Porous sodium alginate/poly (acrylic acid) composites cross-linked with FeCl3 for acid black 1 dye removal from aqueous solution

This study developed a polymeric composite, sodium alginate (SA)/poly (acrylic acid) (PAA) cross-linked with FeCl3 (SA/PAA-Fe), for its function as adsorbent to eliminate acid black 1 dye (AB1) from an aqueous solution. The structural analysis of SA/PAA-Fe revealed a porous structure. To comprehensively evaluate the adsorption of AB1 onto SA/PAA-Fe and gain insight into its mechanism, we examined the effects of solution's pH, initial dye concentration, adsorbent dosage, contact time, and adsorption temperature. The best adsorption conditions for achieving a highly effective removal percentage of 95.43% were a pH of 8.9, contact period of 90 min, and a temperature of 45 °C. Pseudo-second-order and Langmuir models were fitted for the isotherm and kinetic model parameters, respectively. Thermodynamic analyses strongly suggested that the adsorption process occurred was endothermic and spontaneous. The adsorption of AB1 was primarily observed on the solid surface, as confirmed by the SEM-EDS and FTIR measurements.