Chromium(III) removal by poly(ethyleneimine) granular sorbents made by a new process of templated gel filling

By the new process of templated gel-filling (TGF), a gel-type granular sorbent has been prepared using poly(ethyleneimine) as the chelating resin, Cr3+ as the template ion and glutaraldehyde as the crosslinking agent. The templating is found to increase the Cr(III) selectivity of the base resin PEI, in binary mixtures of Cr(III) with Cu(II), Ni(II) and Fe(III). The new TGF sorbent has, however, significant Cr(III) selectivity only relative to Ni(II), being much superior to the commercial resin Chelex-100 in this respect. The Cr(III) sorption on both these sorbents is enhanced significantly by NaCl and Na2SO4, the effect being more marked on the TGF sorbent which shows greater than 100% increase in Cr(III) sorption capacity in 0.5 M NaCl and 0.25 M Na2SO4 solution containing Cr(III) in low concentrations. The sorbent is thus suitable for removing low level chromium from strong salt solutions and has fast kinetics with a tilt of 1.5 min in 2 mM Cr(III) solution.