimens, with the goal of improving the overall quality and reproducibility of tubular ceramic supports. 2. Experimental procedure 2.1 Analysis of the raw materials The chemical composition of kaolin, sourced from Tamazert in the Jijel region (Algeria), is shown in Table 1 . The main impurities detected are CaO, MgO, TiO₂, K₂O, and Fe₂O₃. The particle size distribution of this material, used in the preparation of supports, was determined using the Dynamic Laser Beam Scattering (DLBS) technique. This analysis revealed an average particle size of approximately 9 µm. The presence of fine particles and organic matter in the raw material enhances the plasticity of the green paste. Table 1 Chemical composition of kaolin (wt%), determined by X-ray fluorescence (XRF) analysis. Oxides Al 2 0 3 SiO 2 CaO MgO K 2 O Fe 2 O 3 TiO 2 I. L Percentage (wt%) 34.15 50.56 0.02 0.31 7.18 1.15 0.28 6.35 2.2 Supports preparation In this study, four different elaboration methods were used. Specimens were prepared following the steps indicated in the flowchart in Fig. 1 . In the first and third processes, natural clay (non-calcined starting powders) was used. In the second and fourth processes, the clay was calcined at 900°C for 1 hour to transform kaolin into metakaolin. In the first and second processes, the effects of calcined and non-calcined kaolin on drying shrinkage and the shape of the support were investigated (supports identified as S1 and S2). In the third and fourth processes, the effects of calcination and the addition of organic materials on the properties of the prepared supports were examined. Supports identified as S3 were prepared by adding starch to the raw materials (process 3). After kaolin calcination (process 4), the mixture of kaolin and starch lost its plasticity (supports identified as S4). To improve plasticity and facilitate shaping, organic additives were introduced. The organic additives used were: 4 wt% methocel, derived from methylcellulose (The Dow Chemical Company), as a plasticizer, and 4 wt% amijel, derived from starch (Cplus12072, Cerestar), as a binder. The tubular supports were produced through extrusion, while flat supports were formed using the roll pressing technique. The latter was specifically used to prepare samples for mechanical testing. Sintering was carried out in air, and the appropriate firing schedule was determined based on thermal analysis (gravimetric analysis). Two steps were applied: The first step, conducted at around 600°C, aimed to eliminate organic additives and remove water from the kaolin. The second step involved sintering the samples, which were then maintained at the target temperature for 1 hour. 2.3 Membrane Preparation The same powder used for the preparation of the supports was crushed for 2 hours using a planetary crusher operating at 250 revolutions per minute, then sieved to obtain particles smaller than 50 µm. The average particle size of this powder, intended for membrane preparation, was approximately 4 µm. To prepare a microfiltration (MF) layer using kaolin powder, a deflocculated slip was prepared by mixing 10 wt% kaolin, 20 wt% polyvinyl alcohol (PVA, in a 12 wt% aqueous solution), and 70 wt% water. The slip was deposited onto the support using the slip casting method [ 28 ], with a deposition time of approximately 4 minutes. After drying at room temperature for 24 hours, the microfiltration (interlayer) layer was sintered at 1050°C for 1 hour. The layers were deposited on macroporous supports S3 and S4. The S3 supports had an average pore size (APS) of 1.3 µm and a porosity of 51%, while the S4 supports had an APS of 4.1 µm and the same porosity. The resulting membranes were designated as M1 and M2, respectively. 2.4 Characterization Techniques Various techniques were employed to investigate both the kaolin supports and the corresponding membranes. The crystalline structure was characterized by X-ray diffraction (XRD), while mechanical strength was evaluated through a three-point bending test performed on bar-shaped samples with rectangular cross-sections, using a LLOYD INSTRUMENTS LRX testing machine. Total porosity, average pore size (APS), and pore size distribution were determined by mercury intrusion porosimetry (Micromeritics, Model Autopore 9220) for samples sintered at different temperatures. The presence of potential defects in the supports and membranes was examined by Scanning Electron Microscopy (SEM) (HITACHI S-4500). Tangential filtration experiments were conducted at room temperature using a custom-built pilot system, with nitrogen gas employed to maintain the working pressure. 3. Results and Discussion 3.1 Thermal Analysis Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) were employed to investigate the structural evolution of the starting powders using a SDT 2960 Simultaneous DSC-TGA apparatus (TA Instruments). The measurements were conducted in air, with a heating rate of 10°C/min, from room temperature up to 1200°C. The TGA curve recorded during heating (Fig. 2 a) shows a total weight loss of about 8% for the kaolin samples. This weight loss occurs in two distinct stages: the first, between 25 and 200°C, is attributed to the removal of moisture, while the second stage, between 400 and 600°C, corresponds to the release of water (by vaporization) chemically bound within the kaolin structure. The weight loss in the second stage is more pronounced (Fig. 2 a). In contrast, the weight loss was negligible for the calcined kaolin samples (Fig. 2 b). These observations are further supported by the DSC analysis (Fig. 2 ). The first and third endothermic peaks occurred at 65°C and 497°C, respectively (Fig. 2 a). These correspond to the departure of water, while the second peak, observed at 251°C, corresponds to the release of organic materials. Another stage, characterized by an exothermic reaction, was observed at approximately 983°C (Figs. 2 a and 2 b). The origin of this reaction is still not fully understood. Some researchers attribute it to spinel formation, while others suggest it is due to mullite nucleation [ 29 ]. Consequently, these results support the choice of two heating steps, as previously discussed in the experimental section. 3.2. Drying and Shrinkage Phenomena This study primarily aimed to evaluate the effect of heat treatment of the starting raw materials on the shape and physical properties of membrane supports prepared from kaolin clay. Figures 3 a and 3 b show typical photos of dried supports made from natural and calcined clay, respectively. After the extrusion step, tubular supports are particularly vulnerable to deformation and shrinkage. Experimental tests were carried out to identify the causes of plastic deformation observed in the dried supports. During drying, the removal of molding water from supports made with natural clay induces significant shrinkage, leading to changes in the size and geometry of the supports [ 30 ]. This shrinkage is not uniform across the sample, resulting in visible deformations that often lead to the rejection of the product. This behavior is attributed to the fine particle size and porous structure of kaolin clay, which contributes to high capillary water retention, making the drying process difficult. Moreover, a higher proportion of fine particles increases the extent of shrinkage during drying, which in turn causes warping and the development of cracks. When preparing the clay paste, the powder particles absorb water and retain it within internal cavities due to the natural structure of kaolin. However, after calcination, the volume of water absorbed is significantly reduced approximately halved due to structural transformations in the kaolin. Specifically, calcination removes physically bound water and causes kaolinite to transform into metakaolin. This transformation is evident in the XRD patterns shown in Fig. 4 , where kaolinite peaks are significantly diminished or disappear entirely, indicating the formation of less crystalline, disordered phases such as metakaolin [ 31 ]. As water is removed during drying, pressure gradients form between the interior and exterior of the material, generating internal stresses that lead to further shrinkage, deformation, or even cracking [ 32 – 39 ]. A higher initial water content amplifies this effect. In this study, the water content used during paste preparation was approximately 55% for natural clay and 26% for calcined clay. The reduced water demand in calcined powders is a key factor in minimizing shrinkage. Shrinkage was quantified as the percentage difference between the original diameter (D₀) and the final diameter (D) of the supports, using the following equation: S = ((D₀ – D) / D₀) × 100 Where D₀ is the initial diameter and D is the measured diameter after drying. Figure 5 illustrates the variation in sample diameter as a function of temperature. The results show that drying at 25°C led to a diameter reduction of approximately 19% for supports made from natural clay, and about 7% for those prepared with calcined clay. These findings clearly demonstrate that the use of calcined clay significantly reduces shrinkage during both drying and sintering, thereby decreasing the risk of deformation at low and high temperatures. Following high-temperature firing, a slight reduction in diameter was observed in both types of samples. Nevertheless, specimens prepared from non-calcined clay exhibited greater overall shrinkage compared to those produced from calcined clay. In the temperature range of 1000–1200°C, a pronounced increase in shrinkage was detected in both supports, which is attributed to phase transformations within the material matrix and the initiation of sintering. In conclusion, calcination of the starting powder is an effective technique for reducing deformation during the drying process. It lowers the water content required during mixing, minimizes shrinkage and weight loss, and improves the final shape of the ceramic supports. Under optimal conditions, supports with near-perfect straightness and structural integrity can be achieved through this method. 