Hydrothermally magnetic particles fabricated hydrocalumite based biopolymeric composites for toxic chromium removal

Hexavalent chromium is an emerging environmental pollutant that leads to various effects on living organisms. The developed clay material, hydrocalumite (HC) possesses promising chromium adsorption capacity but because of its powder form it cannot be used in column studies. Hence, it is aimed to prepared HC in an usable hybrid bio-composite form by dispersing HC in biopolymeric matrixes like chitosan (CS) and cellulose (Cel) as HCCS and HCCel bio-composites for Cr(VI) removal from water. For quick separation after adsorption, the magnetic particles sprayed HCCS (Fe₃O₄@HCCS) and HCCel (Fe₃O₄@HCCel) bio-composites were prepared which possess high adsorption capacity. Different instrumental techniques like FTIR, SEM, and EDAX studies were used to examine the synthesized magnetic bio-composites in order to determine their physicochemical properties. The promising adsorbents namely Fe₃O₄@HCCS and Fe₃O₄@HCCel bio-composites were examined for Cr(VI) removal in batch mode. The maximum chromium adsorption capacity of Fe₃O₄@HCCS and Fe₃O₄@HCCel bio-composites were found at 43.4 mg/L and 31.8 mg/L, respectively within 45 min. The Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) isotherms were used to reinterpret the equilibrium data of the synthetic magnetic bio-composites. According to the thermodynamic findings, chromium adsorption onto magnetic bio-composites is an endothermic and spontaneous reaction. The NaOH solution makes it simple to regenerate the chromium adsorbed magnetic bio-composites, which can be successfully employed upto four times. The synthesized Fe₃O₄@HCCS and Fe₃O₄@HCCel bio-composites act as efficient adsorbents for chromium removal.