Polyamine Extractant for Carboxylic Acid Removal from Dilute Aqueous Streams
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Solution Overview
Problem
Current methods are inadequate for efficiently removing carboxylic acids from aqueous solutions at concentrations below 1%wt, particularly in fermentation processes, as they can be harmful to bacteria and require maintaining specific pH levels.
Innovation Solution
A process involving contacting the aqueous solution with a depleted solvent containing polyamine extractants, such as dialkylaminopyridine or alkyl-triazabicyclodecene, to separate and enrich carboxylic acids, allowing for their removal and subsequent recovery, thereby reducing the acid concentration in the solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional extraction methods are used to remove carboxylic acids from aqueous solutions, then acid removal capability is maintained, but extraction efficiency deteriorates at low acid concentrations (below 1%wt)
Solution Approach 1:
The patent changes the chemical parameter of the extractant by using polyamines (specifically triethyleneamine, tetraethyleneamine, or pentaethyleneamine) instead of conventional extractants. These polyamines exhibit significantly higher extraction efficiency for carboxylic acids at low concentrations (below 1%wt) due to their molecular structure and basicity, directly resolving the contradiction between maintaining productivity and handling low quantity concentrations.
2Reliability
If acid concentration is reduced in the fermentation process, then bacterial survival is improved, but acid removal capability must be enhanced
Solution Approach 1:
The patent introduces polyamine extractants as an intermediary substance that mediates between the fermentation process and acid removal requirements. The polyamines selectively extract carboxylic acids from the aqueous fermentation medium, allowing bacteria to survive at higher acid concentrations while maintaining effective acid removal capability through the intermediary extraction action.
3Stability of the object's composition
If pH is maintained at levels required for bacterial survival, then fermentation process stability is improved, but carboxylic acid remains in harmful free acid form
Solution Approach 1:
The patent directly extracts and removes free carboxylic acid from the fermentation medium using polyamine extractants. This taking out approach allows the fermentation process to maintain stable pH conditions for bacterial survival while simultaneously removing the harmful free acid form, resolving the contradiction between fermentation stability and harmful acid concentration.
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 process effectively reduces the carboxylic acid concentration in the aqueous stream, enabling its safe return to the fermentation process and improving the extraction efficiency compared to existing methods, particularly at low acid concentrations.
Implementation Method 1
contacting the aqueous solution with a depleted solvent comprising a polyamine extractant to obtain an extract enriched in free carboxylic acid and a raffinate having a reduced free carboxylic acid content
Data Source
AI summary
The present invention provides a process for removing free carboxylic acid from an aqueous solution comprising a mass fraction of less than 1 %wt of the free carboxylic acid, which process comprises the steps of: (a) contacting the aqueous solution with a depleted solvent comprising a polyamine extractant to obtain an extract enriched in free carboxylic acid and a raffinate having a reduced free carboxylic acid content; and (b) separating the raffinate from the extract, wherein the polyamine extractant is a compound containing at least two nitrogen atoms, and at least one double bond between a nitrogen atom and a carbon atom, wherein the carboxylic acid is produced by the fermentation of biomass.