Removal of toxic elements from aqueous environments using nano zero-valent iron- and iron oxide-modified biochar: a review

Abstract Biochar (BC) has gained attention for removal of toxic elements (TEs) from aqueous media; however, pristine biochar often exhibits low adsorption capability. Thus, various modification strategies in BC have been developed to improve its capability against TEs. Nanoscale zero-valent iron (nZVI) and oxides (FeOx) used as sorbents TE removal. However, these materials are prone agglomeration also expensive, which make their usage limited large-scale applications. The nZVI technical demerits could be resolved by the development BC-based composite through loading or FeOx onto surface. Nano modified (nZVIBC), FeOx-modified (FeOxBC) attracted removing pollutants phases. Nonetheless, a potential use nZVIBC FeOxBC environments not well-realized reviewed. As such, this article reviews: (i) preparation characterization FeOxBC; (ii) capacity retention line with physicochemical properties, (iii) mechanisms FeOxBC. Adopting increases sporptive TEs due surface modifications morphology, functional groups, elemental composition. combined effects nZVI, Fe salts on sorption complex because they very specific This review identified significant opportunities research technology advancement novel effective remediation contaminated water.