Copper hydroxyphosphate nanosheets-covered robust membranes with superhydrophilicity and underwater ultralow adhesive superoleophobicity for oil/water separation and visible light photodegradation

Abstract

With the rapid increase of oil pollution accidents, the purification of oily water has become a serious global problem to be solved. Herein, the Cu2(OH)PO4 nanosheets-covered robust mesh membranes are fabricated by a facile green wet-chemical method at different pH conditions. By the combination of the superwetting ability with photocatalytic performance of Cu2(OH)PO4, the nanosheets-covered mesh membrane fabricated at pH 9.7 exhibits a superhydrophilicity and underwater ultralow oil adhesive superoleophobicity for efficient removal of various oils from water with an oil sliding angle about 1.4°. Simultaneously, the membrane presents a high photocatalytic activity for methylene blue under visible light irradiation. After 15 cycles of separation, the test demonstrates a superior separation stability of the membrane with high permeating flux of ∼94,801 Lm−2 h-1 and separation efficiency above 99.5%. In consideration of the excellent mechanical property, chemical stability, thermal resistance and high separation capacity, the as-prepared mesh membrane is promisingly applied in purifying oily wastewater.