Enhanced defect oxygen of LaFeO3/GO hybrids in promoting persulfate activation for selective and efficient elimination of bisphenol A in food wastewater

The unintended leakage of BPA into food waste has posed a new challenge to ecological and human health, but regrettably, the public has not paid much attention to the BPA elimination in food wastewater. Herein, we explored a facile chemical/thermal strategy for synthesizing perovskite LaFeO3/graphene oxide (LaFeO3/GO) hybrids, selectively capturing and efficiently removing BPA in food wastewater. Strikingly, LaFeO3/GO activating persulfate system exhibited complete BPA degradation efficiency with a higher rate constant of 0.1074 min(-1), approximately 18.2 times than that of pristine LaFeO3. The surprisingly high stability at pH value up to 9.0 expanded the use of catalysts in alkaline conditions. Compared to LaFeO3, LaFeO3/GO can selectively enrich the hydrophobic BPA molecules thanks to the hydrophobicity of benzene rings in GO, which was not disturbed by other hydrophilic substances in the complex food wastewater. Furthermore, high-speed charge transfer, more defect oxygen species and synergistic effects between La and Fe in LaFeO3/GO boosted the generation of radical (OH, SO4-, O-2(-)) and nonradical (O-1(2)), efficiently removing 97% BPA and 51% total organic carbon (TOC) in food wastewater. The biological acute toxicity decreased significantly during the oxidation reaction, consistent with the BPA transformation pathway analyzed by HPLC-MS. This system possessed a remarkable performance in extremely intricate food wastewater, so it might be also available for other various organic contaminants in waters and wastewaters.

Automated summary

The LaFeO3/GO hybrids demonstrated high efficiency in selectively capturing and efficiently removing BPA in food wastewater, thanks to the hydrophobicity of benzene rings in GO and the synergistic effects between La and Fe boosting the generation of radicals. The remarkable performance in removing BPA and TOC suggests potential applications for other organic contaminants in various waters and wastewaters.