3.3 Support materials For the development of high-quality membrane supports, several key properties must be optimized: a well-controlled pore size distribution [ 6 ], high total porosity, a smooth surface free from large defects or macropores, adequate mechanical strength, and strong chemical stability [ 3 ]. To evaluate these characteristics, porosity and average pore size were measured on supports sintered at various temperatures for 60 minutes. The results are shown in Figs. 6 a and 6 b. As expected, an increase in sintering temperature leads to a gradual increase in average pore diameter and a corresponding decrease in total porosity. The reduction in porosity is primarily attributed to material densification and the elimination of smaller pores. The initial increase in average pore diameter can be attributed to the coalescence of adjacent small pores, leading to the formation of larger pore structures. However, at sintering temperatures above 1250°C, both total porosity and average pore diameter exhibit a pronounced decline, indicating significant densification of the material and the possible closure or collapse of larger pores due to enhanced grain growth and pore elimination mechanisms. Moreover, both the average pore size and the porosity are closely related to the preparation method. The results (Figs. 6 a and 6 b) show that the calcination process positively influences the average pore size of the supports (S4) compared to those prepared from kaolin without calcination (S3). For instance, the calcined kaolin supports (S4) exhibited a porosity of approximately 52% and an average pore size of around 4.1 µm, whereas the uncalcined kaolin supports (S3) showed a porosity of about 46% and an average pore size of around 1.4 µm, under the same sintering conditions (1200°C for 1 hour). To further understand the pore structure, the pore size distribution patterns of the supports were analyzed. For example, as presented in Fig. 7 , S3 samples sintered at 1150°C for 1 hour exhibited a nearly single-modal or homogeneous pore size distribution, also referred to as a Single-Modal Pore Size Distribution (SMPSD), as previously reported [ 19 ]. It should be noted that pore size distributions are generally classified into three main types: single-modal (or Gaussian), bimodal, and multimodal. SMPSD typically occurs in samples with a uniform pore size distribution, where the plot of pore volume (%) against pore size exhibits a single peak. In contrast, a Bimodal Pore Size Distribution (BMPSD) displays two distinct or overlapping peaks, indicating the presence of two different pore size ranges. Lastly, a Multimodal Pore Size Distribution (MMPSD) is characterized by more than two distinct or overlapping peaks, suggesting a more complex pore structure. Figure 8 shows the X-ray diffraction (XRD) spectra of samples sintered at 1100°C and 1250°C for 1 hour. The main observed phases are mullite (3Al₂O₃·2SiO₂) and quartz. At 1100°C, quartz is the dominant phase, whereas at the higher temperature of 1250°C, mullite becomes the predominant phase. These identified phases are of particular importance due to their favorable physical and mechanical properties. For instance, mullite is widely used as a refractory material in high-temperature ceramic applications because of its low thermal expansion and high creep resistance. Building on the structural analysis, the mechanical performance of the porous ceramic supports (S4) was also evaluated. Specifically, the flexural strength was measured to assess the effect of sintering temperature. As shown in Fig. 9 , flexural strength is closely linked to the total porosity ratio, which itself is influenced by sintering temperature. For example, a flexural strength of 13 MPa was recorded at a porosity of 62% and an average pore size of approximately 2.6 µm. In contrast, S4 supports with a porosity of around 28% and an average pore size of approximately 3 µm exhibited a significantly higher flexural strength of about 61 MPa. 3.4. Membrane Layer Analysis Figures 10 a and 11 a show typical cross-sections of membranes M1 and M2, which consist of a microfiltration (MF) layer coated onto macroporous S3 and S4 supports, respectively. The microstructure of both membranes demonstrates good homogeneity, an important characteristic for effective MF applications. The quality of the coating layer was visually assessed, revealing smooth surfaces without visible defects such as scale formation or cracks. These visual observations are confirmed by SEM images (Figs. 10 b and 11 b), which show that both membranes have very similar and uniform surface morphologies. The thickness of the microfiltration layer can be controlled by adjusting the proportion of mineral powder in the suspension and the coating time. Under the applied conditions, kaolin layers were deposited onto S3 and S4 supports with average thicknesses of approximately 21 µm and 54 µm, respectively. In both cases, the average pore size of the coated layer was around 0.5 µm. Importantly, the resulting microstructure and pore size distribution key parameters for MF performance can be further tuned by modifying the sintering temperature. Membranes M1 and M2 were characterized in terms of their water permeability. As shown in Fig. 12 , the water flux through the membranes was measured and found to depend on the applied pressure. A linear relationship between the steady-state water flux and the applied pressure was observed, confirming that the pressure gradient is the sole driving force for permeation [ 40 ]. This behavior is characteristic of convective transport, in which the volumetric flow rate is directly proportional to the pressure difference across the membrane. Based on the slopes of the curves in Fig. 12 , the average permeability values for M1 and M2 were approximately 140 and 680 L/(h·m²·bar), respectively. This substantial difference indicates that the characteristics of the support structure play a crucial role in overall membrane performance. Although both supports, S3 and S4, had similar thickness and porosity (as detailed in Table 2 ), they differed in average pore size. The S4 support, which was produced from calcined kaolin powder, exhibited a larger average pore size compared to the S3 support made from uncalcined kaolin. Consequently, the M2 membrane (based on S4) demonstrated a higher water flux than M1, suggesting that pore size may be a more critical factor than porosity in determining membrane permeability [ 41 ]. This observation is consistent with the Hagen–Poiseuille equation, which indicates that flux (and consequently permeability) is directly proportional to the open porosity and the square of the average pore size (APS) [ 42 ]. Table 2 Properties of supports used for the membrane deposition. Type Heating Temperature (°C) Average pore size (µm) Porosity (%) Phases S3 1150 1.3 51 Quartz + mullite S4 1250 4.1 51 Quartz + mullite 4. Conclusions Ceramic multilayer membranes were successfully fabricated using kaolin as the sole raw material. Microfiltration membranes were produced by slip casting, while their supports were prepared by extrusion. The average pore size of the MF membrane was approximately 0.5 µm. The study demonstrated that the preparation process is simple, cost-effective, and suitable for large-scale production. The results further showed that shrinkage and deformation of the clay supports during drying are strongly influenced by the water content of the starting powders. Calcination of the raw material proved essential, as it minimized shrinkage and deformation during drying and firing, thereby enhancing the structural integrity of the supports. Moreover, the use of locally abundant kaolin in Algeria reduces overall manufacturing costs, making this approach promising for the large-scale production of low-cost ceramic membranes. Declarations Declaration of interests The author declares that there are no known financial or personal relationships that could have appeared to influence the work reported in this paper. Author Contribution The author F.B. conceived the study, conducted the research, analyzed the data, and wrote the manuscript. Acknowledgement AcknowledgmentsI would like to express my sincere gratitude to Professor Dr. Harabi Abdelhamid, for his generous support and valuable assistance in reviewing this manuscript. His insightful feedback and constructive suggestions greatly contributed to enhancing the clarity and quality of this work. References Ghouil B, Khebli Z, Bouzerara F, Zermani D, Zitouni C, Youla K, Idoui T, Khennouf T, (2024) Preparation and characterization of low-cost ceramic microfiltration membranes for water treatment. Processing and Application of Ceramics 18(4): 405-413. https://doi.org/10.2298/PAC2404405G Kouras N, Harabi A, Bouzerara F, Foughali L, Policicchio A, Stelitano S, Galiano F, Figoli (2017) A Macro-porous ceramic supports for membranes prepared from quartz sand and calcite mixtures. Journal of the European Ceramic Society 37:3159 - 3165. https://doi.org/10.1016/j.jeurceramsoc.2017.03.059 Khebli Z, Bouzerara F, Brihi N, Figoli A, Russo F, Galiano F, Chahredine S (2023) Fabrication of a zircon microfiltration membrane for culture medium sterilization. Membranes 13(4):399. https://doi.org/10.3390/membranes13040399 Boulkrinat A, Bouzerara