Removal of Cr(VI) from Acid Wastewater by BC/ZnFe2O4Magnetic Nanocomposite via the Synergy of Absorption-Photocatalysis

Photocatalysis is a promising solar energy conversion technology due to its potential applications in water treatment, searching for highly efficient photocatalytic materials is highly desirable. Herein, we have prepared a series of biochar(BC)/ZnFe(2)O(4)magnetic nanocomposites by the calcination-hydrothermal two-step method. BC/ZnFe(2)O(4)owns improved photoabsorption from 400 to 1300 nm. PL spectra of BC/ZnFe(2)O(4)shows a weaker intensity compared with BC and ZnFe2O4, and BC/ZnFe(2)O(4)generates a stronger photocurrent density (similar to 0.08 mu A cm(-2)) than that of BC (0) or ZnFe2O4(0.03 mu A cm(-2)) under the visible light irradiation, implying efficient separation efficiency of photogeneration carriers. The investigation of pH (3, 5, 7, 9, 11) sensitivity of BC/ZnFe(2)O(4)demonstrates that removal efficiency of Cr(VI) achieves the highest rate at pH=3. Under visible light irradiation, BC/ZnFe(2)O(4)as photocatalyst can remove 80 % Cr(VI), higher than that of BC (0) or ZnFe2O4(44 %). In addition, BC/ZnFe(2)O(4)composites exhibit excellent cycling stability and can be easily separated for recycling due to its stability and unique magnetic properties. This work has presented a promising strategy in adsorption-photocatalytic treatment of acidic wastewater containing heavy metals.