Removal of Lead (Pb) Ions by using the Integral Membrane Incorporated with Silica from Rice Husk Ash

Lead (Pb2+) is one of the most toxic heavy metals, causing significant physical, biochemical, and behavioural health issues in humans. Sustainable water management practices and technologies have become crucial as clean water sources diminish. Membrane separation, a chemical-free and cost-effective method, has emerged as the preferred solution, offering economic and environmental benefits. This research focused on utilizing silica from rice husk ash as a cross-linker in the membrane formulation made from a blend of chitosan/polyvinyl alcohol/polysulfone. Chitosan is widely used as an adsorbent for removing heavy metals due to the hydroxyl and amino groups in its structures. This study examines the effect of silica incorporation in the membrane formulation on membrane properties and the removal of lead ions, focusing on various loadings of 1, 4, and 7 wt.%/wt. polymer. The properties were investigated using thermal gravitational analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), and membrane filtration experiments. TGA analysis and FTIR spectrum results showed that introducing silica from rice husk ash (RHA) particles enhanced the membranes' thermal stability and crosslinking structure. The performance results showed that the presence of silica substantially improved permeate flux, percentage removal of lead ions, and antifouling properties. This is because the silica in the RHA particles enhanced the membrane's hydrophilicity, which improves water absorption and permeation rates. 7 wt.%/wt. polymer of silica is the best formulation that removed 94% of the lead ion with the highest water flux and displayed the average antifouling performance with the relative flux recovery (RFR) of 40.26%. The formulated membrane has the potential to be used in wastewater treatment for the removal of lead ions.