New low-cost ultrafiltration membrane made from purified natural clays for direct Red 80 dye removal

[Display omitted] •Purification of natural clays using physicochemical process.•Purified clays used for preparation of ultrafiltration layer pozzolan support.•Obtained membranes were applied for decoloration of Direct Red 80 solutions.•Membranes could reject between 97 and 99% of Direct Red 80.•Low-cost ultrafiltration membranes were successfully prepared from purified clays. This work aims to develop novel ceramic ultrafiltration membranes made from purified natural Moroccan clays. Two raw clays namely Clay A (smooth aspect) and Clay B (rough aspect) were purified via physicochemical treatment. Chemical and mineralogical characterizations demonstrated that obtained purified clays are richer in clayey minerals such as smectite, kaolinite and illite. Thin selective layer was deposed on pozzolan support via spin-coating method using purified clay suspensions and sintered at 800 °C. Prepared membranes were deeply investigated using scanning electron microscopy, pore size, water permeability, and antifouling characterizations. As results, the average pore size is found to be 75 and 90 nm respectively for Clay A and Clay B membranes while the permeability is equal to 14.7 and 16.4 L/h.m2.bar respectively for Clay A and Clay B membranes. The obtained membranes were applied for tangential filtration of Direct Red 80 solution with concentration of 50 ppm under pressure of 3 bar. Experimental results demonstrate that dye rejection could achieve a value of 99 and 97% respectively for Clay A and Clay B membranes. Based on promising filtration results, it can be suggested that prepared UF membranes could be efficiently applied for dyes removal from colored wastewater generated from textile industries.