Application Of Cobalt-manganese Bimetallic Composites For The Detection Of Nitrobenzene Phenols And Their Derivatives In Domestic Water

The development of industry has led to the discharge of nitrobenzene phenols into the waters with the effluent.As a highly toxic and refractory organic pollutant,nitrophenol is harmful to human health and ecological environment.Therefore,rapid and sensitive detection of nitrophenol is crucial.Since nitrophenol and its derivatives are electroactive,they can be detected using electrochemical detection methods.Therefore,in this work,three cobalt-manganese bimetallic composites were prepared and three electrochemical sensors were constructed for the detection of nitrobenzene phenol and its derivatives.The morphology and composition of the electrode modification materials were analyzed using characterization tools.The material synthesis and sensor operating conditions were optimized,and the sensor performance was tested using square wave voltammetry（SWV）.Finally,it was used for the detection of contaminants in real domestic water.The main results are as follows:（1）Pyrolysis-derived materials of Mn-doped ZIF-67 for the electrochemical detection of o-nitrophenolManganese doped ZIF67 was synthesized by co-precipitation and then carbonized to form CoC@Mnand to prepare an electrochemical sensor for detecting o-nitrophenol（o-NP）.Due to the good electrocatalytic properties of CoC@Mn,it can meet the detection of o-NP.The constructed sensor possessed a linear range of 0.5-100μM for the detection of o-NP,with a detection limit of 0.16μM.In addition,it was found to accurately detect o-NP in real lake and tap water samples.（2）A ratiometric electrochemical sensor based on a core-shell structured nitrogen-doped carbon spheres loaded with MnO-doped cobalt for detection of m-and p-nitrophenolA core-shell structured nitrogen-doped carbon-sphere supported MnO-doped cobalt catalyst（MnO@Co/NC）was synthesized,and a ratiometric sensor（MB-MnO@Co/NC/GCE）was constructed by introducing methylene blue（MB）for the detection of m-nitrophenol（m-NP）and p-nitrophenol（p-NP）.Electrochemical tests were performed with the sensors.The linear ranges of MB-MnO@Co/NC/GCE for the detection of m-NP and p-NP were 0.1-80 and 0.1-200μM,respectively,and the limit of detection（LOD）was 0.03μM（S/N=3）.The ratiometric sensor was successfully used for the detection of m-NP and p-NP in local river and tap water.（3）Nitriding carbon nanotube-loaded lamellar spinel structured MnCo₂O_4.5 for electrochemical detection of p-aminophenolA nitrided carbon nanotube-loaded sheet spinel structured MnCo₂O_4.5/NCNTs was prepared by a co-precipitation method followed by pyrolysis,based on which an electrochemical sensor for the detection of p-aminophenol（p-AP）was constructed with linear ranges of 0.1-60μM and 60-600μM and a detection limit of 0.016μM（S/N=3）.The sensitivity was 9.38μAμM^-1cm^-2 and 0.445μAμM^-1cm^-2（S/N=3）.The detection of p-AP in both real well and tap water was accomplished through the successful utilization of the sensor.In this work,three different cobalt-manganese bimetallic composites were prepared to modify the glassy carbon electrode for the electrochemical detection of nitrobenzene phenol and its derivative amino phenol with simple operation,low cost and low pollution.Through the multifaceted synergistic effects between metal-metal,metal-carbon materials and metal-oxygen,the prepared materials have excellent electrocatalytic properties,and the constructed electrochemical sensors are more excellent in reproducibility,stability,interference resistance and sensitivity.