Studies On Fluorescence Detection And Hydrogel Adsorption For Heavy Metal Ions In Water

In recent years,heavy metal ion pollution has been a problem for people.Heavy metal ions are highly biotoxic and can cause protein inactivation,organ failure,and severe life-threatening.Two problems need to be faced in the treatment of heavy metal pollution in water,include the detection of heavy metal ions;and how to efficiently remove heavy metal ions in water.This thesis focuses on the detection and processing of heavy metal ions.The detection of heavy metal ions by fluorescent carbon dots（CDs）and the adsorption of heavy metal ions by composite gels solve the problems of heavy metal detection and processing.Two types of carbon dots（Aphen@CDs and FC-CDs）were successfully prepared for the detection of hexavalent chromium and divalent copper,respectively.Among them,Aphen@CDs is a carbon dot with blue fluorescence prepared by hydrothermalmethodusingcitricacid,ethylenediamineand5-amino-1,10-phenanthroline（Aphen）as raw materials for chromium（VI）.The detection,in the concentration range of 0¹0ppm,the linear equation is:y=0.0632x+1.0674,the linear correlation coefficient is R²=0.999,and the detection limit is 0.015ppm.According to the national chromium（VI）emission standard,the type II water discharge is less than or equal to 0.05ppm.The prepared carbon dots can be used for the detection of chromium（VI）in the second type of water.Among them,FC-CDs is a raw material with folic acid and ethylenediamine as a raw material.It is prepared by hydrothermal method to form a carbon dot with yellow fluorescence.It is used for the detection of copper ions.The linear equation is in the range of 0⁸ ppm Cu²⁺concentration.:y=0.6791 x+0.48,the detection limit is 0.014 ppm.According to the national regulations on copper ion emission standards,the content of Class II water is less than 1ppm,which can be used for the detection of copper ions in Class II water.Cotton fiber,PVA,acrylic acid and acrylamide were used as raw materials to prepare composite gel for metal ion adsorption.The adsorption test results of gel showed that it has good adsorption capacity for cadmium,lead,nickel and copper.All of them are above 100mg/g,and the resolution rate can reach 90%,which can be reused.