Removal of copper and lead ions from rainwater with an alginate-bentonite composite: batch and column studies

The study was conducted on a laboratory scale and the main objective was to evaluate the feasibility of using bentonite and calcium alginate-based granules to adsorb pollutants from rainwater in a columnar system. Therefore, in this study, the fine powder of clay materials was mixed with calcium alginate to obtain capsules that can be easily separated and recovered. These granular sorbents were found to be a new and inexpensive solution for removing heavy metals from water. On the basis of the pollutant adsorption study, the sorption capacities of the adsorbent and bed, adsorption rates, and bed breakthrough time were determined. Characterisation of the structural features of the granules using modern observational and spectroscopic techniques, that is, scanning electron microscopy, Brunauer–Emmett–Teller, and Fourier-transform infrared spectroscopy, was also an important part of the study. The aim of the study was to conduct the adsorption process under dynamic conditions to determine the efficiency of removing copper and lead ions from rainwater. Static adsorption showed a high percentage of copper removal of 72.75% and lead removal of 84.5% for a dose of 2.0 g/L. The column adsorption system showed a high removal rate. Regeneration showed a high efficiency of copper and lead adsorption. In the fourth cycle in the case of Cu(II), 60%, column 2-52.5%, column 3-30%, for Pb(II) for column 1-73%, column 2-76%, column 3-50% were obtained.