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Synthesis of Metal-organic Frameworks (MOFs) Nano-hybrids for Removal of Organic Pollutants from Petrochemical and Colored Wastewaters

Abdi, Jafar | 2018

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 54225 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Vossoughi, Manouchehr; Mahmoodi, Niyaz Mohammad; Alemzadeh, Iran
  7. Abstract:
  8. Physical processes such as adsorption and membrane filtration are in progress and considered as efficient methods in separation and treatment of organic pollutants from petrochemical and colored wastewaters. The advantages of these methods include high energy efficiency, low cost, facile process, and regeneration and implementation ability for a wide range of contaminants. Nevertheless,requirement of suitable materials as adsorbents with high adsorption capacity, capability of preparing membranes based on these materials, optimization of process conditions and removal improvement have still remained as the main challenges; therefore, these topics have been mentioned as main aims of this treatise. Accordingly, in this work, porous zeolitic imidazolate framework-8 (ZIF-8) was synthesized as a kind of metal organic frameworks (MOFs) and then different kinds of adsorbents such as ZIF-8@GO and ZIF-8@CNT hybrid nanocomposites, surface modified ZIF-8 nanoparticles with amine functional group and ZIF-8@SiO2@MnFe2O4 magnetic nanocomposite were prepared based on ZIF-8. The characteristics of these adsorbents were studied using FTIR, XRD, FESEM,SEM, TEM, BET, TGA and VSM techniques. The effect of several influential parameters such as adsorbent dosage, solution pH, initial dye concentration, temperature and contact time were well studied on the removal efficiency of different cationic and anionic dyes. The results showed that the removal rate of malachite green (MG) dye with hybrid nanocomposites was faster than pure ZIF-8.Also, their maximum adsorption capacity (2034 and 3300 mg/g for ZIF-8@GO and ZIF-8@CNT,respectively) were higher than pure ZIF-8 (1667 mg/g) and temperature enhancement had a positive effect on the performance of all adsorbents. The effect of important parameters on the ultrasound assisted adsorption of the mixture of acid blue 92 (AB92) and Direct red 80 (DR80) dyes using ZIF-8 functionalized with 3-Aminopropyltrimethoxysilane (APTES) was investigated and optimized by response surface methodology (RSM). The results illustrated that the surface modification of ZIF-8 nanoparticles and sound irradiation by ultrasonic improved the mass transfer process and subsequently the performance of the adsorbent increased in dye removal. The results of RSM and determination of optimum values for the adsorption of dye molecules from the binary mixture of MO/MG with ZIF-8@SiO2@MnFe2O4 microspores magnetic nanocomposite showed the selective adsorption of MG dye by this adsorbent. Moreover, ANOVA results showed that the adsorbent dosage and sound irradiation time were the most effective parameters on the selective adsorption of MG dye. All prepared adsorbents exhibited high regenerable and reusability and good stability in aqueous phase. Furthermore, the adsorption isotherms, kinetics and thermodynamic were investigated for all adsorbents. From the other side, in this research, we studied the effect of the modulators such as acetic acid and water on the nucleation and formation of UiO-66 crystals. The results indicated that the morphology, particle size and crystallinity of UiO-66 were strongly affected by the presence of the modulators. In order to prepare the UiO-66-NH2/ZIF-8 composite membrane on top of the anodic aluminum oxide (AAO) support, different conditions of time and voltage parameters were evaluated by electrophoretic deposition (EPD) process to make a homogenous UiO-66 seed layer. Then, the intergrowth of UiO-66-NH2 crystals were optimized and finally the surface of the membrane was covered with ZIF-8 particles to get the UiO-66-NH2/ZIF-8 composite membrane. The results of phenol molecules separation from synthetic wastewater showed the excellent performance of this membrane with high rejection efficiency and ultra-high permeation flux. In addition, hybrid nanocomposites of UiO-66-NH2@CNTs with different weight percentage of functionalized carbon nanotubes were synthesized and used as a filler in the matrix of Polyethersulfon (PES) membrane to make mixed matrix membrane (MMM). The results showed that 5% loading of nanocomposite particles as an optimum value, improve the hydrophilic property of the membrane and increase its performance in the purification of colored wastewater including MG and DR80 dyes
  9. Keywords:
  10. Experimental Design ; Hybrid Nanocomposite ; Metal-Organic Framework ; Petrochemical Wastewater ; Dye Wastewater ; Organic Pollutant ; Ultrasound Assisted Adsorption ; Composite Membrane based on Metal Organic Framework (MOF)

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