China
Africa
Explore chapters and articles related to this topic
Electrochemical Methods
Published in Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus, Environmental Chemical Analysis, 2018
Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus
Each ion selective electrode requires a reference electrode which provides a constant known voltage against which to measure the changes in voltage of the indicating electrode. There are different configurations of reference electrodes available, since the reference electrode filling solutions may interfere with some analyses. Each reference electrode has a porous plug which serves as a contact between the solution and the internal electrode filling solution. While a very small quantity of solution diffuses through this plug, it can be enough to change the measured concentration in the sample. In addition, a precipitate of insoluble salt, formed when the sample and the filling solution come into contact, can plug the channel between them, so that the electrode does not function properly. A silver/silver chloride electrode is often used as a reference electrode. This electrode may contain a filling solution of potassium chloride saturated with silver chloride, which can cause a problem if the sample is being analyzed for chloride. Enough chloride ion may pass into the solution to interfere with an accurate measurement. A double junction reference electrode has a second filling solution in an outer electrode chamber, which contacts the inner silver/silver chloride electrode through a porous plug, and the sample through a second plug. The outer chamber filling solution provides a non-reacting solution in contact with the sample. For instance, in the measurement of chloride, a filling solution of potassium nitrate can be used in the outer electrode jacket.
Laboratory Apparatus: Chemicals and Instruments
Published in Barbara A. Hauser, Practical Manual of Wastewater Chemistry, 2018
Types of Reference Electrodes: A Calomel reference electrode has Hg/HgCl internal wires. This kind is used for most routine applications; it is easy to use and maintain, and uses saturated KCl electrolyte; shelf life is 2–3 years. A Silver/Silver Chloride reference electrode has Ag/AgCl internal wires. This is used for high temperature applications, and uses saturated KCl+AgCl electrolyte, to prevent dissolving the internals. A Double Junction reference electrode is a special double body type meant for use with very dirty samples, and with industrial samples which may cause interference due to a component in the sample. A different filling solution can be used. The Gel-type reference electrode is made with a solid filling solution—a permanent gel—not to be refilled. It does diffuse out into the sample slowly through the diffusion port—just as the others do. The electrode is used till the gel is gone (approximately one year); then the electrode is replaced.
Potentiometry: pH and Ion-Selective Electrodes
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Ronita L. Marple, William R. LaCourse
A double junction reference electrode has two junctions. The first junction separates the reference electrode from an intermediate solution, and the second isolates the intermediate solution from the test solution. This reference electrode can be used to minimize contamination of the test solution.
MSWI BA treated with Advanced Dry Recovery: a field scale study on materials’ leaching properties
Published in International Journal of Sustainable Engineering, 2018
Laura Annika Sormunen, Tommi Kaartinen, Riina Rantsi
The leachate samples were taken from two sampling wells, which collected the subsurface leachate from the whole field. The sampling wells were located along the edge of the western part of the field. The leachate sampling period started on the 18th of September, 2014, after the structural layers illustrated in Figure 3 were constructed and finished on the 6th of May, 2015, when a bitumen course (110 mm) was constructed on top of the field. The leachate sampling period was therefore 7.5 months altogether. In total, 14 water samples were taken from both wells during the whole sampling period (i.e. total n = 28). Samples were taken more often in the beginning of the sampling period, and after that, they were taken based on the cumulative amount of leachate at approximately every 300 m3. The leachate pH and temperature were measured with a calibrated handheld device (Oakton Instruments, Waterproof Double Junction pHTestr® 30) in the field during each sampling.
Modified Cascaded H-bridge Multilevel Inverter for Hybrid Renewable Energy Applications
Published in IETE Journal of Research, 2022
PV array Parameters and MJSC-Double junction solar cell: Irradiance –1000 W/m2Temp-25°CIsc-2.02 AIm1.93 ATref-55°CVoc-64.2 VVm-70.4 V.
Friction-assisted pulse electrodeposition of high-performance ultrafine-grained Cu deposits
Published in Surface Engineering, 2021
Xiaofei Xu, Zengwei Zhu, Ziming Xue, Xiaofei Zhan
The electrochemical behaviour of the electrodeposited Cu was measured using a three-electrode system (Figure 1(b)). The cathode and anode were the same as those used in the actual specimen preparation process. A silver chloride reference electrode with a saturated KCl double junction (KCl/AgCl, Ag) electrode was utilised. Polarisation curves were generated in the current density range 0–8 A dm−2 and the potential was swept at a scan rate of 2 mV s−1 from 0 to –800 mV. Under a constant current of 4 A dm−2, the variation in the potential with time over a 20-min period was tested with a sampling interval of 500 ms.