Removal of Microcystis aeruginosa and Microcystin-LR using a graphitic-C3N4/TiO2 floating photocatalyst under visible light irradiation
Removal of Microcystis aeruginosa and Microcystin-LR using a graphitic-C3N4/TiO2 floating photocatalyst under visible light irradiation
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DOI：
10.1016/j.cej.2018.04.182
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发表时间：
2018-09
影响因子：
15.1
通讯作者：
Jingke Song;Xuejia Wang;Jinxing Ma;Xin Wang;Jiayi Wang;S. Xia;Jianfu Zhao
中科院分区：
文献类型：
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作者：
Jingke Song;Xuejia Wang;Jinxing Ma;Xin Wang;Jiayi Wang;S. Xia;Jianfu Zhao
有害藻华(HAB)在世界范围内日益发生，给人类和生态健康带来风险。在这项研究中，我们报告了一种利用浮动异质结光催化剂在可见光照射下灭活铜绿微囊藻的有效替代方法。光催化剂(简称CTAE)是由石墨氮化碳(g-C3N4)和二氧化钛(TiO2)通过简单的溶胶凝胶法负载在Al_2O_3改性膨胀珍珠岩上制成的。二氧化钛中的N/C掺杂以及二氧化钛和g-C3N4之间的相互作用促进了h+和自由基点OH的生成，而不依赖于O2的活化，这有利于在低氧水中应用。考虑了g-C3N4与二氧化钛不同质量比的影响。用X射线衍射仪、氮气吸附/脱附等温线、FESEM/EDS、TEM、XPS、UV-Vis吸收光谱和光致发光光谱等手段对催化剂进行了表征。结果表明，不同含量的g-C3N4对光催化剂的晶体结构、比表面积和孔容都有影响。使用2 g/L的0.03CTAE光催化剂(即g-C3N4与TiO2光催化剂的理论质量比= 0.03)可同时去除88.1%的甲醛。在可见光照射6h后，铜绿假单胞菌的初始浓度为2.7Cells/ × 106ells/mL，微囊藻毒素-LR的初始浓度为50 μg/L，微囊藻毒素-LR的初始浓度为54.4%。随着ADDA链的氧化，微囊藻毒素-LR逐渐降解。每次处理后，漂浮的g-C3N4/TiO2光催化剂都可以很容易地从溶液中回收，在富营养化水体的现场修复方面显示出巨大的潜力。
Harmful algal blooms (HABs) have increasingly occurred worldwide causing human and ecological health risks. In this study, we report on an effective alternative to inactivatingMicrocystis aeruginosaunder visible light irradiation with the use of a floating heterojunction photocatalyst. The photocatalyst (CTAE for short) is made of graphitic carbon nitride (g-C3N4) and TiO2that are loaded on Al2O3-modified expanded perlite via a facile sol-gel method. The N/C doping in TiO2and the interaction between TiO2and g-C3N4enhanced the generation of h+andradical dotOH independent of O2activation, which could facilitate applications in oxygen-deficient waters. Consideration was given to the impacts of different mass ratios of g-C3N4to TiO2. The photocatalysts were characterized by XRD, N2adsorption/desorption isotherms, FESEM/EDS, TEM, XPS, UV–vis absorption and Photoluminescence spectroscopy. Results showed that different contents of g-C3N4had an influence on the crystal structure, specific surface area and pore volumes of the photocatalysts. The use of 2 g/L of 0.03CTAE (i.e., the theoretical mass ratio of g-C3N4to TiO2= 0.03) photocatalyst could simultaneously remove 88.1% ofM. aeruginosaat an initial concentration of 2.7 × 106cells/mL and 54.4% of Microcystin-LR at an initial concentration of 50 μg/L following 6-h of visible light irradiation. Microcystin-LR was gradually degraded with oxidation of the Adda chain occurring. Following each treatment, the floating g-C3N4/TiO2photocatalyst could be readily recovered from the solution, demonstrating a great potential forin situremediation of eutrophic waters.