Preparation of Dopamine-Coated Polysulfone Membrane Functionalized by Au Nanoparticles and Removal of Rhodamine from Wastewater

The composite material based on polysulfone (PSF) membrane was synthesized as an adsorbent to treatment of dye wastewater. Here, a gold nanoparticle-functionalized PSF/PDA adsorbent (PSF/PDA-Au) was prepared by a three-step method, the polysulfone membrane was prepared by phase transformation method, then the membrane was immersed in 2 g/L dopamine solution for 24 h to obtain the dopamine-coated material, the product was eventually immersed in a chlorauric acid solution for 3 h. The chemical composition and morphology of the composite were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS), and measurement of contact angle. The efficiency of the adsorbent was evaluated by a series of experiments on the adsorption of the RhB dye. The reduced water contact angle of the adsorbent showed the improved hydrophilicity. Adsorption experiments have shown that PSF/PDA-Au effectively removes the RhB dye. At the same time, recirculation experiments showed that after four adsorption-desorption cycles, the removal rate can still reach 92.67%, indicating good stability of PSF/PDA-Au. Recyclability and convenient assembly of adsorbent using PSF flat membranes as support material make it an attractive candidate for removing dyes from wastewater.