Rapid Degradation Of Pentachlorophenol With Artificial Antibody Photocatalysts Using Pseudo-template Molecular Imprinting Technology

As one of the typical persistent organic pollutants (POPs), pentachlorophenol (PCP) is recognized to cause severe damage to the environment. Therefore, the use of PCP is prohibited or restricted in many countries. Unfortunately, PCP is still employed in various fields due to its low price and broad-spectrum role. For this reason, it has a direct practical and environmental significance to develop an efficient approach for the treatment of PCP-containing wastewater. Compared to other traditional water treatment techniques, MIP-coated TiO₂ Photocatalytic technology is a new kind of waste-water purification process due to its selective removal of the target pollutants. However, the MIP-coated photocatalysts using PCP as template are not so enfficient because of PCP's poor solubility. To solve the above problems, in this thesis, we describe a new method to prepare pseudo-template molecular imprinted polymer (MIP) coated TiO₂ photoctalysts.The main results are described as follows.(1) MIP-coated photocatalysts for degradating PCP from wastewater have been prepared in the water phase using pseudo-template molecular imprinting technology. The appropriate pseudo-template molecular and the optimized synthesis condition are provided as: pseudo-template molecular DNP, photo-initiating time 50min, solution pH=4.0, the ratio of template to monomer1:1, the quality ratio of MIP to TiO₂ 1:20. Under this optimal condition, PCP can be degradated rapidly.(2) The experimental results obtained during the photodegradation of individual PCP confirmed that the new photocatalysts can promote the degradation of PCP over a wide range of solution pH (from 3 to 11). Furthermore, in the mixture with BPA, the degradation rate of PCP can be rapidly enhanced as the initial concentration of PCP is decreased in binary systems. These indicate that the MIP coating using DNP as pseudo-template can enable the photocatalysts'molecular recognition ability of PCP.(3) Compared with P25, the UV absorption of the aromatic intermediates and the chloride formation yield during the degradation processes over DNP-P25 indicate that the accumulation levels of the byproducts is less and the mineralization rate is faster.This demonstrates that the MIP coating makes it easy for hydroxyl radical attack the aromatic ring of PCP, and thus accelerate the mineralization of PCP to CO₂, H₂O and Cl^-.