Electrocatalytic Performance Of Three Metal Doped Nanomaterials For Benzene Pollutants

With the rapid development of industrialization,some persistent organic pollutants with low biodegradability and high concentration have become the main cause of serious pollution of modern soil and water resources,such as dyes,pesticides and phenolic.At present,there are various methods for the analysis and detection of organic pollutants.Among them,electrochemical method was highly efficienct,sensitivitive and simple-to-operate,so that it was applied to detect phenols and benzimidazoles.The construction of a novel sensing interface was the key for effective electrochemical detection.In this thesis,the novel electrochemical sensors based on three nanomaterials were constructed,which were used for electrochemical detection of the representative environmental pollutants,phenols and benzimidazoles.This study provided a new idea for the detection of organic pollutants in environment with high sensitivity and selectivity,and it also has a certain scientific significance for extending its application in the environmental monitoring,waste management and clinical toxicology research.This paper was divided into five chapters and the main contents were included as follows.A sensitive and selective electrochemical sensor based on poly-(nicotinic acid)(PNA)film and Cd-doped ZnWO₄ nanoneedles organic-inorganic nanocomposite modified carbon paste electrodes(PNA(ii)/Cd(0.02)-ZnWO₄/CPE)was successfully constructed and applied to study the catalytic oxidation of hydroquinone(HQ)and catechol(CC).X-ray diffraction(XRD),scanning electron microscope(SEM)and electrochemical techniques were used to characterize the composition,morphology and electrochemical properties of the modified electrode.The sensor exhibited strong electrocatalytical activity toward the oxidation of HQ and CC for the higher specific surface area of Cd-doped ZnWO₄ nanoneedles,fluent electron transfer capacity and the synergistic effect of inorganic Cd-doped ZnWO₄ and organic PNA.Wide linear ranges were obtained as 1 to 56?M for HQ and 2 to 35?M for CC,with the detection limits of 0.17?M and 0.03?M,in the differential pulse voltammetry(DPV)determination of HQ and CC,respectively.Satisfactory repeatability,stability and anti-interference performance were also achieved on PNA(ii)/Cd(0.02)-ZnWO₄/CPE.Meanwhile,the proposed sensor realized the detection of CC and HQ spiked in local tap water samples successfully.La-doped Yb₂O₃ nanorods have been synthesized using one step hydrothermal synthesis method and further investigated by XRD,SEM and energy dispersive X-ray spectroscopy(EDS).Herein,we report a highly sensitive electrocatalytic sensing interface for bisphenol A(BPA),a typical and widely present organic pollutant in the environment,using La-doped Yb₂O₃ nanomaterials modified carbon paste electrodes(La-Yb₂O₃/CPE).Cyclic voltammetry(CV)and amperometric responses were applied to characterize the electrochemical properties of the sensor.Under the optimal conditions,the oxidation current increased linearly with the increasing concentration of BPA in the range of 0.04-2.6?M and 2.6-15?M with the detection limit of 0.013?M.The modified electrode showed good reproducibility,stability and anti-interference ability.Furthermore,this newly developed sensor was further adopted to measure BPA in tap water and milk samples.The possible electrocatalytic sensing mechanism was also discussed.In this chapter,a novel Nd-doped Cd(OH)₂ nanomaterial was successfully synthesized by hydrothermal method.The morphology and structure were characterized by SEM,EDX-mapping and XRD.A new electrochemical sensing interface was fabricated based on the as-synthesized nanorods and the electrochemical behaviors of Carbendazim(CBZ)on modified carbon paste electrode(CPE)were investigated by EIS and CV.CBZ was analyzed by DPV with a detection limit of 0.067?M(S/N=3)and a linear range of 0.2-54?M.At the same time,the stability and anti-interference of Nd-Cd(OH)₂/CPE were studied and the results were good.