Structural effects of chloraminated seawater on the SW30HR reverse osmosis membrane

[摘要] There is a need for a more comprehensive understanding of how disinfectants, applied to control biofouling of reverse osmosis (RO) membranes, react with the polymeric active layer and affect membrane performance as a result. This work investigates structural and performance changes to the SW30HR RO membrane exposed to seawater disinfected with monochloramine. Batch experiments with RO membranes were conducted to determine the effect of secondary oxidizing agents formed from the reactions of monochloramine with bromide and iodide on membrane structure. Membrane coupons were exposed to varying concentrations of monochloramine (2, 20 and 200 mg/L as Cl2) in synthetic seawater containing proportional levels of bromide (65, 650 and 6,500 mg/L) and iodide (0.06, 0.6 and 6 mg/L) and various contact times to achieve target exposures. Batch experiments also exposed membranes to real seawater treated with monochloramine (2 mg/L as Cl2) for 68 days. Rutherford back-scattering spectrometry (RBS) and ATR-FTIR analyses revealed structural changes corresponding to transformations of reverse osmosis membrane polymers including halogenation of the polyamide active layer and polysulfone support near the interface with the active layer.

[效力级别] monochloramine

[关键词] desalination;monochloramine;polyamide halogenation;polysulfone support halogenation;reverse osmosis membrane