Extraction and recovery of soft metal ion by porous silica coated by hydrophilic polymer gel with hexavalent nitrogen-donor ligand

Abstract

ABSTRACTA hydrophilic N-isopropylacrylamide (NIPA) gel copolymerized with a hexavalent nitrogen donor ligand, N,N,N’,N’-tetrakis(4-propenyloxy-2-pyridylmethyl)ethylenediamine (TPPEN), adsorbs soft metals selectively from the acidic aqueous phase. We are developing porous silica particles coating the TPPEN-NIPA gel with high TPPEN content thinly on the pore surface of porous silica by a new gel-coating method using surface tension. Half of the pore volume of the silica particles remained by the coating of the TPPEN-NIPA gel with the high TPPEN content of 30 mol%. A large separation factor (SF) of Cd(II)/Eu(III) of 60 was observed at pH 2. The proposed chromatographic agent with the high TPPEN content is applicable for practical use.