Pulsed Amperometric Chlorine Detection Electrode System
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Solution Overview
Problem
Amperometric detection systems face performance issues when detecting oxidants like chlorine, especially when the electrode system is exposed to chlorine-free compositions before being exposed to chlorine-containing compositions, leading to adverse effects and prolonged response times.
Innovation Solution
The use of an electrode system with a selectively permeable membrane and a cathode behind it, where a first voltage is applied initially, followed by a pulse of a second voltage different from the first, to facilitate the detection of oxidants such as chlorine in aqueous solutions, with the pulse helping to maintain surface activity and reduce response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode system is exposed to chlorine-free compositions before chlorine-containing compositions, then the system can be reset or maintained, but the response time is prolonged and performance is adversely affected
Solution Approach 1:
The patent applies a preliminary action by exposing the electrode system to a chlorine-free composition before the chlorine-containing composition. This preliminary exposure allows the electrode to be reset and cleaned of any previous chlorine residues, ensuring that the subsequent detection of chlorine is accurate and not influenced by prior contamination. This resolves the contradiction by preparing the electrode in advance for optimal performance.
Solution Approach 2:
The patent extracts the harmful effect of previous chlorine exposure by using a chlorine-free composition to clean the electrode surface before the actual detection. This extraction removes any residual chlorine or chlorine compounds that might interfere with the detection accuracy, thereby restoring the electrode's sensitivity and reducing response time artifacts.
2Measurement precision
If a membrane is used to position the cathode behind it, then selective permeability is achieved, but fouling of the anode may still occur
Solution Approach 1:
The patent uses a membrane as an intermediary between the chlorine-containing composition and the electrode system. The membrane is selectively permeable to chlorine, allowing it to pass through to the cathode for detection, while blocking other potentially fouling substances from reaching the anode. This intermediary structure enables selective detection while protecting the anode from fouling.
Solution Approach 2:
The patent applies local quality by making the membrane selectively permeable to specific substances (chlorine) while blocking others. This selective permeability creates different access conditions for different substances: chlorine can reach the cathode for detection, while fouling agents are blocked from reaching the anode. This localized differentiation of permeability resolves the contradiction between selective detection and fouling prevention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the detection of chlorine by reducing response time and maintaining surface activity, allowing for accurate measurement of a wide range of chlorine concentrations, even in low ppm levels, and preventing fouling of the anode.
Implementation Method 1
The membrane is permeable to the species to be measured, such as chlorine in the form of hypochlorous acid (HOCl) or hypochlorite anion (ClO−) or in the combined form of chloramines
Implementation Method 2
amperometric detection can be used to detect oxidants (such as chlorine) by reduction at a cathode positioned behind a membrane
Implementation Method 3
a voltage appropriate for the species to be detected is applied between two electrodes... The voltage is selected which is sufficient to cause oxidation or reduction of the species to be detected
Data Source
AI summary
A method of measuring oxidant in an aqueous composition using an electrode system comprising a membrane permeable to a species to be measured, a cathode situated behind the membrane, and an electrolyte between the membrane and cathode. Embodiments of the method may include contacting the membrane and an anode with the aqueous composition, and measuring the current between the cathode and anode in response to a first voltage applied between them. A pulse of a second voltage may be applied between the cathode and the anode, where the second voltage is different from the first voltage. Apparatus and computer program products which may perform the method, are also provided.