Development and characterization of sodium alginate beads incorporating functionalized poly(acrylonitrile-co-styrene)/ carbon nanotubes for effective Fe(II) ion adsorption from aqueous solutions

This study details the development and evaluation of sodium alginate-Poly(acrylonitrile-co-styrene)/ Carbon Nanotubes (SA-M*Poly(AN-co-ST)/CNTs) composite beads serve as a highly effective adsorbent for the removal of Fe(II) ions from water solutions. The composite was prepared through the modification and functionalization of poly(acrylonitrile-co-styrene) copolymer with carboxylic acid groups, Subsequently, carbon nanotubes (CNTs) and sodium alginate were integrated to create sturdy gel beads. The composite beads were characterized using SEM, FTIR, and BET surface analysis spectroscopy, revealing a specific surface area of 127.907 m²/g and a pore size of 18.9 Å, indicative of its enhanced adsorption potential. Batch adsorption experiments showed that under optimal conditions pH = 3.0, 80 min of contact time, and an adsorbent dosage of 40 mg, the maximum Fe(II) removal efficiency reached 90 %, with an equilibrium adsorption capacity of 85 mg/g. Kinetic studies showed chemisorption as the main mechanism, following a pseudo-second-order model, while isotherm analysis aligned with the Freundlich model, indicating multilayer adsorption. Furthermore, the composite exhibited commendable reusability, maintaining 80 % of its adsorption capacity after five regeneration cycles. These findings underscore the composite's potential for practical applications in water treatment, offering a sustainable and effective solution for heavy metal remediation.