Large amounts of carbon are stored primarily in dissolved organic matter (DOM), which plays an important indicator of lake eutrophication. However, removing DOM from eutrophic lakes remains a major challenge. Herein, a novel S-scheme flower-like microsphere BiVO/nanosheet g-CN 3D/2D heterojunction was successfully constructed using a two-step method for DOM degradation of real eutrophic lake water in the presence of peroxydisulfate (PDS). 1.0-BiVO/g-CN/PDS exhibited highly efficient photocatalytic performance with an 87.8 % removal rate of DOM for 60 min, which was 5.3 and 8.9 times higher than BiVO/PDS and g-CN/PDS, respectively. Sulfate radical (·SO), hydroxyl radical (·OH) and singlet oxygen (O) were mainly responsible for DOM degradation in the 1.0-BiVO/g-CN/PDS system, and the transformation pathway of O was emphatically analyzed. In addition, the changes of fluorescence components in DOM were detected using synchronous fluorescence spectra, second derivative spectra, and two-dimensional correlated spectroscopy analysis. Humic-like fluorescence, fulvic-like fluorescence, and protein-like substances were removed higher than 85.30 %, 73.02 %, and 67.23 % by the 1.0-BiVO/g-CN catalyst activating the PDS under visible light (VL), respectively. When the toxicity of catalytically treated eutrophic lake water was estimated by growth inhibition of , the biotoxicity of DOM decreased continuously in the BiVO/g-CN/PDS/VL coupling process. Theoretical calculations and photoelectrochemical tests suggested that the BiVO/g-CN/PDS catalytic activity enhancement was attributed to the S-scheme mechanism and hybrid advanced oxidation process. It is expected that this work can provide new insight into DOM degradation in eutrophic lake water by the heterogeneous photocatalysis combined with the PDS activation system.

中文翻译：

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可见光下使用 S 型 BiVO4/g-C3N4 3D/2D 异质结光催化过二硫酸盐活化降解富营养化湖水中溶解的有机物

大量碳主要储存在溶解有机物（DOM）中，它是湖泊富营养化的重要指标。然而，从富营养化湖泊中去除 DOM 仍然是一个重大挑战。在此，利用两步法成功构建了一种新型S型花状微球BiVO/纳米片g-CN 3D/2D异质结，用于在过二硫酸盐（PDS）存在下降解真实富营养化湖水的DOM。 1.0-BiVO/g-CN/PDS表现出高效的光催化性能，60分钟内DOM去除率为87.8%，分别是BiVO/PDS和g-CN/PDS的5.3和8.9倍。硫酸根(·SO)、羟基自由基(·OH)和单线态氧(O)是1.0-BiVO/g-CN/PDS体系中DOM降解的主要原因，重点分析了O的转化途径。此外，利用同步荧光光谱、二阶导数光谱和二维相关光谱分析检测DOM中荧光成分的变化。在可见光（VL）下，1.0-BiVO/g-CN催化剂激活PDS，类腐殖质荧光、类黄腐荧光和类蛋白质物质的去除率分别高于85.30%、73.02%和67.23%。当通过生长抑制来评估催化处理的富营养化湖水的毒性时，DOM的生物毒性在BiVO/g-CN/PDS/VL偶联过程中不断降低。理论计算和光电化学测试表明BiVO/g-CN/PDS催化活性的增强归因于S型机制和混合高级氧化过程。预计这项工作可以为富营养化湖水中DOM降解提供新的见解，非均相光催化结合PDS活化系统。