TY - JOUR
T1 - Nickel-based electrochemical sensor with a wide detection range for measuring hydroxyl ions and pH sensing
AU - Jafari, Behnaz
AU - Muthuvel, Madhivanan
AU - Botte, Gerardine G.
N1 - Funding Information:
This work was supported by the Bill & Melinda Gates Foundation , Seattle, WA [grant number OPP1164132 ]. This work was also partially funded by the Center for Electrochemical Engineering Research (CEER) at Ohio University and the Chemical and Electrochemical Technology and Innovation (CETI) laboratory, Department of Chemical Engineering, Texas Tech University. The authors would like to acknowledge John Goettge, Head Technician, Center for Electrochemical Engineering Research, Ohio University, for his contributions towards building the sensor probe configuration.
Publisher Copyright:
© 2021 The Authors
PY - 2021/8/15
Y1 - 2021/8/15
N2 - The importance of hydroxyl ions concentration measurement in solution necessitates the development of suitable and simple sensing methods for online detection. To address this need, an electrochemical sensor was developed using nickel as the working electrode that enabled specificity towards hydroxyl ions and their successfully quantification. The electrochemical reaction between nickel and hydroxyl ions in solution generates a current which is proportional to the concentration of hydroxyl ions and consequently is also correlated to the pH of the solution. Cyclic voltammetry and chronoamperometry techniques were used to prepare and activate the nickel electrode for detection. The analysis of chronoamperometric experiments in different solutions exhibited three calibration curves between the current and hydroxyl ion concentrations for three regions in the range of 0.3 µM to 4.8 M with a short response time of 14 s. Up to now, no other hydroxyl ion sensor has been reported that can reach this detection limit. This sensor also holds promise to work perfectly in highly alkaline environments where only costly commercial electrodes are available to quantify pH. The results show three linear calibration curves between the current and pH of the solution over the pH range of 7.4 to 14.6. In addition to the wide detection range, the sensor exhibits a relative standard deviation percentage lower than 7% over 9 months of experiments, confirming repeatability of measurements and stability of the electrode. The potential of the proposed method to measure pH in real applications was demonstrated by testing the sensor in solutions containing urea, nitrates, phosphates, and sulfates.
AB - The importance of hydroxyl ions concentration measurement in solution necessitates the development of suitable and simple sensing methods for online detection. To address this need, an electrochemical sensor was developed using nickel as the working electrode that enabled specificity towards hydroxyl ions and their successfully quantification. The electrochemical reaction between nickel and hydroxyl ions in solution generates a current which is proportional to the concentration of hydroxyl ions and consequently is also correlated to the pH of the solution. Cyclic voltammetry and chronoamperometry techniques were used to prepare and activate the nickel electrode for detection. The analysis of chronoamperometric experiments in different solutions exhibited three calibration curves between the current and hydroxyl ion concentrations for three regions in the range of 0.3 µM to 4.8 M with a short response time of 14 s. Up to now, no other hydroxyl ion sensor has been reported that can reach this detection limit. This sensor also holds promise to work perfectly in highly alkaline environments where only costly commercial electrodes are available to quantify pH. The results show three linear calibration curves between the current and pH of the solution over the pH range of 7.4 to 14.6. In addition to the wide detection range, the sensor exhibits a relative standard deviation percentage lower than 7% over 9 months of experiments, confirming repeatability of measurements and stability of the electrode. The potential of the proposed method to measure pH in real applications was demonstrated by testing the sensor in solutions containing urea, nitrates, phosphates, and sulfates.
KW - Electrochemical sensors
KW - Hydroxyl ions detection
KW - Nickel oxyhydroxide
KW - Water quality
KW - pH sensor
UR - http://www.scopus.com/inward/record.url?scp=85111184070&partnerID=8YFLogxK
U2 - 10.1016/j.jelechem.2021.115547
DO - 10.1016/j.jelechem.2021.115547
M3 - Article
AN - SCOPUS:85111184070
VL - 895
JO - Journal of Electroanalytical Chemistry
JF - Journal of Electroanalytical Chemistry
SN - 1572-6657
M1 - 115547
ER -