Fabrication and Wettability Study of WO3 Coated Photocatalytic Membrane for Oil-Water Separation: A Comparative Study with ZnO Coated Membrane

Mohammed A Gondal,Umair Baig,Gareth H Mckinley,Mohamed A Dastageer,Talal F Qahtan,Muhammad S Sadullah

doi:10.1038/s41598-017-01959-y

Abstract

Superhydrophilic and underwater superoleophobic surfaces were fabricated by facile spray coating of nanostructured WO3 on stainless steel meshes and compared its performance in oil–water separation with ZnO coated meshes. The gravity driven oil-water separation system was designed using these surfaces as the separation media and it was noticed that WO3 coated stainless steel mesh showed high separation efficiency (99%), with pore size as high as 150 µm, whereas ZnO coated surfaces failed in the process of oil-water separation when the pore exceeded 50 µm size. Since, nanostructured WO3 is a well known catalyst, the simultaneous photocatalytic degradation of organic pollutants present in the separated water from the oil water separation process were tested using WO3 coated surfaces under UV radiation and the efficiency of this degradation was found to be quite significant. These results assure that with little improvisation on the oil water separation system, these surfaces can be made multifunctional to work simultaneously for oil-water separation and demineralization of organic pollutants from the separated water. Fabrication of the separating surface, their morphological characteristics, wettability, oil water separation efficiency and photo-catalytic degradation efficiency are enunciated.

Highlights

In the age of ever growing industrialization and energy consumption, the mixing of crude oil in sea water and industrial effluents laden with oil components/pollutants are becoming more common and these adversely affects precious water bodies
By the simple method of spray coating, the nanostructured Zinc oxide (ZnO) and WO3 particles were deposited on the stainless steel meshes of different pore dimensions
It was observed that the coated surfaces with appropriate pore sizes showed high efficiency of oil water separation, contrary to the uncoated meshes, through which the oil water mixture just passed without separation

Summary

Introduction

In the age of ever growing industrialization and energy consumption, the mixing of crude oil in sea water and industrial effluents laden with oil components/pollutants are becoming more common and these adversely affects precious water bodies. This method is a gravity driven oil-water separation, where the separating medium is a porous surface like a stainless steel mesh coated with hydrophilic-oleophobic material, (wettable by water and non-wettable by oil).

Results

Conclusion