Study on Retention Behavior of Heavy Metal Lead Ion on Soil Bentonite Mixture

4 ABSTRACT: In this study, it is proposed to obtain breakthrough curves commonly occurring lead ions in any effluents through locally available soil amended with 10% bentonite and determine the diffusion coefficients. The theoretical breakthrough curves of migrating ions in the soil column experiment are generated using mathematical equation applying considering effective diffusion coefficients alone, knowing soil parameters and hydraulic datas. These curves are then compared with experimental curves. In cases where the theoretical and experimental breakthrough curve do not match, there would be need to consider other parameter - retardation factor along with diffusion coefficient. Theoretical curves are generated for sets of diffusion coefficient and retardation factor. The sets which give theoretical curve close to experimentally determined breakthrough curves are accepted. Thus it may be possible to bring out the condition for the dominance of diffusion coefficient and retardation factor. Then knowing the values of diffusion coefficient and retardation factor along with soil porosity and hydraulic gradient it is possible to predict the breakthrough times of different ions in the soil. In this work the breakthrough times of lead ion for the soil of 1m and 0.5m are established. The studies can be extended for any ion or soil after establishing diffusion coefficient and retardation for the concerned ions in the selected liner under different hydrological regimes.