Rapid exfoliation of well-defined vermiculite nanosheets via ultrasound-triggered limited space shear for pollutant adsorption

Rapid exfoliation of well-defined vermiculite nanosheets via ultrasound-triggered limited space shear for pollutant adsorption | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Rapid exfoliation of well-defined vermiculite nanosheets via ultrasound-triggered limited space shear for pollutant adsorption Jinpeng Hou, Yiwen Shen, Xiangkun Zhang, Zhong Li, Weiliang L. Tian, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7503581/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Well-defined vermiculite (VMT) nanosheets with promising physico-chemical properties are commercially appealing and urgently required for various applications. However, it is still challenging to realize rapid scalable production in a green and low-cost way. Herein, an ultrasound-triggered limited space shear method is proposed on the base of shear and cut collision mechanism. Exfoliation of well-defined ultrathin VMT nanosheets is achieved quickly and effectively through the synergy of cut collision effects, ultrasonic forces, and shear forces. The productivity and dimension distribution of VMT nanosheets can be readily regulated by varying the rotation space, rotation speed, and shear and cut collision forces, among which the rotation space is the critical factor. The better peeling effect is achieved under smaller rotation space. Compared to the traditional ball mill method, the time required to produce the same amount of VMT nanosheets is accelerated by a factor of 10 times for the ultrasound-triggered limited space shearer. Besides, the usage of water as exfoliated solution avoids subsequent separation process of traditional salt solvent. The colloidal solution of VMT nanosheets could be stably saved for about 6 months. The obtained VMT nanosheets exhibit excellent performance for rapid adsorption of methylene blue (MB), and can be regenerated without agglomeration and stacking of nanosheets. This rapid and high-yield method can be satisfactorily applied in the production of VMT nanosheets and other two-dimensional (2D) layered materials. Vermiculite Exfoliation Limited space shear Cut and edge collision Pollutant adsorption Figures Figure 1 Figure 2 Figure 3 Figure 4 1. INTRODUCTION Layered nanomaterials represent an interesting opportunity to develop hybrid materials with intentional functionalities [ 1 ] . Since the exploration of atomic layer graphene with extraordinary physical and chemical properties, the novel properties of two-dimensional (2D) materials have spurred tremendous fundamental studies and technological advancements for a wide range of applications [ 2 – 4 ] . The layered aluminosilicate clay mineral known as vermiculite (VMT) is found naturally and is composed of two tetrahedral silicate layers and octahedral sheets that hold magnesium ions [ 5 ] . Due to the partial replacement of silicon with aluminum, the VMT layers have a negative charge. Water molecules and exchangeable cations (K +, Mg 2+ , and Ca 2+) make up the interlayer area, which balances the positive charge deficit caused by the layers. Owing to their natural abundant resources (about 600 million tons’ reserves), unique layered structure, desirable surface chemistry and thermal/mechanical properties, the VMT has piqued the interest of researchers worldwide for both basic study and practical applications [ 6 ] . The resultant one- or few-layer nanosheets, in particular, show intriguing physic-chemical characteristics because of the nanoscale effect, which makes them especially desirable for use in catalysis and mechanical reinforcement as well as flexible electronics [ 7 – 9 ] . The industrial-scale manufacturing of well-defined VMT is urgently needed for several critical applications, including high-temperature, refractory insulation, fire resistance [ 10 ] , optical coatings [ 11 ] and composite fillers [ 12 ] . For instance, VMT is probably going to be utilized as an effective and affordable composite filler in applications including catalysis, ordered self-assembled nanostructures [ 13 ] , organic-inorganic composites, and polymer-based nanocomposites [ 14 ] . Such fillers certainly require large quantities of VMT nanosheets, and thus the exfoliation of VMT is becoming an important technology [ 6 , 15 ] . Unfortunately, two-dimensional nanomaterial exfoliation is mainly reflected in the complexity and difficulty of the preparation process, including the limitations of the exfoliation method, the challenges of material properties, and the difficulty of large-scale production. In addition, two-dimensional materials are sensitive to the chemical environment and are easily contaminated or chemically reacted during the exfoliation process, which further increases the difficulty of exfoliation. There is currently no quick, scalable process that produces vast amounts of well-defined, environmentally friendly VMT nanosheets. The most widely used ball mill in the industry is difficult to exfoliate layered VMT effectively, owing to the tendency of stacking and agglomeration. Besides, the thermal [ 16 , 17 ] exfoliation and microwave exfoliation [ 18 , 19 ] can only get large particles of expanded VMT. Chemical-exfoliation using hydrogen peroxide or mineral acids is normally employed to further improve the yield of nanosheets, [ 6 , 20 – 21 ] but the resultant acidizing VMT with amorphous silica and other structural components is typically defective [ 22 , 23 ] Alternatively, sonication of VMT in certain stabilizing solvents or aqueous surfactant solutions provides opportunity for well-defined VMT nanosheets [ 20 , 24 ] . However, the process for which ultrasound is intended is limited in its scalability since it is employed as an energy source for extended sonication. [ 2 ] . Thus, the above methods eventually exhibit either a high yield or a low defect content, but not both [ 2 ] . To achieve fast VMT manufacturing, one potential approach is to create a scalable exfoliation technique that is combined with sonication. In fine pulverization and emulsification, the high shear pulverizer (also known as the blade pulverizer) has found widespread application [ 2 , 25 , 26 ] . High speed alternating shear with numerous knife heads and a multibladed saw for layered materials are the usual features of a high-shear pulverizer [ 25 ] . Unlike a ball mill, this kind of pulverizer primarily employs waist cutoff in liquid to avoid stacking and aggregation. High shear force, collision impacts, and jet cavitation are the three main components of the hydrodynamics-based high shear pulverizer's operating mechanism [ 25 ] . Van der Waals interactions between layers are overcome by the intense physical contact that rapid and violent fluid movement creates with the layered crystal particles [ 25 ] . A minimal shear rate required to create layered crystal was predicted using a straightforward exfoliation model, or shear-induced interlayer sliding [ 2 ] . Because the shear exfoliation is lateral force, it is necessary to find the force in the longitudinal direction to peel off the layered crystal quickly and effectively. the capacity to exfoliate untreated layered crystals in liquids by combining longitudinal and lateral force would be far more beneficial tactics. The current study demonstrates a fast, green, and highly effective exfoliation process that uses sonication as the longitudinal force and a shear pulverizer as the lateral force to create VMT nanosheets in water. Exfoliating the VMT particles into huge amounts of flawless, non-chemical VMT nanosheets may be done quickly and efficiently. In addition, this VMT nanosheet has excellent performance in several applications, including pollutant adsorption. 