Polymer Membrane Recycling by Hydrothermal Catalyst Separation
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Solution Overview
Problem
Existing recycling methods for polymer electrolyte membranes with metal-containing catalysts are energy-intensive, generate hazardous waste, and result in significant losses and environmental risks due to the use of organic solvents and high temperatures, making it difficult to recover both the polymer and catalyst materials effectively.
Innovation Solution
A hydrothermal treatment process involving water at pressures between 20 bar and 40 bar and temperatures between 200° C. and 250° C. is used to separate polymer and metal-containing catalysts, followed by centrifugation and optional further processing steps to recover both components without organic solvents, allowing for efficient recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If two-stage combustion process at 850-1000°C is used to recycle polymer membranes, then catalyst materials can be recovered, but the process requires extensive reactor linings and downstream gas scrubbing systems due to HF release
Solution Approach 1:
The invention changes the fundamental parameter of the recycling process from high-temperature combustion (850-1000°C) to low-temperature hydrothermal treatment (20-200 bar, up to 250°C). This parameter change eliminates the formation of aggressive HF gas, thereby removing the need for complex reactor linings and downstream gas scrubbing systems while still achieving effective separation and recovery of catalyst materials from the polymer membrane matrix.
2Loss of substance
If aqua regia dissolution is used to separate precious metals, then metal separation can be achieved, but metallic iridium cannot be dissolved and requires repeated Na2O2 oxidation melting
Solution Approach 1:
The invention extracts and separates the catalyst materials from the polymer membrane matrix through hydrothermal treatment before any dissolution steps. This preliminary extraction removes the polymer matrix that would otherwise interfere with subsequent metal separation processes, allowing aqua regia to effectively dissolve platinum group metals without the need for repeated Na2O2 oxidation melting of metallic iridium, thereby significantly improving separation efficiency and productivity.
3Loss of substance
If high temperature combustion is used for recycling, then catalyst materials can be recovered, but the process is energy and time-consuming
Solution Approach 1:
The invention changes the temperature parameter from high-temperature combustion (850-1000°C) to low-temperature hydrothermal treatment (20-200 bar, up to 250°C). This parameter change dramatically reduces the energy input required for the recycling process while still achieving effective separation and recovery of catalyst materials from the polymer membrane, thereby reducing both energy consumption and processing time.
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 method achieves high recovery rates of both polymer and catalyst materials, reducing process steps and environmental risks, while maintaining material integrity and enabling direct reuse, thus conserving resources and lowering costs.
Implementation Method 1
Adding water without adding organic solvents to a polymer membrane comprising a metal-containing catalyst material to form a polymer membrane/water mixture, simultaneously increasing the pressure and the temperature of the polymer membrane/water mixture to a pressure between 20 bar and 40 bar and a temperature between 200° C. and 250° C.
Implementation Method 2
separating the liquid phase and the solid phase
Data Source
AI summary
The invention relates to a method for recycling polymer membranes comprising metal-containing catalyst material. The method comprises the following steps adding water without adding organic solvents to a polymer membrane comprising a metal-containing catalyst material to form a polymer membrane/water mixture, simultaneously increasing the pressure and the temperature of the polymer membrane/water mixture to a pressure between 20 bar and 40 bar and a temperature between 200° C. and 250° C., a liquid phase and a solid phase being formed, and separating the liquid phase and the solid phase.