The Study On Property Of Modification Oxygen-enrichment Membrane Of Polydimethylsilicone

The technology of oxygen enrichment is paid more and more attention with the global development of energy saving and environment protection.With its high oxygen permeability,polydimethylsilicone(PDMS) is a favorable candidate for making oxygen enrichment membranes.With PS as a base membrane, a complex oxygen enrichment membrane is made by introducing high vinyl-PDMS, hydroxy-PDMS and their modificati-ons. The following have been studied:the preparation of crosslinking reagents,the effects of forming conditions on membrane (for example,materials ratio,reaction times,forming temperature,catalyst concentrations,coating concentrations) and operation conditions (testing temperature,op-eration vacuum) on JO2 and oxygen concentration.The introduce of SiO2 into the crosslinking net structure of PDMS membranes and the effects of SiO2 additives quantities,testing temperature,operation vacuum JO2 and oxygen concentration are investigated detailedly.The application of oxygen enrichment membrane on oxidation of cumene and membrane bioreacter is also discussed.It is shown from the research results that, the preparation conditions of crosslinki-ng reagent is:reaction temperature 60℃,reaction time 3h,additives quantities of catalyst 1mL/30mL(material); membrane forming conditions were: material ratio:n(vinyl-PDMS):n(-Si-H)=1:1,n(hydroxy-PDMS):n(TEOS)=2:1,n(hy-droxy-PDMS):n(-Si-H)=1:1; reaction time 3h; coating concentration:m(vinyl-PDMS/-Si-H oxygen-enrichment membrane)=3%,m(hydroxy-PDMS/TEOS oxygen- enrichment membrane)=5%,m(hydroxy-PDMS/-Si-H oxygen-enrichment membrane=5%;catlyst concentration:m(vinyl-PDMS/-Si-H oxygen-enri-chment membrane)=3%,m(hydroxy-PDMS/TEOS oxygen-enrichment membrane)=2%, m(hydroxy-PDMS/-Si-H oxygen-enrichment membrane)=2.5%;membrane forming temperature 80℃; operation vacuum 0.075MPa;testing temperature 25℃.It is demonstrated the synthesis of silicone rubber-SiO2 blended oxygen-enrichment membrane made a 3.5% increase in oxygen concentration and a 11.1%increase in oxygen flux when the membrane contained a mass percentage of 40% SiO2.The operation properties are not degraded by the addition of SiO2.It is shown from the comparison of the above mentioned four types compound coatings on silicone rubber that, the preparation condition of vinyl-PDMS/-Si-H oxygen-enrichment membrane is stable and its oxygen concentration reaches more than 28%. The oxygen-enrichment membrane of (hydroxy-PDMS)/(TEOS) is superior to vinyl-PDMS/-Si-H on oxygen concentration and flux. But the stability of solvent is bad and preparation conditions of the membrane were strict. Oxygen-enriching properties of SiO2 contained silicone rubber membrane are the best with oxygen concentration when it reaches over 29.5%. When the oxygen-enriching membrane is applied to oxidation of cumene, CHP yield is improved almost two times with enriched oxygen as the oxidant than that with air. The removal rate of COD is improved about 30% with enriched oxygen than that with air when the oxygen-enriched membrane is applied to membrane bioreacter. It is shown that the oxygen-enriched membrane has good operational performance.