2. EXPERIMENTAL Materials Industrial expanded VMT (calcined at 1000 o C, particle size 1–4 mm) was purchased from the China Xinjiang Yuli VMT Co. Ltd. Methylene blue and anhydrous ethanol were purchased from the Beijing Chemical Co. Ltd.. All experimental procedures utilized deionized water, and all other compounds were used as analytical solutions (A. R.) without extra purification. Ultrasound-triggered exfoliation of VMT using shear forces In a typical procedure, 15 g of VMT were added to 500 mL deionized water. A high shear mixer in a glass cylinder with four raised pillars on the interior surface (about 10 cm in diameter and 15 cm in the height) was used to perform the exfoliation process at a maximum speed of nearly 28000 rpm. The glass cylinder also included six shearing blades (8 mm x 30 mm each). Using cooling water to maintain a low temperature of around 25 o C, the VMT solution was crushed by shear for five minutes and ultrasonic treatment for two minutes in a single cycle. The dispersions were spun in a centrifuge (Thermo Scientific, Germany) for 30 minutes at 2000 rpm. VMT powder was obtained by carefully removing and spray-drying the supernatant following centrifugation. Adsorption testing The adsorption experiments were conducted in a 50 mL Pyrex flask containing VMT powder aqueous suspension (100 mL). The adsorption activity of VMT powder was monitored by adsorption of methylene blue (MB) with a constant temperature circulator. Typically, a mixture of 100 mL of MB (100 ppm) solution and 0.1-1 g of VMT powder was slowly stirred for several hours under the constant temperature at 30 ◦ C. At given time intervals, 2 mL aqueous suspension were sampled and centrifugalized to remove the solid phase under rev 8000 rpm for 20 min. The supernatant fluid was tested by measuring the absorbance at 664 nm for MB by using UV-vis spectrophotometer. After centrifugation from the solution under 12000 rpm for 30 min, regeneration of the VMT powder was performed by putting the MB-loaded VMT powder into ethanol solution and was stirred with ultrasound at room temperature for 2 minutes. This procedure was carried out three to five times. The VMT powder was then recycled ten times for the subsequent adsorption regeneration cycles. Characterization and measurements High-resolution transmission electron microscopy (HRTEM, JEM-2100) and field emission scanning electron microscopy (SEM, Zeiss Supra 55) were used to analyze the product morphology. Powder X-ray diffraction (XRD, Shimadzu 6000) was used to get crystallographic data. A Bruker Vector 22 spectrophotometer was used to acquire the Fourier transform infrared (FTIR) spectra. UV-vis spectrophotometer (METASH UV-800S spectrophotometer) was performed to measure the concentration of MB in the solution. 3. RESULTS AND DISCUSSION Van der Waals forces hold together a collection of neatly stacked VMT nanosheets, which can be thought of as VMT particles. Since the interaction energy of VMT particles is very low, a variety of sufficiently powerful forces, including collision, shock wave, and shear force, might theoretically cause the delamination of VMT particles [ 27 , 28 ] . The two exfoliation methods-ultrasound and shear-mixing-depend on exerting mechanical stress on the VMT layered structure in order to weaken and eventually rupture it; yet, their mechanisms are very different (Fig. 1 ). The formation, growth, and collapse of gaseous microbubbles in a liquid medium can result in cavitation phenomenon, which can generate locally high pressures (1000 bar) and temperatures (5000 K). This phenomenon causes the layered material to exfoliate vertically because ultrasound can produce a multitude of mechanical, thermal, and physicochemical effects that reduce flake size and increase flake dispersion [ 29 , 30 ] . Conversely, since a high-speed rotor shear-mixes multilayer material dispersion in solvents, a high-shear mixer has shear force and edge collision at the raised wall areas and the primary energy-dissipated rotor swept zone, respectively (Fig. 1 ) [ 31 ] . This occurs when the difference between the rotor razor blade tip's velocity and the fluid around it is greater than the velocity at the rotor center, creating shear forces and collisions that cause the layered material to exfoliate in a lateral direction. It is significant to notice that, due to the weaker collective contact force between layers, tiny sheets peel off the particle surface more easily than thicker ones. Therefore, it is one of the key issues of layered materials exfoliation that the size of layered materials is quickly and efficiently to become smaller and then to peel by various high forces. Obviously, it is the least effective method for ball milling to exfoliate layered materials because it tends to cause stacking and agglomeration. Figure 1 shows the mechanism of the ultrasound-assisted rapid shear method which consists of the rotor blades and ultrasound waves. Extrusion and exfoliation are caused by high-speed fluid flows in the narrow space between the rotor blades and the container wall, which is primarily caused by the blades cutting the layer VMT in the middle of the piece while operating at high speeds and ejecting solvents into the surrounding area. Large fluid velocity gradients are easily capable of inducing high shear force. High blade shear exfoliation is followed by ultrasonic exfoliation. The temperature is simultaneously regulated at a low degree by cooling water. Multiple forces are formed for VMT exfoliation by utilizing both longitudinal and lateral force. Above all, great efficiency may be achieved by directly acting on the weak interface between layers of particles by high viscous shear force generated by fluid flow with ultrasound. Additionally, edge and cut collision effects are often disregarded as a weak force exfoliating layered VMT particles, but in the high shear mixer, they might be the primary force exfoliating layered materials, with cut collision likely to be the primary cause of the layered particles' reduction in size and exfoliation. The leading edges of rotor blades and the container's rising wall have been shown to experience high energy dissipation [ 32 ] ; As a result, when the dispersion periodically and quickly impinges on the rising wall and blade edges, the VMT particles may be subjected to a tremendous cut and edge collision [ 32 ] . The very huge inertial force in the turbulence zone can potentially cause frequent and random collisions between VMT particles. Serious VMT particle pileups have the potential to cause self-exfoliation of the particles, resulting in mono- and multi-layer VMT nanosheets (Fig. 1 ). In addition, when VMT particles in fluid is processed with ultrasound, ultrasound cavitation can be induced by locally high pressures and temperatures. A method for creating multilayer nanomaterials that makes use of shock waves is cavitation, as demonstrated by research [ 33 ] . Even yet, the generation of VMT nanosheets may not be significantly impacted by ultrasound cavitation because ultrasonic exfoliation is longitudinal in comparison to shear exfoliation's lateral force [ 34 ] . Interestingly, near the periphery of VMT particles, where intense and abrupt shocks induced substantial deformation, curl, loose and thin layers replaced the ordered and thick ones (Fig. 1 ). The exfoliating effects of shear forces and ultrasonic pressures may be reinforced in a synergistic way by this destruction. Most notably, the size of VMT nanosheets may be dramatically reduced due to sudden velocity shift, geometrical change, and ultrasound cavitation caused by these frequent and violent impacts, which greatly expedite the exfoliation process. As well known, the best method of stripping is efficiently and safely to maintain the original VMT structure and properties, especially negative charge layer sheet of VMT (lower than − 20 mV) as shown in Fig. 2 b. It is the key to the choice of exfoliated solvent, such as water, organic solvents, salt solution and acid solution. However, with regard to VMT exfoliation in salt solution, the VMT nanosheets was needed to be separated from salt solution, and colloidal solution of VMT nanosheets is rather unstable and reunion, which is process complexity and high cost, and difficult to promote in industry. Moreover, the size of VMT is about 2 µm when VMT: NaCl: Na 6 P 6 O 18 is 1:0.5:0.5, but the particle size becomes larger with the increase of salt ion in Fig. 4Sc, which is further proved that salt ions are not conducive to VMT exfoliation. The pH was observed from initial pH = 3.5 to the final pH = 6.8 in acid solution exfoliation [ 35 ] , then original VMT structure should be destroyed because the inorganic mineral VMT is soluble in acid. In addition, organic solvents are volatile. Therefore, water is green solvent for the rapid and scalable production of well-defined few-layer VMT nanosheets. The efficient of mixer, ultrasound, ball milling, colloid mill, ultrasound-assisted colloid mill, limited space shearer and ultrasound-assisted limited space shearer in water solution was illustrated that limited space shearer and colloid mill is the most effective way for VMT exfoliation, and ball milling widely used in industry did not work in Fig. 2 a, 2 c and 1 S, and negative charge layer sheet of VMT gradually decreases to -35 mV in Fig. 2 b and 2 S, and the time of the liquid pulverizer in to be prepared same amount of VMT nanosheets is increased by about 10 