Département de chimie moléculaire

Electrochem. and membrane ultrafiltration methods (electro-oxidn. and liq. phase polymer based retention technique, LPR, resp.) were off-line coupled to remove As(III) inorg. species from aq. solns. Our main objective was to achieve an efficient extn. of arsenic species by assocg. a polymer-assisted liq. phase retention procedure, based on the As(V) adsorption properties of cationic water-sol. polymers, with an electrocatalytic oxidn. process of As(III) into its more easily removable analog As(V). The electrocatalytic oxidn. of As(III) to As(V) was performed in the presence of different water-sol. poly(quaternary ammonium) salts acting also as supporting electrolyte, i.e. poly(vinylbenzyl)trimethyl ammonium chloride, P(ClVBTA), poly[3-(methacryloylamine)propyl]trimethyl ammonium chloride, P(ClMPTA), and poly(4-vinyl-1-methylpyridinium bromide), P(BrVMP). After complete electrocatalytic conversion of As(III) into As(V), the mixts. were introduced into an LPR cell to remove the As(V)-polymer adducts. Using P(ClMPTA), P(ClVBTA), or P(BrVMP) ammonium salts in a 20:1 polymer:As(III) mol ratio at pH 8, complete (100{%}) retention of the arsenic was achieved. Moreover, the As(V) retention efficiency turned out to be directly related to the net charge consumed during the electrochem. conversion of As(III) to As(V). [on SciFinder(R)]