An industry-academia collaboration, led by professor Toshinori Tsuru at Japan’s Hiroshima University, has developed a new desalination membrane which the researchers claimed can withstand extraordinarily high concentrations of chloride and the cleaning agent, hypochlorite.
The team has made an organosilica material for use in the separation layer of a reverse osmosis membrane. The research team has reported that the membrane’s organosilica chemistry imparts resistance to chloride concentrations of up to 35,000 parts per million (ppm) compared to the 15,000-ppm limit of conventional polyamide membranes and it is stable at temperatures up to 90°C.
The scientists said the membrane also withstands concentrations of hypochlorite at 100- 1,000 ppm. The oxy-chlorine anion is frequently used to prevent biofouling in reverse-osmosis (RO) systems.
The work is the culmination of a five-year project that began in 2011 with support from the Japan Science and Technology Agency.
In laboratory immersion tests, the membrane – based on bis(triethoxysilyl) ethane - showed a sodium chloride rejection greater than 99%, which outstrips commercially available seawater- desalination membranes, while almost equalling their water permeability.