Reactive Liquid-Liquid Extraction of Boric Acid Using 2-Ethyl-1,3-Hexanediol
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Solution Overview
Problem
Current methods for separating boric acid from industrial wastewater are inefficient, particularly due to the use of chloroform as an organic carrier medium, which is toxic and unsuitable for purification, and existing processes are not effective for large-scale boric acid removal or require excessive organic extractants.
Innovation Solution
A reactive liquid-liquid extraction process using 2-ethyl-1,3-hexanediol as a reactant and an aromatic solvent, such as toluene, to form a boric acid ester that is soluble in the organic phase, reducing boric acid content in the aqueous phase with minimal excess diol and organic carrier medium usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chloroform is used as the organic carrier medium, then extraction efficiency is improved, but environmental safety and wastewater contamination worsen
Solution Approach 1:
The patent replaces the toxic chloroform carrier medium with a safer, biodegradable alternative such as aliphatic esters or ethers. This substitution maintains extraction efficiency while eliminating the harmful environmental effects and carcinogenic properties of chloroform, allowing the use of a less persistent, safer substance that degrades naturally after use.
Solution Approach 2:
The patent addresses the inherent toxicity of traditional extraction solvents by selecting carrier mediums that are specifically chosen for their low environmental impact and high biodegradability. The harmful aspect of solvent use is converted into a benefit by selecting solvents that enhance extraction efficiency while simultaneously improving environmental safety and eliminating contamination risks.
2Productivity
If high proportions of organic extractant are used, then extraction efficiency is improved, but process complexity and cost worsen
Solution Approach 1:
The patent optimizes the concentration and composition parameters of the organic phase to achieve high extraction efficiency with reduced solvent quantities. By adjusting parameters such as the ratio of carrier medium to extractant, temperature, and pH, the process achieves effective boric acid removal without requiring excessive organic extractant, thereby simplifying the overall process.
Solution Approach 2:
The patent employs a carefully optimized excess of extractant beyond the stoichiometric requirement to ensure complete boric acid removal, but controls this excess to minimal necessary levels. This partial excess action ensures thorough extraction while avoiding the complexities and costs associated with handling and recovering large volumes of organic solvent.
3Productivity
If 1,3-diols are used in high excess, then extraction efficiency is improved, but substance loss and cost worsen
Solution Approach 1:
The patent optimizes the molar ratio and concentration parameters of the 1,3-diol extractant to achieve the minimum necessary excess for effective boric acid removal. By carefully controlling these parameters, the process maintains high extraction efficiency while minimizing the quantity of diol that must be handled, recovered, and potentially lost during the process.
Solution Approach 2:
The patent implements a recovery system for the 1,3-diol extractant that captures and recycles the solvent after extraction. This recovery process minimizes substance loss by returning the majority of the expensive diol back to the extraction process, reducing both material waste and operational costs while maintaining extraction efficiency.
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 boric acid content by over 65% in one extraction stage and by ≥90% in multiple stages, while being insensitive to organic impurities and allowing for solvent recycling, making it suitable for industrial wastewater treatment.
Implementation Method 1
Reactive extraction using polyols is suitable for the separation of boric acid from industrial wastewater. Boric acid forms hydrophobic complexes with polyols, allowing the boric acid to be transferred from an aqueous phase to an organic phase
Implementation Method 2
the boric acid-containing aqueous phase is contacted with an organic phase containing a diol, whereby a diol-boric acid ester soluble in the organic phase is formed and the boric acid content in the aqueous phase is reduced
Data Source
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AI summary
The present application relates to a process for separating boric acid from a boric acid-containing aqueous phase by reactive liquid-liquid extraction using 2-ethyl-1,3-hexanediol as a reactant and an aromatic solvent as an organic support medium.