Tailor-Made Polyelectrolyte Multilayers for the Removal of Obidoxime from Water in Microfiltration Process

The aim of this study was to develop and review the properties including removal efficacy of novel polyelectrolyte based multilayers against a pharmaceutical, obidoxime (OBD) from water. After examining a wide range of bilayer pairs based on different polyelectrolytes, the layer-by-layer (LbL) modification of polyamide microfiltration membrane with a uniform coating of poly(diallyldimethylammoniumchloride) (PDAC) and poly(sodium styrene sulfonate) (PSS) multilayers was found to be effective in its removal. The characterization of the bilayer pair was done with analytical instruments like UV-vis spectroscopy, ATR-FTIR, spectroscopic ellipsometry, TGA, SEM and AFM. The characterization of bilayer pairs demonstrated the stability and integrity of bilayer pair. The removal efficiency of bilayer buildup was analyzed by adjusting different assembly conditions and other filtration parameters. The maximum removal rate by the bilayer was 99.26% for 7 bilayer with average permeate flux of 6.19 m3/m2 day. These bilayers exhibit stable rejection properties under various applied conditions including change in pH, presence of anions, and macromolecules etc. suggesting its potential rejection application. The major factors that facilitate the rejection are found to be hydrophilic interaction and steric factor. The present study validated the application of polyelectrolyte modified microfiltration membranes as a potentially feasible and promising method for the removal of obidoxime residues from water matrix.