Preparation of Al-loaded magnetic Chinese medicine residue-derived biochar and application of it in fluoride removal
Jingxi Tie, Shuo Sang, Zhenya Shang, Yingqi Li, Zhitao Xu, Molin Lian, Chunbao Du
Abstract
The development and application of new materials for the extreme fluoride pollution problem has drawn increasingly wide attention. Here, Chinese medicine residue, FeSO4.7 H2O, FeCl3.6 H2O and Al(NO3)3 were used as raw materials to create an novel Al-loaded magnetic Chinese medicine residue-derived biochar (Al/Fe3O4/CMRB) adsorbent for effective fluoride adsorption. Al/Fe3O4/CMRB was characterized and used to conduct fluoride adsorption. In the pH range of 4–11, the fluoride adsorption reduced from 37.38 mg/g to 15.84 mg/g. The pseudo-second-order equation and Freundlich equation was the ideal model to describe the adsorption. The thermodynamic study confirmed the spontaneous and exothermic nature of fluoride adsorption by Al/Fe3O4/CMRB. Chloridion, nitrate, and sulfate had no influence on fluoride adsorption when a single anion and all three anions were present. phosphate created a more significant reduction of fluoride adsorption with rising concentrations, whether or not the other three anions were present. Al/Fe3O4/CMRB was an potential composite for aqueous fluoride removal. In addition, Al/Fe3O4/CMRB showed high separation efficiency in a contactless magnetic field, which demonstrated its potential use for large-scale applications in real samples.