Study On The Preparation And Catalytic Activity Of Organic Cu²⁺ Complexes Immobilized On The SBA-15

Chemical structure of synthetic dyes is complex and diverse with aromatic ring,which is stable to the oxidizing agents,light and microbial.Synthetic dyes are biological toxicity and hard-biodegradability.The dyes and their degradation products by anaerobic,aromatic amines,have toxicity with mutagenic effect,carcinogenic effect and teratogenic effect,which is great harmful to the environment and human.Therefore,the effective treatment of dye wastewater has become a key issue in the development of related industries.The Studies show that organic Cu²⁺ complexes could simulate the activity of natural enzymes,which have a certain catalytic effect on the dye degradation.However,these organic Cu²⁺ complexes catalysts have many disadvantages,such as easy loss of active center,unstable structure,and difficult to reuse.It has been reported that the immobilizing of organic Cu²⁺ complexes catalysts on SBA-15 can increase the stability of organic Cu²⁺ complexes catalysts.In this paper,supported organic Cu²⁺ complexes catalysts,Cu-Ar-CH=N-Pr-SBA-15 and Cu-Ar-CH=N-Pr-O-Pr-SBA-15 were prepared.Their composition,structure and morphology are characterized.And the catalytic activities on the dye degradation are investigated.All these could provide experimental and theoretical basis for solving the pollution problem of dye wastewater.The contents in this thesis are listed as following.1)The four catalysts of Cu-Ar^1-4-CH=N-Pr-SBA-15 were prepared from SBA-15,aminopropyl-triethoxysilane,aromatic aldehydes and Cu Cl2.The five catalysts Cu-Ar^5-9-CH=N-Pr-O-Pr-SBA-15 were prepared from SBA-15,hydroxypropylamine,aromatic aldehydes,chloropropyl-triethoxysilane and Cu Cl2.They were characterized by FT-IR,N2 adsorption-desorption,TG,XRD?wide angle,small angle?,TEM,SEM,and XPS.The results showed that the organic Cu²⁺ complexes were prepared with covalently supported on the SBA-15,and the SBA-15 mesoporous structure was not destroyed.2)The methyl orange degradation in the presence of catalysts?4mg/L?with dye concentration 30mg/L,was investigated with the different oxygen,dosage of H₂O₂,the p H value,temperature,electrolyte.It was found that the increase of p H was favorable for the catalytic activity with p H< 9.0,and the catalytic activity was worse at p H >9.0.The increase of temperature was beneficial to the degradation of the dye.The increase of2 2H O Dyen:n was beneficial to the degradation of the dye.The dye could be completely degraded in the presence of-2--3-4 3 4Cl ?SO ?NO ?PO.The degradation of the dye could reach a balance and the degradation rate was 80% in the presence of--2-2 3Br ?NO ?CO.The optimum conditions for the degradation of the dye was2 2H O Dyen:n?28?400:1,p H=9.0 and T=40??3)The degradation effect of seven kinds of dyes?methyl orange,rhodamine B,alizarin red,reactive brilliant red,R,E and O,?were investigated under the conditions of2 2H O Dyen:n?28?400:1,p H=9.0 and T=40?in the presence of catalysts?4mg/L?with dye concentration 30mg/L.It was found that the degradation ratio of methyl orange,rhodamine B,alizarin red and reactive brilliant red were 100% after 3 hours.The degradation ratio of the dye R,E and O containing nitro and bromine were 10²0%after 3 hours.It indicated that the catalysts had substrate selectivity.4)The structure-activity relationship of the catalysts was investigated.It was found that the extension of the chain was favorable for the catalytic activity,and the catalytic activity is better with six-member aromatic ring than five-member aromatic ring in the catalysis structure.5)The mechanical stability and acid-base stability of the catalysts were investigated.It was found that the catalytic activity was good after 7 cycles,and the mesoporous properties of the catalysis were unchanged.It was found that the catalytic activity was lost under the condition of strong acidity,and the catalytic activity could be recovered after adjusting the p H by the addition of base.The catalytic activity was lost under the condition of strong alkaline,and the catalytic activity could not be recovered after adjusting the p H by the addition of acid.The results showed that the catalysts could maintain chemical stability under the condition of acidity to weak alkaline,and the catalysts could not maintain chemical stability under the condition of strong alkaline.6)The degradation products were determined by UV-Vis spectroscopy,HPLC and CO2 detection experiment.And the COD of the dye wastewater was determined by KMn O4 method.The results showed that the degradation products were maleic acid,oxalic acid and CO2,and the CODMn was 6.5¹0 mg/L after degradation.The UV-Vis spectra showed that the absorption of chromophores and benzene ring of the dye decreased.All these show that the catalyst activated hydrogen peroxide treatment of the dye was not only decolorization,but also degradation and mineralization.7)The mechanism of catalysts activated hydrogen peroxide was studied by free radical inhibition test and free radical capture experiment.The kinetics of catalyst treatment of dye was investigated by Graph Pad Prism 5 software.It was found that the process of activating hydrogen peroxide by the catalyst was controlled by hydroxyl radicals,and the kinetic process of the catalysts was consistent with the enzymatic kinetic process.All these show that the small molecule organic copper enzyme model was covalent immobilized on SBA-15 with enzymatic properties.The stability of small molecule enzyme model was increase and could be reused as heterogeneous catalysis.