Persulfate Oxidation System for Carbon Sequestration
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Solution Overview
Problem
Chemical oxidation processes for organic contaminants are hindered by the presence of bicarbonate and carbonate ions, which scavenge free radicals, reducing oxidation efficiency, and lead to metal mobilization, causing secondary contamination concerns.
Innovation Solution
The use of a metal oxide, hydroxide, or peroxide to generate a soluble hydroxide concentration of at least 1×10−4 M to convert carbonic acid, bicarbonate, and other organic forms of carbon to carbonate, while stabilizing metals with agents like phosphate and manganese, and controlling hydroxide concentrations to minimize metal mobilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical oxidation using free radicals is used to degrade organic contaminants, then contaminant degradation is achieved, but bicarbonate and carbonate ions scavenge free radicals reducing oxidation efficiency
Solution Approach 1:
The patent converts the harmful effect of bicarbonate/carbonate ions (which scavenge free radicals) into a beneficial effect by using them as alkaline agents to activate persulfate oxidant. The carbonate/bicarbonate ions that were previously problematic are now utilized to generate sulfate radicals through persulfate activation, transforming the scavenging issue into an activation mechanism that enhances contaminant degradation.
Solution Approach 2:
The patent changes the chemical parameter by introducing persulfate as the oxidant source, which can be activated by alkaline conditions. This parameter change allows the system to generate strong oxidizing species (sulfate radicals) that are less susceptible to scavenging by carbonate ions compared to hydroxyl radicals, thereby maintaining oxidation efficiency in the presence of bicarbonate/carbonate.
2Productivity
If excess oxidant is added to overcome bicarbonate and carbonate inhibition, then contaminant degradation can be maintained, but treatment cost and system complexity increase
Solution Approach 1:
Instead of adding excess oxidant to overcome inhibition, the patent converts the inhibitory bicarbonate/carbonate ions into beneficial activation agents. By using these ions to activate persulfate, the system generates sufficient oxidizing capacity without requiring excess oxidant addition, thereby maintaining productivity while reducing system complexity and treatment cost.
3Reliability
If acid adjustment to low pH is used to prevent carbonate and bicarbonate formation, then oxidant performance is improved, but large amounts of acid are required and carbon dioxide gas is released
Solution Approach 1:
The patent changes the pH parameter approach by operating at alkaline pH (using bicarbonate/carbonate as alkaline agents) rather than adjusting to low pH. This parameter inversion allows the system to maintain high oxidant performance through persulfate activation while avoiding the need for large amounts of acid and preventing carbon dioxide gas release.
Solution Approach 2:
The patent converts the previously harmful alkaline conditions (which formed inhibitory carbonate ions) into beneficial conditions by using the alkaline environment to activate persulfate. The bicarbonate/carbonate ions that were harmful at traditional pH levels are now utilized as activation agents, eliminating the need for acid adjustment and associated problems.
4Ease of operation
If activated carbon is used to adsorb contaminants, then contaminant accessibility to oxidation is improved, but activated carbon is oxidized forming more bicarbonate and carbonate
Solution Approach 1:
The patent converts the harmful effect of bicarbonate/carbonate formation from activated carbon oxidation into a beneficial effect by using these ions as alkaline agents to activate persulfate. The bicarbonate/carbonate that was previously seen as a problem is now utilized to generate sulfate radicals, maintaining contaminant degradation efficiency while allowing continued use of activated carbon for contaminant accessibility.
5Ease of operation
If surfactants are used to desorb organic compounds, then water solubility and oxidation susceptibility are improved, but surfactant oxidation builds inorganic carbon to levels affecting oxidant efficiency
Solution Approach 1:
The patent converts the harmful inorganic carbon buildup from surfactant oxidation into a beneficial activation mechanism. The bicarbonate/carbonate ions formed during surfactant oxidation are used as alkaline agents to activate persulfate, generating sulfate radicals that continue to degrade contaminants effectively, thereby maintaining oxidant efficiency despite continued surfactant use.
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 effectively oxidizes organic contaminants while sequestering inhibitory forms of carbon and minimizing metal solubilization, enhancing contaminant degradation and reducing secondary contamination risks.
Implementation Method 1
Chemical oxidation using free radicals is widely used for degrading or mineralizing organic contaminants
Implementation Method 2
generate a soluble hydroxide concentration of at least 1×10−4 M to convert carbonic acid, bicarbonate, and other organic forms of carbon to carbonate
Implementation Method 3
stabilizing metals with agents like phosphate and manganese, and controlling hydroxide concentrations to minimize metal mobilization
Implementation Method 4
stabilizing metals with agents like phosphate and manganese
Data Source
AI summary
Compositions and methods for oxidizing organic contaminants while sequestering inhibitory forms of carbon. An oxidant capable of producing free radicals oxidizes organic contaminants. A metal oxide, metal hydroxide, or metal peroxide generates a soluble hydroxide concentration of about 1×10−4 M or greater to convert carbonic acid, bicarbonate ion, methane, elemental carbon, and other organic forms of carbon to carbonate ion. A metal having a carbonate with a lower solubility product constant than its hydroxide precipitates the carbonate ion as a metal carbonate, thereby eliminating soluble carbonate as a radical scavenger. Compositions and methods that additionally minimize metal solubilization and sequester solubilized metals are also disclosed.