One-step preparation of lignin-based magnetic biochar as bifunctional material for the efficient removal of Cr(VI) and Congo red: Performance and practical application

The lignin-based magnetic biochar (LMB) was fabricated with a facile one-step solvothermal method. The spherical Fe3O4 was successfully loaded on the lignin-based biochar. LMB could efficiently remove Cr(VI) and Congo red (CR) synergistically with the adsorption of biochar and the catalytic/reduction of Fe3O4. LMB showed a removal efficiency of 100 % for Cr(VI) (100 mg/L) at 30 min. The LMB could be a catalyst to activate persulfate (PS) to degrade CR. The LMB + PS system showed a removal efficiency of 94.3 % for CR at 60 min. Moreover, LMB could simultaneously remove 41.5 % of Cr(VI) and 91.5 % of CR in the mixed Cr(VI) and CR solution. The simulated wastewater studies showed that LMB exhibited superior high Cr(VI) (100 %) and CR (82 %) removal efficiencies with the coexistent of anions, cations, and organic matter. LMB can be effectively applied to remove Cr(VI) and CR and purify different contaminated water bodies.

Automated summary

The lignin-based magnetic biochar (LMB) was prepared using a simple solvothermal method. Fe3O4 spheres were loaded onto the lignin-based biochar. LMB exhibited efficient removal of Cr(VI) and Congo red (CR) through the adsorption of biochar and the catalytic/reduction of Fe3O4.