Research On Removal Efficiency And Mechanism Of Diclofenac In Aqueous

The existence of trace diclofenac organic drug in environment has become a newhot issue.From the distribution of diclofenac in water environment, the organic matterpollution of diclofenac will have growth trend in rivers, lakes and oceans and othernatural water environment. Even in very low concentrations, diclofenac has strongecological interference, and may have synergism with other organic drug in waterenvironment, so the potential hazard of diclofenac to ecological environment isunnegligible. It is significant for us to study the testing methods and removaltechnology of diclofenac in water. It is not appropriate that diclofenac is removed byconventional treatment method for its trace and wide distribution in water. Macrophyteremediation technology was used to remove diclofenac in this research, using thecharacteristics of random distribution and freedom growth, physical ecologicaladsorption effect, so that it can achieve economical, simple and beautiful purposes andremove diclofenac purpose.For this, this study is conducted to develop an analyticalmethod to determine diclofenac in water and macrophyte tissues and removal efficiencyand mechanism of diclofenac in aqueous.This experiment is conducted to study performance liquid chromatographicconditions of diclofenac, trace diclofenac determination method in water andmacrophyte tissues, and has established diclofenac determination method. Bysimulation reactor test, detecting concentrations of diclofenac in reactor aqueoussolution, macrophyte root surface, root, stem, leaves, and detecting physical andchemical index such as conductivity, dissolved oxygen, total organic chemical, to studyabout the remove rule and the remove mechanism of diclofenac.The results and conclusions are as follows:①This study is conducted to develop an analytical method to determine diclofenacin water and macrophyte tissues (Cyperus Alternifolius and Eichhornia Crassipes) withhigh performance liquid chromatography. The diclofenac in the water samples wasseparated and extracted by waters C18solid-phase extraction column, while diclofenacin plant samples was extracted with liquid-phase extraction (methanol). The AgilentEclipse XDB-C18（250mm×4.6mm,5μm）was used as chromatographic column. Themobile phase of HPLC was composed of acetonitrile-3%ice acetic (80/20, v/v), the UVdetection wavelength was set at270nm, the sample volume was50ul. The method had been successfully applied in the determination of diclofenac from water samples andmacrophyte tissue samples with limits of detection of6.0ng/L and1.875ng/g,respectively. The recoveries were92.19-96.19%for water samples and90.79-94.30%for macrophyte samples.②Research shows that the total removal rates of diclofenac in CyperusAlternifolius and Eichhornia Crassipes reactors aqueous solution are69.25±0.24%and58.71±4.18%, respectively, and2.76±1.29%in blank reactor. The removal result maynot be associated with physical and chemical index, but these index such as conductivity,pH, total organic chemical and COD have indicative function to water quality andindirectly reflect the aquatic plant growth environment and conditions. Throughmonitoring analysis on diclofenac concentration change, it was found that diclofenacwere obviously accumulated in two macrophytes.during root surface, root, stem, leavestissues, diclofenac was not detected in leaves tissues, but testing frequency in rootsurface and root tissues was highest. Diclofenac residual quantity showed thedowntrend over time in root surface and bodies of two macrophytes, In70days, thedetection was low, diclofenac may be not in the original form in macrophyte bodies. Inthe removing role, the percentages of diclofenac residual quantity in total diclofenacquantity was very low, was0.33%and no detection in Cyperus Alternifolius andEichhornia Crassipes reactors, respectively. The main remove way was macrophyteabsorption and transformation, rather than macrophyte residual. In70days, the aquaticplants comprehensive removal rate were66.78%and56.38%in Cyperus Alternifoliusand Eichhornia Crassipes reactors, respectively. Through dynamic model analysis, itwas found that best one-level dynamic model in Cyperus Alternifolius and EichhorniaCrassipes reactors were ln(c0/c)=-0.0002x~2+0.0350x-0.1494and ln(c0/c)=-0.0002x~2+0.0257x-0.0509, respectively.