Chlorella sp. EPS loaded alginate microsphere: A novel bionanomaterial for adsorptive removal of sulfamethoxazole from the aqueous solutions

Microalgae exopolysaccharide (EPS) emerge as a sustainable and ecologically robust approach for wastewater treatment, leveraging their inherent capabilities for the adsorption and efficient removal of pollutants. This study proposes novel microalgae EPS polymerized with alginate to form an adsorbent microsphere that can efficiently remove sulfamethoxazole (SMX) from water. The EPS extracted from Chlorella sp. contains different functional groups like amides and polysaccharides that play a significant role in SMX adsorption. FT-IR and 3D-EEM analysis showed that electrostatic attraction is the primary binding force in the adsorption process. The decrease in both the TOC (total organic carbon) value of the SMX solution and its toxicity confirmed the effective adsorption of SMX. When the pH was 7.0, the composite weight was 30 g, and the SMX concentration was 10 mg/L, over 90% of SMX was removed in 90 min. The batch study showed that the pseudo-first-order kinetics and Langmuir adsorption isotherm model fit best. Column studies also showed the potential for semi-industrial scale-up, achieving 98% removal in 800 min, and fitting well to the Adams-Bohart column kinetic model. These conditional changes increase surface area, porosity, and specific binding affinities, optimizing antibiotic remediation by improving adsorption kinetics and responsiveness to environmental conditions. The EPS-alginatemediated adsorption process is safe-by-design and economical, making the proposed composite adsorbent material highly efficient.