Adsorption of Lead, Cadmium and Zinc Ions from Industrial Wastewater by Using Raw Clay and Broken Clay-Brick Waste

摘要

This work studies the adsorption process of lead, cadmium and zinc on clay and clay-brick powders.The adsorption process was affected by various parameters, such as contact time, pH value of metal ions in solutions, the adsorbent mass and metal concentration. The kinetics and the maximum capacity depend on the type of the material ions (atomic weight, atomic radius and electronegativity). The uptake percentage reaches equilibrium state after 160 min for lead and cadmium and 120 min for zinc on clay-brick powder, while it reaches the equilibrium state after 140 min for lead, 160 min for cadmium and 120 min for zinc on clay powder. The uptake percentages of Pb. Cd and Zn increases with the increase pH-value. The sequence of adsorption capacities for lead, cadmium and zinc at constant pH is recorded in the order:lead > cadmium > zinc. The lead, cadmium and zinc removal percentages are, respectively 69, 22.7 and 12.9 %, by using clay powder at pH = 6; while they are, respectively 77.3, 29.48 and 13.5 %, by using clay-brick powder at the same pH.