Fresh biomass derived biochar with high-load zero-valent iron prepared in one step for efficient arsenic removal

Biochar composites, as a kind of common adsorption and purification materials, are usually prepared by carbonizing biomass firstly and then loading with adsorbent. In this study, an innovative facile one-step pyrolysis-loading process was proposed to synthesize a magnetic high-loading zero-valent iron/biochar composite (BC-ZVI) directly from fresh bamboo immersed with FeCl3 solution. Based on fresh biomass, the BC-ZVI composites have an iron load of 18.5%–30.9% and a well-defined nanoporous structure, providing abundant active sites for interface-related processes. Experiments show that BC-ZVI is effective for removing As(III) and As(V) in a wide pH range and in the presence of competing ions. The adsorption capacity of BC-ZVI reaches 129.24 mg g−1 for As(III) and 127.15 mg g−1 for As(V), respectively. The adsorption mechanism was explored and discussed basing on the detailed spectroscopy analysis. Additionally, BC-ZVI showed favorable magnetic recovery and reusability in different water matrix, which demonstrates a potential candidate in removing arsenic from environment water. The proposed fresh biomass-derived one-step pyrolysis-loading approach could inspire low-cost and facile production of functional biochar composites.