Fluence Corporation

Water treatment membrane coating promises chemical-free virus removal

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Courtesy of Fluence Corporation

A novel material coating for water treatment membranes promises to improve the removal of water-borne viruses during treatment.

This hydrogel coating, known as a zwitterionic polymer hydrogel, was created by scientists from Ben-Gurion University of the Negev and the University of Illinois at Urbana-Champaign.

The virus-fighting membrane was created by grafting the new hydrogel coating onto the surface of commercial ultrafiltration membranes.

The substance prevents viruses from both nearing and passing through the membrane. The term zwitterionic describes a substance with both positive and negative charges. The hydrogel weakens viruses, preventing them from accumulating on the modified filter surface. The researchers reported “a significantly higher rate of removal of waterborne viruses,” including human norovirus and adenovirus.

Alternative Water Sources

With more cities seeking alternative water sources as water scarcity increases, recycling of wastewater has increased. The specific concern of the research was the microbial safety of this treated water.

In the United States in particular, potable water reuse has been slow to catch on due to public reluctance, the so-called “ick factor.” Allaying some of these concerns is key in the wider acceptance of municipal water reuse. But some contaminants — particularly pathogenic viruses — remain a concern.

The researchers noted that membrane filtration can remove pathogenic viruses, “but the required energy is intensive.” Grafting the coating on an ultrafiltration polyethersulfone membrane resulted in “a significantly higher virus removal.”

The researchers stated:

This is an urgent matter of public safety. […] Insufficient removal of human Adenovirus in municipal wastewater, for example, has been detected as a contaminant in U.S. drinking water sources, including the Great Lakes and worldwide.

Indeed, when the United States Geological Service and Department of Agriculture collected water samples from eight rivers in the Great Lakes Basin from February 2011 to June 2013, they found both human and bovine viruses in some samples. The two pathogens most frequently detected across the samples studied were human adenovirus (in 9 percent of samples) and bovine polyomavirus (in 11 percent of samples).

Most adenovirus infections are mild and may require only care to help relieve symptoms; however, some fatalities have occurred. The U.S. Navy had an adenovirus outbreak at its Great Lakes basic training facility in 2000. The events were widely studied because there were fatalities.

The researchers said this simple graft-polymerization process is “a promising development for controlling filtration of pathogens in potable water reuse.” They did not indicate what the next steps, if any, would be in the testing, development, or commercialization of the material.

The full paper — “Improvement of virus removal using ultrafiltration membranes modified with grafted zwitterionic polymer hydrogels” — was published in the journal Water Research.

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