Environmental Application of Amphiphilic Star Shaped Block Copolymer for Removal of Aqueous Organic Contaminants

다국어 초록 (Multilingual Abstract)

This study investigated the encapsulation and/or photocatalytic degradation of aqueous organic compounds using newly synthesized three types of star copolymers. Polystyrene-block-poly(N-isopropylacrylamide) (P-PSN) was developed as a polymeric adsorbent containing a hydrophobic core and hydrophilic shell and applied to the removal of benzene from water. The hydrophobic core of star copolymer was effective in the encapsulation of benzene. Chlorophenols can be effectively degraded at a low energy and relatively long wavelength light source (visible light) by both porphyrin-(polystyrene-b-2-dimethylaminoethyl acrylate) (P-PSD) and porphyrin-(b-2-dimethylaminoethyl acrylate) (P-PD) catalysts, however, the encapsulation of chlorophenols were insignificant. The different results of encapsulation for benzene and chlorophenols were due to relatively low molecular weight and density, which were considered to lead to easy encapsulation. The use of P-PSD showed higher efficiency of photocatalytic degradation than P-PD for chlorophenols, because of the presence of a hydrophobic block (polystyrene). This result is due to hydrophobic-hydrophobic interaction which could be enhanced the access possibility for the porphyrin core (photocatalyst). The degradation intermediates and by-products of the chlorophenols were also identified. The analysis results revealed that the degradation of highly-chlorinated phenols was more rapid than the degradation of less-chlorinated phenols, as confirmed by residual chlorinated compound and chloride ions that were released. The newly synthesized star copolymer is non-toxic to bacteria. For these reasons, the star block copolymer has the potential to be utilized for the removal of organic pollutants from sewage and wastewater.

목차 (Table of Contents)

• Abstract
• 1. General introduction
• 1.1. Background
• 1.2. Objectives
• 2. Chapter Ⅰ
• The Encapsulation of Aqueous Benzene Using Star Shaped Block Copolymer
• Abstract
• 2.1. Introduction
• 2.2. Materials and methods
• 2.2.1. Chemicals
• 2.2.2. Synthesis of polystyrene-block-poly(N-isopropylacrylamide) amphiphilic diblock copolymer (PSN)
• 2.2.3. Characterization of star copolymer
• 2.2.4. Encapsulation studies
• 2.2.5. Modeling of equilibrium and kinetic adsorption (encapsulation)
• 2.3. Results and discussion
• 2.3.1. Structure of the diblock copolymer
• 2.3.2. Encapsulation of benzene into copolymer
• 2.3.3. Removal efficiency of benzene via batch experiments
• 2.4. Conclusion
• 3. Chapter Ⅱ
• Application of Star Block Copolymer for Photocatalytic Degradation of Chlorophenols
• Abstract
• 3.1 Introduction
• 3.2. Materials and methods
• 3.2.1. Materials
• 3.2.2. Photoreactor and light source
• 3.2.3. Encapsulation and photocatalysis
• 3.3. Results and discussion
• 3.3.1. Encapsulation of chlorophenols using P-PSD
• 3.3.2. Degradation of chlorophenols by the photocatalysis
• 3.3.3. Identification of evidence for reaction
• 3.4. Conclusion
• 4. Chapter Ⅲ
• Synthesis and Characterization of Star Copolymers with Catalyst and its Application for Chlorinated Phenols Degradation
• Abstract
• 4.1 Introduction
• 4.2. Materials and methods
• 4.2.1. Chemicals and reagents
• 4.2.2. Synthesis of polydimethylamino ethyl acrylate with a porphyrin core star block copolymer (P-PD)
• 4.2.3. Synthesis of polystyrene-block-polydimethylamino ethyl acrylate with a porphyrin core amphiphilic star block copolymer (P-PSD)
• 4.2.4. Star block copolymer (P-PSD & P-PD) analysis
• 4.2.5. Photocatalytic degradation of chlorophenol compounds
• 4.2.6. Analysis of photocatalytic degradation by-products of chlorophenols
• 4.2.7. Data analysis
• 4.2.8. Toxicity assay
• 4.3. Results and discussion
• 4.3.1. Star block copolymer (P-PSD & P-PD) characterization
• 4.3.2. Comparison of photocatalytic degradation of PCP, 2,4,6-TCP and 2,4-DCP
• 4.3.3. Chloride release
• 4.3.4. Identification of photocatalytic degradation products of chlorophenols
• 4.3.5. Bacterial toxicity of newly synthesized catalyst (P-PSD)
• 4.4. Conclusion
• 5. General conclusion
• 6. References