Preparation of Ce/Ferroferric Oxide/food waste-derived biochar for aqueous Cr(VI) adsorption

Abstract Hexavalent chromium Cr(VI) causes serious damage to human health. In this study, food waste (FW) was used as raw material to prepare the food waste-derived biochar (FWB), which was further modified using Ce and Fe2+/Fe3+ co-precipitation to obtain Ce dopped magnetic waste-derived biochar (Ce/Fe3O4/FWB ) material for the efficient Cr(VI) adsorption. The morphology, structure, and characteristics of Ce/Fe3O4/FWB composite were thoroughly investigated, and its Cr(VI) uptake behavior was explored. Ce/Fe3O4/FWB showed the best Cr(VI) adsorption of 20.4 mg/g at pH 2.Additionally, the adsorption suited the pseudo-second-order kinetic equation and the Langmuir equation, and the intra-particle diffusion the main step limited the Cr(VI) adsorption by Ce/Fe3O4/FWB. The thermodynamic investigation discovered that the adsorption owned a spontaneous and endothermic nature. With increasing concentrations of Cl-, SO42- and PO43-, the Cr(VI) uptake was weakened in the sequence of Cl- ＜SO42- ＜PO43-. Adsorbent preparation for Cr(VI) removal utilizing FW as a raw material is a sustainable and environmentally beneficial technology for FW reclamation and Cr(VI)-bearing wastewater treatment.