Study On Preparation And Catalytic Performance Of Transition Metal Sulfides

With the rapid development of science and technology,the global water environment situation is becoming more and more serious.It is of great significance to explore efficient water treatment processes to treat organic polluted water.Advanced oxidation technologies,especially Fenton catalysis and PMS activation catalysis,have attracted extensive attention due to their advantages of high efficiency,non-selective treatment conditions and mild conditions.However,the slow speed of Fe²⁺/Fe³⁺cycle and the disappointed utilization rate of H₂O₂and Fe²⁺in Fenton system with the insufficient active sites and the poor stability of transition metal sulfide catalysts in PMS activation system also limits the development of them.Based on these problems,this topic with transition metal sulfides as the research object,through exploring new Fenton co-catalyst,visible light assitanted Fenton co-catalysts and defect control of PMS activation catalyst to resolute these problems are as follows:（1）A new co-catalyst,CuS-Cu₉S₈ micro-flower was successfully prepared by a facilely hydrothermal method.The related results showed that Rh B solution（20 ppm,100ml）could be degraded 90%in 15 min in the CuS-Cu₉S₈ co-catalytic Fenton system under optimal condition,which is apparently better than that of the conventional Fenton system（59%）.According to characterizations and experiments such as:EPR,XPS,chromogenic experiments,quenching experiments etc,the high co-catalytic activity of CuS-Cu₉S₈ on pollutant degradation can be attributed to the acceleration for the rate-limiting Fe²⁺/Fe³⁺conversion by the exposed Cu⁺/Cu²⁺redox pairs.The cycle experiments show that CuS-Cu₉S₈ has excellent chemical stability.（2）Taking advantage of the synergy between visible light photocatalysis of semiconductor and Fenton co-catalysis,the photocatalysis was introduced into co-catalytic Fenton system.Metallic sulfides(Zn_xCd_1-xS)with different molar ratio of Zn/Cd were constructed by a facile solvothermal technology and applied to photo-Fenton system as both catalyst and co-catalyst for the first time.The catalytic experiments exhibited that photo-Fenton system containing ZCS-3（molar ratio of Zn:Cd=3:7）presented the highest degradation rate for Rhodamine B（30 ppm,100 ml,93.5%）,which showed significant improvement compared with that of photo-system without ZCS-3（43.7%）.The characterizations and experiments（such as:EPR,XPS,chromogenic experiments etc.）showed that the excellent performance of this photo-Fenton system was mainly ascribed to the synergistic effect between photocatalytic and co-catalytic of ZCS-3,thereby a stable double recycles between Zn²⁺/Zn⁺on the surface of ZCS-3 and Fe²⁺/Fe³⁺in solution was successfully established in the catalytic process.（3）A porous carbon-based copper sulfide（CuS_x/C）nanosphere with plentiful sulfur vacancies was obtained and exhibited excellent catalytic activity for degrading pollutants(97.9%for Rhodamine B（Rh B,10 ppm,50 ml）degradation within 6 min in PMS system,which was significantly higher than that of CuS and CuS_x（7.1%and 13.8%）.The high catalytic performance of CuS_x/C was mainly attributed to the existence of plentiful sulfur vacancies,more Cu⁺/Cu²⁺exposed on the CuS_x/C surface,and further provided more active sites for the activation of PMS.Meanwhile,the effectively fixed effect of the CuSx by carbon matrix guaranteed the satisfactory stability and reusability of CuS_x/C.Figure 43 Table 4 Reference 141...