times compared to ball mill in Fig. 1 S, and the XRD (003) reflection peak of exfoliated VMT become stronger and taller indicating that the purity and crystallinity of the VMT was improved in Fig. 2 d, which is further confirmed shear exfoliation is the best way for layered materials exfoliation. Moreover, when lateral force colloid mill was assisted with longitudinal force ultrasound waves, the efficient increased by 13% at limited space shearer and ultrasound-assisted limited space shearer, which is proofed synergistic effect of lateral force and longitudinal force for layered materials exfoliation in Fig. 2 a and 2 c. The technological conditions are the key to the application of VMT exfoliation. The particle size is minimum when the ratio of VMT with water is about 1:2, but the particle size becomes larger with the increase of solid-liquid ratio as shown in Fig. S3a. In Fig. S3b, the particle size decreases as the grinding duration increases. Centrifugal separation might be used to get rid of the big VMT particle size. 0.15 µm of VMT could be obtained by 4000 rpm, and the amount of VMT is maximum. Thus, the optimum process conditions are VMT: water = 1:2 and 4000 rpm for centrifugal separation. The well-defined VMT nanosheets obtained by water-assisted green exfoliated approach was depicted in Fig. 3 . A representative SEM picture of the VMT crystal with a lateral dimension of 0.02 ~ 0.55 µm and a multilayer structure can be seen in Fig. 3 a. The HRTEM image in Fig. 3 b indicates a flat 2D morphology of an individual VMT nanosheet with size of approximately 50 ~ 200 nm. A distinct Tyndall light scattering is seen in the stable colloidal solution of VMT exfoliation (Fig. 3 b Insert), suggesting the presence of numerous nanosheets. It shows the VMT nanosheets have a thickness of around ~ 5 nm, 9 nm, and 11 nm, and a layer spacing of approximately 1 nm (Fig. 3 c and Fig. S7). Therefore, VMT nanosheets is available through water-assisted green exfoliated method. In addition, colloidal solution of VMT nanosheets was obtained at 10000 rpm at 10 min by centrifugation, and the colloidal solution of VMT nanosheets could keep it for 6 months without change through water-assisted VMT exfoliated in Fig. S4a and S5. However, apparent agglomeration for colloidal solution of VMT nanosheets by metal cation exfoliation appeared after 30 min, as showed in Fig. S4c. The above phenomenon is attributed to mutually exclusive of the negative charge sheet of VMT (in Fig. S4d), which is further evidence of the negatively charged layered sheet of VMT (in Fig. 2 b and S2). The self-supporting film of the obtained VMT nanosheets is pale yellow (Insert of Fig. 3 d) while the common vermiculite film is a yellow (Fig. 3 d). Therefore, theory of homosexual charge rejection describes the stable liquid solution composed of VMT nanosheets, which would increase the scope of VMT application, especially in the organic and inorganic composite materials [ 36 ] . XRD measurement provides additional confirmation of the layer space of the VMT nanosheet. The detected diffraction peak at 2 θ = 8.64 o (1.02 nm) is the (003) reflection of the VMT material, as seen in Fig. 3 e [ 37 , 38 ] . After exfoliation, the (003) peak raises to 2 θ = 9.31 o (0.95 nm). The exfoliated VMT showed an approximately 6.5-fold increase in the intensity of the (003) peak as compared to enlarged VMT, indicating better purity. The inter-planar intervals of around 1 and 0.32 nm, which correspond to the spacing between two planes (003) and (009) of VMT, respectively, are clearly visible in the HRTEM picture shown in Fig. 3 c. The FTIR spectra of both pristine and exfoliated VMT (Fig. 3 f) show that Si-O, Al-O, and Si-O vibrations are responsible for the peaks at 457 cm − 1 , 682 cm − 1 , 998 cm − 1 , respectively [ 39 ] . Hydration HOH and -OH vibration are responsible for the peaks at 1640 cm − 1 and 3431 cm − 1[ 40 ] . The intensity of the peak of exfoliated VMT is greater than VMT, but the FTIR spectrum of VMT and exfoliated VMT is the same. Here, the water-assisted green exfoliated method helps to design and build VMT nanocomposites by maintaining the layered sheet structure of VMT in addition to achieving VMT purification. The unique nanometer effect of VMT nanosheets in adsorption application was exploited. How to obtain a narrow particle size distribution of VMT nanosheets is the primary problem. The ultracentrifuge rate separation method has been introduced into isolate/capture intermediate product for the observation and understanding of VMT exfoliation [ 41 ] . Fig. S6 showed the flat 2D morphology of an individual VMT sheet was obtained by centrifuge separation at different speeds. The size of the VMT sheets at 4000 and 6000 rpm is determined to be approximately length 2 ~ 5 µm with width 2 ~ 4 µm and the VMT sheet is opaque (Fig. S6a and b), demonstrating the thickness of the VMT sheets is thicker and including many layers VMT, which implied the VMT was not effectively exfoliation. Fig. S6c and 6d showed the size of the VMT sheets at 8000 and 10000 rpm is approximately length 1000 ~ 1500 nm with width 400–1000 nm, and different VMT layer stacked together was to be seen morphology of an individual VMT sheet, proving that the VMT is a layered mineral, and the multi-layered VMT sheets are stacked together. The few layered VMT nanosheets at 12000 and 14000 rpm was obtained (approximately length 600 ~ 1000 nm with width 400–600 nm) and translucent, which indicated it was thinner than others. Therefore, VMT sheets of different thicknesses and sizes could be achieved by centrifuge separation. As we all know, the smaller the size and the thinner the thickness, the higher the surface utilization rate and the better the adsorption effect. The study examined the adsorption of MB solution (100 mg L − 1 ) with varying VMT sizes (VMT and VMT sheets generated by separating from expanded VMT at rpms of 2000, 4000, 6000, 8000, and 10000). With the decrease of the VMT sheets size, the intensity of the newly formed characteristic peak at k max = 665 nm is gradually decreased in Fig. 3 and S8. With the reduction in the size of the VMT sheets, the hue shift is noticeable enough to be seen with the unaided eye. Mazarine, the typical hue of the MB solution, is present at the start of the adsorption process. Following the reduction in the size of the VMT sheets, the enlarged VMT and VMT sheets produced at 2000 rpm, 4000 rpm, 6000 rpm, 8000 rpm, and 10000 rpm, respectively, show nearly colorless colors for 70 min, 60 min, 20 min, 10 min, 5 min, and less than 5 min (Fig. 3 and S8). It is noteworthy that the rapid adsorption of MB is mainly due to that nano effect of VMT nanosheets. The removal rate of MB by VMT nanosheets is keeping above 99% after under 5 min, indicating that the VMT nanosheets by water-assisted VMT exfoliated method has excellent nano effect. It is an importance work to gain an efficient and low-cost sorption regeneration process because the adsorption-regeneration is the key step in the wastewater treatment for industrial application. After each adsorption complete, the adsorbent VMT nanosheets was separated with centrifuge. The adsorbent of the MB-loaded VMT nanosheets was put into ethanol solution, and was dispersed with ultrasound for 2 minutes. Then the above solution was subjected to centrifugation and the above process was repeated for about 5 times. The adsorbent VMT nanosheets was reused for 10 times in Fig. 4 h. The regeneration ratio of the VMT nanosheets sample is over 95% for 10 cycles, and the adsorbed solute can be regenerated by distillation and organic solvent can be recycled, which the green organic solvent regeneration method effectively avoids VMT nanosheets agglomeration and stacking in the high temperature calcination regeneration method commonly. Therefore. The prepared VMT nanosheets is a potential recyclable candidate for dye adsorption. 