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.

A Hierarchical Conical Array with Controlled Adhesion and Drop Bounce Ability for Reducing Residual Non-Newtonian Liquids

As a result of frequent food waste and environmental pollution,there has been an increasing demand for the development of packaging materials that intrinsically inhibit and reduce likelihood of non-Newtonian liquids adherence.In this work,inspired from ciliary structures on the leg of water strider,the hierarchical conical array was formed by magnetic field control and laser etching without any mask.Due to the tapered geometry of the cones and the multiscale surface roughness of the array,the droplets would bounce many times after impacting with the superhydrophobic surface(SHS)and roll off.By changing the spaces and apex angles of conical microcolumns the SHS has controlled adhesion,superior self-cleaning property and droplets bounce performance for a variety of non-Newtonian viscous liquids.After suffering from various types of damage including repeated tape tearing,finger touch and folding test,the SHS still maintained excellent superhydrophobic property,which may have potential application as all kinds of packaging interface materials.We demonstrate that the excellent droplets bounce behavior of the hierarchical array enables the efficient and robust prevention of food liquids adhesion.