Polyester-Wool Fabric Separation by Acid Hydrothermal Recycling
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Solution Overview
Problem
Current methods for recycling polyester/wool blend textiles are environmentally harmful and costly due to the use of substances like sodium hydroxide and bio-enzymes, which are not only detrimental to the environment but also expensive.
Innovation Solution
A method involving an acid-catalyzed hydrothermal reaction at 160° C. to 170° C. using an acid catalyst aqueous solution to degrade wool fibers from polyester fibers, with a circulation and backflow process to reduce the solid-to-liquid ratio and acid catalyst usage, facilitating separation and recycling of polyester fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sodium hydroxide or bio-enzyme is used to degrade wool fibers, then wool fibers can be separated from polyester fibers, but the process becomes more harmful to the environment and more expensive
Solution Approach 1:
The patent changes the chemical parameters of the degradation process by using organic acid catalysts (formic acid, acetic acid, propionic acid, or their mixtures) instead of traditional strong bases like sodium hydroxide. This parameter substitution maintains effective wool fiber degradation while reducing environmental harm, as organic acids are biodegradable and less harmful to ecosystems compared to strong alkaline substances.
Solution Approach 2:
The patent employs readily available, low-cost organic acid catalysts that can be easily obtained from common sources. These short-chain organic acids are inexpensive, effective at degrading wool fibers under hydrothermal conditions, and can be disposed of or neutralized more easily than industrial-strength chemicals, thereby reducing both cost and environmental burden.
2Reliability
If sodium hydroxide or bio-enzyme is used to degrade wool fibers, then wool fibers can be separated from polyester fibers, but the process becomes more expensive
Solution Approach 1:
The patent employs readily available, low-cost organic acid catalysts that can be easily obtained from common sources. These short-chain organic acids are inexpensive, effective at degrading wool fibers under hydrothermal conditions, and can be disposed of or neutralized more easily than industrial-strength chemicals, thereby reducing both cost and environmental burden.
Solution Approach 2:
The patent changes the chemical parameters of the degradation process by using organic acid catalysts (formic acid, acetic acid, propionic acid, or their mixtures) instead of traditional strong bases like sodium hydroxide. This parameter substitution maintains effective wool fiber degradation while reducing environmental harm, as organic acids are biodegradable and less harmful to ecosystems compared to strong alkaline substances.
3Reliability
If traditional recycling methods are used, then wool fibers can be degraded, but the process requires more solvent and time
Solution Approach 1:
The patent optimizes the physical parameters of the degradation process by conducting hydrothermal treatment at elevated temperatures (100-200°C) and pressures. These parameter changes enhance the reactivity of organic acid catalysts and accelerate wool fiber degradation kinetics, allowing the process to achieve effective degradation with reduced solvent volumes and shorter reaction times compared to ambient temperature methods.
4Reliability
If traditional recycling methods are used, then wool fibers can be degraded, but the process requires more time
Solution Approach 1:
The patent optimizes the physical parameters of the degradation process by conducting hydrothermal treatment at elevated temperatures (100-200°C) and pressures. These parameter changes enhance the reactivity of organic acid catalysts and accelerate wool fiber degradation kinetics, allowing the process to achieve effective degradation with reduced solvent volumes and shorter reaction times compared to ambient temperature methods.
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 effectively separates and recycles polyester fibers while being environmentally friendly and cost-effective, with a reduced reaction time and solvent usage, achieving a high recycle rate of polyester fibers.
Implementation Method 1
treating the waste fabric with an acid catalyst aqueous solution at 160° C. to 170° C., such that the wool fibers of the waste fabric are degraded and separated from the polyester fibers
Data Source
AI summary
A method for processing a waste fabric containing polyester and wool fibers includes the following steps. The method is to treat the waste fabric with an acid catalyst aqueous solution at 160° C. to 170° C. The wool fibers are degraded and completely separated from the polyester fibers in a treatment process. Afterwards, the polyester fibers are recycled.