4. CONCLUSIONS In summary, this study showed a new, quick, and efficient way to produce small VMTs using a combination of shear and ultrasonic pressures. The high shear generator's cut and edge collision have an impact on how successful the exfoliation is. Furthermore, by raising the cut collision rate and lateral force supported with longitudinal force ultrasonic waves, the VMT exfoliation may be further increased. The thickness and size of VMT nanosheets can be controlled by changing shear and cut collision forces, rotation space and rotate speed. The time to be prepared same amount of VMT nanosheets by the ultrasound-assisted limited space shearer was 3–5 min with respect to ball mill is 24–32 h, which indicated shear exfoliation is preference to layered materials and high efficiency. Furthermore, XRD and HRTEM showed that VMT nanosheets were relatively free of structural defects. The stable colloidal solution of VMT nanosheets could be maintained for more than about six months. The sorting nanoparticles of different sizes VMT was achieved by the ultracentrifuge rate separation method. The VMT nanosheets has excellent performance for removal of MB. Moreover, the above green organic solvent regeneration method could be effectively avoided VMT nanosheets agglomeration and stacking compared to the high temperature calcination regeneration method. This unique and scalable exfoliation method is expected to provide a new avenue for the liquid-phase synthesis of various layered materials, environmentally benign and user-friendly ways, such as black scale and MoS 2 . Declarations CONFLICT OF INTEREST The authors don't have any conflict of interest in the publication of the manuscript. SUPPORTING INFORMATION Supporting figures include additional characterization. Author Contribution Jinpeng Hou: Conceptualization, Methodology, Software, Investigation, Formal Analysis, Writing-Original Draft, Funding Acquisition,;Yiwen Shen: Visualization, Investigation;Xiangkun Zhang: Data Curation, Writing-Original Draft;Zhong Li: Supervision;Weiliang Tian:Conceptualization, Resources, Supervision, Writing-Review & Editing. Software, Validation;Tonghui Shen: Data Curation;Kewei Zhang: Conceptualization ACKNOWLEDGEMENTS J. Hou and Y. Shen contributed equally to this work. 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Khammassi, S., Tarfaoui, M., Škrlová, K., et al., Poly (Lactic acid)(PLA)-Based nanocomposites: impact of vermiculite, silver, and graphene oxide on thermal stability, isothermal crystallization, and local mechanical behavior. Journal of Composites Science , 2022, 6, 112. Tian, W., Li, H., Qin, B., et al., Tuning the wettability of carbon nanotube arrays for efficient bifunctional catalysts and Zn-air batteries. Journal of Materials Chemistry A , 2017, 5, 7103–7110. Tian, W., Li, Z., Zhang, K., et al., Facile synthesis of exfoliated vermiculite nanosheets as a thermal stabilizer in polyvinyl chloride resin. RSC advances , 2019, 9, 19675–19679. Zhang, K., Xu, J., Wang, K. Y., et al., Preparation and characterization of chitosan nanocomposites with vermiculite of different modification. Polymer Degradation and Stability , 2009, 94, 2121–2127. You, H., Zhang, K., Zhang, X., et al., Fabrication of transparent ultrathin films with ordered solid luminescence by LBL assembly of CdTe quantum dots with exfoliated vermiculite. Applied Clay Science , 2022, 230, 106710. Deng, L., Wang, X., Kuang, Y., et al., Development of hydrophilicity gradient ultracentrifugation method for photoluminescence investigation of separated non-sedimental carbon dots. Nano Research , 2015, 8, 2810–2821. Additional Declarations No competing interests reported. Supplementary Files SupportingInformation.docx Cite Share Download PDF Status: Posted 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7503581","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":511626777,"identity":"183a37d9-6e0a-4e5a-b8b5-f350eabb9830","order_by":0,"name":"Jinpeng Hou","email":"","orcid":"","institution":"Tarim University","correspondingAuthor":false,"prefix":"","firstName":"Jinpeng","middleName":"","lastName":"Hou","suffix":""},{"id":511626780,"identity":"5266608a-6226-4f61-9584-6e5c36b58880","order_by":1,"name":"Yiwen Shen","email":"","orcid":"","institution":"Tarim University","correspondingAuthor":false,"prefix":"","firstName":"Yiwen","middleName":"","lastName":"Shen","suffix":""},{"id":511626785,"identity":"f071527b-e9d0-4e00-bc55-9d730f5b674d","order_by":2,"name":"Xiangkun Zhang","email":"","orcid":"","institution":"Tarim University","correspondingAuthor":false,"prefix":"","firstName":"Xiangkun","middleName":"","lastName":"Zhang","suffix":""},{"id":511626788,"identity":"48c8b678-9f41-42f3-ad03-c130cedf57c2","order_by":3,"name":"Zhong Li","email":"","orcid":"","institution":"Tarim University","correspondingAuthor":false,"prefix":"","firstName":"Zhong","middleName":"","lastName":"Li","suffix":""},{"id":511626789,"identity":"55e4491f-646e-4350-aeb8-0fa87150c686","order_by":4,"name":"Weiliang L. Tian","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAr0lEQVRIiWNgGAWjYFAC5sYDQFKOjb35AHEaeBgYG0BKjfl4jiWQpiVxnkSOAnFa7CUSGw583FGb3saQw8Dwo2IbEbYAtRyceeZ4bhvD2QOMPWduE6FFOrHhMG/bsdw2xr4EZsY2ErSkszHzGJCkpSaBjY1oLfcfAv3SdsCwjYct4SBRfmHvOXzwwce2Onn5+Y8PPvhRQYQWKDgMJg8QrR4I6khRPApGwSgYBSMNAABw/j7PQf4dXgAAAABJRU5ErkJggg==","orcid":"","institution":"Tarim University","correspondingAuthor":true,"prefix":"","firstName":"Weiliang","middleName":"L.","lastName":"Tian","suffix":""},{"id":511626790,"identity":"cb1ba087-ca0c-4078-96ae-f402e5c70055","order_by":5,"name":"Tonghui Shen","email":"","orcid":"","institution":"Tarim University","correspondingAuthor":false,"prefix":"","firstName":"Tonghui","middleName":"","lastName":"Shen","suffix":""},{"id":511626791,"identity":"c3c54705-6b5e-4522-9f63-b0bc47670f66","order_by":6,"name":"Kewei W. Zhang","email":"","orcid":"","institution":"Tarim University","correspondingAuthor":false,"prefix":"","firstName":"Kewei","middleName":"W.","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2025-09-01 02:38:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7503581/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7503581/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":91010998,"identity":"f587cecd-dd3c-4a24-a21a-2a4b851a4605","added_by":"auto","created_at":"2025-09-10 15:39:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":461507,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic illustration of the exfoliation of VMT: the high shear generator (left side); main energy dissipation regions of the high shear mixer (center section); the schematic model of preparing VMT nanosheets by collision, shear force, and ultrasound waves(right side).\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-7503581/v1/bb12f48fd8f565be9bff45a7.png"},{"id":91010239,"identity":"f2923849-655c-42b2-8c3c-f877dbda26e1","added_by":"auto","created_at":"2025-09-10 15:31:41","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":199728,"visible":true,"origin":"","legend":"\u003cp\u003eThe VMT Particle size(a), Zeta potential(b), volume (%) of particle cumulative(c), XRD(d) of mixer, ultrasound, ball milling, colloid mill, ultrasound-assisted colloid mill, limited space shearer and ultrasound-assisted limited space shearer.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-7503581/v1/bb516c90a53d770f9252b0fd.png"},{"id":91010999,"identity":"7ed8a2de-58a1-45b8-9ba9-60dcb0a1e370","added_by":"auto","created_at":"2025-09-10 15:39:41","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":495519,"visible":true,"origin":"","legend":"\u003cp\u003e(a) SEM image of the VMT crystal (Inset of expanded VMT), (b, c) HRTEM images of few-layer exfoliated VMT nanosheets (Inset c of selected-area electron diffraction (SAED) pattern of VMT lattice), (d) self-supporting film of common vermiculite solution (Inset of self-supporting film of the VMT nanosheets), (e) XRD patterns and (f) FTIR spectra of the VMT and exfoliated VMT.\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-7503581/v1/2a31d549fb418e14306ef416.png"},{"id":91011277,"identity":"1d4c7b07-53a5-427d-9e15-ee918585ba6f","added_by":"auto","created_at":"2025-09-10 15:47:41","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":542416,"visible":true,"origin":"","legend":"\u003cp\u003e(a-f) Adsorption spectra of MB with VMT nanosheets obtained by separation from 0 rpm (a), 2000 rpm (b), 4000 rpm (c), 6000 rpm (d), 8000 rpm (e) and 10000 rpm (f). (g) Change of adsorption rate at 30 min with the separation rate. (h) Regeneration ratio of the VMT nanosheets under different cycles.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-7503581/v1/0ef68832070d1e3ea5ddd07f.png"},{"id":91661167,"identity":"2c5cc0f5-9662-4b74-abc2-d3c913bc6e13","added_by":"auto","created_at":"2025-09-18 21:01:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2066131,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7503581/v1/0d0a2f24-3e9f-4bb5-8df1-abe8b5673531.pdf"},{"id":91010242,"identity":"193d0481-098c-4714-bbcf-0ca7501544bb","added_by":"auto","created_at":"2025-09-10 15:31:41","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":165935,"visible":true,"origin":"","legend":"","description":"","filename":"SupportingInformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-7503581/v1/cd764670f0e4c6fde4ebfde1.