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Green Synthesis of Metal-Organic Framework Based Biopolymer for the Removal of Dye and Pharmaceutical Pollutants in Water

Shahmansoori, Maryam | 2024

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 56993 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Yaghmaee, Soheila
  7. Abstract:
  8. In this research, in order to overcome the limitations of the current wastewater treatment technologies, two types of green biocomposite, biocompatible, with high removal capacity for emerging pollutants from wastewater have been synthesized. The general steps of doing the work in this treatise for each category of biocomposite include green synthesis, processing and optimization of the synthesis method, structural characterization of the synthesized compounds, checking their performance to remove the model pollutant, investigating the effect of operational parameters on the removal efficiency, determining kinetics, isotherm and mechanism. And at the end was the assessment of biocomposite stability. The first type of biocomposite named CS/ZIF8/TiO2 (CZT) was synthesized based on chitosan modified with zeolitic imidazolate framework (ZIF-8) and titania (TiO2) and using water as a green solvent. To investigate the effect of the synthesis method and the amount of TiO2 on the efficiency of the photocatalytic process, CZT composite was synthesized by two different methods (in situ and mixing) and also with two different amounts of TiO2 (0.2 and 0.4 grams). Among the synthesized three-component and two-component composites, the three-component composite synthesized by in situ growth method with 0.2 g of titania (CZ0.2TI) showed the highest photocatalytic decolorization of Malachite green dye under visible light irradiation. The prepared materials were characterized through different analyses. The synergistic effect of ZIF-8, TiO2 and chitosan in the composite increased the decolorization ability of Malachite green dye under visible LED light irradiation. Decolorization reached 94.5% at optimal pH (pH=6.5) after 180 minutes and 98.2% at normal pH (pH=3.93) after 300 minutes. The effect of operating parameters, including initial dye concentration, photocatalyst dose and solution pH, on the photocatalytic degradation of dye by CZ0.2TI composite was studied. The photocatalytic decolorization reaction of the composite followed zero-order kinetics, and superoxide radicals played an essential role during the photocatalytic process. The second type of biocomposite named CSZ67 was synthesized hierarchically based on chitosan modified with ZIF-67 zeolitic imidazolate framework at room temperature using water as a green solvent. In this study, CSZ67 biocomposite beads with different [CS]:[Co] molar ratios were synthesized and their performance was compared for Malachite green dye adsorption. The synthesized compounds were characterized using different analyses. Among the three biocomposites synthesized with different molar ratios, CSZ67-1 showed the highest removal efficiency (96%) and adsorption capacity (476 mg/g) at optimum pH 7. The effect of operating parameters, including initial dye concentration, adsorbent dose and solution pH, on dye adsorption by CSZ67-1 was studied. Dye removal followed pseudo-second-order kinetics and Freundlich isotherm. In this thesis, to investigate the possibility of using CSZ67-1 composite to remove pharmaceutical pollutants, tetracycline antibiotic was used as a model pollutant. The results showed that the CSZ67-1 biocomposite with a removal efficiency of 75% for tetracycline not only has a high efficiency for the adsorption of Malachite green cationic dye, but also shows a good performance for the adsorption of tetracycline as a pharmaceutical pollutant
  9. Keywords:
  10. Chitosan ; Metal-Organic Framework ; Photocatalytic Degradation ; Tetracyclines ; Malachite Green Dyes ; Green Synthesis ; Pollution Removal ; Dye Pollutants ; Pharmaceutical Pollutants

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