Author/Authors :
M. Mahdi Biodiesel Research Team (BRT), Microbial Biotechnology and Biosafety Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Mahdasht, Karaj, Iran , A. Shirazi Biodiesel Research Team (BRT), Microbial Biotechnology and Biosafety Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Mahdasht, Karaj, Iran , Meisam Tabatabaei Biodiesel Research Team (BRT), Microbial Biotechnology and Biosafety Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Mahdasht, Karaj, Iran , M. Javad A. Shirazi Young Researchers Club, Science and Research Branch, Islamic Azad University, Tehran, Iran , Yaghoub Mansourpanah Biodiesel Research Team (BRT), Microbial Biotechnology and Biosafety Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Mahdasht, Karaj, Iran , Ali Kargari Department of Petrochemical Engineering, Amirkabir University of Technology (Tehran Polytechnic)
كليدواژه :
direct contact membrane distillation , desalination , PTFE membrane , membrane characteristics
چكيده لاتين :
Membrane distillation process is an emerging technology for separation purposes traditionally
accomplished by conventional distillation or reverse osmosis. This process is based on the
hydrophobic characteristics of microporous membranes solely allowing the vapor to pass
through the pores of the membrane. Because specific membranes for membrane distillation have
not been developed yet, microfiltration membranes made of hydrophobic polymers are usually
used. In this work, twelve flat sheet commercial membranes made of PTFE were used and their
characteristics were investigated under different operating conditions contain three feed
temperatures (40, 60 and 80oC), four hot feed flow rates (200, 400, 600 and 800mL/min), four
cold stream flow rates (100, 200, 300 and 400mL/min), two feed concentrations (35 and 45g/L).
Membranes properties contain pore size, thickness, support layer and salt rejection investigated.
Long term performance for all membranes investigated to evaluation of direct contact membrane
distillation as stand-alone desalination process. Results shown that feed temperature has the
major effect on the permeate flux. Increase of hot feed flow rate led to reduction of polarizations
effect and increased the permeate flux, while cold stream flow rate had negligible effect.
Membranes with pore sizes of 0.45 and 1.0μm achieved higher flux while membrane with pore
size of 0.22μm achieved higher salt rejection. Increase of membrane thickness led to decrease of
the permeate flux due to increase of mass transfer resistance. Support layers had negligible effect
on the permeate flux and salt rejection.
