Atoms, the basic units of chemistry, are called ions when an atom gains or loses electrons. And, a new ionic water treatment technology is being developed to treat drinking water and wastewater from dangerous toxins.
Engineers from Rice University in Houston, Texas, respectively the lab of engineer Qilin Li, are designing a system than can be tuned to selectively pull toxins from drinking water and wastewater from factories, sewage systems and oil and gas wells.
Li, who is a professor of civil and environmental engineering and of materials science and nanoengineering, said “There are a lot of ions in water. Not everything is toxic. For example, sodium chloride (salt) is perfectly benign. We don’t have to remove it unless the concentration gets too high. For many applications, we can leave non-hazardous ions behind, but there are certain ions that we need to remove.”
The heart of Rice’s system is a set of novel composite electrodes that enable capacitive deionization. The charged, porous electrodes selectively pull target ions from fluids passing through the maze-like system. When the pores get filled with toxins, the electrodes can be cleaned, restored to their original capacity and reused.
The new technology has the potential to be used to remove arsenic from drinking water wells, lead and copper from water that is piped, and in industrial applications where there are calcium and sulfate ions that form scale buildup.
Reverse osmosis, a well-known water treatment system, removes everything. The goal of the ionic system is to
determine a way to just remove minor components and therefore save money and energy.
Right now, it’s being built to work with current commercial water-treatment systems. There is optimism the system could be scaled-down to be used for in-home water purification systems for the future.