Preparation Of Cu-based Supported Catalysts And Study On The Catalytic Oxidation Properties

Industrial/agricultural production and people’s daily life are accompanied by the production of a large amount of organic sewage.Most of the organic matters in sewage are highly toxic.If the sewage is discharged into the environment without effective treatment,organic pollutants will cause a series of environmental problems such as water pollution and soil pollution,and even seriously threaten human’s health and life.Therefore,it is necessary to take effective measures to remove organic matters before sewage discharge.As an efficient sewage treatment technology,Fenton oxidation is widely used in the removal of various organic pollutants.Compared with traditional Fe-based Fenton-like catalysts,Cu-based Fenton-based catalysts have faster reaction rates and wider p H operable ranges,and have been developed rapidly in recent years.However,there are still some problems such as the low utilization efficiency of metal active components and the limited catalytic performance.Based on this,this dissertation synthesized low-valent metal ion modified or low-valent metal catalysts by various methods,and loaded them on different supports to prepare supported catalysts so as to enhance the catalytic performances.The presence of the carrier not only improves the dispersion of metal particles,but also helps to reduce the particle size and improve the utilization of metal active components.The specific content is as follows:（1）A novel Cu^（Ⅰ）self-doped Cu WO₄/g-C₃N₄ Fenton-like catalysts were in situ synthesized through a solvothermal method.By changing the loading amount of Cu WO₄,a series of composites with different Cu WO₄/g-C₃N₄ ratios were obtained.The morphology and structure of the catalysts were systematically analyzed by TEM,XRD,FT-IR and other characterization methods.The catalytic performances of the catalysts were evaluated by degrading rhodamine B（Rh B）.It was found that when the Cu WO₄ loading was 30 wt%,the Cu WO₄/g-C₃N₄ composite degraded 100%of Rh B within 90 min,showing the best Fenton-like catalytic activity.And the catalytic activity was improved with the increase of initial p H.In addition,a large number of Cu^（Ⅰ）in the catalyst was the main active species for activating hydrogen peroxide.The synergistic effect of Cu WO₄ and g-C₃N₄ also promoted the redox cycle of Cu^（Ⅰ）/Cu^（Ⅱ）.Quenching experiments revealed that·OH,·O₂^–and ¹O₂ all contributed to the dye degradation,but ¹O₂ as the main reactive species.（2）Petaloid Si O₂ supported well-dispersed Cu/Cu₂O Fenton-like catalysts were synthesized by low temperature solvothermal and carbothermal reduction methods.By adjusting the amount of Cu（NO₃）₂,Cu/Cu₂O nanoparticles with different ratios could be obtained.When the adding amount of Cu（NO₃）₂ was 6 mmol（6-CS）,the particles of Cu/Cu₂O was about 42 nm and dispersed well.With the increase of Cu（NO₃）₂ addition,Cu/Cu₂O occurred serious agglomeration.The catalytic performances of the catalysts were evaluated by degrading 100 mg·L^-1 tetracycline hydrochloride（TC）.It was found that 6-CS showed the optimum catalytic activity.About 89.4%of TC was degraded within 40 min.The excellent catalytic performance could be attributed to the abundant exposed highly reactive metal sites and accelerated redox cycle of Cu^（Ⅰ）/Cu^（Ⅱ）.In addition,the catalyst had strong anti-interference ability to various impurities in water.Quenching experiments revealed that·OH,·O₂^–and ¹O₂ were all involved in the catalytic degradation of TC.（3）g-C₃N₄ modified silica fume supported Cu-Mn Fenton-like catalysts were synthesized by a simple heat treatment process.g-C₃N₄/silica fume composites with different Cu/Mn molar ratios were obtained by adjusting the Cu/Mn ratio(CN-S-C_xM_5-x).The EDS result indicated that Cu and Mn species were uniformly dispersed on the g-C₃N₄/silica fume composite support.The catalytic performances of the catalysts were evaluated by degrading3-chlorophenol（3-CP）.It was found that CN-S-C₁M₄ degraded 88.3%of Rh B within 30 min,showing the best Fenton-like catalytic activity.The excellent catalytic performance was mainly attributed to the Cu-Mn bimetallic synergy and the presence of a large number of oxygen vacancies,both of whose promoted the redox cycle.Quenching experiments revealed that·OH and ¹O₂ were the main reactive oxygen species for the degradation of 3-CP.