doi:10.1038/nindia.2015.150 Published online 16 November 2015
Researchers have synthesized a porous aerogel membrane that can extract water from oil–water emulsions1. This biopolymer membrane is potentially useful for recovering water from oil–water emulsions in industrial wastewater.
Discharging untreated industrial wastewater results in oil–water emulsions entering water bodies. These emulsions threaten aquatic life because they rapidly increase the chemical and biological oxygen demands of water bodies.
The researchers synthesized the highly porous aerogel membrane by mixing chitosan with plant-derived genipin and the polymer agarose, which is derived from red seaweed. They then probed the efficiencies of the membrane in extracting water from two oil–water emulsions: a crude biodiesel–water emulsion and oil-laden wastewater.
The scientists evaluated the time-dependent separation of water from the emulsions. The membrane allowed water to pass through it, but it blocked the oily components of the emulsions. The membrane separated almost 99 per cent of the water in the emulsions.
This separation process deformed the membrane surface, but washing it in deionized water restored its surface porosity, allowing it to be reused. “When buried in soil, the membrane degraded under normal soil conditions, suggesting that it is biodegradable,” says lead researcher Ramavatar Meena.
1. Chaudhary, J. P. et al. Chitosan-based aerogel membrane for robust oil-in-water emulsion separation. ACS Appl. Mater. Interfaces 7, 24957–24962 (2015)