Sustainable Biopolymer and Basalt-Derived Filters for Enhanced Water Purification

This study aimed to develop environmentally friendly and sustainable water purification techniques by developing chitosan beads, alginate beads and PAA-modified basalt, and subsequently evaluating their removal performance against heavy metals (Co, Cd, Cu, Pb) and emerging contaminants (MC-LR and microplastics). Surface functional groups of the sorbents were characterized using FT-IR, while adsorption experiments were conducted to determine removal efficiencies and propose underlying mechanisms. The results demonstrated that chitosan beads effectively removed Cu2+ and MC-LR through electrostatic interactions and hydrogen bonding of amine groups. Alginate beads exhibited superior performance for Cd2+ and Pb2+ removal, attributed to ion-exchange reactions mediated by abundant carboxyl groups. PAA-modified basalt achieved the highest efficiency for Co2+ and microplastic removal, driven by its porous structure, high surface area, and introduced carboxyl functionalities. Overall, these findings highlight the critical role of interactions between the physiochemical properties of pollutants and the surface functionalities of sorbents and suggest that hybrid sorbent systems may provide an effective strategy for addressing complex, multi-pollutant water environments.