Preparation Of MOF-derived Sulfide And Its Photocatalytic Reduction Of Cr(Ⅵ)

With the rapid development of industry,a large quantity of industrial production wastes containing Cr（Ⅵ）are discharged into nature,causing water pollution and soil pollution,which seriously harming people’s production and life.The toxic pollutant Cr（Ⅵ）can be reduced to non-toxic,innocuous and easy to treat Cr（Ⅲ）by photocatalytic technology.At present,reducing of Cr（Ⅵ）to Cr（Ⅲ）is the more green and safe method for the treatment of Cr（Ⅵ）wastewater.As a kind of emerging new materials,MOF-derived materials are prepared by using metal-organic frameworks（MOFs）as precursors and controlling reactants and reaction conditions.And it has the advantages of diversity,adjust ability and simple preparation.The combination of MOF-derived materials and photocatalytic technology in wastewater treatment has become one of the research hotspots of many scholars.Herein,the photocatalytic reduction of Cr（Ⅵ）by MOF-derived tin sulfide,MOF derived copper sulfide and MOF derived zinc were sulfide was studied.And by controlling the temperature of heat treatment in the reaction process and the content of sulfur powder in raw materials,the effects of temperature and sulfur powder was explored,and then the influence on the performance of reduction Cr（Ⅵ）was explored.Specific research results are as follows:（1）Sn-MOF was prepared by soaking and stirring with SnCl₂、C₈H₆O₄ and Na OH as raw materials.Sn-MOF was evenly mixed with sulfur powder and further treated by heat treatment to obtain MOF-derived tin sulfide.The experiment of characterization and reduction experiments of Cr（Ⅵ）by common photocatalyst characterization methods such as XRD、PL、DRS and XPS show that when the ratio of Sn-MOF to sulfur powder was 1:3,the product obtained after heat treatment at 600℃has a good performance of photocatalytic reduction of Cr（VI）,and 91.51%of Cr（VI）can be reduced to Cr（Ⅲ）for3 h.The composition of the sample is Sn S₂ and Sn S.At the same time,the sample has showed good photocatalytic performance.（2）Cu-MOF was synthesized from（CH₃COO）₂Cu·H₂O and C₆H₅NO₂ by mechanochemical method.The mixture of Cu-MOF and sulfur powder was further heat treated to obtain MOF-derived copper sulfide.The experiments of characterization and reduction Cr（Ⅵ）by XRD、PL、DRS and XPS showed that when the ratio of Cu-MOF to sulfur powder was 1:2,the product obtained after heat treatment at 550℃has a good performance of photocatalytic reduction Cr（Ⅵ）,79.70%of Cr（Ⅵ）can be reduced to Cr（Ⅲ）for 5 h.The composition of the sample is Cu_7.2S₄,Cu_1.8S,Cu₈S₅.Meanwhile,The photoelectron-hole recombination rate of the sample was low and the visible light absorption performance is good.（3）Zn-MOF was synthesized by mechanical method using ZnO and C₈H₆O₄ as raw materials.MOF-derived zinc sulfide was obtained by heat treatment after Zn-MOF was mixed with sulfur powder uniformly.The common characterization methods such as XRD、PL、DRS and XPS were used to characterize and reduce Cr（Ⅵ）.And when the ratio of Zn-MOF to sulfur powder was 1:3,the product obtained after heat treatment at550℃has a good performance of photocatalytic reduction Cr（Ⅵ）,91.7%of Cr（Ⅵ）can be reduced to Cr（Ⅲ）for 3 h.The composition of the sample is Zn S and ZnO.In the meantime,the sample has good visible light absorption performance and large specific surface area.