Solar desalination of oilfield brines using nanogel materials

Abstract

The oil and gas industry is currently facing an environmental and economic challenge with the production of water from their wells. In this paper, a novel solution to these challenges is proposed by implementing solar absorbing hydrogels to aid in the desalination of this brine. The hydrogel uses poly(vinyl alcohol) as its backbone and insulator and is crosslinked with polypyrrole as the solar absorber. Internal features show improved fluid flow into the hydrogel which are supported by swelling tests. Dimensions of this hydrogel can affect the overall performance. Data shows that hydrogels with a thickness of at least 2 cm have the highest desalination rate. To apply it to oilfield brines, a lab-stock brine with a TDS concentration of 230,000 ppm was used as well as untreated produced water samples collected from select geological formations. Lab-stock brines showed desalination rates nearly 2.5 times higher when these hydrogels were used and field samples showed desalination rates up to 4.5 times higher. Condensed water samples showed greater than 99% decreases in major ions present in the water.