(215c) Enhancing Selectivity of Salicylic Acid Degradation By Using Molecular Imprinted Doped TiO2 Under Solar Light

The doped TiO₂ photocatalysts have been widely applied for the wastewater treatment because of high photocatalytic activity and chemical stability under solar light. However, poor selectivity of doped TiO₂ photocatalysis is unfavorable to photocatalytic removal of highly toxic low-level organic pollutants in polluted waters in the presence of other less toxic high-level pollutants. A new strategy of increasing this selectivity is the surface modification of doped TiO₂ via coating a thin layer of molecular imprinted polymer (MIP), which provides molecular recognition ability toward the target molecules. Firstly, we prepared a doped TiO₂ sample which has high photocatalytic activity under simulated solar light in this paper. Then, o-phenylenediamine was taken as the functional monomer and salicylic acid was taken as the target molecular. The polymerization was initiated photocatalytically by UV light illumination on doped TiO₂ without using any other chemical initiator or cross-linker, causing in situ coating of the imprinted layer onto the surface of doped TiO₂. MIP-doped-TiO₂photocatalyst samples, which had the special interaction between the target salicylic acid and the footprints polymer via the functional groups (-NH₂, -OH and –COOH), were prepared. Lastly, an aqueous solution of salicylic acid (20mg/L, target pollutant) and phenol (100mg/L, nontarget pollutant) was chosen as the simulated wastewater system, and MIP-doped-TiO₂was adopted as the photocatalyst of selective degradation of salicylic acid. The results indicated that the degradation rate of salicylic acid could be increased 70% by using MIP-doped-TiO₂, comparing with neat doped TiO_2, under simulated solar light. The degradation rate of phenol was decreased 90% under the same conditions. The selectivity of salicylic acid degradation by using MIP-Doped-TiO₂ under simulated solar light was remarkably increased.