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Rapid exfoliation of well-defined vermiculite nanosheets via ultrasound-triggered limited space shear for pollutant adsorption","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eLayered nanomaterials represent an interesting opportunity to develop hybrid materials with intentional functionalities\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Since the exploration of atomic layer graphene with extraordinary physical and chemical properties, the novel properties of two-dimensional (2D) materials have spurred tremendous fundamental studies and technological advancements for a wide range of applications\u003csup\u003e[\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. The layered aluminosilicate clay mineral known as vermiculite (VMT) is found naturally and is composed of two tetrahedral silicate layers and octahedral sheets that hold magnesium ions\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. Due to the partial replacement of silicon with aluminum, the VMT layers have a negative charge. Water molecules and exchangeable cations (K\u003csup\u003e+,\u003c/sup\u003e Mg\u003csup\u003e2+\u003c/sup\u003e, and Ca\u003csup\u003e2+)\u003c/sup\u003e make up the interlayer area, which balances the positive charge deficit caused by the layers. Owing to their natural abundant resources (about 600\u0026nbsp;million tons\u0026rsquo; reserves), unique layered structure, desirable surface chemistry and thermal/mechanical properties, the VMT has piqued the interest of researchers worldwide for both basic study and practical applications\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. The resultant one- or few-layer nanosheets, in particular, show intriguing physic-chemical characteristics because of the nanoscale effect, which makes them especially desirable for use in catalysis and mechanical reinforcement as well as flexible electronics \u003csup\u003e[\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe industrial-scale manufacturing of well-defined VMT is urgently needed for several critical applications, including high-temperature, refractory insulation, fire resistance\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e, optical coatings\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e and composite fillers\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. For instance, VMT is probably going to be utilized as an effective and affordable composite filler in applications including catalysis, ordered self-assembled nanostructures\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e, organic-inorganic composites, and polymer-based nanocomposites\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. Such fillers certainly require large quantities of VMT nanosheets, and thus the exfoliation of VMT is becoming an important technology\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e. Unfortunately, two-dimensional nanomaterial exfoliation is mainly reflected in the complexity and difficulty of the preparation process, including the limitations of the exfoliation method, the challenges of material properties, and the difficulty of large-scale production. In addition, two-dimensional materials are sensitive to the chemical environment and are easily contaminated or chemically reacted during the exfoliation process, which further increases the difficulty of exfoliation. There is currently no quick, scalable process that produces vast amounts of well-defined, environmentally friendly VMT nanosheets. The most widely used ball mill in the industry is difficult to exfoliate layered VMT effectively, owing to the tendency of stacking and agglomeration. Besides, the thermal\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e exfoliation and microwave exfoliation\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e can only get large particles of expanded VMT. Chemical-exfoliation using hydrogen peroxide or mineral acids is normally employed to further improve the yield of nanosheets,\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e but the resultant acidizing VMT with amorphous silica and other structural components is typically defective\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e Alternatively, sonication of VMT in certain stabilizing solvents or aqueous surfactant solutions provides opportunity for well-defined VMT nanosheets\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e. However, the process for which ultrasound is intended is limited in its scalability since it is employed as an energy source for extended sonication.\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Thus, the above methods eventually exhibit either a high yield or a low defect content, but not both\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. To achieve fast VMT manufacturing, one potential approach is to create a scalable exfoliation technique that is combined with sonication.\u003c/p\u003e\u003cp\u003eIn fine pulverization and emulsification, the high shear pulverizer (also known as the blade pulverizer) has found widespread application\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e. High speed alternating shear with numerous knife heads and a multibladed saw for layered materials are the usual features of a high-shear pulverizer\u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e. Unlike a ball mill, this kind of pulverizer primarily employs waist cutoff in liquid to avoid stacking and aggregation. High shear force, collision impacts, and jet cavitation are the three main components of the hydrodynamics-based high shear pulverizer's operating mechanism\u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e. Van der Waals interactions between layers are overcome by the intense physical contact that rapid and violent fluid movement creates with the layered crystal particles\u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e. A minimal shear rate required to create layered crystal was predicted using a straightforward exfoliation model, or shear-induced interlayer sliding\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Because the shear exfoliation is lateral force, it is necessary to find the force in the longitudinal direction to peel off the layered crystal quickly and effectively. the capacity to exfoliate untreated layered crystals in liquids by combining longitudinal and lateral force would be far more beneficial tactics.\u003c/p\u003e\u003cp\u003eThe current study demonstrates a fast, green, and highly effective exfoliation process that uses sonication as the longitudinal force and a shear pulverizer as the lateral force to create VMT nanosheets in water. Exfoliating the VMT particles into huge amounts of flawless, non-chemical VMT nanosheets may be done quickly and efficiently. In addition, this VMT nanosheet has excellent performance in several applications, including pollutant adsorption.\u003c/p\u003e"},{"header":"2. EXPERIMENTAL","content":"\u003cp\u003e\u003cstrong\u003eMaterials\u003c/strong\u003e\u003cp\u003eIndustrial expanded VMT (calcined at 1000 \u003csup\u003eo\u003c/sup\u003eC, particle size 1\u0026ndash;4 mm) was purchased from the China Xinjiang Yuli VMT Co. Ltd. Methylene blue and anhydrous ethanol were purchased from the Beijing Chemical Co. Ltd.. All experimental procedures utilized deionized water, and all other compounds were used as analytical solutions (A. R.) without extra purification.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eUltrasound-triggered exfoliation of VMT using shear forces\u003c/strong\u003e\u003cp\u003eIn a typical procedure, 15 g of VMT were added to 500 mL deionized water. A high shear mixer in a glass cylinder with four raised pillars on the interior surface (about 10 cm in diameter and 15 cm in the height) was used to perform the exfoliation process at a maximum speed of nearly 28000 rpm. The glass cylinder also included six shearing blades (8 mm x 30 mm each). Using cooling water to maintain a low temperature of around 25 \u003csup\u003eo\u003c/sup\u003eC, the VMT solution was crushed by shear for five minutes and ultrasonic treatment for two minutes in a single cycle. The dispersions were spun in a centrifuge (Thermo Scientific, Germany) for 30 minutes at 2000 rpm. VMT powder was obtained by carefully removing and spray-drying the supernatant following centrifugation.