Fabrication and characterization of coated ceramic membranes from natural sources for water treatment applications

Abstract

This study aimed to fabricate ceramic membranes for water treatment applications using natural and cost-effective materials. This is the first-time white clay, Arabic gum, and marble powder were used in ceramic membranes. Two ceramic membranes were fabricated using an extrusion process: substrate A and substrate B. The JMP software (Version 15) was used to obtain the optimal recipes for the two substrates, which were white clay (62.7 %), silica flour (32.3 %), and Arabic gum (5 %) for substrate A and white clay (63 %), silica flour (26.8 %), and marble powder (10.2 %) for substrate B. Additionally, the effect of waste glass in the coating layer on the separation rate was examined. The ceramic membranes were analysed using various techniques, including X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), laser diffraction particle size analysis, thermogravimetric analysis (TGA), and a universal testing machine. The morphologies of the membranes were observed using scan electron microscopy (SEM), and their chemical resistances were evaluated. The flux across the substrates was measured using a crossflow filtration system, and it was found that substrate B had a higher flux (116 L/m2h) than substrate A (77 L/m2h). This was probably due to its higher porosity (34 %) compared to substrate A (29 %). Substrate A, with a coating layer (CO-2), exhibited the highest removal efficiency of approximately 99.2 % for synthetic feed water composed of tap water and bentonite clay, with an average particle size of 1.1 μm and turbidity of 13 ± 0.2 NTU. The costs of ceramic membranes A and B were estimated to be approximately 51 and 47 USD/m2, respectively. Their cost-effectiveness results from the use of low-cost materials that do not require high sintering temperatures. This study demonstrates that these ceramic membranes are not only affordable but also possess desirable properties for water treatment applications.