F, Harabi A, Harrouche K, Stelitano S, Russo F, Galiano F, Figoli A (2020) Synthesis and characterization of ultrafiltration ceramic membranes used in the separation of macromolecular proteins. Journal of the European Ceramic Society 40 (15) : 5967–5973. https://doi.org/10.1016/j.jeurceramsoc.2020.06.060 Kadiri C, Harabi A, Bouzerara F, Foughali L, Brihi N, Hallour S, Guechi A, Boudaira B (2020) Preparation and properties of tubular macroporous ceramic membrane supports based on natural quartz sand and dolomite. Journal of the Australian Ceramic Society 56: 379–387. https://doi.org/10.1007/s41779-019-00338-2 Zhou T, Xue K, Zhang H, Chen H, Li Z (2025) Analysis of pore size control and application of ceramic membrane based on particle sintering method. Energy, 328:136721. https://doi.org/10.1016/j.energy.2025.136721 Yang Y, Yu H, Hu Z, Yang R, Tang S, Tang T, Chen X, Wang Q, Wang Y, Chang Q (2025) Facile fabrication of ceramic tight ultrafiltration membrane with high permeability for rapid separation of dye molecules. Separation and Purification Technology 368 (17): 132945. https://doi.org/10.1016/j.seppur.2025.132945 Akoumeh R, Al-Ejji M, Aljaoni B, Abbas M (2025) Advances in ceramic membrane technology: Versatility of fabrication technique, industrial applications, and challenges. Inorganic Chemistry Communications 179:114685. https://doi.org/10.1016/j.inoche.2025.114685 Chen T, Fan W, Xu P, Chen X, Qiu M, Fan Y (2024) Construction of asymmetric ceramic membranes with identical source interlayer on fly ash support by dip-coating. Journal of the European Ceramic Society, 44 (15):16765. https://doi.org/10.1016/j.jeurceramsoc.2024.116765 Medjemem N, Harabi A, Bouzerara F, Foughali L, Boudaira B, Guechi A, Brihi N (2016) Elaboration and characterization of low cost ceramics microfiltration membranes applied to the sterilization of plant tissue culture media. J. Taiwan. Inst. Chem. Eng. 59:79. https://doi.org/10.1016/j.jtice.2015.07.032 Bouazizi A, Saja S, Achiou B, Ouammou M, Calvo J.I, Aaddane A, Alami Younssi S (2016) Elaboration and characterization of a new flat ceramic MF membrane made from natural Moroccan bentonite Application to treatment of industrial wastewater. Applied Clay Science 32:33-40. https://doi.org/10.1016/j.clay.2016.05.009 El Mrabet H, Elazhar M, Moussaoui I, Moumouh J, Addar F. Z, Tahaikt M, Elazhar F, Mohamed T, El Haloui N, Elmidaoui A (2025) Technico-economic assessment of membrane filtration as post-treatment of biological denitrification for brackish groundwater. Desalination and Water Treatment, 322 :101160. https://doi.org/10.1016/j.dwt.2025.101160 Aryanti P.T. P, Harsono B, Warsa Biantoro M.F, Romariyo R, Putri T.A, Hakim A.N, Setia G.A, Saputra D.I, Khoiruddin K (2025) The role of membrane technology in palm oil mill effluent (POME) decontamination: Current trends and future prospects. Journal of Environmental Management, 374 :124094. https://doi.org/10.1016/j.jenvman.2025.124094 Changrong X, Xiaoxia G, Fanqing Li, Dingkun P, Guangyao M (2001) Preparation of asymmetric Ni:ceramic composite membrane by electroless plating. Colloids and Surfaces A: Physicochemical and Engineering Aspects 179:229-235. https://doi.org/10.1016/S0927-7757(00)00642-7 Gao J.m, Yan Z, Wang B, Ma Z, Guo Y (2024) Preparation of whisker mullite ceramic membrane from coal fly ash for efficient oil-water separation. Ceramics International 50(18):32727-32736. https://doi.org/10.1016/j.ceramint.2024.06.082 Wang S, Yu Ma X, Wang Y.L, Cui S.P, Nie Z, Li Q.Y, Wei Q (2019) Preparation and desalination performance of porous planar cordierite membranes using industrial solid waste as main silica source. Ceramics International 45:5932-5940. https://doi.org/10.1016/j.ceramint.2018.12.062 Zou J, Dai Q, Zhou X, Qin H, Guo W, ao P, Xiao H (2024) Preparation of alumina disc ceramic membrane with enhanced abrasion resistance for dynamic membrane filtration. Ceramics International 50:9354-9362. https://doi.org/10.1016/j.ceramint.2023.12.251 Li S, Li Y, Wei C, Wang P, Gao P, Zhou L, Wen G (2021) One step co-sintering of silicon carbide ceramic membrane with the aid of boron carbide. Journal of the European Ceramic Society 41(2):181-1188. https://doi.org/10.1016/j.jeurceramsoc.2020.09.065 Bouzerara F, Harabi A, Achour S, Larbot A (2006) Porous ceramic supports for membranes prepared from kaolin and doloma mixtures. Journal of the European Ceramic Society 26:1663-1671. https://doi.org/10.1016/j.jeurceramsoc.2005.03.244 Boulkrinat A, Bouzerara F (2021) Elaboration of tubular titania microfiltration membranes for wastewater treatment. Desalination and Water Treatment 211:319–322. https://doi.org/10.5004/dwt.2021.26366 Boudaira B, Harabi A, Bouzerara F, Zenikheri F, Foughali L, Guechi A (2016) Preparation and characterization of membrance supports for microfiltration and ultrafiltration using kaolin (DD2) and CaCO 3 , Desalination and Water Treatment. 57:5258. https://doi.org/10.1080/19443994.2015.1021998 Ghouil B, Harabi A, Bouzerara F, Boudaira B, Guechi A, Demir M.M, Figoli A (2015) Development and characterization of tubular composite ceramic membranes using natural alumino-silicates for microfiltration applications. Materials Characterization 103 :18-27. https://doi.org/10.1016/j.matchar.2015.03.009 Ghouil B, Harabi A, Bouzerara F, Brihi N (2016) Elaboration and characterization of ceramic membrane supports from raw materials used in microfiltration. Des. Wat. Treat. 57(12): 5241-5245. https://doi.org/10.1080/19443994.2015.1021098 Khebli Z, Djardire R, Boulkrinat A, Bouzerara F (2022) Elaboration of zirconia microfiltration membranes tested with methylene blue filtration, Desalination and Water Treatment, 279:4–7. doi:10.5004/dwt.2022.29061 Aouadja F, Bouzerara F, Guvenc C.M, Demir M.M (2022) Fabrication and properties of novel porous ceramic membrane supports from the (Sig) diatomite andalumina mixtures. Boletín de la Sociedad Española de Cerámica y Vidrio 61(5):531-540. https://doi.org/10.1016/j.bsecv.2021.04.002 Makhloufi K, Moussi B, Srarfi F, Tagorti M.A (2024) Development of ceramic filtering membranes based on Tunisian clay and phosphate sludge in wastewater treatment, Solid State Sciences 148:107430. https://doi.org/10.1016/j.solidstatesciences.2023.107430 Fu Z, Eckstein U, Dellert A, Roosen A (2015) In situ study of mass loss, shrinkage and stress development during drying of cast colloidal films Journal of the European Ceramic Society 35:2883–93. https://doi.org/10.1016/j.jeurceramsoc.2015.03.029 Khemakhem M, Khemakhem S, Ben Amar R (2014) Surface modification of microfiltration ceramic membrane by fluoroalkylsilane. Desalination and Water Treatment 52:1786-1791. https://doi.org/10.1080/19443994.2013.807023 Boudaira B, Harabia A, Bouzerara F, Condom S (2009) Preparation and characterization of microfi ltration membranes and their supports using kaolin (DD2) and CaCO 3 . Desalination and Water Treatment 9(1–3):142-148. https://doi.org/10.5004/dwt.2009.764. Collard J.M, Arnaud G, Fohr J.P, Dragon A (1992) The drying-induced deformations of a clay plate. International Journal of Heat and Mass Transfer 35(5):1103-1114. https://doi.org/10.1016/0017-9310(92)90171-N Bassir Diop M, Grutzeck M.W, Molez L (2011) Comparing the performances of bricks made with natural clay and clay activated by calcination and addition of sodium silicate calcination and addition of sodium silicate. Applied Clay Science 54:172–178. https://doi.org/10.1016/j.clay.2011.08.005. Hammouda I, Jlassi K, Mihoubi D (2015) Changes in the physicomechanical characteristics of a ceramic paste during drying. Comptes Rendus Mécanique, 343:419–428. https://doi.org/10.1016/j.crme.2015.06.001 Augier F, Coumans W.J, Hugget A, Kaasschieter E.F (2002) On the risk of cracking in clay drying. Chemical Engineering Journal 86:133–138. https://doi.org/10.1016/S1385-8947(01)00279-0 Silva W. P.d, Silva L.D.d, Farias V.S.O.l, Silva C.M.P.S (2013) Water migration in clay slabs during drying: A three-dimensional numerical approach. Ceramics International 39:4017–30. https://doi.org/10.1016/j.ceramint.2012.10.252. Jan Kowalskin S, Banaszak J, Rybicki (2010) A Plasticity in materials exposed to drying, Chemical Engineering Science 65:5105–16. https://doi.org/10.1016/j.ces.2010.06.006 Eid J, Taibi S, Fleureau J. M, Hattab M (2015) Drying, cracks and shrinkage evolution of a natural silt intended for a new earth building material. Impact of reinforcement. Construction and Building Materials 86 :120–132. https://doi.org/10.1016/j.conbuildmat.2015.03.115 Banaszak J, Kowalski S.J (2005) Theoretical and experimental analysis of stresses and fractures in clay like materials during drying. Chemical Engineering and Processing 44:497–503. https://doi.org/10.1016/j.cep.2004.06.012 Kim S, Sung J. H, Lim S, Ahn K.H (2015) A generality in stress development of silica/poly(vinyl alcohol)mixtures during drying process, Progress in Organic Coatings 88:304–309. https://doi.org/10.1016/j.porgcoat.2015.07.011 Misra R, Barker A.J, James East (2002) Controlled drying to enhance properties of technical ceramics. Chemical Engineering Journal 86:111–116. https://doi.org/10.1016/S1385-8947(01)00280-7 Maisarah M.B, Norhayati A, Yuzo N (2019) Preparation of porous ceramic membranes from Sayong ball clay. Journal of Asian Ceramic Societies 7(4:417–425. https://doi.org/10.1080/21870764.2019.1658339 Hong Kim J, Choo K.H, Sang Yi H, Lee S, Lee C.H (2001) Effect of membrane support material on permeability in the microfiltration of brining waste water, Desalination, 140:55-65. https://doi.org/10.1016/S0011-9164(01)00354-X Kaur H, Bulasara V.K, Gupta R.K (2016) Effect of carbonates composition on the permeation characteristics of low-cost ceramic membrane