Hypochlorous Acid Electrolysis Cell pH Control
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Solution Overview
Problem
Existing methods for producing aqueous solutions of hypochlorous acid and/or hypochlorite result in solutions with low storage stability, leading to a significant decrease in concentration over time, which compromises their effectiveness.
Innovation Solution
A process involving electrolysis of a NaCl solution with specific conditions, including a pH adjustment to 5 to 6, is used to produce a storage-stable aqueous solution comprising hypochlorous acid and/or hypochlorite. This is achieved by introducing the aqueous NaCl solution into an electrolysis cell with separate compartments and applying direct current to produce and stabilize the solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolysis methods are used to produce hypochlorous acid solutions, then the solution can be produced with antimicrobial activity, but the storage stability is low and concentration decreases significantly over time
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pH value (adjusting to 5-6.5), temperature (0-25°C), and electrical conductivity (0.5-5 mS/cm) of the electrolyte solution, as well as controlling the current density and electrolysis time. These parameter optimizations stabilize the hypochlorous acid concentration and prevent rapid decomposition, thereby improving storage stability and reducing concentration loss over time
2Reliability
If the concentration of hypochlorous acid is maintained high for effectiveness, then antimicrobial activity is improved, but the solution becomes less stable and decomposes faster
Solution Approach 1:
The patent resolves this contradiction by optimizing the pH value to 5-6.5, which is the critical parameter for stabilizing hypochlorous acid. At this pH range, the solution maintains high antimicrobial effectiveness while significantly reducing the decomposition rate, thereby achieving both high concentration stability and sustained antimicrobial activity
Solution Approach 2:
The patent employs feedback control by continuously monitoring the pH value, temperature, and electrical conductivity during electrolysis and storage, and adjusting the electrolysis parameters accordingly. This feedback mechanism ensures the solution maintains optimal stability and effectiveness throughout its storage period
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
The proposed method results in a storage-stable solution where the concentration of hypochlorous acid or hypochlorite decreases by no more than 10 to 30% over several months, maintaining the solution's effectiveness and logistical advantages.
Implementation Method 1
The present invention relates to methods for preparing storage-stable aqueous solutions comprising hypochlorous acid and/or salts thereof. One commonly used process involves electrolysis of a NaCl solution, usually using electrolysis cells.
Implementation Method 2
there is a membrane or diaphragm in the electrolysis cell which separates the cell into an anode compartment and a cathode compartment. Only small ions such as sodium and hydroxide ions can pass through the membranes or diaphragms used in this process
Data Source
AI summary
A process for preparing a storage-stable aqueous solution comprising hypochlorous acid and/or hypochlorite includes introducing an aqueous NaCl solution into an electrolysis cell comprising a cathode compartment and an anode compartment separated by a membrane, wherein the aqueous NaCl solution is introduced into the cathode compartment via a first feed line and into the anode compartment via a second feed line, and wherein the aqueous NaCl solution comprises more than 100 ppm NaCl and has an electrical conductivity of less than 5 mS/cm, applying a direct current to a cathode in the cathode compartment and to an anode in the anode compartment to produce a cathode solution in the cathode compartment and an anode solution in the anode compartment, and mixing a portion of the cathode solution with the aqueous NaCl solution prior to its introduction into the anode compartment and/or with the anode solution in the anode compartment and/or with the anode solution in a discharge line associated with the anode compartment, to produce a storage-stable aqueous solution comprising hypochlorous acid and/or hypochlorite dischargeable via discharge line and has a pH value of 5 to 6.