화산재에 의한 수용액의 납 이온 흡착특성

초록

The feasibility of using volcanic ash for lead ion removal from wastewater was evaluated. The adsorption experiments were carried out in batch tests using volcanic ash that was treated with either NaOH or HCl prior to the use. Volcanic ash dose, temperature and initial Pb(Ⅱ) concentration were chosen as 3 operational variables for a 23 factorial design. Ash dose and concentration were found to be significant factors affecting Pb(Ⅱ) adsorption. The removal of Pb(Ⅱ) was enhanced with increasing volcanic ash dose and with decreasing the initial Pb(Ⅱ) concentration. Pb(Ⅱ) adsorption on the volcanic ash surface was spontaneous reaction and favored at high temperatures. Calculation of Gibb's free energy indicated that the adsorption was endothermic reaction. The equilibrium parameters were determined by fitting the Langmuir and Freundlich isotherms, and Langmuir model better fitted to the data than Freundlich model. BTV(base-treated volcanic ash) showed the maximum adsorption capacity() of 47.39mg/g. A pseudo second-order kinetic model was fitted to the data and the calculated values from the kinetic model were found close to the values obtained from the equilibrium experiments. The results of this study provided useful information about the adsorption characteristics of volcanic ash for Pb(Ⅱ) removal from aqueous solution.

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