Abstract: Symmetrical quaternary ammonium compounds of the formula ##STR1## are disclosed, wherein each Ar is identical and is phenyl or a condensed polynuclear aryl group having 2 to 4 aryl nuclei, each R is identical and is alkyl of 1 to 4 carbon atoms, X.sup..crclbar. is a salt-forming anion of valence 1 or 2 and n is 1 or 2 depending on the choice of X. Also disclosed are apparatus and processes for the recovery of heavy metals such as silver, gold and other precious metals from solution in water. The disclosed quaternary ammonium compounds are adsorbed to a suitable substrate, preferably alumina, and the treatment water is passed therethrough. A second bed of divided metal such as aluminum is disclosed for use in series with the bed incorporating the quaternary ammonium compounds.

Abstract: Symmetrical quaternary ammonium compounds of the formula ##STR1## are disclosed, wherein each Ar is identical and is phenyl or a condensed polynuclear aryl group having 2 to 4 aryl nuclei, each R is identical and is alkyl of 1 to 4 carbon atoms, X.sup..crclbar. is a salt-forming anion of valence 1 or 2 and n is 1 or 2 depending on the choice of X. Also disclosed are apparatus and processes for the recovery of heavy metals such as silver, gold and other precious metals from solution in water. The disclosed quaternary ammonium compounds are adsorbed to a suitable substrate, preferably alumina, and the treatment water is passed therethrough. A second bed of divided metal such as aluminum is disclosed for use in series with the bed incorporating the quaternary ammonium compounds.