Chemical aging and impacts on hydrophilic and hydrophobic polyether sulfone (PES) membrane filtration performances

To better understand the effect of chemical aging processes on membrane filtration performance, this study assessed chemical aging of hydrophobic and hydrophilic polyether sulfone (PES) membranes via static immersion in and dynamic filtration with a sodium hypochlorite solution. After chemical aging, the membrane's physicochemical characteristics (i.e., surface porosity, roughness, surface charge and hydrophobicity, modifiers distribution) and mechanical properties (i.e., tensile strength and elongation) were holistically studied. The results indicate the aging process was dependent on the aging intensity (e.g., 1–10 days) and modes (static or dynamic). PES membranes demonstrated faster and severer degradation in dynamic filtration than in static immersion. Furthermore, AFM-IR and FTIR microscopy with IR mapping were used to analyze the distribution of modifiers on the membrane surface after the aging treatment. Finally, the membrane filtration performance was investigated with the pure water permeability and the foulant rejection.