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Synthesis of Nano Porous Mixed Matrix Polymeric Membranes by TIPS Method for Gas Separation Application

Jahanbakhsh Asl, Hannaneh | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45417 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Soltanie, Mohammad
  7. Abstract:
  8. Mixed matrix membranes (MMMs) are new generation of membranes which possess simple processability of polymeric membranes and high separation ability of zeolitic membranes. The present study, concentrates on the fabrication of MMM for CO2/CH4 separation in a combined method as encompasses not only higher permeability but also superior selectivity in comparison with conventional polymeric membranes. The most appropriate technique for MMM making, is the process which provides participation of distributed zeolite particles in separation efficiently while the polymeric matrix acts just like a particle support and dose not play an effective role in separation. Investigations demonstrates that liquid-liquid thermally induced phase separation (L-L TIPS) method, creates desired structure for MMM. However, TIPS method requires elevated temperature to prepare homogen polymeric solution which makes it restricted. Therefore, we employed a combined method to fabricate membranes based on solvent-nonsolvent and thermally induced phase separation.
    As a result, the prepared polymeric solution has diluent in addition of a few amount of solvent and being homogenized in relatively lower temperatures compared with TIPS method. As a final point, employed method created a combination of conditions required for zeolite particles cooperation at separation and lower preparation temperature.As the first step, various combination conditions investigated and different polymeric membranes manufactured by homogenized solution at 140°C for 2 hr containing 27.5 wt. % polyethersulfone, various amount of phenyl benzoate as diluent and N-Methylpyrrolidone (NMP) as solvent. A variety of tests conducted on the membranes which demonstrated the reduction of porosity, distilled water flow, average pore sizes, and glassing temperature by increases at phenyl benzoate/NMP ratio. Moreover, at 3:1 ratio of phenyl benzoate/NMP, bath temperature had a direct relation with ultimate porosity and average pores size, in contrast any increase at bath temperature lead to glassing temperature reduction. In conclusion, optimum state obtained for a mixed matrix membrane with 3:1 ratio of phenyl benzoate/NMP, 25 wt. % polyethersulfone, and 20-30 wt. % Sapo-34 zeolite. Results indicated that elevation of zeolite concentration at membrane, lessen the porosity and glassing temperature however ascend heat resistance and the CO2/CH4 selectivity. At last, for a mixed matrix membrane including 30 wt. % Sapo-34 zeolite at 2 bar pressure, maximum number for selectivity of CO2/CH4 was 80.37
  9. Keywords:
  10. Carbon Dioxide ; Methane ; Mixed-Matrix Membrane ; Solvent-Nonsolvent and Thermally Induced Phase Separation Combination Method ; Zeolite SAPO-34

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