Enhanced adsorptive removal of carbendazim from water by FeCl3-modified corn straw biochar as compared with pristine, HCl and NaOH modification

Carbendazim residues were widely present in the worldwide water which caused a potential risk to water ecosystem and human health. Therefore, it is necessary to develop environmentally friendly ways to eliminate its residue in the contaminated water environments. Herein, the corn straw biochars were prepared at 300 (BC300), 500 (BC500), and 700 °C (BC700). Moreover, using BC700 as precursor, three novel adsorbents of acid, alkali, and iron magnetization modified biochar (named as BC700H, BC700N, and BC700M, respectively) were synthesized to adsorptive removal of carbendazim from water. Results showed that the adsorption capacity of six biochar materials for carbendazim was in the following order BC700M>BC700H>BC700N>BC700 >BC500 >BC300. The maximum adsorption amount of BC700M reached up to 108.1 mg g−1. The adsorption of carbendazim was a spontaneous, endothermic, and randomly increasing process, while both physisorption and chemisorption were involved in adsorption process for all prepared biochar materials. For BC700M, pore filling, π-π interaction, oxygen-containing groups, and Fe-O complexation were main mechanisms. The BC700M can be easily separated and regenerated at least five times under a wide pH range. Overall, as compared to the other five biochar materials, this study indicates that Fe-modified corn straw biochar is a promising and sustainable adsorbent for carbendazim removal from water environment.