supports. Journal of Industrial and Engineering Chemistry 44 :185–194. https://doi.org/10.1016/j.jiec.2016.08.026 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 14 Apr, 2026 Read the published version in International Journal of Material Forming → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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1","display":"","copyAsset":false,"role":"figure","size":89293,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram showing the main processes used for the preparation of membrane supports\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/7c97a950ba54305011f9d1bf.jpg"},{"id":93661692,"identity":"18b01a13-9521-4d71-84aa-81305d340444","added_by":"auto","created_at":"2025-10-16 08:21:15","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":82925,"visible":true,"origin":"","legend":"\u003cp\u003eDSC and TGA curves of kaolin samples: (a) non-calcined kaolin, (b) calcined kaolin\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/083efe9a860cf43654598992.jpg"},{"id":93662878,"identity":"a5685cac-5b03-48a6-8538-ce0ec340ca73","added_by":"auto","created_at":"2025-10-16 08:29:15","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":100641,"visible":true,"origin":"","legend":"\u003cp\u003eTypical photographs of dried supports prepared from: (a) uncalcined powder, (b) calcined powder\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/c3acbd1e8d194b1b8dcee3d7.jpg"},{"id":93661695,"identity":"61a9c8e2-f827-43d7-ab9f-db653937e5ce","added_by":"auto","created_at":"2025-10-16 08:21:15","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":59918,"visible":true,"origin":"","legend":"\u003cp\u003eXRD spectra of: (a) uncalcined powder, (b) calcined powder at 900 °C. M: Muscovite; Q: Quartz; K: Kaolinite\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/9159d363803d68b510b7d5cf.jpg"},{"id":93662880,"identity":"c4168031-cddc-4556-a74b-c028739c2f8d","added_by":"auto","created_at":"2025-10-16 08:29:15","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":46221,"visible":true,"origin":"","legend":"\u003cp\u003eRadial shrinkage (%) of specimens prepared from calcined and uncalcined powders as a function of temperature\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/8465f90a42085fdda0ba170b.jpg"},{"id":93661697,"identity":"4afeb7fe-6e15-4e66-98af-d72775f195d0","added_by":"auto","created_at":"2025-10-16 08:21:15","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":82179,"visible":true,"origin":"","legend":"\u003cp\u003ePorous volume (%) and average pore size as a function of sintering temperature for (a) S3 samples prepared from non-calcined kaolin using Process 3, and (b) S4 samples prepared from calcined kaolin using Process 4\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/9e8984751a66390dc2226a0c.jpg"},{"id":93661720,"identity":"91ed8a55-e269-4507-8bd2-640dfd85dad1","added_by":"auto","created_at":"2025-10-16 08:21:16","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":42700,"visible":true,"origin":"","legend":"\u003cp\u003ePore size distribution in a kaolin + 20 wt% starch sample sintered at 1150 °C\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/d487e9bc8bd0ba82202b7c0b.jpg"},{"id":93661698,"identity":"9a235948-0ca0-44de-a947-6d7182aaa34c","added_by":"auto","created_at":"2025-10-16 08:21:15","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":57004,"visible":true,"origin":"","legend":"\u003cp\u003eXRD spectra of samples sintered at different temperatures for 1 hour. M: Mullite; Q: Quartz\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/e02b97bd46ea2264f3b043eb.jpg"},{"id":93661706,"identity":"e08ed3ca-1038-497a-a07c-76421f814f3d","added_by":"auto","created_at":"2025-10-16 08:21:15","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":40090,"visible":true,"origin":"","legend":"\u003cp\u003eFlexural strength as a function of sintering temperature for kaolin + 15 wt% starch (S4) samples using Process 4\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/172207b404dcb306cbfbfa94.jpg"},{"id":93661712,"identity":"febdb2f6-4e25-4967-9c90-baf01aa00ca7","added_by":"auto","created_at":"2025-10-16 08:21:15","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":165114,"visible":true,"origin":"","legend":"\u003cp\u003eSEM micrographs showing (a) the cross-sectional view and (b) the surface morphology of the membrane deposited on a support prepared from uncalcined kaolin (S3)\u003c/p\u003e","description":"","filename":"10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/bd7172ea3920f087f7fbfbd4.jpg"},{"id":93663117,"identity":"a9e8747f-3e07-42b6-a104-1b8c1ead1391","added_by":"auto","created_at":"2025-10-16 08:37:15","extension":"jpg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":193269,"visible":true,"origin":"","legend":"\u003cp\u003eSEM micrographs showing (a) the cross-sectional view and (b) the surface morphology of the membrane deposited on a support prepared from calcined kaolin (S4)\u003c/p\u003e","description":"","filename":"11.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/8ba1d387f4279bf5a9a49191.jpg"},{"id":93661713,"identity":"311202f6-90dc-47cb-8ec1-e5dc984f8a22","added_by":"auto","created_at":"2025-10-16 08:21:15","extension":"jpg","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":49986,"visible":true,"origin":"","legend":"\u003cp\u003ePermeate flux as a function of applied pressure with distilled water for membranes M1 and M2\u003c/p\u003e","description":"","filename":"12.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/ab5e2cffb32ed931977c5c95.jpg"},{"id":107350898,"identity":"3268ed71-9b8a-4a3b-b379-9a8e0960c066","added_by":"auto","created_at":"2026-04-20 16:06:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1278549,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7721763/v1/7e9ee311-10df-4118-80a8-c71058e528aa.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparative Study on the Effects of Calcination Temperature of Kaolin Clay on the Fabrication and Properties of Ceramic Membranes","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eSeparation processes are essential in industrial applications. Among these methods, membrane technology stands out for its cost-effectiveness and exceptional selectivity. Ceramic membranes, in particular, offer distinct advantages over their polymeric counterparts [\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5 CR6 CR7 CR8\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Their superior chemical, mechanical, and thermal stability make them a more reliable choice in demanding environments, far surpassing the performance of organic membranes. Microfiltration (MF) and ultrafiltration (UF) are highly effective techniques for removing particles, microorganisms, and colloidal substances from suspensions [\u003cspan additionalcitationids=\"CR11 CR12\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Consequently, there has been growing interest in the development of inorganic membranes, particularly ceramic ones, for these applications [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. These membranes typically consist of a thin separation layer supported by a porous substrate with a larger average pore size (APS) than that of the separation layer. Commercial supports and membranes are generally manufactured from ceramic compounds such as alumina (Al₂O₃), cordierite (2MgO.2Al₂O₃.5SiO₂), silicon carbide (SiC), and mullite (3Al₂O₃.2SiO₂) [\u003cspan additionalcitationids=\"CR16 CR17\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. While these materials exhibit excellent mechanical and thermal properties, they are relatively expensive. To reduce production costs and promote the use of locally available resources, various processing routes have been proposed for fabricating membrane supports from kaolin [\u003cspan additionalcitationids=\"CR20 CR21 CR22\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], a naturally abundant and inexpensive raw material [\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. These efforts also aim to valorize local natural materials. Accordingly, the present study investigates the preparation of both supports and membrane layers from locally sourced kaolin.\u003c/p\u003e\u003cp\u003eTubular ceramic supports for membranes can be prepared using various shaping techniques. Among these, extrusion is widely employed due to its simplicity and suitability for producing long tubular structures. The main steps of this process include paste preparation, extrusion, drying, and firing. Among these steps, drying plays a critical role in the overall process chain, as it significantly affects the final quality of the product. However, several challenges can arise during the drying stage [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. One of the primary difficulties is maintaining the structural integrity of long extruded samples, particularly those made from kaolin clay, which are prone to deformation. Another common issue is the cracking or breakdown of specimens during drying. This is mainly caused by the removal of water from the samples, leading to substantial drying shrinkage and, consequently, mechanical stress. Despite the importance of the extrusion method for fabricating clay-based membrane supports, the calcination step of the starting powder is rarely addressed in the literature. While a few studies explicitly mention calcination, most omit this detail even though it is implicitly assumed as part of the process. In particular, the calcination of kaolin clay prior to extrusion is often overlooked, despite its critical role in shaping the final properties of the support.