Enhanced adsorption of rhodamine B from water by Fe-N co-modified biochar: Preparation, performance, mechanism and reusability

To adsorb rhodamine B (RhB) in wastewater by pristine biochar was limited, while the modified biochar has shown great potential adsorption performance. Here, coconut shell mixed with FeSO4 center dot 7H(2)O and urea was prepared to synthesize Fe-N co-modified biochar by once pyrolysis method at 500 degrees C. The results showed Fe-N-BC had larger surface area (972.8714 m(2).g(-)(1)), higher developed porous structure (0.65016 cm(3) .g(-)(1)), and more oxygen-containing groups, which collectively contributed to significantly improve the adsorption performance of the Fe-N-BC towards RhB. The maximum adsorption capacity of RhB reached 12.41 mg.g(-1) by Fe-N-BC which was 1.58, 1.43 and 1.26 folds than that of BC, N-BC and Fe-BC, respectively. The mechanism of adsorption for Fe-N-BC towards RhB including ion exchange, pore filling, surface complexation, H-bond and pi-pi interaction. This study indicates that Fe-N-BC is an excellent adsorbent for RhB removal from wastewater.

Automated summary

This study successfully synthesized Fe-N co-modified biochar using a one-step pyrolysis method, demonstrating significantly improved adsorption performance compared to other types of biochar, with higher adsorption capacity and excellent adsorption mechanisms.