Impregnated type sorbents based on benzo-15-crown-5 for gold(III) extraction from hydrochloric solutions

A series of sorbents based on benzo-15-crown-5, various supports (styrene-divinylbenzene LPS-500, hydrophobized silica gel), and diluents (octan-1-ol, nitrobenzene, 1,1,7-trihydrododecafluoroheptanol (FHA), ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (C(4)mim(+)Tf(2)N(-))) and without diluents was obtained. The sorbents without diluents with the benzo-15-crown-5 content 20-30% have the maximum sorption characteristics (recovery of gold higher than 90%). The influence of the diluent and support nature, procedure of support pretreatment, impregnation time and temperature, and the solvent for impregnation on the sorption characteristics was studied. The maximum sorption characteristics were found for the sorbents based on the styrene-divinylbenzene support LPS-500. A high selectivity of the obtained sorbents toward gold was established, and the recovery of gold higher than 95% was achieved by the optimization of the synthesis procedure of the sorbents.