Immobilization of a highly efficient adsorbent in biopolymer hydrogel beads with an established interconnected network explored for selective dye adsorption

Abstract

The removal of persistent and toxic dyes from wastewater is a significant environmental challenge. The present demonstrates the preparation of a novel composite adsorbent from reduced graphene oxide (RGO) and bentonite, encapsulated in sodium alginate beads (SA/RGO/BENT), for the adsorption of methylene blue. GO was effectively reduced to RGO using choline hydroxide as a green solvent and catalyst, producing a negatively charged adsorbent surface that enables selective adsorption of cationic dyes. Adsorption experiments were conducted to evaluate the effects of pH, adsorbent dosage, contact time, and initial dye concentration on the adsorption capacity. Experimental results demonstrated that SA/RGO/BENT beads exhibit remarkable adsorption capacity, achieving removal efficiencies of up to 97.92%. The adsorption process follows pseudo-second-order kinetics and Langmuir adsorption isotherm. Furthermore, the study explores the feasibility of scaling up the adsorption process and discusses its potential applications in wastewater treatment. Overall, this research provides valuable insights into sustainable methods for removing methylene blue from wastewater, emphasizing the potential of adsorption technology for environmental remediation.