\u003c/p\u003e\u003cp\u003eCalcining the starting powder can significantly influence the microstructure of the resulting supports, including their shape, porosity, and the formation of microcracks, all of which directly affect the mechanical and functional properties of the supports. Therefore, understanding the impact of calcination on the material\u0026rsquo;s behavior during drying and shaping is essential for optimizing the manufacturing process.\u003c/p\u003e\u003cp\u003eThe aim of the present study is to investigate the influence of calcination temperature and drying method on the shape and structural integrity of extruded samples, given the high technological relevance of these parameters. Specifically, this work examines the effects of calcined kaolin clay on drying shrinkage, weight loss, and the final form of the specimens, with the goal of improving the overall quality and reproducibility of tubular ceramic supports.\u003c/p\u003e"},{"header":"2. Experimental procedure","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Analysis of the raw materials\u003c/h2\u003e\u003cp\u003eThe chemical composition of kaolin, sourced from Tamazert in the Jijel region (Algeria), is shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The main impurities detected are CaO, MgO, TiO₂, K₂O, and Fe₂O₃. The particle size distribution of this material, used in the preparation of supports, was determined using the Dynamic Laser Beam Scattering (DLBS) technique. This analysis revealed an average particle size of approximately 9 \u0026micro;m. The presence of fine particles and organic matter in the raw material enhances the plasticity of the green paste.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eChemical composition of kaolin (wt%), determined by X-ray fluorescence (XRF) analysis.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOxides\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAl\u003csub\u003e2\u003c/sub\u003e0\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eCaO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMgO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eK\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI. L\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePercentage (wt%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e34.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50.56\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e6.35\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Supports preparation\u003c/h2\u003e\u003cp\u003eIn this study, four different elaboration methods were used. Specimens were prepared following the steps indicated in the flowchart in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. In the first and third processes, natural clay (non-calcined starting powders) was used. In the second and fourth processes, the clay was calcined at 900\u0026deg;C for 1 hour to transform kaolin into metakaolin.\u003c/p\u003e\u003cp\u003eIn the first and second processes, the effects of calcined and non-calcined kaolin on drying shrinkage and the shape of the support were investigated (supports identified as S1 and S2). In the third and fourth processes, the effects of calcination and the addition of organic materials on the properties of the prepared supports were examined.\u003c/p\u003e\u003cp\u003eSupports identified as S3 were prepared by adding starch to the raw materials (process 3). After kaolin calcination (process 4), the mixture of kaolin and starch lost its plasticity (supports identified as S4). To improve plasticity and facilitate shaping, organic additives were introduced. The organic additives used were: 4 wt% methocel, derived from methylcellulose (The Dow Chemical Company), as a plasticizer, and 4 wt% amijel, derived from starch (Cplus12072, Cerestar), as a binder.\u003c/p\u003e\u003cp\u003eThe tubular supports were produced through extrusion, while flat supports were formed using the roll pressing technique. The latter was specifically used to prepare samples for mechanical testing.\u003c/p\u003e\u003cp\u003eSintering was carried out in air, and the appropriate firing schedule was determined based on thermal analysis (gravimetric analysis). Two steps were applied:\u003c/p\u003e\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"457\" height=\"69\"\u003e\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eThe first step, conducted at around 600\u0026deg;C, aimed to eliminate organic additives and remove water from the kaolin.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe second step involved sintering the samples, which were then maintained at the target temperature for 1 hour.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Membrane Preparation\u003c/h2\u003e\u003cp\u003eThe same powder used for the preparation of the supports was crushed for 2 hours using a planetary crusher operating at 250 revolutions per minute, then sieved to obtain particles smaller than 50 \u0026micro;m. The average particle size of this powder, intended for membrane preparation, was approximately 4 \u0026micro;m.\u003c/p\u003e\u003cp\u003eTo prepare a microfiltration (MF) layer using kaolin powder, a deflocculated slip was prepared by mixing 10 wt% kaolin, 20 wt% polyvinyl alcohol (PVA, in a 12 wt% aqueous solution), and 70 wt% water. The slip was deposited onto the support using the slip casting method [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], with a deposition time of approximately 4 minutes. After drying at room temperature for 24 hours, the microfiltration (interlayer) layer was sintered at 1050\u0026deg;C for 1 hour.\u003c/p\u003e\u003cp\u003eThe layers were deposited on macroporous supports S3 and S4. The S3 supports had an average pore size (APS) of 1.3 \u0026micro;m and a porosity of 51%, while the S4 supports had an APS of 4.1 \u0026micro;m and the same porosity. The resulting membranes were designated as M1 and M2, respectively.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Characterization Techniques\u003c/h2\u003e\u003cp\u003eVarious techniques were employed to investigate both the kaolin supports and the corresponding membranes. The crystalline structure was characterized by X-ray diffraction (XRD), while mechanical strength was evaluated through a three-point bending test performed on bar-shaped samples with rectangular cross-sections, using a LLOYD INSTRUMENTS LRX testing machine. Total porosity, average pore size (APS), and pore size distribution were determined by mercury intrusion porosimetry (Micromeritics, Model Autopore 9220) for samples sintered at different temperatures. The presence of potential defects in the supports and membranes was examined by Scanning Electron Microscopy (SEM) (HITACHI S-4500). Tangential filtration experiments were conducted at room temperature using a custom-built pilot system, with nitrogen gas employed to maintain the working pressure.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Thermal Analysis\u003c/h2\u003e\u003cp\u003eThermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) were employed to investigate the structural evolution of the starting powders using a SDT 2960 Simultaneous DSC-TGA apparatus (TA Instruments). The measurements were conducted in air, with a heating rate of 10\u0026deg;C/min, from room temperature up to 1200\u0026deg;C.\u003c/p\u003e\u003cp\u003eThe TGA curve recorded during heating (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea) shows a total weight loss of about 8% for the kaolin samples. This weight loss occurs in two distinct stages: the first, between 25 and 200\u0026deg;C, is attributed to the removal of moisture, while the second stage, between 400 and 600\u0026deg;C, corresponds to the release of water (by vaporization) chemically bound within the kaolin structure. The weight loss in the second stage is more pronounced (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea). In contrast, the weight loss was negligible for the calcined kaolin samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). These observations are further supported by the DSC analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The first and third endothermic peaks occurred at 65\u0026deg;C and 497\u0026deg;C, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea). These correspond to the departure of water, while the second peak, observed at 251\u0026deg;C, corresponds to the release of organic materials. Another stage, characterized by an exothermic reaction, was observed at approximately 983\u0026deg;C (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). The origin of this reaction is still not fully understood. Some researchers attribute it to spinel formation, while others suggest it is due to mullite nucleation [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Consequently, these results support the choice of two heating steps, as previously discussed in the experimental section.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.2. Drying and Shrinkage Phenomena\u003c/h2\u003e\u003cp\u003eThis study primarily aimed to evaluate the effect of heat treatment of the starting raw materials on the shape and physical properties of membrane supports prepared from kaolin clay. Figures\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea and \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb show typical photos of dried supports made from natural and calcined clay, respectively. After the extrusion step, tubular supports are particularly vulnerable to deformation and shrinkage.