The Electron Shuttle of Aloe-Emodin Promotes the Cu-FeOOH Solid Solution Photocatalytic Membrane to Activate Hydrogen Peroxide for the Degradation of Tannic in Traditional Chinese Medicine Wastewater

The inactive macromolecular substances would result in the membrane fouling and reduce the membrane flux in treating traditional Chinese medicine wastewater. Here, we report a novel photocatalytic membrane and utilize aloe-emodin (AE) as electron shuttle synergistically doped into Cu-FeOOH solid solution, then support the photocatalyst AE/Cu-FeOOH on PVDF membrane, which can effectively degrade tannic (95.69 %, 60 min). Furthermore, even after 6 hours of tannic solution filtration, the membrane maintains a high flux of 517 L m(-2) h(-1) bar(-1). Combined with various spectral and photoelectric performance tests confirmed that AE/Cu-FeOOHPVDF possesses high separation and transfer efficiency of photogenerated carriers. Meanwhile DFT calculation showed that the composite has better adsorption properties and H2O2 activation ability. AE provided e(-) to Cu-FeOOH, which accelerated the redox reaction process of Fe and Cu ions and produced more stable active free radicals to degrade tannic. This study provides a more environmentally friendly approach for utilizing photocatalytic membranes in the treatment of traditional Chinese medicine wastewater.