Inkjet printing of dopamine followed by UV light irradiation to modify mussel-inspired PVDF membrane for efficient oil-water separation

Mussel-inspired polydopamine (PDA) modification of membrane is an effective alternative for improving permeation flux and anti-fouling performance. Meanwhile, efficient method for oil-water emulsions separation is still highly desired. However, problems, such as time-consuming process and low utilization ratio of expensive raw material, have always been stumbling block to application of this strategy. In this study, inkjet printing of dopamine (DA) followed by UV light irradiation to modify mussel-inspired polyvinylidene fluoride (PVDF) membrane was proposed. Accordingly, PVDF membrane was inkjet printed by alternately using DA inks and alkaline tris (hydroxymethyl) aminomethane (Tris) ink. The resultant membrane was then subjected to photopolymerization under UV irradiation to form a PDA layer. Successful formation of PDA layer on membrane surface was verified by series of physical and chemical methods . The optimized membrane (DA 80-60 /PVDF) exhibited superior oil/water separation performance with 1.5 times permeate flux higher than that of the pristine PVDF membrane and above 99% oil rejection rate. Meanwhile, the modified membranes showed satisfactory stability in aqueous solution with wide pH range (pH 2.0–7.0). The novel membrane modification method proposed in this study is facile, cost-saving and environment-friendly, serving as a competitive candidate for fabrication of efficient membranes for oil-water emulsion separation.