"Our process will work especially well with brines holding salt concentrations above 5.5 percent," Sirkar said. Currently, 5.5 percent is the highest percentage of salt in brine that can be treated using reverse osmosis.
"We especially like our new process because we can fuel it with low grade, inexpensive waste heat," Sirkar said. "Cheap heat costs less, but can heat brine efficiently."
The science behind Sirkar's membrane distillation process is simple. The inexpensive fuel heats the water forcing it to evaporate from the salt solution. The cleansed vapor then travels through nano-sized pore in the membrane to wind up condensed in the cold water on the membrane's other side.
"The basic principles of membrane separation have been known for a long time," said Sirkar. "Intestines in animals and humans are semi-permeable membranes. Early experiments to study the process of separation were performed by chemists using samples of animal membranes."
Today, membrane separation processes depend on the design of the membrane and the membrane module. The size of the pores is often key to determining which molecular components in either a liquid or gas form will pass through the membrane. Typically molecules flow from a region of high to low concentration. Pressure or concentration differences on both sides of the membrane cause the actual separation to occur. As pore size decreases, the membrane's efficie
Contact: Sheryl Weinstein
New Jersey Institute of Technology