Qiu, W, Sun, J, Fang, M, Luo, S, Tian, Y, Dong, P, Xu, B & Zheng, C 2019, 'Occurrence of antibiotics in the main rivers of Shenzhen, China: Association with antibiotic resistance genes and microbial community.', The Science of the total environment, vol. 653, pp. 334-341.View/Download from: UTS OPUS or Publisher's site
The occurrence and distribution of antibiotics were investigated in surface water and sediment collected from the main rivers of Shenzhen, China. Total concentrations of 20 selected antibiotics ranged from 36.510 to 1075.687 ng L-1 (mean 244.992 ng L-1) in 31 water samples and from 28.124 to 2728.810 ng g-1 (mean 680.169 ng g-1) in 31 sediment samples. Notably, STZ and SDZ were the dominant antibiotics in both water and sediment as their higher concentrations compared with the other compounds. Furthermore, comprehensive profiling of antibiotic resistance genes (ARGs) and microbial community was performed to gain an understanding of the evolution and dissemination of ARGs in microbial communities caused by the occurrence of antibiotics in sediment samples from Maozhou River. As a result, the sul1 gene was found to be the most abundant ARG and Proteobacteria was the most abundant microorganism in all the samples (37.4-51.7%), followed by Bacteroidetes (15.3-18.4%). Statistical analysis figured out the relations among antibiotics, ARGs and microbial community. A specific conclusion could be drawn from the positive correlations among the bla_d gene, Fusobacteria, and sulfamethoxazole. It suggests that antibiotics may be positively linked to the expression of ARGs in certain bacteria, and thus high reproduction would occur within the bacterial community. Overall, the widespread distribution of ARGs underscores the need for further research on the mechanism of antibiotics influence as emerging contaminants in the environment and the associated risks to microbial community.
Altaee, A, Xu, B, Ahmed, MB, Zhou, JL, Xu, G & Wu, M 2018, 'Graphitic carbon nitride based nanocomposites for the photocatalysis of organic contaminants under visible irradiation: Progress, limitations and future directions', Science of the Total Environment, vol. 633, pp. 546-559.View/Download from: UTS OPUS or Publisher's site
Graphitic carbon nitride (g-C3N4) has drawn great attention recently because of its visible light response, suitable energy band gap, good redox ability, and metal-free nature. g-C3N4 can absorb visible light directly, therefore has better photocatalytic ability under solar irradiation and is more energy-efficient than TiO2. However, pure g-C3N4 still has the drawbacks of insufficient light absorption, small surface area and fast recombination of photogenerated electron and hole pairs. This review summarizes the recent progress in the development of g- C3N4 nanocomposites to photodegrade organic contaminants in water. Element doping especially by potassium has been reported to be an efficient method to promote the degradation efficacy. In addition, compound doping improves photodegradation performance of g-C3N4, especially Ag3PO4-g-C3N4 which can completely degrade 10 mg L−1 of methyl orange under visible light irradiation in 5 min, with the rate constant (k) as high as 0.236 min−1. Moreover, co-doping enhances the photodegradation rate of multiple contaminants while immobilization significantly improves catalyst stability. Most of g-C3N4 composites possess high reusability enabling their practical applications in wastewater treatment. Furthermore, environmental conditions such as solution pH, reaction temperature, dissolved oxygen, and dissolved organic matter all have important effects on the photocatalytic ability of g-C3N4 photocatalyst. Future work should focus on the synthesis of innovative g-C3N4 nanocomposites for the efficient removal of organic contaminants in water and wastewater.
Xu, B, Wu, M, Pan, C, Sun, Y, Yuan, D, Tang, L & Xu, G 2017, 'Aquatic photolysis of hydroxylated polybromodiphenyl ethers under direct UV irradiation: a case study of 2′-HO-BDE-68', Environmental Science and Pollution Research, vol. 24, no. 16, pp. 14409-14416.View/Download from: Publisher's site
Xu, B, Ahmed, MB, Zhou, JL, Altaee, A, Wu, M & Xu, G 2017, 'Photocatalytic removal of perfluoroalkyl substances from water and wastewater: Mechanism, kinetics and controlling factors.', Chemosphere, vol. 189, pp. 717-729.View/Download from: UTS OPUS or Publisher's site
This review focuses on heterogeneous photocatalysis of perfluoroalkyl substances (PFAS) which are of worldwide concern as emerging persistent organic contaminants. Heterogeneous photocatalysis is an effective and advanced technology for PFAS removal from water with relatively high efficacy. During photocatalysis, various short chain perfluorocarboxylic acids (PFCA) are produced as intermediates and the efficacy is related to the photo-generated hole (h+) and photo-generated electron (e-). PFAS photodegradation in water under UV irradiation is most effective by using In2O3 as the catalyst, followed by Ga2O3 and TiO2. Significantly, modifying the chemical composition or morphology of the catalyst can improve its efficacy for PFAS removal. In2O3 porous nanoplates were found to have the best performance of 100% PFAS decomposition under UV light with rate constant (kt) and half-time (τ1/2) of 0.158 min-1 and 4.4 min, respectively. Catalysts perform well in acidic solution and increasing temperature to a certain extent. The photocatalytic performance is reduced when treating wastewater due to the presence of dissolved organic matter (DOM), with the catalysts following the order: needle-like Ga2O3 > In2O3 > TiO2. Future studies should focus on the development of novel photocatalysts, and their immobilization and application for PFAS removal in wastewater.