SUP-pH6.3 Digital pH Tester For Water

Introduction

Digital pH tester is suitable for online monitoring of pH/ORP value of drinking water and wastewater. There are many methods to measure pH value, mainly chemical analysis method, test paper method and potentiometric method. Now we mainly introduce the potentiometric method to measure pH value.

The electrode used in the potentiometric method is called a primary cell. A primary cell is a system that serves to convert the energy of a chemical reaction into electrical energy. The voltage of this cell is called the electric potential (EMF). This electric potential (EMF) consists of two half-cells, one of which is called the indicator electrode, whose potential is related to a specific ionic activity, such as H. The other half-cell is the reference half-cell, usually called the reference electrode, which is generally connected to the measurement solution and to the measuring instrument.

For example, an electrode made of a silver wire inserted in a salt solution containing silver ions, at the interface between the wire and the solution, due to the different activity of silver ions in the two phases of the metal and salt solution, the charging process of ions is formed, and a certain potential difference is formed. The silver ions that lose electrons into the solution. This process eventually reaches an equilibrium when no external current is applied for countercharging, that is, if no current is present. The voltage present in this equilibrium state is called the half-cell potential or electrode potential. Such an electrode (as described above) consisting of a metal and a solution containing this metal ion is called a type I electrode.

This potential is measured relative to a reference electrode whose potential is independent of the composition of the salt solution. Such a reference electrode with an independent potential is also referred to as a second electrode. For this type of electrode, the metal conductor is covered with a layer of a slightly soluble salt of the metal (e.g., Ag/Agcl) and inserted into an electrolyte solution containing the salt anion of the metal. The half-cell potential or electrode potential depends on the activity of this anion.

The voltage between these two electrodes follows the Nernst formula
　　Where: E - potential
　　E0 - standard voltage of the electrode
　　R - gas constant (8.31439 joules/mol and °C)
　　T- absolute Kelvin temperature (example: 20°C corresponds to 273.15 + 20 = 293.15 Kelvin)
　　F-Faraday's constant (96493 coulometric/equivalent)
　　n-chemical valence of the ion under test (silver = 1, hydrogen = 1)
　　ln (aMe) - the logarithm of the ion activity aMe

Features

• Integral wall-mounted type, simple installation and easy maintenance.
• Composite electrode, separated electrode, accurate and stable measurement.

Specification

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pH Electrode

Offers a full range of ph electrodes for measuring different media. Such as sewage, pure water, drinking water etc.