Adsorption of copper(II) onto perlite

Perlite samples activated by H2SO4 solutions were utilized as adsorbents fo r the removal of Cu(II) ions from solutions at different pHs, ionic strengt hs, and temperatures. It has been found that the amount of Cu(II) adsorbed increased with increased pH, whereas it decreased as the ionic strength, te mperature, and acid activation increased. Adsorption isotherms correlated r easonably well with the Langmuir adsorption isotherm and Langmuir parameter s of adsorption isotherm (Q(m) and K) were found with the aid of the linear ized Langmuir isotherm. The entalphy change for Cu2+ adsorption has been es timated as -5.14 +/-1 and 4.38 +/-1 kJ/mol for unexpanded and expanded perl ite samples, respectively. Proton stoichiometry (x) was calculated from Kur batov plot using the amount of Cu(II) adsorbed at different pH. The dimensi onless separation factor (R) has shown that perlite can be used for removal of Cu(II) ion from aqueous solutions, but unexpanded perlite is more effec tive. (C) 2001 Academic Press.