Effective removal of Cr(vi) from aqueous solution by biochar supported manganese sulfide.

In order to remove hexavalent chromium (Cr(vi)) efficiently and simplify the adsorbent preparation process, we employed a single step method to prepare a new biochar supported manganese sulfide material. The nanoscale MnS particles were highly soldered on the biochar support surface, and this adsorbent displayed the effective removal of Cr(vi) (98.15 mg L) synergistic effect between adsorption and reduction/precipitation under weak acid conditions (pH = 5.0-6.0). The adsorption kinetic data were described well by the pseudo second-order kinetic model, suggesting that the reaction process was a chemisorption process. The adsorption isotherm data were described well by the Redlich-Peterson model, further suggesting that this reaction was a hybrid chemical reaction-sorption process. In addition, the Dubinin-Radushkevich isotherm model with 8.28, 8.57, and 12.91 kJ mol adsorption energy also suggests that it was a chemisorption process. The simple and eco-friendly preparation process, low-cost, and the high removal efficiency could make it a promising material for the purification of Cr(vi)-contaminated wastewater.