Influence Of Biofilm In Natural Water System On Diffusion Coefficient Of The DGT

DGT is short for Diffusive gradients in Thin-films Technique,and its called the film diffusion gradient technique in Chinese,which is a continuous passive sampling technique.Both organic matter and inorganic matter that occurd in soil,sediment and solution can be measured by this technique.In the process of monitoring,the tested object orientation in the DGT technical diffusion phase diffusion is the control of the monitored object collection step,by monitoring the diffusion coefficient of content is the basis of the DGT quantitative acquisition monitored object parameters.The growth of the biofilm may affect the diffusion thickness and the diffusion coefficient when the biofilm is monitored.The effect of biofilm on the diffusion coefficient of diffident season different days in same nature water system,and the effect of biofilm on the diffusion coefficient of the same season of different days in different nature water system,is explored in this paper.First of all,the growth of biofilm was observed.With time increases,the biofilm grows continuously,and its thickness and density will change in different media.Through the characterization of its morphology:the camera takes pictures and the microscope takes pictures and records its growth trajectory.Second,the scanning electron microscopy was used to observe the characterization of the biofilms.Diatom species and metal oxide agglomerate can be observed and these substances are the factors that affect the diffusion.In the use of DGT device,these factors can affect the performance of the device.Finally,the diffusion coefficient of filtration membrane with different growth days,different water systems and different materials was measured.In advance,the standard curve of phenol was prepared for the conversion of concentration and absorbance.The diffusion coefficient of the membrane without biofilm was used as the reference standard.Then,this paper measure the diffusion coefficient every three days and compare their difference.The results show that the diffusion coefficient decreases with the increase of the days;At the same time,the diffusion coefficient of tetracycline and copper ion through filtration membrane is simulated by analyzing the experimental data of diffusion coefficient.