Removal of heavy metals from domestic wastewater using Beneficiated Kaolin Clay, Silver Oxide and zinc Oxide nanocomposite

This study describes the removal of total iron, cadmium, lead, copper, manganese, arsenic, mercury silver and zinc from domestic wastewater disposed of via sewers, using Beneficiated Kaolin Clay (BKC), BKC/Ag, BKC/ZnO and BKC/Ag/ZnO nanocomposite adsorbents produced by blending Silver Oxide (Ag) and Zinc Oxide (ZnO) nanoparticles with kaolin clay. High Resolution Transmission Electron Microscope (HRTEM) results showed that the produced adsorbents were polycrystalline in nature, while the interplanar spacing and average crystalline sizes are 1.775 – 4.712 nm and 26. 834 – 40.258 nm respectively, according to X-Ray Diffractometer (XRD) analysis. The Dispersive X – Ray Fluorescence (XRF) analysis indicated that SiO2/Al2O3 ratios for BKC/Ag, BKC/ZnO and BKC/Ag/ZnO nanocomposites adsorbents were 1.5170, 1.4818 and 1.5231 respectively. Brunauer – Emmett – Teller (BET) analysis showed that the desorption average pore sizes fell in the mesopore widths of 13.8994 – 16.9233 nm and surface areas of 1.0545 - 14.5126 m2.g-1. The removal efficiencies of the produced adsorbents followed this trend: BKC/Ag/ZnO > BKC/Ag > BKC/ZnO > BKC. These adsorbents were excellent in the removal of total iron, cadmium, lead, copper, manganese, arsenic, mercury silver and zinc pollutants from domestic wastewater, and hence, recommended for large scale production.