نقش مواد تشكيل دهنده خاك در نفوذپذيري و انتقال سرب و روي

The Effect of Soil Composition on Hydraulic Conductivity and Transport of Lead and Zinc in Clay Soils

Soil composition have detrimental effects on the resulting bulk density and hydraulic conductivity of clay soils because of the rearrangement of the solid particles and chemical stabilization. In this study aimed at the simulation of natural soil, kaolinite and kaolinite with calcium carbonate (KC), silica gel (KS), and both calcium carbonate and silica gel (KSC) were compacted at different moisture contents according to ASTM standards. These mixtures of compacted clays were then exposed to leaching by distilled water, followed by a solution of heavy metals. Experimental results indicate that the dry density and coefficient of hydraulic conductivity significantly influenced by soil constituents. Specifically kaolinite exhibits a low dry density and a high coefficient of permeability, compared to other soils (KS, KC and KSC). As penneant flow approaches a stationary regime, greater pore volumes of effluents result, and an increase in the coefficient of permeability are observed in all types of soils. Tests confirm that chemical reactions are responsible for the permeability increases up to a constant value. Expressly, kaolinite mixtures with silica gel or calcium carbonate exhibit a coefficient of permeability almost one orders less than that of kaolinite. Results indicate the importance of silica gel as an additive for the reduction of the permeability in clay soils. Soil waste physicochemical chemical interaction was simulated through a coupled go-chemical and transport model.