Hydrophobic Deep Eutectic Solvent for Salt-Free Cotton Reactive Dyeing
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Solution Overview
Problem
Current reactive dyeing methods for cotton fabrics face challenges such as low dye uptake, high water and salt usage, and environmental pollution, with existing non-aqueous dyeing technologies like supercritical carbon dioxide and organic solvent dyeing facing industrial scalability issues due to equipment requirements and environmental concerns.
Innovation Solution
A hydrophobic deep eutectic solvent system composed of natural ingredients like terpene-derived hydrogen bond donors and acceptors is used as a dyeing medium, eliminating the need for inorganic salts and allowing for water-reduced, salt-free dyeing, forming a semi-stable emulsion with reactive dyes for efficient dyeing and cyclic reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional water bath reactive dyeing is used, then complete chromatography and bright color are achieved, but a large amount of water and neutral electrolyte are required, increasing wastewater treatment difficulty
Solution Approach 1:
The patent changes the fundamental parameter of the dyeing medium from water to hydrophobic deep eutectic solvent, which fundamentally alters the dyeing mechanism. This parameter change eliminates the need for neutral electrolytes and significantly reduces water consumption while maintaining color brightness and chromatography completeness through the unique solvation properties of the DES system
Solution Approach 2:
The hydrophobic deep eutectic solvent acts as an intermediary medium that facilitates dye-fiber interaction without requiring additional electrolytes. The solvent mediates the dyeing process by providing a suitable environment for dye dissolution and transfer to fibers, eliminating the need for water and traditional electrolyte additives
2Reliability
If reactive dyes are used under alkaline conditions to achieve covalent bonding with cellulose fibers, then color fastness is improved, but dye hydrolysis occurs, increasing wastewater pollution
Solution Approach 1:
The patent changes the pH parameter of the dyeing medium by using hydrophobic deep eutectic solvent instead of alkaline water bath. This parameter change prevents dye hydrolysis that occurs under alkaline conditions while still achieving covalent bonding between reactive dyes and cellulose fibers, thereby eliminating harmful hydrolyzed dyes from wastewater
Solution Approach 2:
The patent converts the hydrophobicity of the deep eutectic solvent, which initially seemed to be a limitation for dissolving ionic dyes, into a beneficial feature. The hydrophobic environment prevents unwanted side reactions like hydrolysis while the hydrogen bonding capability of DES ensures adequate dye dissolution and fiber penetration, achieving both color fastness and environmental friendliness
3Quantity of substance
If supercritical carbon dioxide dyeing is used to reduce water consumption, then water usage is reduced, but equipment complexity and operational requirements increase
Solution Approach 1:
The patent uses a simple, inexpensive hydrophobic deep eutectic solvent system that can be easily prepared from readily available components. Unlike supercritical CO2 systems requiring complex high-pressure equipment, this DES-based method uses conventional dyeing equipment, making it economically viable and industrially scalable without sophisticated infrastructure
Solution Approach 2:
The patent changes the physical state parameter of the dyeing medium from supercritical fluid to liquid deep eutectic solvent. This parameter change eliminates the need for high-pressure equipment and complex temperature control systems while maintaining the water-reduced advantage, as the liquid DES can be used in conventional dyeing machines
4Reliability
If organic solvents are used as dyeing medium to avoid dye hydrolysis, then fixation rate is improved, but environmental and safety problems arise, increasing cost
Solution Approach 1:
The patent uses a composite deep eutectic solvent system composed of hydrogen bond donors and acceptors in specific ratios. This composite structure provides the beneficial properties of organic solvents (preventing hydrolysis, high fixation rate) while eliminating their harmful environmental and safety effects, as the DES components are non-toxic, biodegradable, and environmentally friendly
Solution Approach 2:
The patent converts the typically harmful organic solvent components into beneficial, environmentally friendly deep eutectic solvent components. By selecting hydrogen bond donors and acceptors from natural or bio-based sources, the system achieves high fixation rates comparable to organic solvents while eliminating toxicity and environmental persistence issues
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 method achieves dyeing results comparable to traditional water bath methods while significantly reducing water and salt usage, enabling cost-effective and environmentally friendly cyclic dyeing with improved color fastness and reduced wastewater discharge.
Implementation Method 1
A deep eutectic solvent (DES) is usually composed of two or more compounds, i.e., a combination of a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA), which can be connected to each other by hydrogen bonds
Implementation Method 2
A small amount of dye aqueous solution and the HDES form a semi-stable emulsion system
Data Source
AI summary
The present disclosure discloses application of a deep eutectic solvent in textile dyeing, belonging to the technical field of ecological dyeing and finishing of textiles. A natural hydrophobic deep eutectic solvent system (HDES) is first used as a dyeing medium to perform reactive dyeing on cotton. Firstly, the prepared natural hydrophobic deep eutectic solvent is mixed with a small amount of dye aqueous solution at high speed to prepare dye liquor, and then cotton fabric soaked with alkali liquor is put into a dye bath for dyeing. The dyeing method doesn't require addition of inorganic salts and other dyeing auxiliaries, but uses a small amount of water and alkali agent to achieve the same dyeing effect as traditional water bath, and the dyeing medium is safe and environment-friendly. After dyeing, cyclic dyeing can be achieved by simply separating the dye bath, which truly realizes green dyeing of reactive dyes.