Preparing Sustainable Membranes Made From Zeolite–Smectite for Treating Textile Wastewater and Pulp Industry Wastewater

Abstract

Low-cost separation techniques are crucial for treating wastewater. Developing inexpensive membranes made from natural materials has become a popular research area in recent years. Tubular membranes were produced by adding 10% organic additives to a mixture of 80% zeolite and 10% smectite. New composite ceramic membranes from zeolite and smectite were prepared using the extrusion method to create a plastic paste and characterized using XRD, SEM, EPMA, and FTIR. The impact of sintering temperature (T_sint, 850–950 °C) on membrane properties, such as microstructure, mechanical strength (MS), water permeability, and filtration performance, was investigated. The MS and shrinkage rate increased with T_sint. At 950 °C, the resulting composite membrane exhibited a high MS of over 65 MPa, a relatively low porosity of 30%, appropriate for membrane filtration, and a water permeability of 65 L·h⁻¹·m⁻²·bar⁻¹. When applied to remove pollutants from wastewater, this membrane demonstrated a high color retention of 98.4% from an aqueous Evans blue-colored solution (Effluent 1). For extensive application to wastewater treatment, this membrane showed a high-efficiency level for treating real effluent produced by the pulp industry, removing 62.4% of chemical oxygen demand, 36% of hardness, and 82% of color. Finally, an ultrasonic cleaning procedure allowed the restoration of 70% of the initial permeability after four cycles for both effluents. Thanks to the exciting properties offered by these membranes and their competitive cost of less than $ 20·m⁻², these membranes are appropriate for treating industrial wastewater.