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eAdsorption testing\u003c/strong\u003e\u003cp\u003eThe adsorption experiments were conducted in a 50 mL Pyrex flask containing VMT powder aqueous suspension (100 mL). The adsorption activity of VMT powder was monitored by adsorption of methylene blue (MB) with a constant temperature circulator. Typically, a mixture of 100 mL of MB (100 ppm) solution and 0.1-1 g of VMT powder was slowly stirred for several hours under the constant temperature at 30\u003csup\u003e◦\u003c/sup\u003eC. At given time intervals, 2 mL aqueous suspension were sampled and centrifugalized to remove the solid phase under rev 8000 rpm for 20 min. The supernatant fluid was tested by measuring the absorbance at 664 nm for MB by using UV-vis spectrophotometer. After centrifugation from the solution under 12000 rpm for 30 min, regeneration of the VMT powder was performed by putting the MB-loaded VMT powder into ethanol solution and was stirred with ultrasound at room temperature for 2 minutes. This procedure was carried out three to five times. The VMT powder was then recycled ten times for the subsequent adsorption regeneration cycles.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCharacterization and measurements\u003c/strong\u003e\u003cp\u003eHigh-resolution transmission electron microscopy (HRTEM, JEM-2100) and field emission scanning electron microscopy (SEM, Zeiss Supra 55) were used to analyze the product morphology. Powder X-ray diffraction (XRD, Shimadzu 6000) was used to get crystallographic data. A Bruker Vector 22 spectrophotometer was used to acquire the Fourier transform infrared (FTIR) spectra. UV-vis spectrophotometer (METASH UV-800S spectrophotometer) was performed to measure the concentration of MB in the solution.\u003c/p\u003e\u003c/p\u003e"},{"header":"3. RESULTS AND DISCUSSION","content":"\u003cp\u003eVan der Waals forces hold together a collection of neatly stacked VMT nanosheets, which can be thought of as VMT particles. Since the interaction energy of VMT particles is very low, a variety of sufficiently powerful forces, including collision, shock wave, and shear force, might theoretically cause the delamination of VMT particles\u003csup\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e. The two exfoliation methods-ultrasound and shear-mixing-depend on exerting mechanical stress on the VMT layered structure in order to weaken and eventually rupture it; yet, their mechanisms are very different (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The formation, growth, and collapse of gaseous microbubbles in a liquid medium can result in cavitation phenomenon, which can generate locally high pressures (1000 bar) and temperatures (5000 K). This phenomenon causes the layered material to exfoliate vertically because ultrasound can produce a multitude of mechanical, thermal, and physicochemical effects that reduce flake size and increase flake dispersion\u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e. Conversely, since a high-speed rotor shear-mixes multilayer material dispersion in solvents, a high-shear mixer has shear force and edge collision at the raised wall areas and the primary energy-dissipated rotor swept zone, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003csup\u003e[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e. This occurs when the difference between the rotor razor blade tip's velocity and the fluid around it is greater than the velocity at the rotor center, creating shear forces and collisions that cause the layered material to exfoliate in a lateral direction.\u003c/p\u003e\u003cp\u003eIt is significant to notice that, due to the weaker collective contact force between layers, tiny sheets peel off the particle surface more easily than thicker ones. Therefore, it is one of the key issues of layered materials exfoliation that the size of layered materials is quickly and efficiently to become smaller and then to peel by various high forces. Obviously, it is the least effective method for ball milling to exfoliate layered materials because it tends to cause stacking and agglomeration. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the mechanism of the ultrasound-assisted rapid shear method which consists of the rotor blades and ultrasound waves. Extrusion and exfoliation are caused by high-speed fluid flows in the narrow space between the rotor blades and the container wall, which is primarily caused by the blades cutting the layer VMT in the middle of the piece while operating at high speeds and ejecting solvents into the surrounding area. Large fluid velocity gradients are easily capable of inducing high shear force. High blade shear exfoliation is followed by ultrasonic exfoliation. The temperature is simultaneously regulated at a low degree by cooling water. Multiple forces are formed for VMT exfoliation by utilizing both longitudinal and lateral force. Above all, great efficiency may be achieved by directly acting on the weak interface between layers of particles by high viscous shear force generated by fluid flow with ultrasound.\u003c/p\u003e\u003cp\u003eAdditionally, edge and cut collision effects are often disregarded as a weak force exfoliating layered VMT particles, but in the high shear mixer, they might be the primary force exfoliating layered materials, with cut collision likely to be the primary cause of the layered particles' reduction in size and exfoliation. The leading edges of rotor blades and the container's rising wall have been shown to experience high energy dissipation\u003csup\u003e[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e; As a result, when the dispersion periodically and quickly impinges on the rising wall and blade edges, the VMT particles may be subjected to a tremendous cut and edge collision\u003csup\u003e[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e. The very huge inertial force in the turbulence zone can potentially cause frequent and random collisions between VMT particles. Serious VMT particle pileups have the potential to cause self-exfoliation of the particles, resulting in mono- and multi-layer VMT nanosheets (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In addition, when VMT particles in fluid is processed with ultrasound, ultrasound cavitation can be induced by locally high pressures and temperatures. A method for creating multilayer nanomaterials that makes use of shock waves is cavitation, as demonstrated by research\u003csup\u003e[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. Even yet, the generation of VMT nanosheets may not be significantly impacted by ultrasound cavitation because ultrasonic exfoliation is longitudinal in comparison to shear exfoliation's lateral force\u003csup\u003e[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/sup\u003e. Interestingly, near the periphery of VMT particles, where intense and abrupt shocks induced substantial deformation, curl, loose and thin layers replaced the ordered and thick ones (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The exfoliating effects of shear forces and ultrasonic pressures may be reinforced in a synergistic way by this destruction. Most notably, the size of VMT nanosheets may be dramatically reduced due to sudden velocity shift, geometrical change, and ultrasound cavitation caused by these frequent and violent impacts, which greatly expedite the exfoliation process.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs well known, the best method of stripping is efficiently and safely to maintain the original VMT structure and properties, especially negative charge layer sheet of VMT (lower than \u0026minus;\u0026thinsp;20 mV) as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb. It is the key to the choice of exfoliated solvent, such as water, organic solvents, salt solution and acid solution. However, with regard to VMT exfoliation in salt solution, the VMT nanosheets was needed to be separated from salt solution, and colloidal solution of VMT nanosheets is rather unstable and reunion, which is process complexity and high cost, and difficult to promote in industry. Moreover, the size of VMT is about 2 \u0026micro;m when VMT: NaCl: Na\u003csub\u003e6\u003c/sub\u003eP\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e18\u003c/sub\u003e is 1:0.5:0.5, but the particle size becomes larger with the increase of salt ion in Fig.