\u003c/p\u003e\u003cp\u003eExperimental tests were carried out to identify the causes of plastic deformation observed in the dried supports. During drying, the removal of molding water from supports made with natural clay induces significant shrinkage, leading to changes in the size and geometry of the supports [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. This shrinkage is not uniform across the sample, resulting in visible deformations that often lead to the rejection of the product.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThis behavior is attributed to the fine particle size and porous structure of kaolin clay, which contributes to high capillary water retention, making the drying process difficult. Moreover, a higher proportion of fine particles increases the extent of shrinkage during drying, which in turn causes warping and the development of cracks. When preparing the clay paste, the powder particles absorb water and retain it within internal cavities due to the natural structure of kaolin.\u003c/p\u003e\u003cp\u003eHowever, after calcination, the volume of water absorbed is significantly reduced approximately halved due to structural transformations in the kaolin. Specifically, calcination removes physically bound water and causes kaolinite to transform into metakaolin. This transformation is evident in the XRD patterns shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, where kaolinite peaks are significantly diminished or disappear entirely, indicating the formation of less crystalline, disordered phases such as metakaolin [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAs water is removed during drying, pressure gradients form between the interior and exterior of the material, generating internal stresses that lead to further shrinkage, deformation, or even cracking [\u003cspan additionalcitationids=\"CR33 CR34 CR35 CR36 CR37 CR38\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. A higher initial water content amplifies this effect. In this study, the water content used during paste preparation was approximately 55% for natural clay and 26% for calcined clay. The reduced water demand in calcined powders is a key factor in minimizing shrinkage.\u003c/p\u003e\u003cp\u003eShrinkage was quantified as the percentage difference between the original diameter (D₀) and the final diameter (D) of the supports, using the following equation:\u003c/p\u003e\u003cp\u003eS = ((D₀ \u0026ndash; D) / D₀) \u0026times; 100\u003c/p\u003e\u003cp\u003eWhere D₀ is the initial diameter and D is the measured diameter after drying.\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e illustrates the variation in sample diameter as a function of temperature. The results show that drying at 25\u0026deg;C led to a diameter reduction of approximately 19% for supports made from natural clay, and about 7% for those prepared with calcined clay. These findings clearly demonstrate that the use of calcined clay significantly reduces shrinkage during both drying and sintering, thereby decreasing the risk of deformation at low and high temperatures.\u003c/p\u003e\u003cp\u003eFollowing high-temperature firing, a slight reduction in diameter was observed in both types of samples. Nevertheless, specimens prepared from non-calcined clay exhibited greater overall shrinkage compared to those produced from calcined clay. In the temperature range of 1000\u0026ndash;1200\u0026deg;C, a pronounced increase in shrinkage was detected in both supports, which is attributed to phase transformations within the material matrix and the initiation of sintering.\u003c/p\u003e\u003cp\u003eIn conclusion, calcination of the starting powder is an effective technique for reducing deformation during the drying process. It lowers the water content required during mixing, minimizes shrinkage and weight loss, and improves the final shape of the ceramic supports. Under optimal conditions, supports with near-perfect straightness and structural integrity can be achieved through this method.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Support materials\u003c/h2\u003e\u003cp\u003eFor the development of high-quality membrane supports, several key properties must be optimized: a well-controlled pore size distribution [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], high total porosity, a smooth surface free from large defects or macropores, adequate mechanical strength, and strong chemical stability [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. To evaluate these characteristics, porosity and average pore size were measured on supports sintered at various temperatures for 60 minutes. The results are shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea and \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb. As expected, an increase in sintering temperature leads to a gradual increase in average pore diameter and a corresponding decrease in total porosity. The reduction in porosity is primarily attributed to material densification and the elimination of smaller pores. The initial increase in average pore diameter can be attributed to the coalescence of adjacent small pores, leading to the formation of larger pore structures. However, at sintering temperatures above 1250\u0026deg;C, both total porosity and average pore diameter exhibit a pronounced decline, indicating significant densification of the material and the possible closure or collapse of larger pores due to enhanced grain growth and pore elimination mechanisms. Moreover, both the average pore size and the porosity are closely related to the preparation method. The results (Figs.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea and \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb) show that the calcination process positively influences the average pore size of the supports (S4) compared to those prepared from kaolin without calcination (S3). For instance, the calcined kaolin supports (S4) exhibited a porosity of approximately 52% and an average pore size of around 4.1 \u0026micro;m, whereas the uncalcined kaolin supports (S3) showed a porosity of about 46% and an average pore size of around 1.4 \u0026micro;m, under the same sintering conditions (1200\u0026deg;C for 1 hour).\u003c/p\u003e\u003cp\u003eTo further understand the pore structure, the pore size distribution patterns of the supports were analyzed. For example, as presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, S3 samples sintered at 1150\u0026deg;C for 1 hour exhibited a nearly single-modal or homogeneous pore size distribution, also referred to as a Single-Modal Pore Size Distribution (SMPSD), as previously reported [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIt should be noted that pore size distributions are generally classified into three main types: single-modal (or Gaussian), bimodal, and multimodal. SMPSD typically occurs in samples with a uniform pore size distribution, where the plot of pore volume (%) against pore size exhibits a single peak. In contrast, a Bimodal Pore Size Distribution (BMPSD) displays two distinct or overlapping peaks, indicating the presence of two different pore size ranges. Lastly, a Multimodal Pore Size Distribution (MMPSD) is characterized by more than two distinct or overlapping peaks, suggesting a more complex pore structure.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e shows the X-ray diffraction (XRD) spectra of samples sintered at 1100\u0026deg;C and 1250\u0026deg;C for 1 hour. The main observed phases are mullite (3Al₂O₃\u0026middot;2SiO₂) and quartz. At 1100\u0026deg;C, quartz is the dominant phase, whereas at the higher temperature of 1250\u0026deg;C, mullite becomes the predominant phase. These identified phases are of particular importance due to their favorable physical and mechanical properties. For instance, mullite is widely used as a refractory material in high-temperature ceramic applications because of its low thermal expansion and high creep resistance.\u003c/p\u003e\u003cp\u003eBuilding on the structural analysis, the mechanical performance of the porous ceramic supports (S4) was also evaluated. Specifically, the flexural strength was measured to assess the effect of sintering temperature. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, flexural strength is closely linked to the total porosity ratio, which itself is influenced by sintering temperature. For example, a flexural strength of 13 MPa was recorded at a porosity of 62% and an average pore size of approximately 2.6 \u0026micro;m. In contrast, S4 supports with a porosity of around 28% and an average pore size of approximately 3 \u0026micro;m exhibited a significantly higher flexural strength of about 61 MPa.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.4. Membrane Layer Analysis\u003c/h2\u003e\u003cp\u003eFigures \u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003ea and \u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003ea show typical cross-sections of membranes M1 and M2, which consist of a microfiltration (MF) layer coated onto macroporous S3 and S4 supports, respectively. The microstructure of both membranes demonstrates good homogeneity, an important characteristic for effective MF applications. The quality of the coating layer was visually assessed, revealing smooth surfaces without visible defects such as scale formation or cracks. These visual observations are confirmed by SEM images (Figs.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003eb and \u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003eb), which show that both membranes have very similar and uniform surface morphologies.