Membrane Separation Using pH Adjustment for Component Enrichment

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Solution Overview

Problem

Membrane separation processes in industry face challenges with high solvent addition, which can affect component separation, require additional purification steps, and impact reaction conditions and by-product formation, particularly in homogeneous catalysis, leading to reduced space-time yields and economic viability issues.

Innovation Solution

A membrane separation process that adds an acid or base to the mixture before separation, specifically using a membrane material like polyaryl ether ketone (PAEK) or ceramic membranes, to minimize solvent addition and ensure stability, thereby enriching the target component in the retentate without affecting reaction conditions or space-time yields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If aromatic solvents are added to improve membrane separation properties, then retention and permeability are improved, but solvent concentration increases affecting the component to be separated and requiring additional purification steps

Engineering Contradiction:

Improveseparation propertiesVSAvoidsolvent addition

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent changes the chemical nature of the additive from aromatic solvents to acids or bases, utilizing pH-dependent solubility changes to achieve separation. This parameter change (from organic solvent to pH modifier) improves separation efficiency without the harmful effects of aromatic solvent accumulation in the retentate stream

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces acids or bases as intermediary substances that mediate the separation process by altering the solubility and charge state of the component to be separated. This intermediary approach allows for enhanced membrane permeability and retention without the intermediary (aromatic solvent) ending up in the final product stream

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If aromatic solvents are added to improve membrane separation properties, then retention is improved, but additional aromatic solvent is retained by the membrane and ends up in the reactor via the retentate stream

Engineering Contradiction:

ImproveretentionVSAvoidsolvent effect on reaction conditions

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the separation mechanism from solvent-based to pH-based separation. By adjusting pH with acids or bases, the component to be separated undergoes solubility and charge changes that enhance membrane retention without introducing harmful aromatic solvents into the retentate stream that would affect reaction conditions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful effect of pH changes into a beneficial separation mechanism. The pH adjustment that would normally be considered a process parameter change is instead used as the primary separation mechanism, turning a potential disadvantage into the key advantage that prevents aromatic solvent contamination

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If aromatic solvents are added to improve membrane separation properties, then permeability is improved, but space-time yield in the reactor is lowered

Engineering Contradiction:

ImprovepermeabilityVSAvoidspace-time yield

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the approach to improving permeability from adding aromatic solvents to adjusting pH with acids or bases. This parameter change achieves enhanced permeability through pH-dependent solubility changes without introducing substances that would lower space-time yield in the reactor

Inventive Principle:

Principle #35Parameter changes

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

The process effectively separates components with minimal solvent addition, maintaining reaction integrity and economic viability by stabilizing the membrane and optimizing retention and permeability, reducing by-product formation and solvent retention in the retentate.

Implementation Method 1

membrane separation in which—depending on the component to be separated—an acid or a base is added to the mixture before the membrane separation

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

membrane separation process in which a so-called organophilic nanofiltration (oNF) membrane was used

Methodology Applied

Scientific EffectSemipermeable membrane: Semipermeable Membrane

Implementation Method 3

the reaction solution prior to the membrane separation contains an acid in an amount of ≥0.1% by weight

Methodology Applied

Scientific EffectpH adjustment:

Implementation Method 4

addition of at least 5% by weight of an aromatic solvent to a mixture from which a component was then separated

Methodology Applied

Scientific EffectSolvation: Solvation

Data Source

PatentUS12064755B2Process for separating one or more components from a mixture

Publication Date: 2024.08.20 EVONIK OXENO GMBH & CO KG

AI summary

The invention relates to a process for separating one or more components from a mixture by a membrane separation in which—depending on the component to be separated—an acid or a base is added to the mixture before the membrane separation.