Many research works are striving to purify oil contaminated wastewater. Membrane with distinct affinity toward oil or water is one of the most promising method for oil-induced wastewater treatment. However, with the emulsifier present in most wastewater, the immiscible oil/water mixture is more difficult to be separated. Meanwhile, making use of the most abundant resource of seawater, solar vapour generation has emerged as a sustainable method for water distillation. However, traditional solar steam technologies still rely on expensive or cumbersome optical infrastructure or suffer from low energy efficiency. A water purification system with the ability to treat industrial oily wastewater and distill seawater is yet to be developed. In this thesis, a robust electrospun nanofibrous poly(vinyl alcohol) membrane (NPM) decorated with slow oxidization of polypyrrole nanoparticles was synthesized to realise dual-functional water purification. Scanning electron microscopy (SEM) was utilized to characterize the morphology of the NPM. Fourier-transform infrared spectroscopy (FTIR) was used to verify the chemical composition of the NPM. Contact angle tests were carried out to validate superhydrophilicity/underwater superoleophobicity of the NPM. Repeated oil/water emulsion separation tests were conducted to obtain the results of separation efficiency, separation flux and anti-fouling property of the NPM. UV-vis was utilized to test the light absorption ability of the NPM. Simulated sun tester was used to test the solar vapor generation capacity of the NPM. In summary, the NPM is capable of separating sundry organic solvents-water emulsions with a separation efficiency of over 99.99%. The NPM is also capable of desalinating the seawater under one sun solar radiation with an evaporation rate of 2.87 kg m-2 h-1.