\u003c/p\u003e\u003cp\u003eThe thickness of the microfiltration layer can be controlled by adjusting the proportion of mineral powder in the suspension and the coating time. Under the applied conditions, kaolin layers were deposited onto S3 and S4 supports with average thicknesses of approximately 21 \u0026micro;m and 54 \u0026micro;m, respectively. In both cases, the average pore size of the coated layer was around 0.5 \u0026micro;m. Importantly, the resulting microstructure and pore size distribution key parameters for MF performance can be further tuned by modifying the sintering temperature.\u003c/p\u003e\u003cp\u003eMembranes M1 and M2 were characterized in terms of their water permeability. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e, the water flux through the membranes was measured and found to depend on the applied pressure. A linear relationship between the steady-state water flux and the applied pressure was observed, confirming that the pressure gradient is the sole driving force for permeation [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. This behavior is characteristic of convective transport, in which the volumetric flow rate is directly proportional to the pressure difference across the membrane. Based on the slopes of the curves in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e, the average permeability values for M1 and M2 were approximately 140 and 680 L/(h\u0026middot;m\u0026sup2;\u0026middot;bar), respectively. This substantial difference indicates that the characteristics of the support structure play a crucial role in overall membrane performance.\u003c/p\u003e\u003cp\u003eAlthough both supports, S3 and S4, had similar thickness and porosity (as detailed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), they differed in average pore size. The S4 support, which was produced from calcined kaolin powder, exhibited a larger average pore size compared to the S3 support made from uncalcined kaolin. Consequently, the M2 membrane (based on S4) demonstrated a higher water flux than M1, suggesting that pore size may be a more critical factor than porosity in determining membrane permeability [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. This observation is consistent with the Hagen\u0026ndash;Poiseuille equation, which indicates that flux (and consequently permeability) is directly proportional to the open porosity and the square of the average pore size (APS) [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eProperties of supports used for the membrane deposition.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eType\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHeating Temperature (\u0026deg;C)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAverage pore size (\u0026micro;m)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePorosity\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePhases\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eS3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1150\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eQuartz\u0026thinsp;+\u0026thinsp;mullite\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eS4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1250\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eQuartz\u0026thinsp;+\u0026thinsp;mullite\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eCeramic multilayer membranes were successfully fabricated using kaolin as the sole raw material. Microfiltration membranes were produced by slip casting, while their supports were prepared by extrusion. The average pore size of the MF membrane was approximately 0.5 \u0026micro;m. The study demonstrated that the preparation process is simple, cost-effective, and suitable for large-scale production.\u003c/p\u003e\u003cp\u003eThe results further showed that shrinkage and deformation of the clay supports during drying are strongly influenced by the water content of the starting powders. Calcination of the raw material proved essential, as it minimized shrinkage and deformation during drying and firing, thereby enhancing the structural integrity of the supports. Moreover, the use of locally abundant kaolin in Algeria reduces overall manufacturing costs, making this approach promising for the large-scale production of low-cost ceramic membranes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eDeclaration of interests\u003c/h2\u003e\u003cp\u003eThe author declares that there are no known financial or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eThe author F.B. conceived the study, conducted the research, analyzed the data, and wrote the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eAcknowledgmentsI would like to express my sincere gratitude to Professor Dr. Harabi Abdelhamid, for his generous support and valuable assistance in reviewing this manuscript. His insightful feedback and constructive suggestions greatly contributed to enhancing the clarity and quality of this work.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eGhouil B, Khebli Z, Bouzerara F, Zermani D, Zitouni C, Youla K, Idoui T, Khennouf T, (2024) Preparation and characterization of low-cost ceramic microfiltration membranes for water treatment. Processing and Application of Ceramics 18(4): 405-413. https://doi.org/10.2298/PAC2404405G\u003c/li\u003e\n\u003cli\u003eKouras N, Harabi A, Bouzerara F, Foughali L, Policicchio A, Stelitano S, Galiano F, Figoli (2017) A Macro-porous ceramic supports for membranes prepared from quartz sand and calcite mixtures. Journal of the European Ceramic Society 37:3159 - 3165. https://doi.org/10.1016/j.jeurceramsoc.2017.03.059\u003c/li\u003e\n\u003cli\u003eKhebli Z, Bouzerara F, Brihi N, Figoli A, Russo F, Galiano F, Chahredine S (2023) Fabrication of a zircon microfiltration membrane for culture medium sterilization. Membranes 13(4):399. https://doi.org/10.3390/membranes13040399\u003c/li\u003e\n\u003cli\u003eBoulkrinat A, Bouzerara F, Harabi A, Harrouche K, Stelitano S, Russo F, Galiano F, Figoli A (2020) Synthesis and characterization of ultrafiltration ceramic membranes used in the separation of macromolecular proteins. Journal of the European Ceramic Society 40 (15) : 5967\u0026ndash;5973. https://doi.org/10.1016/j.jeurceramsoc.2020.06.060\u003c/li\u003e\n\u003cli\u003eKadiri C, Harabi A, Bouzerara F, Foughali L, Brihi N, Hallour S, Guechi A, Boudaira B (2020) Preparation and properties of tubular macroporous ceramic membrane supports based on natural quartz sand and dolomite. Journal of the Australian Ceramic Society 56: 379\u0026ndash;387. https://doi.org/10.1007/s41779-019-00338-2\u003c/li\u003e\n\u003cli\u003eZhou T, Xue K, Zhang H, Chen H, Li Z (2025) Analysis of pore size control and application of ceramic membrane based on particle sintering method. Energy, 328:136721. https://doi.org/10.1016/j.energy.2025.136721\u003c/li\u003e\n\u003cli\u003eYang Y, Yu H, Hu Z, Yang R, Tang S, Tang T, Chen X, Wang Q, Wang Y, Chang Q (2025) Facile fabrication of ceramic tight ultrafiltration membrane with high permeability for rapid separation of dye molecules. Separation and Purification Technology 368 (17): 132945. https://doi.org/10.1016/j.seppur.2025.132945\u003c/li\u003e\n\u003cli\u003eAkoumeh R, Al-Ejji M, Aljaoni B, Abbas M (2025) Advances in ceramic membrane technology: Versatility of fabrication technique, industrial applications, and challenges. Inorganic Chemistry Communications 179:114685. https://doi.org/10.1016/j.inoche.2025.114685\u003c/li\u003e\n\u003cli\u003eChen T, Fan W, Xu P, Chen X, Qiu M, Fan Y (2024) Construction of asymmetric ceramic membranes with identical source interlayer on fly ash support by dip-coating. Journal of the European Ceramic Society, 44 (15):16765. https://doi.org/10.1016/j.jeurceramsoc.2024.116765 \u003c/li\u003e\n\u003cli\u003eMedjemem N, Harabi A, Bouzerara F, Foughali L, Boudaira B, Guechi A, Brihi N (2016) Elaboration and characterization of low cost ceramics microfiltration membranes applied to the sterilization of plant tissue culture media. J. Taiwan. Inst. Chem. Eng. 59:79. https://doi.org/10.1016/j.jtice.2015.07.032\u003c/li\u003e\n\u003cli\u003eBouazizi A, Saja S, Achiou B, Ouammou M, Calvo J.I, Aaddane A, Alami Younssi S (2016) Elaboration and characterization of a new flat ceramic MF membrane made from natural Moroccan bentonite Application to treatment of industrial wastewater. Applied Clay Science 32:33-40. https://doi.org/10.1016/j.clay.2016.05.009 \u003c/li\u003e\n\u003cli\u003eEl Mrabet H, Elazhar M, Moussaoui I, Moumouh J, Addar F. Z, Tahaikt M, Elazhar F, Mohamed T, El Haloui N, Elmidaoui A (2025) Technico-economic assessment of membrane filtration as post-treatment of biological denitrification for brackish groundwater. Desalination and Water Treatment, 322 :101160. https://doi.org/10.1016/j.dwt.2025.101160\u003c/li\u003e\n\u003cli\u003eAryanti P.T. P, Harsono B, Warsa Biantoro M.F, Romariyo R, Putri T.A, Hakim A.N, Setia G.A, Saputra D.I, Khoiruddin K (2025) The role of membrane technology in palm oil mill effluent (POME) decontamination: Current trends and future prospects. Journal of Environmental Management, 374 :124094. https://doi.org/10.1016/j.jenvman.2025.124094 \u003c/li\u003e\n\u003cli\u003eChangrong X, Xiaoxia G, Fanqing Li, Dingkun P, Guangyao M (2001) Preparation of asymmetric Ni:ceramic composite membrane by electroless plating. Colloids and Surfaces A: Physicochemical and Engineering Aspects 179:229-235. https://doi.org/10.1016/S0927-7757(00)00642-7\u003c/li\u003e\n\u003cli\u003eGao J.m, Yan Z, Wang B, Ma Z, Guo Y (2024) Preparation of whisker mullite ceramic membrane from coal fly ash for efficient oil-water separation. Ceramics International 50(18):32727-32736. https://doi.org/10.1016/j.ceramint.2024.06.082\u003c/li\u003e\n\u003cli\u003eWang S, Yu Ma X, Wang Y.L, Cui S.P, Nie Z, Li Q.Y, Wei Q (2019) Preparation and desalination performance of porous planar cordierite membranes using industrial solid waste as main silica source. Ceramics International 45:5932-5940. https://doi.org/10.1016/j.ceramint.2018.12.062 \u003c/li\u003e\n\u003cli\u003eZou J, Dai Q, Zhou X, Qin H, Guo W, ao P, Xiao H (2024) Preparation of alumina disc ceramic membrane with enhanced abrasion resistance for dynamic membrane filtration. Ceramics International 50:9354-9362. https://doi.org/10.1016/j.ceramint.2023.12.251\u003c/li\u003e\n\u003cli\u003eLi S, Li Y, Wei C, Wang P, Gao P, Zhou L, Wen G (2021) One step co-sintering of silicon carbide ceramic membrane with the aid of boron carbide. Journal of the European Ceramic Society 41(2):181-1188. https://doi.org/10.1016/j.jeurceramsoc.2020.09.065\u003c/li\u003e\n\u003cli\u003eBouzerara F, Harabi A, Achour S, Larbot A (2006) Porous ceramic supports for membranes prepared from kaolin and doloma mixtures. Journal of the European Ceramic Society 26:1663-1671. https://doi.org/10.1016/j.jeurceramsoc.2005.03.244\u003c/li\u003e\n\u003cli\u003eBoulkrinat A, Bouzerara F (2021) Elaboration of tubular titania microfiltration membranes for wastewater treatment. Desalination and Water Treatment 211:319\u0026ndash;322. https://doi.org/10.5004/dwt.2021.26366\u003c/li\u003e\n\u003cli\u003eBoudaira B, Harabi A, Bouzerara F, Zenikheri F, Foughali L, Guechi A (2016) Preparation and characterization of membrance supports for microfiltration and ultrafiltration using kaolin (DD2) and CaCO\u003csub\u003e3\u003c/sub\u003e, Desalination and Water Treatment. 