Treatment system selectively removes toxins from water

The Rice University lab of engineer Qilin Li is building a water treatment system that can be tuned to selectively pull toxins from drinking water and wastewater from factories, sewage systems and oil and gas wells.

"Traditional methods to remove everything, such as reverse osmosis, are expensive and energy intensive," said Li, the lead scientist and co-author of a study about the new technology published in Environmental Science & Technology. "If we figure out a way to just fish out these minor components, we can save a lot of energy."

According to Rice, a set of novel composite electrodes that enable capacitive deionisation are central to the system. The charged, porous electrodes selectively pull target ions from fluids passing through it When the pores get filled with toxins, the electrodes can be cleaned, restored to their original capacity and reused.

"This is part of a broad scope of research to figure out ways to selectively remove ionic contaminants," said Li, a professor of civil and environmental engineering and of materials science and nanoengineering. "There are a lot of ions in water. Not everything is toxic. For example, sodium chloride is perfectly benign. We don't have to remove it unless the concentration gets too high.