Long-Lasting Filtration of Oily Water by Anti-Fouling Underwater Oleophobic Sand Particles

The produced water from the oilfield was purified with filter material and then injected back into the ground. The serpentine filter material was easy to harden with the increase in filtration amount, which affected the water quality. A superhydrophilic/underwater oleophobic serpentine filter material was successfully prepared by a simple method of coating modification, which exhibited long-lasting filtration of oily water, good filtration and anti-fouling properties, and resistance to harden. The film-forming material of the superhydrophilic/underwater oleophobic coating was composed of SiO 2 particles with small size, which could completely and evenly cover the filter particle. The weight loss was only 7.6% after mechanical stirring for 90 min. Compared with the original filter material, the superhydrophilic/underwater oleophobic serpentine filter material showed a better anti-fouling ability and resistance to harden. The filtration of crude oil emulsion and oil slick sewage showed a better backwashing performance. After 35 cycles of continuous filtration of suspended solids in wastewater, the backwashing rate reached 78.4%. The results provided an effective method for the filtration of oily wastewater in the oilfield.