Ion Chromatography Eluent Recycling with Catalytic Gas Elimination

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Solution Overview

Problem

Ion chromatography systems face challenges in preparing high-purity eluents due to contamination issues and the logistical difficulties of continuous eluent preparation and disposal, which can lead to compromised performance and increased costs.

Innovation Solution

The system incorporates a suppressor with effluent recycling, catalytic gas elimination columns, and eluent purification columns to recycle and purify eluents, including a delay conduit to decompose unstable oxidative species, ensuring consistent and high-purity eluent production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If off-line eluent preparation is used, then operator control is maintained, but contamination occurs and preparation is tedious

Engineering Contradiction:
Improveeluent purityVSAvoideluent preparation convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system enables self-service eluent preparation through automated on-line generation using electrolysis of high purity water, eliminating manual intervention while maintaining high purity standards. The electrolytic cell automatically produces the required eluent concentrations without operator handling of chemicals.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Manual mechanical preparation processes are replaced with electrochemical generation. Instead of physically mixing chemicals and adjusting concentrations manually, the system uses electrical current to electrolyze water and generate eluents in-situ, automating the entire preparation process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If on-line electrolytic eluent generation is used, then eluent purity is improved and preparation is automated, but high purity water consumption increases and waste disposal is required

Engineering Contradiction:
Improveeluent purityVSAvoidwater consumption and waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The system recovers and recycles the eluent after it has been used in the chromatographic separation. The recycling pump returns the eluent to the electrolytic cell where it is regenerated through continued electrolysis, creating a closed-loop system that eliminates waste disposal and minimizes water consumption.

Inventive Principle:
Principle #34Discarding and recovering

3Loss of substance

If eluent recycling is implemented, then waste disposal is reduced and operational costs decrease, but gas buildup occurs and system complexity increases

Engineering Contradiction:
Improvewaste eluent disposalVSAvoidrecycling system complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The gaseous byproducts (hydrogen and oxygen) generated during electrolysis are extracted and removed from the recycling loop through dedicated gas venting ports. This separation allows the liquid eluent to be continuously recycled while the gases are safely discharged, preventing pressure buildup and maintaining system operation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If continuous eluent recycling is used, then operational costs and labor are reduced, but oxidative species may form and affect analysis

Engineering Contradiction:
Improvecontinuous operation efficiencyVSAvoidoxidative species interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system converts potentially harmful oxidative species into beneficial outcomes. The continuous electrolysis process that generates oxidative byproducts also simultaneously regenerates the eluent, maintaining its analytical performance. The recycling process transforms what could be contaminants into part of the continuous regeneration cycle, ensuring eluent quality without requiring additional purification steps.

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

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 reliability and efficiency of ion chromatography by maintaining chromatographic efficiency, reducing contamination, and minimizing waste disposal costs through continuous, high-purity eluent recycling.

Implementation Method 1

The net result of the electrochemical processes in an electrolytic suppressor is that the combined effluent from the suppressor anode and cathode chambers is a mixture of hydrogen gas, oxygen gas, and the aqueous solution containing the eluent components

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

the effluent from the outlet of the electrolytic suppressor regenerant chamber is passed through the catalytic gas elimination column packed with a Pt catalyst that induces the reaction between hydrogen gas and oxygen gas to form water

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP2260298B1Ion chromatography systems with flow-delay eluent recycle
Publication Date: 2015.10.21 DIONEX CORP
  • EP2260298B1 patent drawingFigure 1
  • EP2260298B1 patent drawingFigure 2
  • EP2260298B1 patent drawingFigure 3

AI summary

A chromatographic method including chromatographically separating sample ionic species in an eluent stream, detecting the separated sample ionic species, catalytically combining hydrogen and oxygen gases or catalytically decomposing hydrogen peroxide in a catalytic gas elimination chamber (31), and recycling the effluent stream from the catalytic gas elimination chamber to the chromatography separation column (10). The residence time between the detector (14) and said chamber (31) is at least one minute to facilitate decomposition of unstable oxidative compounds. Also, flowing the recycle sequentially through two detector effluent flow channels of an electrolytic membrane suppressor (28). Also, applying heat or UV energy between the detector (14) and the chamber (31). Also, detecting bubbles after the chamber. Also, a Platinum group metal catalyst and ion exchange medium in the chamber. Apparatus for performing the methods.