Sorption aided process for the removal and recovery of Zinc (II) using salicylaldoxime immobilised silica gel

Abstract

<span style="font-size:14.0pt;font-family:" times="" new="" roman";color:black;mso-bidi-font-weight:="" bold"="" lang="EN-IN">Salicylaldoxime immobilised silica gel was used as an effective solid phase surface, for the preconcentration, removal or recovery of zinc ion from aqueous phase. The efficiency was tested by the equilibrium sorption study both in batch and column operations. The efficiency increases with the shaking period, agitation speed, adsorbent dose, temperature and flow rate but is independent on the volume of the solution. Maximum adsorption was found to occur at <i>p</i>H 5.5. Alkali metal, alkaline earth metal and ammonium salts do not influence the adsorption process. Heavy metal ions viz. Cu(II), Ni(II), Co(II) and Fe(III) get adsorbed by the said process but at much different <i>p</i>H values. Complexing ligands like EDT A and cyanide markedly decrease the adsorption of Zn(II) by the said procedure. The adsorption data fits well the Langmuir adsorption isotherm model. The negative free energy change indicates that the process is favourable as well as spontaneous. The merit of the process lies with its high preconcentration factor.

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