A two-stage degradation coupling photocatalysis to microalgae enhances the mineralization of enrofloxacin. (April 2022)

• Record Type: Journal Article
• Authors: Lu, Zhikun; Xu, Yifeng; Peng, Lai; Liang, Chuanzhou; Liu, Yiwen; Ni, Bing-Jie
• Is Part Of: Chemosphere. Volume 293(2022)
• Publication Date: 2022-04
• Subjects: Antibiotics -- Photocatalysis -- Algae -- Mineralization -- Degradation products and pathways; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.133523
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The coupling of photocatalytic and algal processes has been used for the removal of widespread antibiotics. The removal capacities of the individual and the combined system against enrofloxacin were tested and compared in this work. Due to the low tolerance of the algae to enrofloxacin, the target compound was barely degraded during the individual algal treatment. In the individual photocatalytic process, the mineralization efficiency (defined as the ratio between the produced carbon dioxide and the initial) reached ∼57% with the remaining formed as transformation products. In contrast, a two-stage treatment incorporating photocatalytic and algal processes removed enrofloxacin completely and increased the mineralization efficiency to ∼64% or more. The addition of the citric acid as external co-substrate further elevated the mineralization efficiency with a factor of 1.25 compared to that of the individual photocatalysis. Different degradation products in both individual and integrated processes were identified and compared. The degradation pathways were found to involve the attack of the piperazine moiety and quinolone core. The results indicated the potential application of the combined photocatalytic-algal treatment in removal of veterinary antibiotics and improved our understanding of the underlying mechanisms and pathways. Graphical abstract: Image 1 Highlights: C. vulgaris was inhibited by enrofloxacin but promoted by photocatalytic products. Photocatalytic-algal treatment increased mineralization efficiency of enrofloxacin. The addition of co-substrates enhanced mineralization efficiency of enrofloxacin. Various degradation products were identified in photocatalytic-algal processes.