Fabrication and characterization of the novel tubular ceramic membrane using walnut shells and its application in TiO₂ nanoparticles separation from suspension

Low-cost ceramic membranes have become highly popular in water treatment and gas separation industries. This study focuses on creating an affordable yet efficient ceramic membrane for effective separation processes. The cost-effective fabrication process combines locally sourced raw materials with optimal manufacturing techniques, resulting in minimal production expenses. To create this unique, low-cost ceramic membrane, a mixture of kaolin, quartz, and additives like zirconia and dolomite is used in shaping and sintering procedures. Walnut shell powder serves as a pore-forming agent, while carmellose sodium acts as a membrane-binding agent. The membrane is prepared through extrusion with dimensions of 110 mm in length and 12 mm in diameter, and it is sintered at temperatures of 850 degree celsius, 900 degree celsius, and 950 degree celsius. Various analytical methods, including FESEM, XRD, and TGA, are employed for comprehensive characterization. The water flux increased with increasing pressure (54-215 kPa), and the pore diameter obtained from the test was consistent with the pore size obtained from FESEM. The membranes' pore size increases with higher sintering temperatures while porosity decreases. The membrane demonstrates mechanical strength, chemical stability, and high rejection efficiency in TiO2 separation. The total cost of one tubular membrane comes out to be $112 per square meter.