Accumulation Of Tc In Water Environment By Diffusive Gradients In Thin-Films Technique

In recent years,the presence of tetracycline antibiotics has been detected in soil and water environments,and it affects humans and ecosystems through drinking water and the food chain.Therefore,it is necessary to investigate a simple and a reliable tool.The diffusive gradients in thin-films technique(DGT)incorporates an ion-exchange resin separated from the solution by an ion-premeable gel membrane and controls the ion exchange in order to obtain quantitative analytical data in situ.The DGT sampler has several advantages:it can measure trace tetracycline in water;it yields time-averaged concentrations over the length of the deployment period;compared with the traditional sampling method,it can better reflect the spatio-temporal changes of tetracycline.This dissertation established methodology of sampling of Tc by DGT technique.The major results and contents of this thesis are as follows:A method of sampling Tc by DGT technique was established,using PES as the diffusive phase and the activated carbon-gel as the binding gel.The diffusion coefficient of Tc in the PES and the effect of ionic strength on the diffusion coefficient were measured by the diffusive cell.The interaction between the diffusion phase and tetracycline was also studied.The validity of activated carbon gel-DGT,effect of pH and ionic strength on the activated carbon gel-DGT performance and application of DGT in NanHu waters was investigated.The results indicate that the diffusion coefficient of Tc is 1.01×10-6 cm2·s-1,the effect of ionic strength on the diffusion coefficient is small.A small amount of adsorption of Tc will not affect the sampling of Tc by DGT technique.Sampling of Tc using activated carbon gel-DGT was consistent over the pH 3 to 8 range and the.0.01 to 100 mmol·L-1 ionic strength range.The method also performs predictably in NanHu waters.The technique is considered to be a viable passive tool for sampling Tc.