Enrichment and Recovery of Cr(VI) from Aqueous Solution via a Monolithic Loofah Sponge Modified by Tannins and Arginine

In this study, a monolithic loofah sponge (LS) matrix, which was pretreated by hemicellulase and decorated by amino and guanidine, was successfully endowed with two functions: adsorption and recovery for Cr(VI). As an adsorbent, the modified LS (LS–TAA) has a high adsorption capacity (327.91 mg/g) for Cr(VI), and can be handily reused because of its integrity, good mechanical strength and convenient separation from aqueous solution. As a carrier, the residue of Cr-loaded LS–TAA was discovered to be pure Cr2O3 nanoparticles after calcination. The effect of hemicellulase pretreatment and influencing factors, adsorption kinetics, thermodynamics and isotherm adsorption models were investigated. The samples were characterized by various means including SEM, EDX, FT–IR, XRD, XPS and TEM. The results demonstrated that the LS–TAA should be viewed as a low-cost environment functional material with application potential to treat Cr-polluted wastewater.