Synthesis of  ZnO/Zeolite from Coal Fly Ash and its Utilization for Clindamycin Adsorption

Abstract This research aims to obtain FA-based zeolites modified with zinc oxide (ZFA-ZnO) to adsorb the antibiotic clindamycin. The method used in this research was hydrothermal synthesis using an autoclave to obtain ZFA-ZnO and a batch system was used for adsorption capacity measurements. ZFA-ZnO was characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM-EDS). The analyses of the clindamycin solution were conducted using an Ultraviolet-Visible (UV-Vis). Based on the results of XRD and SEM characterization, the best synthesis conditions were obtained at a temperature of 160oC for 9 h as indicated by an increase in the zeolite and ZnO crystal phases and a smaller average particle size. Magnetic ZFA-ZnO at a temperature of 160oC (ZFA-ZnO160 M) is a type of zeolite with the highest adsorption percentage, namely, 89.41%. Adsorption data shows that the optimum pH for adsorbing the antibiotic clindamycin is pH 6 with an adsorption percentage of ZFA160 M of 82.43% and ZFA-ZnO160 M of 94.5%. The adsorption isotherm data for ZFA160 M best fits the Langmuir model, while for ZFA-ZnO160 M fits the Redlich Peterson isotherm model. The adsorption mechanism is thought to occur in a monolayer through the interaction of active Si-O functional groups on the zeolite as proven by functional group absorption analysis using FTIR.