Boron-Doped Diamond Electrode Purification of Chloride Solutions
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Solution Overview
Problem
Current methods for removing organic compounds from chloride-containing aqueous process solutions are energy-intensive, complex, and often result in the formation of chlorinated organic compounds, which can be toxic and difficult to handle, especially in chlor-alkali electrolysis processes where they can damage equipment.
Innovation Solution
An electrochemical method using a boron-doped diamond electrode at a pH of at least 11 and a potential greater than 2.5V against the reverse hydrogen electrode, which prevents the formation of chlorine in the oxidation state zero or greater, allowing for the efficient removal of organic impurities without generating harmful chlorinated compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrochemical oxidation is used to remove organic impurities, then organic compounds are removed from the solution, but chlorine in oxidation state zero or greater than zero is generated which can form toxic chlorinated organic compounds
Solution Approach 1:
The patent applies parameter changes by controlling the electrode potential to remain below the chlorine evolution potential (1.36V vs SHE) while maintaining sufficient oxidation power through alternative mechanisms. By adjusting potential parameters and using boron-doped diamond electrodes with specific catalytic properties, the process achieves organic compound oxidation without chlorine generation, resolving the contradiction between purification effectiveness and harmful byproduct formation
Solution Approach 2:
The patent converts the potentially harmful high oxidative environment into a beneficial process by utilizing the electrode surface catalysis of boron-doped diamond electrodes. These electrodes facilitate direct electron transfer oxidation of organic compounds, transforming what would otherwise be a chlorine-generating harsh oxidation environment into a selective, controlled oxidation process that eliminates organics without forming chlorinated byproducts
2Manufacturing precision
If steam stripping and activated carbon treatment are used to purify chloride-containing solutions, then organic impurities are removed, but the process requires multiple stages and regular replacement of adsorbent materials
Solution Approach 1:
The patent extracts and eliminates the need for complex multi-stage treatment processes and adsorbent materials by implementing a single-stage electrochemical oxidation process. The electrochemical method directly degrades organic impurities in situ, removing the requirement for separate steam stripping units, activated carbon beds, and associated operational complexities, thus simplifying the overall purification system while maintaining effectiveness
Solution Approach 2:
The patent replaces mechanical/physical separation methods (steam stripping, adsorption on activated carbon) with an electrochemical oxidation mechanism. This substitution eliminates the need for mechanical equipment and consumable adsorbent materials, replacing them with an electrical field-driven chemical process that is more compact, easier to operate, and does not require regular material replacement
3Manufacturing precision
If ozonolysis is used to treat sodium chloride-containing process water, then organic contaminants are oxidized, but the process is very energy- and cost-intensive
Solution Approach 1:
The patent applies parameter changes by operating at controlled electrode potentials below the thermodynamic potential for chlorine evolution (1.36V vs SHE). This parameter control enables selective oxidation of organic contaminants at lower energy inputs compared to ozonolysis, while the use of boron-doped diamond electrodes with high catalytic activity further reduces the energy required to achieve effective oxidation, resolving the contradiction between purification quality and energy consumption
4Manufacturing precision
If complete evaporation and thermal treatment are used to remove organic impurities, then organic components are decomposed, but water must be completely evaporated making the process uneconomical due to high energy consumption
Solution Approach 1:
The patent extracts and eliminates the need for complete water evaporation by implementing electrochemical oxidation that directly degrades organic impurities in the aqueous phase. This approach removes the energy-intensive evaporation and thermal treatment steps entirely, allowing treatment of dilute solutions without the prohibitive energy costs associated with bulk water evaporation, thus resolving the contradiction between purification quality and energy economy
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 method effectively reduces the total content of organic impurities to low levels, avoiding the formation of chlorinated compounds and enabling the safe reuse of process water in chlor-alkali electrolysis, with minimal disruption and energy consumption.
Implementation Method 1
the oxidation of the organic impurities is carried out anodically without generating chlorine in the oxidation state of zero or greater than zero
Implementation Method 2
electrochemical removal of organic compounds from chloride-containing aqueous process solutions
Data Source
Figure 1
AI summary
The invention relates to a method for the electrochemical purification of chloride-containing, aqueous process solutions, which are contaminated with organic chemical compounds, using a boron-doped diamond electrode at a pH value of at least 9.5.