Electrochemical Detection Research And Application Of Typical Groundwater Pollutants Based On Carbon Nanomaterials

Groundwater pollution prevention and control work is grounded in investigation and monitoring,and the quality and efficiency of the investigation are the keys to the success of pollution prevention,repair,and emergency treatment.And the advancement of on-site rapid testing technology is one of the effective means to improve the quality and efficiency of investigations.Based on the electrochemical principle,with the goal of serving the on-site investigation.the electrochemical detection study was carried out on the typical groundwater pollution index Cr(Ⅵ),Pb2+、NO2-,RhB.Four kinds of electrochemical sensors with high efficiency,stability,environmental protection,low cost and easy access were prepared by using carbon based nanomaterials.And combined with the development of portable electrochemical workstation,a water quality on-site electrochemical detection platform is constructed and applied in the investigation of contaminated sites,which provides a convenient and efficient working method for the investigation of groundwater pollution,and can promote the progress of groundwater pollution investigation technology and the development of carbon based nano materials in electrochemical detection.(1)A CB/CCE electrochemical sensor for the detection of Cr(Ⅵ)was prepared by ultrasonic dispersion of Ketjenblack and drop coating of modified carbon cloth electrode.The high conductivity of Ketjenblack will accelerates the charge transfer on the electrode surface,also the rich mesoporous structure and large specific surface area can improve the catalytic performance of the electrode.The linear detection range of electrochemical sensor through i-t method is 0.025-483 μM,and the detection limit is 9.88 nM under the optimal conditions,which show the obvious advantages compare with other studies.(2)By simple high temperature water treatment,a kind of hoCC electrochemical sensor was prepared to detect Pb2+.The Keto group and defect degree on the treated carbon cloth surface increase,which will improve the conductivity and detection sensitivity.Under the optimal condition,the linear detection range of DPASV is 0.06-1.6 μM,and the detection limit is 30 nM.(3)Bi2Se3@MWNTs material modified glassy carbon electrode was obtained by ultrasonic compounding to construct Bi2Se3@MWNTs/GCE electrochemical sensor for detecting NO2-.The excellent catalytic performance of Bi2Se3 and the strong conductivity of MWNTs are combined in Bi2Se3@MWNTs to promote the adsorption and oxidation of NO2-.Under the optimal conditions,the linear detection range measured by i-t method is 0.02～6000 μM,and the detection limit is 20 nM.In addition to high performance,the problem of electrode poisoning and environmental pollution caused by the use of metal catalysts are also avoided to this sensor.(4)A MWNTs-COOH/GCE electrochemical sensor for the detection of RhB was prepared by the oxidation of MWNTs with piranha solution and further hydrothermal treatment.A large number of activated carbon sites on the carboxylated MWNTs can improve the degree of defects,which enhances the hydrophilicity.And the efficient detection of RhB was realized through the oxidation of the C=N bond of RhB by carboxyl groups.Under the optimal conditions,the linear detection range obtained by i-t method is 0.05～850 mM,and the detection limit is 2.66 nM.(5)A portable electrochemical workstation was designed according to the field working conditions.It has the advantages of low rated voltage,simultaneous data transmission and power supply by USB.In addition to the detection function,the portable workstation also retains the common electrochemical analysis methods with no loss in sensitivity and accuracy.It can be combined with computer and electrochemical sensor to form a water quality field electrochemical detection platform.(6)By the conducted portable electrochemical detection platform for water quality,the application investigation was carried out on the Pb pollution site in Zhongshan City and the Cr(VI)pollution site in Xining City.Then grasped the pollution degree and pollution scope of the site,analyzed the causes and modes of pollution,and summarized the application effects and experience.