Electrochemical Sensor for the Detection of SO<sub>2</sub> in the Low-ppb Range

Hodgson, Alexia W.E.; Jacquinot, Patrick; Hauser, Peter C.

doi:10.1021/ac9812429

Cited by 77 publications

(41 citation statements)

References 40 publications

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“…The dependence between signal and square root of Reynolds number is shown in Figure 4a for the sensor with gold working electrode containing the electrolyte A. Following the Equation 15 an increase in Reynolds number is accompanied by an increase in the sensor signal. For low values of volumetric flow rate the dependence between signal and square root of Reynolds number is almost linear, above a certain value (50 cm 3 min…”

Section: Resultsmentioning

confidence: 97%

“…We proposed the Equation 15, which indicates that the sensor signal depends on volumetric flow rate of the analyte and absorption properties of applied aprotic solvent, when keeping the analyte concentration constant. The signals from four amperometric sulfur dioxide sensors differing in a type of the working electrode and a composition of the internal electrolyte were analyzed.…”

Section: Discussionmentioning

confidence: 99%

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Influence of Analyte Flow Rate on Signal and Response Time of the Amperometric Gas Sensor with Nafion Membrane

Gębicki

Chachulski

2009

Electroanalysis

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This paper presents results of an investigation on influence of volumetric flow rate on the signal and response time of a prototype of sulfur dioxide gas sensor with Nafion membrane. The sensors differing in type of working electrode and composition of internal electrolyte were compared. We used Au and Pt working electrodes obtained via vacuum sublimation deposition on a Nafion membrane surface. The electrolytes were aqueous solutions of sulfuric acid of the summary concentration 5 mol dm À3 (electrolyte A). The electrolyte B contained an addition of dimethylsulfoxide (DMSO); the water/DMSO molar ratio was 2 : 1. Based on a proposed equation, which takes diffusion resistance into account, the obtained sensor signals were analyzed for the flow rate within a range of 0 -100 cm 3 min À1. The sensor response time was also determined for the above flow rate range.

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Section: Resultsmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Influence of Analyte Flow Rate on Signal and Response Time of the Amperometric Gas Sensor with Nafion Membrane

Gębicki

Chachulski

2009

Electroanalysis

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“…Modern electrochemical sensors have sensitivities in the parts per billion by volume (ppb) range (Hodgson et al, 1999), enabling sensitive, real-time pollutant measurements. However, accurate calibration of such sensors poses a major challenge.…”

Section: Introductionmentioning

confidence: 99%

Calibration and assessment of electrochemical air quality sensors by co-location with regulatory-grade instruments

et al. 2018

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Abstract. The use of low-cost air quality sensors for air pollution research has outpaced our understanding of their capabilities and limitations under real-world conditions, and there is thus a critical need for understanding and optimizing the performance of such sensors in the field. Here we describe the deployment, calibration, and evaluation of electrochemical sensors on the island of Hawai'i, which is an ideal test bed for characterizing such sensors due to its large and variable sulfur dioxide (SO 2 ) levels and lack of other co-pollutants. Nine custom-built SO 2 sensors were colocated with two Hawaii Department of Health Air Quality stations over the course of 5 months, enabling comparison of sensor output with regulatory-grade instruments under a range of realistic environmental conditions. Calibration using a nonparametric algorithm (k nearest neighbors) was found to have excellent performance (RMSE < 7 ppb, MAE < 4 ppb, r 2 > 0.997) across a wide dynamic range in SO 2 (< 1 ppb, > 2 ppm). However, since nonparametric algorithms generally cannot extrapolate to conditions beyond those outside the training set, we introduce a new hybrid linear-nonparametric algorithm, enabling accurate measurements even when pollutant levels are higher than encountered during calibration. We find no significant change in instrument sensitivity toward SO 2 after 18 weeks and demonstrate that calibration accuracy remains high when a sensor is calibrated at one location and then moved to another. The performance of electrochemical SO 2 sensors is also strong at lower SO 2 mixing ratios (< 25 ppb), for which they exhibit an error of less than 2.5 ppb. While some specific results of this study (calibration accuracy, performance of the various algorithms, etc.) may differ for measurements of other pollutant species in other areas (e.g., polluted urban regions), the calibration and validation approaches described here should be widely applicable to a range of pollutants, sensors, and environments.

