Selective removal of zinc from single and industrial aqueous solutions using ecologically sustainable ceramic adsorptive aggregates

This research endeavors to develop ecologically sustainable ceramic adsorptive aggregate (CAAs) for zinc removal via adsorption techniques. The study synthesized three distinct CAAs employing natural zeolite (65 wt%), nanoclay (15 wt%), spent coffee grounds (15 wt%), and FeSO₄.7H₂O (5 wt%). The characterization of these CAAs included assessments of particle and bulk densities, specific surface area (SSA) and total porosity. The findings revealed particle densities ranging from 2.60 to 2.73 g/cm³, bulk densities between 0.54 and 0.64 g/cm³, SSAs from 40 to 90 m²/g, and total porosities of 49.6 to 60.9%. The adsorption kinetics were consistent with pseudo-second order and Elovich models, while the isotherm data were best described by Freundlich and Redlich-Peterson models. The CAAs demonstrated substantial Zn adsorption capacities, varying from 20 to 29.48 mg/g. Moreover, the application of CAAs proved effective in the removal of zinc and other metals from steel mill wastewater, suggesting that these aggregates represent a viable, cost-effective, and environmentally benign solution for wastewater treatment and various other environmental applications.