The Adsorption Characteristic Study Of Phthalate Acid Esters(Environmental Hormone) On Sediment Along Yellow River In Lanzhou

Environmental hormone is a class of chemical compounds in environment. It may affect human and wildlife on their normal endocrines ,cause reproductive, developmental and behavioral disorder. Phthalate acid esters(PAEs) are an important group of environmental hormone. Their main applications are as plasticizers in the manufacture of plastics. In recent years, large amount of plastics have caused a wide distribution of PAEs into environment. PAEs become one of the most prevalent contaminants. The adsorption and desorption characterize of three phthalate acid esters dimethyl phthalate (DMP), diethyl phthalate(DEP)and di-butyl phthalate (DBP)on sediment t along the Yellow River in lanzhou have been studied in this paper, which are environmental hormone.Phthalate acid esters are slightly soluble in water, which make it necessary to pretreatment before determination. Three PAEs were extracted from water sample using solid phase extraction on HLB cartridge (200mg, 6mL), a production of Waters corporation. Several main factors (eluting solvent, eluting volume, eluting rate and washing solvent) in solid-phase extraction (SPE) were optimized by orthogonal design. The optimum condition of SPE and the analyzed condition of liquid chromatogram were established.The adsorption isotherms of DMP, DEP and DBP on sediment were obtained using the batch equilibration method. A model describing the adsorption behavior of PAEs on sediment was according to the experiment data. The research result indicated that the adsorption isotherm of PAEs , regardless of ionic and neutral forms ,were non-linear and obeyed to the Freundlich equation. MeantimeAdsorption isotherm equation of DMP, DEP and DBP are obtained by analysing the isotherm adsorption change of three PAEs and comparing the accuracy of the three adsorption equilibrium model (Linear equations, Frendlich equation and Langmuir equation) is described three phthalates adsorption isotherms on sediments .The results showed that adsorption isotherms of three PAEs were non-linear and obeyed to the Freundlich equation. Meanwhile, the factors (temperature, pH, ionic strength, heavy metal ions and sediment treatment) which affect the adsorption were discussed, it is found the temperature change have effect on adsorption of PAEs, but other four factors have no effect on it. DMP is selected as investigation object for desorption behavior from sediment in this papers. The whole desorption process of DMP is divided into fast and slow part. The DMP desorption rate is diffirent in different time on sediment, it showed that the rate decreased gradually with extending time and approaching to equilibrium. Desorption model is determined by applying four different desorption kinetics equation (a kinetic equation, parabolic equation, Two-constant equation and Elovich equation).It is found that desorption process is a non-homogeneous diffusion process.