NJIT Professor Examining Alternative To Desalinating Water

Chemical engineer Kamalesh Sirkar, PhD, a distinguished professor at New Jersey Institute of Technology (NJIT) and an expert in membrane separation technology, is leading a team of researchers to develop a method to desalinate water, university officials announced on Feb. 9. Sirkar, who holds more than 20 patents in the field of membrane separation, said that using his technology, engineers will be able to recover water from brines with the highest salt concentrations. The Bureau of Reclamation in the U.S. Department of Interior is funding the project.

"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 membrane distillation process uses inexpensive fuel to heat the water and forces it to evaporate from the salt solution; the cleansed vapor then travels through nano-sized pores in the membrane and condenses in the cold water on the membrane's other side.

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 efficiency and selectivity increases. Membrane separation processes are used in biomedical, biotechnology, chemical, food, petrochemical, pharmaceutical and water treatment industries to separate/purify/concentrate liquid solutions or cellular suspensions or gaseous mixtures.

Typically Sirkar works with miniscule membranes, smaller in size than nanometers. A nanometer is one billionth of a meter.

Sirkar envisions many future applications for his process. "Desalinating seawater to stimulate economic development and create potable water always has an attentive audience," he said.

Additional information on membrane separation technology research can be found at http://www.njit.edu/alumni/pdf/BeertoBlood.pdf.

Kamalesh K. Sirkar: http://chemicaleng.njit.edu/people/profiles/sirkar.php

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