Bipolar Membrane Electrodialysis Exogenous Acid Conductivity

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Solution Overview

Problem

Existing electrodialysis processes using three-compartment bipolar membrane apparatuses face challenges in achieving commercially acceptable current efficiencies and yields when producing weak acids, often requiring the introduction of heat or additional ion exchange resins.

Innovation Solution

The introduction of an aqueous electrolyte comprising an exogenous acid with a pKa lower than the amino acid into the acid compartment of a three-compartment bipolar membrane electrodialysis apparatus improves ion conductivity and allows for the production of amino acids with commercially acceptable current efficiencies and yields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a three-compartment bipolar membrane apparatus is used to produce weak acids like amino acids, then the process can achieve acid formation through water splitting, but the current efficiency and yield remain insufficient without additional modifications

Engineering Contradiction:

Improvecurrent efficiencyVSAvoidacid production yield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

A strong acid (HCl) is introduced as an intermediary substance into the acid compartment to mediate the electrodialysis process. The strong acid provides high conductivity ions (H+ and Cl-) that facilitate efficient current flow and ion transport, enabling the bipolar membrane to effectively produce the desired weak acid (amino acid) through water splitting while maintaining high current efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical conductivity parameter of the acid compartment is changed by adding strong acid electrolyte. This parameter change transforms the poorly conducting weak acid solution into a highly conducting strong acid solution, enabling efficient electrodialysis operation and improving both current efficiency and production yield

Inventive Principle:

Principle #35Parameter changes

2Reliability

If heat is introduced into the process to improve acid production, then the dissociation of weak acid may be enhanced, but the process complexity and energy consumption increase

Engineering Contradiction:

Improveacid dissociationVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The thermal energy input method is replaced with a chemical/electrical energy approach. Instead of using heat to enhance acid dissociation, the process uses electrical energy-driven electrodialysis with strong acid addition, where the electric field directly drives ion migration and water splitting at the bipolar membrane, achieving acid production without thermal input

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If ion exchange resin is installed within the acid compartment to improve conductivity, then the current efficiency may increase, but the device complexity and maintenance requirements increase

Engineering Contradiction:

Improvecurrent efficiencyVSAvoidapparatus structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The ion exchange resin component is extracted/removed from the system. Instead of installing solid ion exchange resin within the acid compartment, the process uses soluble strong acid (HCl) that dissolves in the aqueous electrolyte to provide the necessary ions for conductivity, simplifying the apparatus structure while maintaining high current efficiency

Inventive Principle:

Principle #2Taking out (Extraction)

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 enhances the solubility and conductivity of the acid compartment, leading to increased conversion of amino acid salts to their corresponding acids with high yields and improved current efficiencies, thus overcoming the limitations of previous methods.

Implementation Method 1

Bipolar membranes are capable of splitting water directly into H+ and OH− ions without the formation of gasses such as H2 or O2

Methodology Applied

Scientific EffectWater splitting: Electrolysis

Implementation Method 2

the H+ and OH− ions generated by water splitting in the interfacial region of the membrane migrate under the influence of an electric field to the cathode and anode, respectively

Methodology Applied

Scientific EffectIon migration under electric field: Electrophoresis

Implementation Method 3

an aqueous electrolyte comprising an exogenous acid is added to the acid compartment... enhances the solubility and conductivity of the acid compartment

Methodology Applied

Scientific EffectIon conductivity enhancement: Electrolyte

Data Source

PatentUS20250091013A1Three-Compartment Bipolar Membrane Electrodialysis Of Salts Of Amino Acids

Publication Date: 2025.03.20 MONSANTO TECHNOLOGY LLC

AI summary

This invention relates to an improved electrodialysis method for preparing an amino acid from a salt of the amino acid utilizing a three-compartment bipolar membrane electrodialysis process wherein an aqueous electrolyte comprising an exogenous acid is added to the acid compartment of a three-compartment bipolar membrane apparatus. The exogenous acid is different than the amino acid and typically has a pKa less than the pKa of the amino acid.