(512c) Experimental Study of the Potential of Nano-Fibrous Membranes in Water Treatment Systems for Rural Communities | AIChE

(512c) Experimental Study of the Potential of Nano-Fibrous Membranes in Water Treatment Systems for Rural Communities

Authors 

Kumar, V., Indian Institute of Technology Delhi
Farnood, R., University of Toronto
Water is a crucial component for expecting life on earth. Having covered 70% of earth’s total surface, lack of drinking water is an escalating problem worldwide. Apart from the decreasing ground water level, available ground water in most of the places is contaminated by various ions above safe limits. Also, the increasing environmental pollution degrade the quality of fresh water available to human use. Rising population, industrialization, agriculture sector and urbanization have played a major role in depleting underground water level and polluting surface water resources. Desalination appears to be a promising practice to meet the fresh water demand. Effective techniques of water treatment and desalination need major focus to combat the issue.

Membrane Distillation is one such technology having high potential to produce fresh water and it has gained popularity due to the unique advantages it offers. Membrane distillation as a process for supplying fresh water, using microporous hydrophobic membranes, was introduced by Bodell for the first time. In 1967, Findley reported the basic theory and findings of the process.

The following experimental study concentrate on treatment of waste water using membrane distillation process. In membrane distillation systems, a warm feed solution comes in contact with microporous hydrophobic membrane, mass transfer occur due to vapor pressure gradient, and the vapor pass through the membrane pores to the permeate side. The vapors are collected and condensed outside the membrane cell. The hydrophobic membranes are fabricated using electrospinning process, under application of high electric field, which forms the fiber due to charge repulsion. The fiber mat properties i.e. pore size, thickness, porosity, roughness are controlled by electrospinning parameters and polymer solution characteristics. The fabricated membranes are characterized and tested for performance in membrane distillation systems. The effect of process parameters like feed temperature, flow rate, concentration on system performance is observed. The performance is defined in terms of permeate flux, permeate conductivity and rejection rate. The percentage reduction in permeate flux was also investigated at regular intervals of experimental runs. The process is run for longer durations to observe scaling of membrane. This study shows that membrane distillation is a viable technique for producing fresh water from wastewater/saline water. The process can be studied further for high performance membranes and alternative energy sources to obtain low cost treatment systems.