CNQDs/Ag_(3)PO_(4)/g-C_(3)N_(4)复合光催化材料的制备及其对双酚A的降解性能

Preparation of CNQDs/Ag_(3)PO_(4)/g-C_(3)N_(4) composite photocatalyst and its degradation performance of bisphenol A

采用溶剂热法和原位沉淀法制备了CNQDs/Ag_(3)PO_(4)/g-C_(3)N_(4)三元复合光催化剂,通过SEM、TEM、XRD、FT-IR、XPS、BET等手段对其进行了表征;以BPA为目标污染物,考察了pH、BPA初始浓度、催化剂投加量及光照强度等因素对BPA去除效果的影响;同时,对该三元复合催化剂光催化降解BPA的机制进行了探讨。结果表明,CNQDs/Ag_(3)PO_(4)/g-C_(3)N_(4)在反应60 min时对BPA的去除率可以达到100%,分别为g-C_(3)N_(4)、Ag_(3)PO_(4)、Ag_(3)PO_(4)/g-C_(3)N_(4)的7.74、2.09和1.38倍;光催化降解BPA的最佳反应条件为:pH为11、污染物质量浓度为5 mg·L^(−1)、催化剂投加量为1 g·L^(−1)、光照强度为500 W;在光催化降解BPA的过程中,主要反应活性物种为·O_(2)^(−)和h^(+)。基于GC-MS对反应过程中间产物的检测结果,推测出BPA可能的2种降解路径:一是BPA先转化为单环有机物,再转化为二氧化碳和水;二是BPA经活性物种直接开环形成简单烷烃,最后氧化成二氧化碳和水。

The CNQDs/Ag_(3)PO_(4)/g-C_(3)N_(4) ternary composite photocatalyst was prepared by solvothermal method and in-situ precipitation method,and it was characterized by SEM,TEM,XRD,FT-IR,XPS,BET and other ways;BPA was the target pollutant,the effects of factors such as pH,BPA concentration,catalyst dosage and light intensity on BPA removal were investigated;at the same time,the mechanism of photocatalytic degradation of BPA by the ternary composite catalyst was discussed.The results showed that 100%removal rate of BPA occurred in 60 minutes after CNQDs/Ag_(3)PO_(4)/g-C_(3)N_(4) photocatalytic degradation,which was 7.74 times of g-C_(3)N_(4),2.09 times of Ag_(3)PO_(4) and 1.38 times of Ag_(3)PO_(4)/g-C_(3)N_(4),respectively.The optimal reaction conditions for photocatalytic degradation of BPA were following:pH 11,BPA concentration of 5 mg·L^(−1),catalyst dosage of 1 g·L^(−1),and light intensity of 500 W.In the process of photocatalytic degradation of BPA,the main reactive species are·O_(2)−and h+.Based on the detection results of intermediate products in the reaction process by GCMS,two possible degradation paths of BPA were inferred,one was that BPA first transformed into monocyclic organic matter,then into CO_(2) and H_(2)O,the other one was BPA transformed into simple alkane through direct ring opening reaction,then were oxidized into CO_(2) and H_(2)O.