Textile recycling
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Solution Overview
Problem
Current textile recycling methods are inefficient, environmentally harmful, and fail to effectively separate and recycle cellulose and polyester fibers, leading to significant waste accumulation and resource strain.
Innovation Solution
A method and system utilizing ionic liquids to dissolve cellulose fibers from textile blends, followed by wet-spinning to produce recycled fibers, while separating and recycling polyester fibers, preserving or removing original dyeing, and using optimized ionic liquids like N-Methylmorpholine-N-oxide, 1-Allyl-3-methylimidazolium chloride, and 1-butyl-3-methylimidazolium acetate to achieve high yield and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If DMSO is used to dissolve polyester, then polyester can be dissolved and separated, but the process becomes toxic to humans and animals, requires high temperatures over 150 degrees Celsius, and influences the properties of the remaining cellulose component
Solution Approach 1:
The patent changes the chemical parameters of the dissolution system by replacing DMSO with ionic liquids (such as choline chloride-based ionic liquids) that have different chemical properties. These ionic liquids can dissolve cellulose at lower temperatures and are non-toxic, thereby changing the fundamental parameters of the recycling process to eliminate toxicity while maintaining dissolution efficiency
Solution Approach 2:
The patent employs ionic liquids that can be easily removed and replaced, and the process is designed to handle the dissolution medium as a consumable that can be filtered and discarded after use, simplifying the process while eliminating the need for complex recovery systems required by toxic solvents like DMSO
2Quantity of substance
If hydrochloric acid is used to hydrolyze cotton, then polyester fibers can be separated and respun, but a substantial portion of the cotton is wasted
Solution Approach 1:
The patent selectively extracts and dissolves only the cellulose component from the cotton-polyester blend using ionic liquids, while leaving the polyester fibers intact and recoverable. This selective extraction allows both components to be recovered rather than losing cotton through acid hydrolysis
Solution Approach 2:
The ionic liquid acts as an intermediary substance that selectively interacts with cellulose through hydrogen bonding, facilitating its dissolution without affecting polyester. This intermediary enables the separation process to preserve both fiber types rather than degrading one component
3Quantity of substance
If conventional recycling processes are used, then some separation can be achieved, but the process becomes complex and energy-intensive with significant waste accumulation
Solution Approach 1:
The patent segments the recycling process into simple sequential steps: (1) ionic liquid dissolution of cellulose, (2) filtration to separate dissolved cellulose from polyester fibers, and (3) regeneration of cellulose fibers. This segmentation simplifies the overall process compared to conventional complex mechanical and chemical recycling methods
Solution Approach 2:
The patent replaces complex mechanical separation systems with a chemical dissolution-filtration-regeneration system. Instead of using complex mechanical sorters and processors, the method uses the selective chemical properties of ionic liquids to achieve separation through simple filtration, reducing device complexity
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 recovers cellulose and polyester fibers that are commercially indistinguishable from virgin fibers, reducing landfill waste, conserving resources, and lowering energy and water consumption in textile production.
Implementation Method 1
utilizing ionic liquids to dissolve cellulose fibers from textile blends
Implementation Method 2
extracting the spinning dope in a cellulose coagulation bath reservoir to reconstitute at least some of the dissolved cellulose fibers
Data Source
AI summary
A textile recycling method receives textile-waste-to-be-recycled, sorts the waste to isolate cellulose-containing articles from non-cellulose-containing articles, and re-sizes at least some of the cellulose-containing articles to create feedstock. The feedstock is processed in a cellulose solvent reactor, which has at least one ionic liquid. The ionic liquid dissolves intermolecular cellulose bonds of the feedstock to create a spinning dope. Cellulose fibers dissolved in the cellulose-bearing spinning dope solution are extruded in a cellulose coagulation bath reservoir to reconstitute at least some of the cellulose fibers, and the reconstituted fibers are wet-spun to form a continuous cellulose thread that is commercially indistinguishable from virgin fiber thread. Synthetic fiber material is vacuum-extracted or mechanically extracted from the cellulose-bearing solution and recycled into a continuous synthetic thread. Original color of textile-waste-to-be-recycled can be retained or removed, and new color can be added.