| Weihe River is one of the major rivers in Guanzhong area, the development of the Guanzhong area plays a vital role. However, with the development of industrialization, types, production, usage and emissions of toxic chemicals harmful chemicals has increased dramatically, the Weihe River water quality is facing a serious threat. The main source of persistent organic pollutants(POPs) are pesticides, industrial chemicals and the production of by-products with high toxicity, persistence, accumulation and mobility and other characteristics, to have serious human health and environmental hazards.With the increasing advances in science and awareness of environmental protection, research POPs environmental behavior has increasingly become one of the hot research content. Therefore, the migration of Adsorption POPs in Weihe River water environment in the region for understanding the process of POPs in the environment, ecological risk assessment and water pollution control is of great significance.This paper chooses the typical persistent organochlorine pesticide heptachlor(Heptachlor) as adsorbate, using relatively clean section of the Weihe River marsh surface sediment as an adsorbent. The static and dynamic tests adsorption Simulation.(1) Selection of silt, sand and sand three kinds of sand samples heptachlor adsorption kinetics were measured and used lagergren adsorption rate equation to fit the experimental data. The results showed that: Lagergren pseudo- second adsorption rate equation than Lagergren pseudo-first adsorption rate equation is more in line with the assay procedure;(2) Measurement of the three kinds of sand samples of heptachlor adsorption isotherms, and use equation, adsorption Henry Freundlich equation, Langmuir equation, Henry-Langmuir equation and Henry-Freundlich isotherm equation to fit the experimental data. The results showed that: three kinds of sand samples heptachlor solution adsorption isotherms are nonlinear, with the effect of H-F fitting adsorption isotherm best; and obtain the characteristic equation and parameters of the adsorption process, obtaining the static stop factor is 35.22;(3) Based on the adsorption characteristics of sand-like equations and solving related parameters to calculate the retardation factor expression by reverse problem. Calculated 50μg / L of heptachlor in the sand in the sand like the retardation factor Rd = 13.37;(4) Analysis of the p H value of the solution heptachlor, sand-like particle, heptachlor initial concentration, sand-like organic matter content and temperature on the adsorption capacity of the adsorption of sand samples. The results show that: with the increase of p H, adsorption sand sample of heptachlor continue to decrease; with the increase of sand-like particle of sand sample adsorption amount of heptachlor continue to decrease; with the initial concentration of heptachlor increase the adsorption capacity of the sand sample heptachlor increasing; with the increase of sand-like organic matter content, adsorption sand sample of heptachlor increasing; as the temperature increases the absorption amount of sand kind of heptachlor increasing;(5) The Cl- tracer tests and heptachlor migration in sand column test, and calculated retardation factor of heptachlor in the sand in the sand samples. The results showed that: Clpenetration rate in the sand column was 1.37 m / d, heptachlor migration in sand columns rate of 0.0096 m / d, heptachlor in sand sand samples in dynamic retardation factor of 146.71;(6) By adsorption of heptachlor build dynamic numerical model in sand samples obtained at the heptachlor longitudinal diffusion coefficient D = 1.0356m2 / d; simulation to predict the migration of heptachlor, the value of the dynamic test results obtained Rd It can be used as the basis for the migration of heptachlor. |
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