engleski

Preliminary Assessment of Potential Disposal of Mercury-saturated Natural and Modified Zeolite Clinoptilolite

Utilization of natural raw materials, such as zeolites, for the remediation of mercury- contaminated environments is desirable. The main issue is the possibility of disposing mercury-saturated zeolite in nature without negative impact on the environment. In order to get an answer to this issue, the sorption properties of natural and modified zeolite were first examined. Two-stage modification of the natural zeolite was performed with aqueous solutions of Fe(NO)3∙9H2O and Na2S∙9H2O, with detailed physicochemical characterization. At the defined optimal sorption conditions, pHo = 2 and solid/liquid ratio of 10 g/L, the obtained sorption capacity of natural zeolite was 0.282 mmol Hg/g, and of modified zeolite 0.966 mmol Hg/g. Almost 3.5-fold higher sorption capacity of modified zeolite justifies modification method. Leaching experiments confirmed that the modified zeolite retains mercury better than the natural one. The Toxicity Characteristic Leaching Procedure indicated the presence of mercury in leachates above the prescribed value of 0.2 mg/L, pointing that saturated zeolites should be stabilized/solidified before disposal.

natural zeolite, modified zeolite, sorption, leaching, mercury

nije evidentirano