Peracetic acid (PAA) has been proposed as a cleaning agent for polyamide-based water purification membranes, but its potential of being used as a disinfectant for the membrane feed in wastewater recycling systems has not been thoroughly investigated. In this work, we showed that PAA induced much less change in the performance and material characteristics of NF90 polyamide membranes than the traditional disinfectant chlorine. Upon exposure to 1–180 g h L-1 of PAA, the change in membrane water flux and the rejection of salt and neutral organic compounds was significantly less than that resulted from chlorine exposure at levels as low as 1 g h L-1. The presence of two wastewater constituents, chloride or Fe(II), did not significantly impact membrane performance upon exposure to PAA. Surface characterization showed that oxygen was incorporated into polyamide by PAA, some of which could be attributed to the formation of carboxylic acid groups. Experiments using a model aromatic amide, benzanilide, indicated an unexpected role of PAA in protecting membrane from radicals formed by Fe(II) and the H2O2 present in commercial PAA formulations. Furthermore, product identification suggests that both amide bond breakage and ring oxidation are possible reaction mechanisms for PAA. This is one of the pioneering efforts to demonstrate the viability of PAA as a disinfectant for wastewater recycling systems.

Compatibility of polyamide membranes with peracetic acid disinfectant: A comparative study with chlorine

ACS Fall 2021

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