A granular chitosan adsorbent modified with Cu(II) for effective sulfate groundwater remediation

Abstract

Sustainable treatment of sulfate contaminated groundwater is a challenging global water security issue that significantly impacts human and ecosystem health. Herein, the utility of a recently developed granular chitosan-Cu(II) biocomposite adsorbent (CP-Cu) for the adsorption of sulfate from environmental groundwater systems is reported. Several types of groundwater samples (Wells-1, -2, -3 and -4) were investigated for sulfate removal via a fixed-bed column, characterized by kinetic adsorption parameters in laboratory and groundwater samples. The lowest exhaustion time for CP-Cu was observed for Well 3, due to its high sulfate concentration of 6772 mg/L. In turn, the adsorption capacity under dynamic conditions for Well 3 was the highest (153 mg/g) compared to the other groundwater samples. Modeling of the experimental sulfate removal under dynamic conditions was achieved using the Thomas, Yoon-Nelson, and Adam-Bohart models. The best-fit results showed that the Thomas and Yoon-Nelson model described the breakthrough curves favourably, as compared with the Adam-Bohart model. The prediction of the sulfate adsorption capacities by the Thomas model are in close agreement with the experimental results. This study contributes to the field of surface and interfacial processes through the adsorption of sulfate for a unique type of granular modified chitosan-Cu(II) bioadsorbent system to afford sustainable and efficacious treatment of environmental groundwater.