Boron substituted MFI-type zeolite-coated mesh for oil-water separation

A boron substituted zeolite-coated mesh was synthesized by a secondary growth method. The inclusion of boron ions significantly increased the hydrophilicity of the resultant mesh. Using gravity as the driving force and upon exposure to a water/oil mixture, water permeated into and through the zeolite mesh, while oil was rejected. With increasing boron content in the zeolite-coated mesh, the hydrophilicity of the mesh was enhanced, while the oil droplet contact angle increased from 136.8° to 162.0°. For a B/Si ratio of 0.04, the zeolite-coated mesh showed super-hydrophilicity. At this ratio, the oil rejection rate of the zeolite-coated mesh reached >99% for a water flux of >14,000 L m⁻² h⁻¹. The zeolite-coated mesh showed high chemical stability and the aforementioned oil rejection rate whether treated with acidic, basic or hot media. The mesh were successfully reproduced by a simple re-calcination method due to their thermal stability. Slight degradation of the oil rejection performance less than 1% was observed after the third re-calcination. Various organic solvents, such as n-hexane, cyclohexane, mineral oil, and vegetable oil were also separated via boron substituted zeolite-coated mesh, in conjunction with oil rejection rates of >96.5%.