Effect of Temperature on The Removal of Some Heavy Elements by Friedel’s Salt

Abstract

The performance of Friedel’s salt (FS: 3CaO•Al2O3•CaCl2•10H2O), a layered double hydroxide (LDHs), as an adsorbent for iron (Fe3+) and cobalt (Co2+) removal from their solution is investigated. Friedel’s salt is synthesized by reaction of tricalcium aluminate with calcium chloride. The stability of FS at different pHs is studied. Also, the adsorption affinity of Friedel’s salt for iron (Fe3+) and cobalt (Co2+) ions from aqueous solutions at different concentrations and various initial pHs at room temperature and at 50ºC is examined. The results show a higher stability of FS at pH=6 than at pH=4 & 8. Friedel’s salt can adsorb all Fe3+ ions from solutions of concentration 0.1mM/l at pH= 4 and 6. Where as, all Co2+ ions can be adsorbed from (0.5mM/l) solution at pH= 4. Furthermore, increasing the temperature to 50º C affects positively the rate of adsorption of iron and cobalt ions on the FS.

Keywords: LDHs, Friedel’s salt, adsorption/exchange, iron, cobalt.