“Cu核-Cu_2O壳”粒子可见光催化降解酚类废水的研究

Photocatalytic degradation of phenolic pollutants by using visible light responsive "Cu core-Cu_2O shell" catalyst

以对硝基苯酚溶液为模拟废水,用自制的"Cu核-Cu2O壳"粒子对其进行光催化氧化试验,考察了光照时间、催化剂用量、对硝基苯酚的初始质量浓度、溶液的pH值和光源等对降解过程的影响。结果表明,对硝基苯酚溶液质量浓度为40 mg.L-1,催化剂投加量为2g.L-1,光照120min后降解率达到95%,降解反应符合一级反应动力学。与其他同类光催化剂相比,"Cu核-Cu2O壳"粒子具有较高的光催化活性,而且光催化过程中有氢氧自由基产生,对对硝基苯酚的降解较彻底。

The article is concerned about our research findings in photocatalytic degradation of phenolic pollutants by using visible light responsive ＂Cu coreCu2O shell＂ catalyst micron-sized ＂Cu core-Cu2O shell＂ catalyst.The photo-catalysts we have used are prepared by reducing CuSO4 to ＂Cu core-Cu2O shell＂ catalyst characterized by X-ray diffraction（XRD） and transmission electron microscope（TEM）.For our research purpose,we have investigated photocatalytic degradation of phenolic compounds in aqueous solution under the visible light.The results of our experiments show that the new catalyst under way was highly responsive under the visible light.The so-called ＂Cu core-Cu2O shell＂ type catalyst was found to involve a few factors,such as the reaction time,the quantity of catalyst,the initial concentration of p-nitrophenol,the solution of pH and the different kinds of sources light,of which may affect the photocatalytic and degradative properties.The optimum conditions as we found can be stated as follows： the initial concentration of p-nitrophenol—40 mg·L-1;the quantity of catalyst—2 g·L-1;the solution of pH is equal to 3 to 11 while the visible light resource is irradiating during 120 min in the optimal perspective moment.All the above said conditions permitted,the degradation rate of p-nitrophenol is expected to reach 95%.However,it is the UV-visible absorption spectra that substantiated the result of degradation.In addition,the TOC studies indicate that the main part of p-nitrophenol has been mineralized into CO2 and H2O.When the industrial phenol sewage was used to examine the photoactivity, we have found that the degradation of industrial phenol sewage is likely to take place under either sunlight or metal halide light at a similar rate（about 90%）.Compared with other similar photocatalysts,it would be more significant to note the photocatalytic activity of ＂Cu core-Cu2O shell＂ particles.Besides, we have also studied the kinetics of photocatalytic decomposing organic contaminants with ＂Cu core-Cu2O shell＂ type catalyst,the result of of which is that the kinetics of P-nitrophenol in slurry system tends to follow the first order model,with the equation eing ln（ρ0/ρt）=kt.Our study of the mechanism of the degradation process indicates that the hydroxyl radicals can be found during the process of photocatalytic degradation,which may induce the total degradation of the p-nitrophenol.Therefore,the ＂Cu core-Cu2O shell＂ catalyst is expected to be chosen as an excellent photocatalyst candidate for sewage treatment.