Photocatalytic Degradation Of Imidazolium Ionic Liquids And Its Mechanism

Ionic liquids (ILs) mean liquid salts, composed of entirely organic cations and inorganicanions at or near room temperature, also known as low-temperature molten salt. ILs haveattracted considerable interest in the diverse fields of synthesis, catalysis, materials science,separation technology, and CO2capture because of their unique physicochemicalcharacteristics, such as tunable structures and properties, negligible vapor pressure, excellentchemical and thermal stability, and high polarity and ionic conductivity. With someachievement of industrial processes and commerical applications of ionic liquids, certainfactors include ultimate disposal issues and environmental risk assessments (recylability andtoxicity), so it is necessary to find efficient and economic ways to remove the ILs.In this paper, photocatalysts were synthesised by impregnation and in-situ method, theywere denoted as X%TiO2/SBA-15and DCQ-X%TiO2/SBA-15. Then all the photocatalystswere firstly characterized by FT-IR、XRD、BET、Raman and TEM. The FT-IR and Ramanresults showned that TiO2and DCQ were successfully loaded onto the matrix ofX%TiO2/SBA-15and DCQ-X%TiO2/SBA-15photocatalysts of impregnation and in-situmethod. The XRD、BET、TEM results indicated that photocatalysts by impregnation hadintergal pore structure and photocatalysts by in-situ method. The two-dimensional hexagonalstructure of SBA-15is partially maintained in the samples of CP-10%TiO2/SBA-15andDCQ-CP10%TiO2/SBA-15. With the content of TiO2increasing further, the highly orderedmesopore structures are almost destroyed completely. These synthesized photocatalysts weredegradated imidazolium-based ionic liquids. Under the optimum photocatalysis reactionconditions of T=25℃, t=3h,[Imidazolium ionic liquids]=0.2mM, Visible light, pH=3.87,[DCQ-X%TiO2/SBA-15]=1g/L,[H2O2]=400mM, The degradation rate of [BMIM]Br can beachieved above90%, The degradation rate of [HMIM]Br can be achieved above98%, The[OMIM]Br can be degraded completely in90min. The degradation rate ofDCQ-X%TiO2/SBA-15under visible light was higher than X%TiO2/SBA-15under UV. Itincreased about20%-30%than the degradation rate of X%TiO2/SBA-15under UV.