\u0026nbsp;4Sc, which is further proved that salt ions are not conducive to VMT exfoliation. The pH was observed from initial pH\u0026thinsp;=\u0026thinsp;3.5 to the final pH\u0026thinsp;=\u0026thinsp;6.8 in acid solution exfoliation\u003csup\u003e[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/sup\u003e, then original VMT structure should be destroyed because the inorganic mineral VMT is soluble in acid. In addition, organic solvents are volatile. Therefore, water is green solvent for the rapid and scalable production of well-defined few-layer VMT nanosheets. The efficient of mixer, ultrasound, ball milling, colloid mill, ultrasound-assisted colloid mill, limited space shearer and ultrasound-assisted limited space shearer in water solution was illustrated that limited space shearer and colloid mill is the most effective way for VMT exfoliation, and ball milling widely used in industry did not work in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eS, and negative charge layer sheet of VMT gradually decreases to -35 mV in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eS, and the time of the liquid pulverizer in to be prepared same amount of VMT nanosheets is increased by about 10 times compared to ball mill in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eS, and the XRD (003) reflection peak of exfoliated VMT become stronger and taller indicating that the purity and crystallinity of the VMT was improved in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed, which is further confirmed shear exfoliation is the best way for layered materials exfoliation. Moreover, when lateral force colloid mill was assisted with longitudinal force ultrasound waves, the efficient increased by 13% at limited space shearer and ultrasound-assisted limited space shearer, which is proofed synergistic effect of lateral force and longitudinal force for layered materials exfoliation in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec.\u003c/p\u003e\u003cp\u003eThe technological conditions are the key to the application of VMT exfoliation. The particle size is minimum when the ratio of VMT with water is about 1:2, but the particle size becomes larger with the increase of solid-liquid ratio as shown in Fig. S3a. In Fig. S3b, the particle size decreases as the grinding duration increases. Centrifugal separation might be used to get rid of the big VMT particle size. 0.15 \u0026micro;m of VMT could be obtained by 4000 rpm, and the amount of VMT is maximum. Thus, the optimum process conditions are VMT: water\u0026thinsp;=\u0026thinsp;1:2 and 4000 rpm for centrifugal separation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe well-defined VMT nanosheets obtained by water-assisted green exfoliated approach was depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. A representative SEM picture of the VMT crystal with a lateral dimension of 0.02\u0026thinsp;~\u0026thinsp;0.55 \u0026micro;m and a multilayer structure can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea. The HRTEM image in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb indicates a flat 2D morphology of an individual VMT nanosheet with size of approximately 50\u0026thinsp;~\u0026thinsp;200 nm. A distinct Tyndall light scattering is seen in the stable colloidal solution of VMT exfoliation (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb Insert), suggesting the presence of numerous nanosheets. It shows the VMT nanosheets have a thickness of around ~\u0026thinsp;5 nm, 9 nm, and 11 nm, and a layer spacing of approximately 1 nm (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec and Fig. S7). Therefore, VMT nanosheets is available through water-assisted green exfoliated method. In addition, colloidal solution of VMT nanosheets was obtained at 10000 rpm at 10 min by centrifugation, and the colloidal solution of VMT nanosheets could keep it for 6 months without change through water-assisted VMT exfoliated in Fig. S4a and S5. However, apparent agglomeration for colloidal solution of VMT nanosheets by metal cation exfoliation appeared after 30 min, as showed in Fig. S4c. The above phenomenon is attributed to mutually exclusive of the negative charge sheet of VMT (in Fig. S4d), which is further evidence of the negatively charged layered sheet of VMT (in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb and S2). The self-supporting film of the obtained VMT nanosheets is pale yellow (Insert of Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed) while the common vermiculite film is a yellow (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed). Therefore, theory of homosexual charge rejection describes the stable liquid solution composed of VMT nanosheets, which would increase the scope of VMT application, especially in the organic and inorganic composite materials\u003csup\u003e[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eXRD measurement provides additional confirmation of the layer space of the VMT nanosheet. The detected diffraction peak at 2\u003cem\u003eθ\u003c/em\u003e\u0026thinsp;=\u0026thinsp;8.64\u003csup\u003eo\u003c/sup\u003e (1.02 nm) is the (003) reflection of the VMT material, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ee\u003csup\u003e[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/sup\u003e. After exfoliation, the (003) peak raises to 2\u003cem\u003eθ\u003c/em\u003e\u0026thinsp;=\u0026thinsp;9.31\u003csup\u003eo\u003c/sup\u003e (0.95 nm). The exfoliated VMT showed an approximately 6.5-fold increase in the intensity of the (003) peak as compared to enlarged VMT, indicating better purity. The inter-planar intervals of around 1 and 0.32 nm, which correspond to the spacing between two planes (003) and (009) of VMT, respectively, are clearly visible in the HRTEM picture shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec. The FTIR spectra of both pristine and exfoliated VMT (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ef) show that Si-O, Al-O, and Si-O vibrations are responsible for the peaks at 457 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 682 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 998 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively\u003csup\u003e[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]\u003c/sup\u003e. Hydration HOH and -OH vibration are responsible for the peaks at 1640 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 3431 cm\u003csup\u003e\u0026minus;\u0026thinsp;1[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/sup\u003e. The intensity of the peak of exfoliated VMT is greater than VMT, but the FTIR spectrum of VMT and exfoliated VMT is the same. Here, the water-assisted green exfoliated method helps to design and build VMT nanocomposites by maintaining the layered sheet structure of VMT in addition to achieving VMT purification.\u003c/p\u003e\u003cp\u003eThe unique nanometer effect of VMT nanosheets in adsorption application was exploited. How to obtain a narrow particle size distribution of VMT nanosheets is the primary problem. The ultracentrifuge rate separation method has been introduced into isolate/capture intermediate product for the observation and understanding of VMT exfoliation\u003csup\u003e[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]\u003c/sup\u003e. Fig. S6 showed the flat 2D morphology of an individual VMT sheet was obtained by centrifuge separation at different speeds. The size of the VMT sheets at 4000 and 6000 rpm is determined to be approximately length 2\u0026thinsp;~\u0026thinsp;5 \u0026micro;m with width 2\u0026thinsp;~\u0026thinsp;4 \u0026micro;m and the VMT sheet is opaque (Fig. S6a and b), demonstrating the thickness of the VMT sheets is thicker and including many layers VMT, which implied the VMT was not effectively exfoliation. Fig. S6c and 6d showed the size of the VMT sheets at 8000 and 10000 rpm is approximately length 1000\u0026thinsp;~\u0026thinsp;1500 nm with width 400\u0026ndash;1000 nm, and different VMT layer stacked together was to be seen morphology of an individual VMT sheet, proving that the VMT is a layered mineral, and the multi-layered VMT sheets are stacked together. The few layered VMT nanosheets at 12000 and 14000 rpm was obtained (approximately length 600\u0026thinsp;~\u0026thinsp;1000 nm with width 400\u0026ndash;600 nm) and translucent, which indicated it was thinner than others. Therefore, VMT sheets of different thicknesses and sizes could be achieved by centrifuge separation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs we all know, the smaller the size and the thinner the thickness, the higher the surface utilization rate and the better the adsorption effect. The study examined the adsorption of MB solution (100 mg L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) with varying VMT sizes (VMT and VMT sheets generated by separating from expanded VMT at rpms of 2000, 4000, 6000, 8000, and 10000). With the decrease of the VMT sheets size, the intensity of the newly formed characteristic peak at k max\u0026thinsp;=\u0026thinsp;665 nm is gradually decreased in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and S8. With the reduction in the size of the VMT sheets, the hue shift is noticeable enough to be seen with the unaided eye. Mazarine, the typical hue of the MB solution, is present at the start of the adsorption process. Following the reduction in the size of the VMT sheets, the enlarged VMT and VMT sheets produced at 2000 rpm, 4000 rpm, 6000 rpm, 8000 rpm, and 10000 rpm, respectively, show nearly colorless colors for 70 min, 60 min, 20 min, 10 min, 5 min, and less than 5 min (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and S8). It is noteworthy that the rapid adsorption of MB is mainly due to that nano effect of VMT nanosheets. The removal rate of MB by VMT nanosheets is keeping above 99% after under 5 min, indicating that the VMT nanosheets by water-assisted VMT exfoliated method has excellent nano effect.