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“…These requirements narrow down the possible sensors that can be used. Liquid electrochemical cells cannot operate in high humidity and high temperature conditions [1]. Metal oxide sensors usually are not the best choice in environments with low and changing concentration of oxygen [2,3].…”

Section: Introductionmentioning

confidence: 99%

SiC–FET based SO2 sensor for power plant emission applications

Darmastuti

Bur

Möller

et al. 2014

Sensors and Actuators B: Chemical

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Thermal power plants produce SO 2 during combustion of fuel containing sulfur. One way to decrease the SO 2 emission from power plants is to introduce a sensor as part of the control system of the desulphurization unit. In this study, SiC-FET sensors were studied as one alternative sensor to replace the expensive FTIR (Fourier Transform Infrared) instrument or the inconvenient wet chemical methods. The gas response for the SiC-FET sensors comes from the interaction between the test gas and the catalytic gate metal, which changes the electrical characteristics of the devices. The performance of the sensors depends on the ability of the test gas to be adsorbed, decomposed, and desorbed at the sensor surface. The feature of SO 2 , that it is difficult to desorb from the catalyst surface, makes it known as catalyst poison.It is difficult to quantify the SO 2 with static operation, even at the optimum operation temperature of the sensor due to low response levels and saturation already at low concentration of SO 2 . The challenge of SO 2 desorption can be reduced by introducing dynamic operation in a designed temperature cycle operation (TCO). The intermittent exposure to high temperature can help to desorb SO 2 . Simultaneously, additional features extracted from the sensor data can be used to reduce the influence of sensor drift. The TCO operation, together with pattern recognition, may also reduce the baseline and response variation due to changing concentration of background gases (4-10% O 2 and 0-70% RH), and thus it may improve the overall sensor performance. In addition to the laboratory experiment, testing in the desulphurization pilot unit was performed. Desulphurization pilot unit has less controlled environment compared to the laboratory conditions. Therefore, the risk of influence from the changing concentration of background gas is higher. In this study, Linear Discriminant Analysis (LDA) and Partial Least Square (PLS) were employed as pattern recognition methods. It was demonstrated that using LDA quantification of SO 2 into several groups of concentrations up to 2000 ppm was possible. Additionally, PLS analysis indicated a good agreement between the predicted value from the model and the SO 2 concentration from the reference instrument of the pilot plant. 3 IntroductionSO 2 is one of the major air pollutants because it is a precursor of acid rain, forms acid particulates, and is dangerous for human health. However, in a thermal power plant, SO 2 is generally produced when sulfur containing fuel is combusted. In flue gas cleaning processes, SO 2 is usually removed by absorption with lime (CaOH 2 .2H 2 O) or other compounds having high alkalinity. State-of-the-art desulphurization can remove more than 98% of the SO 2 from the flue gas. With increasing environmental concerns, the regulation of SO 2 emission from thermal power plants has become stricter. The installation of sensors in the flue gas duct has been proposed as one of the alternatives to improve the efficiency of the desulphurization un...

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Electrochemical Sensor for the Detection of SO₂ in the Low-ppb Range

Cited by 77 publications

References 40 publications

Influence of Analyte Flow Rate on Signal and Response Time of the Amperometric Gas Sensor with Nafion Membrane

Influence of Analyte Flow Rate on Signal and Response Time of the Amperometric Gas Sensor with Nafion Membrane

Calibration and assessment of electrochemical air quality sensors by co-location with regulatory-grade instruments

SiC–FET based SO2 sensor for power plant emission applications

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Electrochemical Sensor for the Detection of SO2 in the Low-ppb Range

Cited by 77 publications

References 40 publications

Influence of Analyte Flow Rate on Signal and Response Time of the Amperometric Gas Sensor with Nafion Membrane

Influence of Analyte Flow Rate on Signal and Response Time of the Amperometric Gas Sensor with Nafion Membrane

Calibration and assessment of electrochemical air quality sensors by co-location with regulatory-grade instruments

SiC–FET based SO2 sensor for power plant emission applications

Contact Info

Product

Resources

About

Electrochemical Sensor for the Detection of SO₂ in the Low-ppb Range