Preliminary investigation of zinc transport through zeolite-X barrier: Linear isotherm assumption

Hydrated sodium zeolite-X was synthesized and tested to evaluate its technical feasibility as a permeable reactive barrier (PRB) for remediating contaminated groundwater. Laboratory tests have been performed to characterize the synthesized material and determine some of its important physical and chemical properties. Batch and column techniques were used to give insight into the optimum conditions at which this material can efficiently retain zinc, as a model for bivalent cations, from contaminated aqueous solution. The batch investigations were directed to study the effect of initial zinc concentration and the plume pH on the retention characteristics. It was found that zeolite-X will efficiently remove Zn2+ ions from slightly contaminated groundwater under slightly acidic or alkali conditions. For highly contaminated groundwater and under acidic conditions, the zeolite efficiency for remediating the groundwater is reduced. Then zinc transport under saturated conditions was studied using column technique. Two methods were used to estimate the hydrodynamic dispersion coefficient; namely Brigham and nonlinear fitting. Simple analytical pulse model was used to preliminary investigate zinc transport through the barrier and a comparison between the two methods was performed. It was found that nonlinear regression method produces more realistic prediction for zinc transport.

► Zeolite-X was prepared and proposed as permeable reactive barrier (PRB). ► This material was suggested as a PRB for remediating slightly acidic and alkaline plume (pH > 6). ► It will efficiently remove Zn from slightly contaminated groundwater. ► Zeolite-X could be uses as part of multiple reactive barrier or as a secondary PRB. ► Nonlinear estimation method will produce more realistic prediction for the breakthrough curves.