57:5258. https://doi.org/10.1080/19443994.2015.1021998\u003c/li\u003e\n\u003cli\u003eGhouil B, Harabi A, Bouzerara F, Boudaira B, Guechi A, Demir M.M, Figoli A (2015) Development and characterization of tubular composite ceramic membranes using natural alumino-silicates for microfiltration applications. Materials Characterization 103 :18-27. https://doi.org/10.1016/j.matchar.2015.03.009\u003c/li\u003e\n\u003cli\u003eGhouil B, Harabi A, Bouzerara F, Brihi N (2016) Elaboration and characterization of ceramic membrane supports from raw materials used in microfiltration. Des. Wat. Treat. 57(12): 5241-5245. https://doi.org/10.1080/19443994.2015.1021098\u003c/li\u003e\n\u003cli\u003eKhebli Z, Djardire R, Boulkrinat A, Bouzerara F (2022) Elaboration of zirconia microfiltration membranes tested with methylene blue filtration, Desalination and Water Treatment, 279:4\u0026ndash;7. doi:10.5004/dwt.2022.29061\u003c/li\u003e\n\u003cli\u003eAouadja F, Bouzerara F, Guvenc C.M, Demir M.M (2022) Fabrication and properties of novel porous ceramic membrane supports from the (Sig) diatomite andalumina mixtures. Bolet\u0026iacute;n de la Sociedad Espa\u0026ntilde;ola de Cer\u0026aacute;mica y Vidrio 61(5):531-540. https://doi.org/10.1016/j.bsecv.2021.04.002\u003c/li\u003e\n\u003cli\u003eMakhloufi K, Moussi B, Srarfi F, Tagorti M.A (2024) Development of ceramic filtering membranes based on Tunisian clay and phosphate sludge in wastewater treatment, Solid State Sciences 148:107430. https://doi.org/10.1016/j.solidstatesciences.2023.107430 \u003c/li\u003e\n\u003cli\u003eFu Z, Eckstein U, Dellert A, Roosen A (2015) In situ study of mass loss, shrinkage and stress development during drying of cast colloidal films Journal of the European Ceramic Society 35:2883\u0026ndash;93. https://doi.org/10.1016/j.jeurceramsoc.2015.03.029\u003c/li\u003e\n\u003cli\u003eKhemakhem M, Khemakhem S, Ben Amar R (2014) Surface modification of microfiltration ceramic membrane by fluoroalkylsilane. Desalination and Water Treatment 52:1786-1791. https://doi.org/10.1080/19443994.2013.807023\u003c/li\u003e\n\u003cli\u003eBoudaira B, Harabia A, Bouzerara F, Condom S (2009) Preparation and characterization of microfi ltration membranes and their supports using kaolin (DD2) and CaCO\u003csub\u003e3\u003c/sub\u003e. Desalination and Water Treatment 9(1\u0026ndash;3):142-148. https://doi.org/10.5004/dwt.2009.764.\u003c/li\u003e\n\u003cli\u003eCollard J.M, Arnaud G, Fohr J.P, Dragon A (1992) The drying-induced deformations of a clay plate. International Journal of Heat and Mass Transfer 35(5):1103-1114. https://doi.org/10.1016/0017-9310(92)90171-N\u003c/li\u003e\n\u003cli\u003eBassir Diop M, Grutzeck M.W, Molez L (2011) Comparing the performances of bricks made with natural clay and clay activated by calcination and addition of sodium silicate calcination and addition of sodium silicate. Applied Clay Science 54:172\u0026ndash;178. https://doi.org/10.1016/j.clay.2011.08.005.\u003c/li\u003e\n\u003cli\u003eHammouda I, Jlassi K, Mihoubi D (2015) Changes in the physicomechanical characteristics of a ceramic paste during drying. Comptes Rendus M\u0026eacute;canique, 343:419\u0026ndash;428. https://doi.org/10.1016/j.crme.2015.06.001\u003c/li\u003e\n\u003cli\u003eAugier F, Coumans W.J, Hugget A, Kaasschieter E.F (2002) On the risk of cracking in clay drying. Chemical Engineering Journal 86:133\u0026ndash;138. https://doi.org/10.1016/S1385-8947(01)00279-0\u003c/li\u003e\n\u003cli\u003eSilva W. P.d, Silva L.D.d, Farias V.S.O.l, Silva C.M.P.S (2013) Water migration in clay slabs during drying: A three-dimensional numerical approach. Ceramics International 39:4017\u0026ndash;30. https://doi.org/10.1016/j.ceramint.2012.10.252.\u003c/li\u003e\n\u003cli\u003eJan Kowalskin S, Banaszak J, Rybicki (2010) A Plasticity in materials exposed to drying, Chemical Engineering Science 65:5105\u0026ndash;16. https://doi.org/10.1016/j.ces.2010.06.006\u003c/li\u003e\n\u003cli\u003eEid J, Taibi S, Fleureau J. M, Hattab M (2015) Drying, cracks and shrinkage evolution of a natural silt intended for a new earth building material. Impact of reinforcement. Construction and Building Materials 86 :120\u0026ndash;132. https://doi.org/10.1016/j.conbuildmat.2015.03.115\u003c/li\u003e\n\u003cli\u003eBanaszak J, Kowalski S.J (2005) Theoretical and experimental analysis of stresses and fractures in clay like materials during drying. Chemical Engineering and Processing 44:497\u0026ndash;503. https://doi.org/10.1016/j.cep.2004.06.012\u003c/li\u003e\n\u003cli\u003eKim S, Sung J. H, Lim S, Ahn K.H (2015) A generality in stress development of silica/poly(vinyl alcohol)mixtures during drying process, Progress in Organic Coatings 88:304\u0026ndash;309. https://doi.org/10.1016/j.porgcoat.2015.07.011\u003c/li\u003e\n\u003cli\u003eMisra R, Barker A.J, James East (2002) Controlled drying to enhance properties of technical ceramics. Chemical Engineering Journal 86:111\u0026ndash;116. https://doi.org/10.1016/S1385-8947(01)00280-7\u003c/li\u003e\n\u003cli\u003eMaisarah M.B, Norhayati A, Yuzo N (2019) Preparation of porous ceramic membranes from Sayong ball clay. Journal of Asian Ceramic Societies 7(4:417\u0026ndash;425. https://doi.org/10.1080/21870764.2019.1658339\u003c/li\u003e\n\u003cli\u003eHong Kim J, Choo K.H, Sang Yi H, Lee S, Lee C.H (2001) Effect of membrane support material on permeability in the microfiltration of brining waste water, Desalination, 140:55-65. https://doi.org/10.1016/S0011-9164(01)00354-X\u003c/li\u003e\n\u003cli\u003eKaur H, Bulasara V.K, Gupta R.K (2016) Effect of carbonates composition on the permeation characteristics of low-cost ceramic membrane supports. Journal of Industrial and Engineering Chemistry 44 :185\u0026ndash;194. https://doi.org/10.1016/j.jiec.2016.08.026\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Membranes, Supports, Extrusion, Drying, Microfiltration","lastPublishedDoi":"10.21203/rs.3.rs-7721763/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7721763/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study presents the development and optimization of multilayer porous ceramic membranes for microfiltration, using kaolin as both the functional microfiltration (MF) layer and the macroporous support. A common challenge with tubular supports made from extruded raw kaolin is deformation during drying. To overcome this, kaolin calcination was investigated as a processing strategy. Pre-calcination prior to shaping significantly reduced shrinkage and deformation, thereby improving the structural integrity of the supports. The calcination temperature was found to be a key parameter, influencing support quality, enlarging the average pore size, and enhancing water flux\u0026mdash;achieving up to a fivefold increase compared with uncalcined samples. Furthermore, the effect of sintering temperature on porosity, pore size distribution, and mechanical strength was systematically examined. The fabricated MF membranes exhibited an average pore size of ~\u0026thinsp;0.5 \u0026micro;m. Filtration tests with distilled water demonstrated their suitability for tangential microfiltration applications.\u003c/p\u003e","manuscriptTitle":"Comparative Study on the Effects of Calcination Temperature of Kaolin Clay on the Fabrication and Properties of Ceramic Membranes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-16 08:21:10","doi":"10.21203/rs.3.rs-7721763/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f92ca10d-ee75-47e8-b35e-e260e4be2c46","owner":[],"postedDate":"October 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-20T16:03:59+00:00","versionOfRecord":{"articleIdentity":"rs-7721763","link":"https://doi.org/10.1007/s12289-025-01964-x","journal":{"identity":"international-journal-of-material-forming","isVorOnly":false,"title":"International Journal of Material Forming"},"publishedOn":"2026-04-14 15:59:25","publishedOnDateReadable":"April 14th, 2026"},"versionCreatedAt":"2025-10-16 08:21:10","video":"","vorDoi":"10.1007/s12289-025-01964-x","vorDoiUrl":"https://doi.org/10.1007/s12289-025-01964-x","workflowStages":[]},"version":"v1","identity":"rs-7721763","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7721763","identity":"rs-7721763","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}