Synthesis of iron modified rice straw biochar toward arsenic from groundwater

The potential of Fe modified biochar (BC) as an alternative, inexpensive adsorbent for removing As(V) from wastewater was investigated. BC was synthesized from the slow pyrolysis of rice straw and then modified with FeCl₃. The result from FTIR and SEM-EDX demonstrated that Fe had loaded successfully on the surface of biochar. In comparison to the raw biochar, the Fe modified BC not only had stronger magnetic property but also showed much greater ability to remove As(V) from aqueous solution. The Fe modified BC showed a maximum adsorption with an initial solution pH of 5.0. The adsorption data were better fitted with the Langmuir isotherm and pseudo-second kinetic model. The maximum adsorption capacity (q_max) by the modified BC, based on the Langmuir isotherm, was 26.9 mg g⁻¹. The Fe-modified BC can be an effective, inexpensive, and environmentally sustainable adsorbent to replace typical granular activated carbons (AC) commonly utilized in the treatment of arsenic-contaminated wastewater. (paper)