Porous Cellulose Beads via Deep Eutectic Solvent
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Solution Overview
Problem
Current methods for producing porous cellulose beads are cumbersome, require highly toxic and corrosive solvents, and result in beads with large pores and broad pore size distribution, leading to poor adsorption performance, making them unsuitable for industrial-scale applications.
Innovation Solution
A method involving the preparation of a fine cellulose dispersion using a low-temperature alkaline aqueous solution and the addition of a crosslinking agent, followed by emulsification and coagulation, to produce cellulose beads with a narrow pore size distribution and enhanced adsorption performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods dissolve cellulose in highly corrosive and toxic solvents like calcium thiocyanate aqueous solution, then cellulose can be dissolved and processed, but the solvent is highly corrosive and toxic making it difficult to design a plant and the resulting beads have large pores and broad pore size distribution leading to poor adsorption performance
Solution Approach 1:
The patent changes the fundamental parameter of the solvent system from highly corrosive calcium thiocyanate solution to a non-toxic, biodegradable deep eutectic solvent composed of choline chloride and water. This parameter change eliminates the harmful effects while maintaining the ability to dissolve cellulose and form porous beads with controlled pore size distribution suitable for adsorption applications
Solution Approach 2:
The patent employs a composite solvent system (deep eutectic solvent) formed by combining choline chloride and water in specific ratios. This composite material provides the necessary solvation power for cellulose while being environmentally benign, replacing the single-component toxic solvents traditionally used in cellulose processing
2Productivity
If conventional methods use calcium thiocyanate aqueous solution to dissolve and coagulate cellulose, then porous cellulose beads can be produced, but the beads have considerably large pores and broad pore size distribution resulting in small specific surface area and poor adsorption performance
Solution Approach 1:
The patent controls the pore size distribution by adjusting parameters including the choline chloride to water ratio in the deep eutectic solvent, cellulose concentration, and coagulation conditions. These parameter changes result in beads with narrow pore size distribution and optimized specific surface area for high adsorption performance
Solution Approach 2:
The patent replaces the chemical mechanism of calcium thiocyanate dissolution with a physical-chemical mechanism using deep eutectic solvent formation. This substitution enables precise control over the gelation and pore formation processes, producing beads with uniform and controlled pore structures
3Ease of manufacture
If substituent groups are bound to hydroxy groups of cellulose to improve solubility, then cellulose can be dissolved in general solvents, but the steps are cumbersome and molecular weight decreases during reacting and removing substituent groups reducing carrier strength
Solution Approach 1:
The patent extracts and eliminates the need for substituent group modification steps entirely by using deep eutectic solvent that can directly dissolve native cellulose. This removes the complex multi-step process of introducing and then removing substituent groups, simplifying the manufacturing process while preserving molecular weight and carrier strength
Solution Approach 2:
The deep eutectic solvent acts as an intermediary that enables direct dissolution of cellulose without chemical modification. The solvent mediates between the insoluble cellulose and the processing requirements, allowing dissolution and subsequent bead formation without the need for chemical substituent groups
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 efficiently produces cellulose beads with improved mechanical strength and adsorption performance, eliminating the need for toxic solvents and simplifying the production process, making them suitable for industrial use as effective adsorbents.
Implementation Method 1
preparing a fine cellulose dispersion by mixing a low temperature alkaline aqueous solution and cellulose
Implementation Method 2
adding a crosslinking agent to the fine cellulose dispersion
Implementation Method 3
contacting the emulsion with a coagulating solvent
Data Source
AI summary
The objective of the present invention is to provide a method for easily and efficiently producing cellulose beads which have pore shape suitable for an adsorbent and of which adsorption performance is excellent without using highly toxic and highly corrosive auxiliary raw material and without industrially disadvantageous cumbersome step. The method for producing porous cellulose beads according to the present invention is characterized in comprising (a) the step of preparing a fine cellulose dispersion by mixing a low temperature alkaline aqueous solution and cellulose, (b) the step of preparing a mixed liquid by adding a crosslinking agent to the fine cellulose dispersion, (c) the step of preparing an emulsion by dispersing the mixed liquid in a dispersion medium, (d) the step of contacting the emulsion with a coagulating solvent.