ABSTRACT
Basic anion exchange resins retain the anionic nitrogen (N) species, that is, nitrate, nitrite, and cyanide, while ammonium ion is adsorbed on resins of the sulfonic acid type. Cyanide ion (CN), when present as an alkali cyanide or soluble metal cyanide, is readily adsorbed on strongly basic resins in the hydroxide forms. Co adsorbed with cyanide are other anions such as nitrate, nitrite, sulfate, and phosphate, but not metal cations and also not ammonia. Adsorption of azo dyes on cation exchange resins has been employed for the microchemical detection of nitrite using the resin spot tests. Free ammonia or ammonium ion is not adsorbed on basic anion exchange resins in the hydroxide forms. From neutral to slightly acid solutions ammonium ion is adsorbed on cation exchange resins of the sulfonic acid type to an extent comparable to that of Potassium (K).
