Degradation of rhodamine B in a novel bio-photoelectric reductive system composed of Shewanella oneidensis MR-1 and Ag3PO4
Degradation of rhodamine B in a novel bio-photoelectric reductive system composed of Shewanella oneidensis MR-1 and Ag3PO4
复制标题
由 Shewanella oneidensis MR-1 和 Ag3PO4 组成的新型生物光电还原系统中罗丹明 B 的降解
DOI：
10.1016/j.envint.2019.03.010
复制
发表时间：
2019
影响因子：
11.8
通讯作者：
Han Qing Yu
中科院分区：
文献类型：
--
作者：
Xiang Xiao;Xiao Lin Ma;Zhao Ying Liu;Wen Wei Li;Hang Yuan;Xiao Bo Ma;Li Xia Li;Han Qing Yu
光催化技术被广泛应用于污染物的降解。由于一些具有氧化性的污染物容易被还原而不是被氧化，而且在有氧的情况下，光生电子引起的还原反应是有限的，因此光催化还原技术比氧化更适用于降解具有氧化性的污染物。本工作建立了一种新型的生物光电还原降解系统(BPRDS)，该系统由一株具有电化学活性的白氏杆菌MR-1和可见光催化剂Ag3PO4在厌氧条件下组成，并通过对典型有机污染物罗丹明B(RhB)的降解来评价其光降解性能。所合成的Ag3PO4纳米粒子在400-800 nm的整个可见光谱范围内都有吸收。在厌氧条件下，BPRDS可在可见光照射下降解RHB，但在没有Shewanellacells的情况下不能降解。阻断跨膜电子传递链MTR呼吸通路可降低BPRDS中重组人血红蛋白的降解率。核黄素的剂量也显著降低了RhB的降解率。这些结果表明，Shewanella释放的电子参与了RhB的光降解，这是通过一个逐步的N-脱乙基过程实现的。在BPRDS中，RhB是通过光还原而不是光氧化降解的。这项工作有助于开发用于污染物降解的物理-化学-微生物一体化系统，有助于更好地了解生物光电还原降解机理，并有利于其在环境修复中的应用。
Photocatalytic catalysis is widely used for pollutant degradation. Since some pollutants with oxidative nature are readily reduced rather than oxidized and reductive reaction caused by photogenerated electrons is limited in the presence of oxygen, photocatalytic reduction process is more applicable for the degradation of pollutants with oxidative nature than oxidation. In this work, a novel bio-photoelectric reductive degradation system (BPRDS), composed of an electrochemically active bacteriumShewanella oneidensisMR-1 and a visible-light photocatalyst Ag3PO4, was established under anaerobic conditions and its photodegradation performance was evaluated through degrading rhodamine B (RhB), a typical organic pollutant. The as-synthesized Ag3PO4nanoparticles exhibited absorption in the entire visible spectral range of 400–800 nm. RhB could be degraded in BPRDS with visible light irradiation under anaerobic conditions, but not be decomposed in the absence ofShewanellacells. Block of Mtr respiratory pathway, a transmembrane electron transport chain, resulted in a reduction in degradation rate of RHB in BPRDS. Dose of riboflavin also substantially decreased the RhB degradation. These results suggest that the electrons released byShewanellawere involved in the RhB photodegradation, which was achieved via a stepwiseN-deethylation process. In BPRDS, RhB was degraded by photoreduction, rather than photooxidation. This work is useful to develop integrated physico-chemical-microbial systems for pollutant degradation, facilitate better understanding about the biophotoelectric reductive degradation mechanisms and beneficial to their applications for environmental remediation.