Progress on electrochemical sensors for the determination of heavy metal ions from contaminated water

2018 ◽  
Vol 6 (2) ◽  
pp. 91-111 ◽  
Author(s):  
Xiangzi Dai ◽  
Shuping Wu ◽  
Songjun Li
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Electrochemical Sensors ◽  
Contaminated Water

scholarly journals ZnO-nanostructure-based electrochemical sensor: Effect of nanostructure morphology on the sensing of heavy metal ions

2018 ◽  
Vol 9 ◽  
pp. 2421-2431 ◽  
Author(s):  
Marina Krasovska ◽  
Vjaceslavs Gerbreders ◽  
Irena Mihailova ◽  
Andrejs Ogurcovs ◽  
Eriks Sledevskis ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Electrochemical Sensors ◽  
Zno Nanorods ◽  
Large Diameter ◽  
Chemical Properties ◽  
Volume Ratio ◽  
Zno Nanostructures ◽  
Zno Nanostructure

ZnO nanostructures are promising candidates for use in sensors, especially in electrochemical sensors and biosensors, due to their unique physical and chemical properties, as well as sensitivity and selectivity to several types of contamination, including heavy metal ions. In this work, using the hydrothermal method, nanostructures of ZnO were synthesized in four different morphologies: nanorods, nanoneedles, nanotubes and nanoplates. To determine the peculiarities of adsorption for each morphology, a series of electrochemical measurements were carried out using these nanostructured ZnO coatings on the working electrodes, using aqueous solutions of Pb(NO3)2 and Cd(NO3)2 as analytes with different concentrations. It was found that the sensitivity of the resulting electrochemical sensors depends on the morphology of the ZnO nanostructures: the best results were achieved in the case of porous nanostructures (nanotubes and nanoplates), whereas the lowest sensitivity corresponded to ZnO nanorods with a large diameter (i.e., low surface-to-volume ratio). The efficiency of sedimentation is also related to the electronegativity of adsorbate: it has been shown that all observed ZnO morphologies exhibited significantly higher sensitivity in detecting lead ions compared to cadmium ions.

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