\u003c/p\u003e\u003cp\u003eIt is an importance work to gain an efficient and low-cost sorption regeneration process because the adsorption-regeneration is the key step in the wastewater treatment for industrial application. After each adsorption complete, the adsorbent VMT nanosheets was separated with centrifuge. The adsorbent of the MB-loaded VMT nanosheets was put into ethanol solution, and was dispersed with ultrasound for 2 minutes. Then the above solution was subjected to centrifugation and the above process was repeated for about 5 times. The adsorbent VMT nanosheets was reused for 10 times in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eh. The regeneration ratio of the VMT nanosheets sample is over 95% for 10 cycles, and the adsorbed solute can be regenerated by distillation and organic solvent can be recycled, which the green organic solvent regeneration method effectively avoids VMT nanosheets agglomeration and stacking in the high temperature calcination regeneration method commonly. Therefore. The prepared VMT nanosheets is a potential recyclable candidate for dye adsorption.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"4. CONCLUSIONS","content":"\u003cp\u003eIn summary, this study showed a new, quick, and efficient way to produce small VMTs using a combination of shear and ultrasonic pressures. The high shear generator's cut and edge collision have an impact on how successful the exfoliation is. Furthermore, by raising the cut collision rate and lateral force supported with longitudinal force ultrasonic waves, the VMT exfoliation may be further increased. The thickness and size of VMT nanosheets can be controlled by changing shear and cut collision forces, rotation space and rotate speed. The time to be prepared same amount of VMT nanosheets by the ultrasound-assisted limited space shearer was 3\u0026ndash;5 min with respect to ball mill is 24\u0026ndash;32 h, which indicated shear exfoliation is preference to layered materials and high efficiency. Furthermore, XRD and HRTEM showed that VMT nanosheets were relatively free of structural defects. The stable colloidal solution of VMT nanosheets could be maintained for more than about six months. The sorting nanoparticles of different sizes VMT was achieved by the ultracentrifuge rate separation method. The VMT nanosheets has excellent performance for removal of MB. Moreover, the above green organic solvent regeneration method could be effectively avoided VMT nanosheets agglomeration and stacking compared to the high temperature calcination regeneration method. This unique and scalable exfoliation method is expected to provide a new avenue for the liquid-phase synthesis of various layered materials, environmentally benign and user-friendly ways, such as black scale and MoS\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCONFLICT OF INTEREST\u003c/h2\u003e\u003cp\u003eThe authors don't have any conflict of interest in the publication of the manuscript.\u003c/p\u003e\u003ch2\u003eSUPPORTING INFORMATION\u003c/h2\u003e\u003cp\u003eSupporting figures include additional characterization.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eJinpeng Hou: Conceptualization, Methodology, Software, Investigation, Formal Analysis, Writing-Original Draft, Funding Acquisition,;Yiwen Shen: Visualization, Investigation;Xiangkun Zhang: Data Curation, Writing-Original Draft;Zhong Li: Supervision;Weiliang Tian:Conceptualization, Resources, Supervision, Writing-Review \u0026amp; Editing. Software, Validation;Tonghui Shen: Data Curation;Kewei Zhang: Conceptualization\u003c/p\u003e\u003ch2\u003eACKNOWLEDGEMENTS\u003c/h2\u003e\u003cp\u003eJ. Hou and Y. Shen contributed equally to this work. This work was supported by National Natural Science Foundation of China (Nos. 21761029, 51973099), Open Laboratory of State Key Laboratory of Organic and Inorganic Composites (oic-202301006, oic-202101011), Central Government Guiding Funds for Local Science and Technology Development (Z135050009017, 2022ZY015), Innovation Group Project of Tarim University (Nos. TDZKCQ201901), the Taishan Scholar Program of Shandong Province (Nos. tsqn201812055), Graduate research innovation project of Tarim University (Nos. TDGRI202107).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWang, Z. Y., Zhu, W. 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Y., et al., Preparation and characterization of chitosan nanocomposites with vermiculite of different modification. \u003cem\u003ePolymer Degradation and Stability\u003c/em\u003e, 2009, 94, 2121\u0026ndash;2127.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYou, H., Zhang, K., Zhang, X., et al., Fabrication of transparent ultrathin films with ordered solid luminescence by LBL assembly of CdTe quantum dots with exfoliated vermiculite. \u003cem\u003eApplied Clay Science\u003c/em\u003e, 2022, 230, 106710.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDeng, L., Wang, X., Kuang, Y., et al., Development of hydrophilicity gradient ultracentrifugation method for photoluminescence investigation of separated non-sedimental carbon dots. \u003cem\u003eNano Research\u003c/em\u003e, 2015, 8, 2810\u0026ndash;2821.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"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":"Vermiculite, Exfoliation, Limited space shear, Cut and edge collision, Pollutant adsorption","lastPublishedDoi":"10.21203/rs.3.rs-7503581/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7503581/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWell-defined vermiculite (VMT) nanosheets with promising physico-chemical properties are commercially appealing and urgently required for various applications. However, it is still challenging to realize rapid scalable production in a green and low-cost way. Herein, an ultrasound-triggered limited space shear method is proposed on the base of shear and cut collision mechanism. Exfoliation of well-defined ultrathin VMT nanosheets is achieved quickly and effectively through the synergy of cut collision effects, ultrasonic forces, and shear forces. The productivity and dimension distribution of VMT nanosheets can be readily regulated by varying the rotation space, rotation speed, and shear and cut collision forces, among which the rotation space is the critical factor. The better peeling effect is achieved under smaller rotation space. Compared to the traditional ball mill method, the time required to produce the same amount of VMT nanosheets is accelerated by a factor of 10 times for the ultrasound-triggered limited space shearer. Besides, the usage of water as exfoliated solution avoids subsequent separation process of traditional salt solvent. The colloidal solution of VMT nanosheets could be stably saved for about 6 months. The obtained VMT nanosheets exhibit excellent performance for rapid adsorption of methylene blue (MB), and can be regenerated without agglomeration and stacking of nanosheets. This rapid and high-yield method can be satisfactorily applied in the production of VMT nanosheets and other two-dimensional (2D) layered materials.\u003c/p\u003e","manuscriptTitle":"Rapid exfoliation of well-defined vermiculite nanosheets via ultrasound-triggered limited space shear for pollutant adsorption","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-10 15:31:36","doi":"10.21203/rs.3.rs-7503581/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":"59da9d98-8fcd-40aa-bd5e-6c5c815c8e8b","owner":[],"postedDate":"September 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-18T20:53:20+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-10 15:31:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7503581","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7503581","identity":"rs-7503581","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}