โ Scribed by N.S.C. Becker; R.J. Eldridge
No coin nor oath required. For personal study only.
Strong-base and weak-base anion exchangers are able to remove mercury(II) selectively from chloride-containing solutions at pH 1.5. Leakages are lower from the strong base resin IRA900 than from the weakly basic IRA93, but at initial Hg concentrations of 10-40 mg/1 mercury leakage from both is below 20 tzg/l over at least several hundred bed volumes. Conventional regenerants are ineffective, but Hg(II) is readily desorbed by complexing agents. Desorption reaches 100% in 5 bed volumes of 1.5 M aqueous 1,2-diaminoethane or about 15 bed volumes of 1 M sodium sulfite solution. In some cases the desorbed Hg(lI) complex crystallizes from the regeneration effluent, allowing the regenerant to be recycled. Chemical or electrolytic reduction of the recovered Hg(II) yields valuable byproduct Hg(I) or Hg(0).
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