Novel in-situ electroflotation driven by hydrogen evolution reaction (HER) with polypyrrole (PPy)-Ni-modified fabric membrane for efficient oil/water separation

Efficient separation of oil/water emulsion is still a worldwide challenge. Herein, a new conception/strategy of insitu electroflotation driven by hydrogen evolution reaction (HER) combining with a polypyrrole (PPy)-Ni-modified fabric membrane was proposed for efficient oil/water separation. To realize this new conception, nickel-decorated polyester fabric membrane was successfully fabricated via facile electroless Ni plating process on the polypyrrole (PPy)-modified surface. The Ni-decorated fabric membrane processed superhydrophilicity, underwater superoleophobicity and excellent electrical conductivity (electrical resistance of similar to 14.1 Omega), which could serve as cathode for HER. The fabric membrane itself couldn't separate oil/water emulsion, but achieved extremely high permeation (above 12526.5 L m(-2) h (-1)) and oil rejection (above 98.6%) for separating stratified oil/water mixtures under gravity force. By applying an extra electric field on the conductive fabric membrane, an in-situ electroflotation process driven by HER can be produced. Under the optimized electroflotation conditions (20.0 V cm(-1) electric field intensity, 20 g L-1 electrolyte concentration and 30 min electroflotation time) in this study, this new process could efficiently separate oil/water emulsion with high permeation flux (840.6 L m(-2) h (-1)) and oil rejection (98.5%). The present work provided a new conception of in-situ electroflotation-membrane separation process for treatment of oily wastewater, showing strong application significance.

Automated summary

A new conception/strategy of in-situ electroflotation driven by hydrogen evolution reaction (HER) combined with a polypyrrole (PPy)-Ni-modified fabric membrane was proposed for efficient oil/water separation. The Ni-decorated fabric membrane exhibited superhydrophilicity, underwater superoleophobicity and excellent electrical conductivity, serving as cathode for HER. The optimized electroflotation process efficiently separated oil/water emulsion with high permeation flux and oil rejection, showing strong application significance in treating oily wastewater.