可见光/石墨相氮化碳/溴化氧铋/过二硫酸盐体系高效降解活性蓝19的增强效应及路径

Enhancement effect and path of vis/g-C3N4/BiOBr/PS system for efficient degradation of active blue 19

为探究光催化降解蒽醌染料活性蓝19(RB19)过程中蒽醌的光敏特性对去除率的影响,以石墨相氮化碳/溴化氧铋(g-C3N4/BiOBr)为光催化材料,引入光照(vis)与过二硫酸盐(PS),构成协同催化氧化体系,考察光激发产物半醌自由基(Q-·)的形成及其参与、增强体系氧化能力的作用机制,采用单因素(材料投加量、初始pH、活性蓝19初始质量浓度、过硫酸盐投加量、光照强度)分析方法,探究Q-·增强效应的影响,使用降解动力学方法及LC/MS评估降解后废水的毒性。结果表明:Q-·的形成不仅加速了过硫酸盐的活化过程,Q-·与氢醌(H2Q)、醌(Q)形成的循环作用也强化了材料的光催化效应,在模拟太阳光照射下(300 W),催化剂用量为0.1 g·L^(-1)和PS投加量为400 mg·L^(-1)时,Q-·引发的长链式自由基反应使该体系在80 min内对40 mg·L^(-1)的RB19的降解率可达到100%;反应条件对催化效果影响的大小顺序为材料投加量>初始pH>RB19初始质量浓度>过硫酸盐投加量>光照强度;Q-·中间体的形成有效提高了体系内自由基的含量,是反应后废水毒性显著降低的主要原因。由此可知,体系内Q-·所引发的自降解自循环、长链式自由基效应是实现RB19高效降解的主要因素。本研究结果可为开发蒽醌类染料废水处理技术的开发及实际应用提供参考。

To investigate the influence of the photosensitive properties of anthraquinone on the removal efficiency of anthraquinone-based Reactive Blue 19(RB19)by photocatalytic degradation,the graphitic phase carbon nitride/bismuth bromide oxide(g-C3N4/BiOBr)was used as the photocatalytic material,and light(vis)together with peroxydisulfate(PS)were introduced,and a synergistic catalytic oxidation system was built.The formation of semiquinone radicals(Q-·)during the degradation process,and the mechanism of their participation and enhancement of the oxidation capacity were investigated.The effect of Q-·-enhancement effect was investigated by single factor(material dosing,initial pH,initial mass concentration of RB19,PS dosing,and light intensity)analysis method.The toxicity of the degraded wastewater was assessed by the degradation kinetics method and LC/MS.The results showed that the formation of Q-·not only accelerated the activation of PS,but also enhanced the photocatalytic effect of the material due to its cyclic action with hydroquinone(H2Q)and quinone(Q).Under the simulated sunlight(300 W),at the catalyst dosage of 0.1 g·L^(-1)and the PS dosage of400 mg·L^(-1),the long chain radical reaction initiated by Q-·in the process of deriving other free radicals enabled the system to completely degrade RB19 with initial concentration of 40 mg·L^(-1)within 80 min.The influence of the four factors followed the order:material dosage>initial pH>RB19 initial concentration>light intensity.The significant reduction of wastewater toxicity after the reaction was mainly attributed to the formation of semi-quinone radical intermediates,which could effectively increase the content of free radicals in the system.In conclusion,the self-degradation,self-cycling and long-chain radical effect induced by Q-·within the system was the main reason for achieving an efficient degradation of RB19.The results of this study can provide a reference for the development and practical application of anthraquinone dyestuff wastewater treatment technology.