Batch and Column Studies for Metal Removal/Uptake under Uncontrolled/Controlled pH Conditions by Granular Activated Alumina from Mono-, Binary- and Ternary-Metal Ion Systems of Cu(II), Pb(II) and Cr(III) at Fixed Total Initial Concentrations
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The present work is aimed at carrying out kinetics, equilibrium and column studies for metal removal/uptake under uncontrolled/controlled pH conditions by granular activated alumina (GAA) from mono-, binary- and ternary-metal ion systems of Cu(II), Pb(II) and Cr(III) at fixed total initial metal ion concentration in the solution. The total metal uptakes under controlled pH conditions and total metal removals under uncontrolled pH conditions were observed to be similar and fairly independent of proportion of initial metal ion concentrations present in selected combinations of binary- and ternary-metal ion systems as long as total initial metal ions concentration in the combinations was approximately 0.60 meq/L. During two sets of batch tests, displacement of already adsorbed target mono-metal ions back into solution was observed along with non-target metal removal under uncontrolled pH conditions and non-target metal uptake under controlled pH conditions. When GAA loaded with a mono-metal system or combination of binary metal ion system during the first three loading cycles was exposed to another mono-metal ion system or another combination of binary-metal ion system in the fourth loading cycle, additional metal removal under uncontrolled pH conditions and additional metal uptake under controlled pH conditions of the other metal ions was observed. Further, the variations in metal removals and metal uptakes at equilibrium from mono-metal ion systems generally appeared to overlap at 95% confidence intervals with variations in total metal removals and total metal uptakes at equilibrium from the combinations of binary-metal ion systems and varied within a small band with the ternary-metal ion system having total initial metal ion concentration of 0.60 meq/L.
Supervisor: Mohammad Jawed