Enhanced oxidation of polyamide membranes using monochloramine and ferrous iron

Gabelich, Christopher J.; Frankin, John C.; Gerringer, Fredrick W.; Ishida, Kenneth P.; Suffet, I. H.

doi:10.1016/j.memsci.2005.02.034

Cited by 96 publications

(62 citation statements)

References 21 publications

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“…The mechanism of chloramine attack on PA membranes has also been reported in the literature [11,15,27]. In these studies, the formation of amidogen radicals (•NH 2 ) has been suggested with the presence of some metal ions acting to catalyze their formation [15].…”

Section: Introductionmentioning

confidence: 87%

“…This suggests that the metal ions catalyse the formation of the •NH 2 radicals that can, in turn, lead to increased membrane degradation [15,27].…”

Section: Loss Of Chloramine In the Presence Of Metal Ionsmentioning

confidence: 99%

“…The effects of chlorination on RO membranes that are made of PA have been widely reported in the literature [10][11][12][13][14][15][16][17][18]. Generally these studies conclude that chlorine causes irreversible damage to the PA membrane resulting in a loss of membrane integrity.…”

Section: Introductionmentioning

confidence: 99%

“…In these studies, the formation of amidogen radicals (•NH 2 ) has been suggested with the presence of some metal ions acting to catalyze their formation [15]. The formation of the radical species occurs by a two-step electron transfer mechanism with the •NH 2 radical produced as an intermediate product [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

“…It is suggested that the mechanism of degradation is the same as that observed for chlorine and chlorine dioxide although the aggressiveness of chloramine is somewhat lower [11,31]. The precise degradation pathways that lead to the ultimate failure of the PA membrane layer in the presence of chloramine are still relatively unexplored [15].…”

Section: Introductionmentioning

confidence: 99%

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Degradation of polyamide reverse osmosis membranes in the presence of chloramine

2011

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Exposure to relatively low concentrations of chlorinated chemicals such as hypochlorite can reduce the performance and ultimately result in the failure of polyamide (PA) reverse osmosis membranes. Whereas the tolerance of PA membranes to chloramine solutions is considerably higher than that of hypochlorite, the presence of some metal ions can potentially catalyze and accelerate degradation reactions. Spectroscopic techniques are commonly used to qualitatively assess the chemical degradation of membranes by observing changes in structural peaks. This paper presents a technique to quantitatively evaluate changes in PA membranes exposed to chloramine by means of a peak ratio derived from a typical amide peak and an invariant peak in the same spectrum. The effect of some common metal ions and combinations of these on the peak ratio parameter derived from a typical amide peak is also reported.

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