Adsorptive removal of potentially toxic metals (cadmium, copper, nickel and zinc) by chemically treated laterite: Single and multicomponent batch and column study

Efficiency of chemically treated laterite was tested to remove, copper, cadmium, zinc and nickel (potentially toxic metals) from drinking water. Infrared spectroscopy confirms the uptake of these contaminants by treated laterite. Optimum treatment parameters are observed at 10 mg/L adsorbent concentration, 0.26 mm particle size and pH range of 6-9. Maximum uptake capacities are observed to be 3.7 mg/g (0.03 mmol/g), 2.8 mg/g (0.04 mmol/g), 2.8 mg/g (0.04 mmol/g) and 2 mg/g (0.03 mmol/g), for cadmium, copper, zinc and nickel, respectively. Adsorption was endothermic and physical in nature. Fixed bed column study was carried out using a multicomponent feed having concentration 5 mg/L of each potentially toxic metal, and the effect of bed depth and flow rate were observed. Corresponding to a specific process condition, saturation was faster for nickel followed by zinc, cadmium and copper. The column was also tested for a real-life toxic metal contaminated river sample, collected from Yamuna River, New Delhi (GPS location 30 degrees 54/N and 76 degrees 59/E).