Removal of hexavalent chromium from aqueous systems using jujube tree branch biochar-loaded nano zero-valent iron

Abstract This study developed a composite material (JBC-nZVI) using jujube tree branch biochar (JBC) to support nano zero-valent iron (nZVI) for hexavalent chromium (Cr(VI)) removal from aqueous solutions. The porous structure of JBC improved nZVI dispersion, reducing aggregation and enhancing reactivity and stability. The composite was characterized using SEM-EDS, BET, FT-IR, and particle size distribution analysis. Under optimized conditions (50 mg/L Cr(VI), pH 3, 1 g/L dosage), JBC-nZVI achieved 88.7 % Cr(VI) removal in 120 min. Kinetic studies showed the removal followed a pseudo-second-order model, with chemical adsorption as the main process. JBC-nZVI facilitated electron transfer between Cr(VI) and nZVI, promoting the reduction process. XRD and XPS analyses revealed that Cr(VI) removal involved adsorption, reduction, and coprecipitation. This composite not only provides an efficient method for Cr(VI) remediation but also valorizes jujube tree branch biomass waste, enhancing nZVI stability and offering a novel approach for environmental cleanup.