GO/Al₂O₃复合纳滤膜的制备及其稳定性能研究

Using an tubular Al₂O₃ ultrafiltration membrane with an average pore diameter of 20 nm as the carrier, after modified by dopamine, a pressure-driven deposition method was used to successfully prepare a GO/Al₂O₃ composite nanofiltration membrane that can be stable in aqueous solution for a long time. The thickness of GO layer can be controlled by changing the loading amount. The results showed that the pure water permeability of all GO/Al₂O₃ composite nanofiltration membranes decreased and then reached a steady state during the cross-flow filtration. In addition, the pure water permeability of GO/Al₂O₃ composite nanofiltration membranes decreased as the GO loading amount increased. The permeability and rejection of GO/Al₂O₃ composite nanofiltration membranes remained stable when GO loading amount was greater than 90 mg/m². As the storage time (in pure water) extended, the cross-linking of GO sheets caused by residual salt ions during tests led to a higher rejection of GO/Al₂O₃ composite nanofiltration membranes towards monovalent and divalent salts. After being immersed in pure water for 680 h, the GO/Al₂O₃ composite nanofiltration membrane with GO loading amount of 140 mg/m² showed the highest Na₂SO₄ rejection of 91.0%. The rejections of GO/Al₂O₃ composite nanofiltration membranes towards four salt solutions were as follows: R(Na₂SO₄) > R(MgSO₄) > R(NaCl) > R(MgCl₂).