Removal of Pb2+, Cd2+, and Cu2+ from phosphoric acid solution using the chitosan-modified natural zeolite

Sorption ability of the chitosan‐modified natural zeolite for Pb2+, Cd2+, and Cu2+ cations was investigated. The influence of time and concentration of heavy metals on their sorption from concentrated (85% H3PO4) phosphoric acid was determined. At 20 and 40 min of sorption curves, there are a number of maxima probably due to desorption of cations from the sorbent into the acid. According to the results, sorption of the modified zeolite for lead cation is the least in the whole interval of time. In the case of equal concentrations of all cations (CPb = CCd = CCu), sorption of lead, cadmium, and copper was 94.81–95.09%, 96.55–97.50%, and 97.53–98.14%, respectively. Sorption curves in the case of equal Pb2+ and Cd2+, but higher concentrations of Cu2+, are the same for all cations. Sorption of cadmium varies from 95.48% to 97.55%. Copper and lead sorbed in a less amount, in the case of (СРb = СCd