scholarly journals A SOLID Fe2O3-GRAPHITE COMPOSITE ELECTRODE FOR pH MEASUREMENT

2015 ◽  
Vol 12 (12) ◽  
pp. 44-47
Author(s):  
Suchi Srivastava ◽  
Raja Ram Pradhananga

A solid Fe2O3-graphite composite electrode was prepared and investigated for use as a potentiometric pH sensor. The electrode was constructed by mixing iron (III) oxide, oxidized graphite and wax that was put over silver disc onto a polypropylene rod. The response of the electrode was investigated by measuring electrode potential as a function of pH.The effect of composition of the electrode material (Fe2O3 and oxidized graphite ration) on the electrode response was investigated. The electrode with 40% Fe2O3, 30% graphite and 30% wax by mass was found to give the best potentiometric response. This electrode behaves in Nernstian manner with a potentiometric gradient of 56.6±0.4 mV per unit change in pH at 25?C within the working range of pH 2-9.The electrode was also used for the end-point detection in potentiometric acid-base titrations and found to be an excellent electrode for pH-metric titration. The effect of oxidation of electrode on pH response was investigated by dipping electrode in 0.1N KMnO4, 1:1HNO3 and 0.1N Ce4+ solutions for different interval of time. This treatment of the electrode with oxidizing agents increased the standard electrode potential of the electrode however potential gradient per unit change in pH remains unaltered. Low cost, quick response and easy to prepare are the advantages of the iron oxide - graphite composite electrode as a pH sensor. However some metal ions and oxidising agents interfered in the determination of pH using this electrode which is the limitation of using these electrodes.Scientific World, Vol. 12, No. 12, September 2014, page 44-47

2015 ◽  
Vol 15 (1) ◽  
pp. 61-66
Author(s):  
Ranjan Nepal ◽  
Raja Ram Pradhananga

Lead oxide-graphite composite electrode for pH measurement had been fabricated with different percentage of PbO2 in the composite. The proportions of lead oxide affected the sensitivity of the electrode. The electrode composed of 50% lead oxide and 50% graphite gave reproducible result and behaved in Nernstian manner with a potential gradient of -58.8±0.3 mV per unit change in pH. Metal ions such as iron (II), iron (III) and lead (II) interfered in the measurement of pH, while silver (I), copper (II), oxidizing agents such as dichromate and permanganate do not interfere. In absence of interfering ion, the lead oxide-graphite composite electrode could be used for the measurement of pH from 2 to 11. This electrode can also be used as an indicator electrode for acid base titrations. Low cost, quick response, easy to fabricate are some of the advantages of the lead oxide-graphite composite electrode. This electrode is also found to be sensitive to Pb2+ -ions and can be used as a Pb2+-ion sensor up to 10-4M.DOI: http://dx.doi.org/10.3126/njst.v15i1.12015  Nepal Journal of Science and TechnologyVol. 15, No.1 (2014) 61-66


2020 ◽  
Vol 26 (4) ◽  
pp. 126-132
Author(s):  
Su-Yong Nam ◽  
Shinyoung Kim ◽  
Se-Hoon Park ◽  
Hyun Jin Nam

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 14 ◽  
Author(s):  
Libu Manjakkal ◽  
Wenting Dang ◽  
Nivasan Yogeswaran ◽  
Ravinder Dahiya

In this work, we present a potentiometric pH sensor on textile substrate for wearable applications. The sensitive (thick film graphite composite) and reference electrodes (Ag/AgCl) are printed on cellulose-polyester blend cloth. An excellent adhesion between printed electrodes allow the textile-based sensor to be washed with a reliable pH response. The developed textile-based pH sensor works on the basis of electrochemical reaction, as observed through the potentiometric, cyclic voltammetry (100 mV/s) and electrochemical impedance spectroscopic (10 mHz to 1 MHz) analysis. The electrochemical double layer formation and the ionic exchanges of the sensitive electrode-pH solution interaction are observed through the electrochemical impedance spectroscopic analysis. Potentiometric analysis reveals that the fabricated textile-based sensor exhibits a sensitivity (slope factor) of 4 mV/pH with a response time of 5 s in the pH range 6–9. The presented sensor shows stable response with a potential of 47 ± 2 mV for long time (2000 s) even after it was washed in tap water. These results indicate that the sensor can be used for wearable applications.


2010 ◽  
Vol 22 (20) ◽  
pp. 2460-2466 ◽  
Author(s):  
Afsaneh Safavi ◽  
Norooz Maleki ◽  
Fariba Tajabadi

2016 ◽  
Vol 229 ◽  
pp. 609-617 ◽  
Author(s):  
Rahim Rahimi ◽  
Manuel Ochoa ◽  
Tejasvi Parupudi ◽  
Xin Zhao ◽  
Iman K. Yazdi ◽  
...  

