Recyclable hydrogel beads from sodium alginate@cellulose/GO for aqueous solution purification from heavy metals

An improved adsorption capacity was achieved in a new composites of recyclable adsorbents made of cellulose, alginate, and graphene oxide (SA/Cell./GO). To purify water systems of heavy metals, sustainable materials such as pulp fiber and cellulosic biomass cellulose, and cost-effective polymers alginate and graphene oxide with a high adsorption capability, were utilized. The as-synthesized hydrogel beads were characterized using HRSEM, EDX, XRD, and FTIR-ATR techniques. Batch adsorption experiments of lead and cadmium in water were used to assess the adsorption properties of SA/Cell./GO hydrogel beads. This study looked at how different factors such initial metal concentration, pH, temperature, adsorbent dosage, contact time, and adsorption dosage affected metals adsorption. At a pH of 5.5 and an adsorbent dosage of 0.6 g/L, the results reveal that the removal effectiveness of cadmium ions reached 99.5% after 60 min, while the removal efficiency of lead ions reached 100% after 40 min. An adsorption mechanism and kinetics model based on pseudo-first-order kinetics was the most fitted. Results from equilibrium adsorption experiments were consistent with the Freundlich adsorption isotherm. Pre- and post-adsorption HRSEM, EDX, XRD, and FTIR-ATR analyses verified that SA/Cell./GO was highly effective for adsorbing Cd and Pb metals, simultaneously.