Adsorption behavior and mechanism of Cr(VI) by modified biochar derived from Enteromorpha prolifera

Biochar that was derived from Enteromorpha prolifera and magnetically modified (BCF600) was evaluated for its physicochemical properties and Cr(VI) adsorption behavior and mechanism. The results showed that the modified biochar was less porous on surface and loaded with γ-Fe2O3 particles. BCF600 exhibited a maximum adsorption capacity for Cr(VI), which acquired from the Langmuir model of 88.17 mg g-1 and a removal efficiency of 97.71%, for 100 mg L-1 of Cr(VI). The adsorption of Cr(VI) by BCF600 decreased with increasing pH and background ion intensity. Based on the FTIR results, the change in the -OH groups on the surface after adsorption confirmed that electrostatic interaction was likely the preponderant mechanism. In addition, the BCF600 could be easily separated using a magnet and displayed high recyclability. Therefore, this magnetic biochar derived from Enteromorpha prolifera has the potential to serve as a highly efficient adsorbent for water pollution control.