Author(s):  
Muhittin Yağmur Polat ◽  
Abdullah Beyaz ◽  
İbrahim Çilingir

Liquid chemical fertilizers are widely used in modern agriculture. The pH values of these fertilizers are important in terms of their effectiveness in the field application and their effect on the soil-water pH balance. Therefore, it is necessary to measure the pH and other properties of liquid fertilizers with fast, practical and inexpensive methods. With the advancing technology, pH value has been started to measure more accurately and efficiently with the help of low-cost devices. In this study, a low-cost pH meter was developed using a low-cost pH sensor, an Arduino UNO R3 microcontroller board, and a software written in the C/C++ programming language. The developed pH meter was used to measure the pH values of liquid chemical fertilizers. Close variations were observed between the values obtained from it and the values measured by an accredited, laboratory-type pH meter. According to the pH measurements of the two pH meters, R2 ranged 88.1% to 99.3%, average error range 0.14 to 0.28, and average error percentage ranged 1.56% to 6.81% for three different types of liquid fertilizers. In light of these results, it was shown that the developed low-cost pH meter can be useful for practical pH measurement applications.


2020 ◽  
Author(s):  
Hongjie Dai ◽  
Guanzhou Zhu ◽  
Xin Tian ◽  
Hung-Chun Tai ◽  
Yuan-Yao Li ◽  
...  

Abstract Sodium is a promising anode material for batteries due to its low standard electrode potential, high abundance and low cost. In this work, we report a new rechargeable ~ 3.5 V sodium ion battery using Na anode, amorphous carbon-nanosphere cathode and a starting electrolyte comprised of AlCl3 in SOCl2 with fluoride-based additives. The battery, exhibiting ultrahigh ~ 2800 mAh/g first discharge capacity, could cycle with a high reversible capacity up to ~ 1000 mAh/g. Through battery cycling, the electrolyte evolved to contain NaCl, various sulfur and chlorine species that supported anode’s Na/Na+ redox and cathode’s chloride/chlorine redox. Fluoride-rich additives were important in forming a solid-electrolyte interface, affording reversibility of the Na anode for a new class of high capacity secondary Na battery.


2020 ◽  
Vol 10 (2) ◽  
pp. 2258-2271

Inceptions for chemical process automation are presented in this study. A chemical process demonstrated by neutralization reaction was designed, built, and tested experimentally towards evaluating automation and control algorithms through the Arduino Mega platform. The main objective parameter in this work was selected to be the product pH value, which was evaluated based on several scenarios that targeted various changes in direct and indirect effects. Two main branched ideas were investigated in this study; the first was dealt with the application of Arduino board in the automation of chemical process; the second was dedicated to studying integration of Arduino board in controlling the targeted pH parameter in the product side. Upon examining different automation scenarios, an algorithm was developed to approach the product quality of specific pH and temperature efficiently. The automation algorithm was further developed by integrating the process dynamics and control concepts towards speeding up the pH set point's reach. To make this happen, the pump's speed was corrected and tuned based on the feedback signal from the pH sensor. Consequently, the setpoint was reached in shorter periods, attaining considerable savings in time (≈ 35%). Based on the study outcomes, it is believed that Arduino open source is a challenging and promising low-cost platform, proved useful for mimicking control and automation of chemical processes.


2020 ◽  
Vol 10 (23) ◽  
pp. 8419
Author(s):  
Adriana Remes ◽  
Florica Manea ◽  
Sorina Motoc (m. Ilies) ◽  
Anamaria Baciu ◽  
Elisabeta I. Szerb ◽  
...  

A novel electrochemical glucose sensor was developed, based on a multiwall carbon nanotubes (MWCNTs)-copper-1,3,5-benzenetricarboxylic acid (CuBTC)-epoxy composite electrode, named MWCNT-CuBTC. The electrode nanocomposite was prepared by a two-roll mill procedure and characterized morphostructurally by scanning electron microscopy (SEM). The CuBTC formed defined crystals with a wide size distribution, which were well dispersed and embedded in the MWCNTs. Its electrical conductivity was determined by four-point probe contact (DC) conductivity measurements. The electroactive surface area, determined using cyclic voltammetry (CV), was found to be 6.9 times higher than the geometrical one. The results of the electrochemical measurements using CV, linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), chronoamperometry (CA) and multiple pulse amperometry (MPA) showed that the MWCNT-CuBTC composite electrode displayed high electrocatalytic activity toward the oxidation of glucose and, as a consequence, very high sensitivity. The best sensitivity of 14,949 µAmM−1cm−1 was reached using MPA at the potential value of 0.6 V/SCE, which was much higher in comparison with other copper-based electrodes reported in the literature. The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of an effective glucose sensor.


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