Preparation And Application Of Carbon-based Fluorescence Sensor With Environmental Function

With the advent of the information age,and the iterative acceleration of economic development,a large number of industrial and domestic waste liquids are discharged at will after extensive production,resulting in the deterioration of the water ecological environment.For a long time,heavy metal pollution in water resources has become one of the most complex,serious,and urgent areas of many environmental problems.Heavy metals are difficult to degrade,persistent,toxic and easy to accumulate,so when they enter the human body through a variety of ways,they will accumulate in the human body,directly or indirectly affect the brain,kidney,liver,esophagus,skin and other organ damage,and even cause cancer and death in serious cases.Therefore,we urgently need to develop a method that can conveniently detect heavy metal ions in the environment.At present,carbon-based fluorescent sensors have attracted the research interest of scholars due to their simplicity,high efficiency,low cost,non-destructiveness,and fast response,and have become one of the important means to detect heavy metal ions.This paper mainly discusses the preparation of carbon-based fluorescent sensors and their application in the detection of heavy metal ions in the environment.The main work is as follows:(1)Preparation of carbon dots and fluorescent composite films and their application in hexavalent chromium ions detection.In this part of the work,we designed and synthesized a novel fluorescent carbon dots with yellow emission characteristics using ophenylenediamine and DL-Thioctic acid as raw materials.The carbon dots have excellent photostability,and show an obvious fluorescence enhancement effect on hexavalent chromium ions in water environment,and the limit of detection can reach 0.64 μM.In addition,we also compounded it with polyvinyl alcohol to make a fluorescent composite film,which has good hydrophilicity and can also be used for sensitive and efficient detection of hexavalent chromium ions in water environment,and has obvious visual effects,which can be used as potential applications in real environment and biological detection scenes.(2)Preparation of fluorescent emulsion and its application in silver ion detection.In this study,we used the carbon dots obtained in the first part of the experiment as the fluorescent agent to prepare the fluorescent emulsion of carbon dots composite polyacrylic acid and the fluorescent emulsion of carbon dots hybrid polyurethane through physical doping and chemical bonding of the emulsion,respectively.The two preparation methods are easy to operate and environmentally friendly,and the obtained fluorescent emulsions have green photoluminescence and good stability,and exhibit strong fluorescence quenching,wide detection range,good selectivity and high sensitivity for silver ions.They have been well used in actual water samples.In addition,we also made it into a fluorescent coating,which also showed a good visual detection effect for silver ions detection.This not only verifies that the coating raw material itself does not contain heavy metals,but also provides a new direction for the development of fluorescent coatings.