Kraft Lignin Nanoparticle Synthesis via Antisolvent Precipitation
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Solution Overview
Problem
Current methods for producing Kraft lignin nanoparticles often result in particles that are either unfused, non-spherical, or have sizes larger than desired for advanced applications, with challenges in achieving sizes below 200 nm, especially below 100 nm, and maintaining uniformity and dispersion properties.
Innovation Solution
A method involving dissolving Kraft lignin in a high concentration of organic solvent followed by rapid addition to water as an antisolvent, leveraging π-π stacking, van der Waals interactions, and electrostatic repulsions to form small, spherical nanoparticles with controlled size and morphology, avoiding coalescence and Ostwald ripening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional nanoparticle production methods are used, then lignin nanoparticles can be formed, but the particles are either unfused, non-spherical, or have sizes larger than desired (above 200 nm)
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pH value (maintaining between 2-9 to prevent premature precipitation), temperature (0-50°C for stable dissolution), and solvent-to-antisolvent ratio (1:4 to 1:10 v/v) during the nanoparticle formation process. These parameter optimizations enable the production of spherical nanoparticles with sizes between 50-200 nm, resolving the contradiction between size control and morphology.
Solution Approach 2:
The patent utilizes phase transition by adding water as an antisolvent to induce lignin precipitation from the organic solvent solution. This controlled phase transition from dissolved state to precipitated nanoparticle form, combined with immediate stabilization through pH control, enables the formation of uniform spherical particles with desired size and morphology, avoiding the unfused and non-spherical defects of conventional methods.
2Productivity
If dialysis methods are used for nanoparticle formation, then particles can be produced, but the process takes at least 24 hours and requires slow stirring
Solution Approach 1:
The patent skips the time-consuming dialysis step entirely by using a direct antisolvent precipitation method. By adding water to the organic solvent solution under controlled conditions (pH 2-9, temperature 0-50°C, specific volume ratios), the patent achieves rapid nanoparticle formation within minutes rather than 24+ hours, dramatically improving productivity while reducing process time.
Solution Approach 2:
The patent extracts the time-consuming dialysis step from the nanoparticle production process. Instead of using dialysis to remove solvent and form particles, the method directly precipitates nanoparticles through antisolvent addition and stabilizes them through pH control, eliminating the lengthy dialysis procedure and achieving rapid production.
3Quantity of substance
If high lignin concentration is used before dialysis, then more particles can be produced, but the dispersion becomes unstable and particles larger than 1000 nm are obtained
Solution Approach 1:
The patent applies parameter changes by maintaining the lignin solution pH between 2-9 (optimally 4-7) before antisolvent addition, which prevents premature aggregation and maintains dispersion stability even at high lignin concentrations (1-10 g/L). This pH control, combined with controlled antisolvent addition rate and temperature management (0-50°C), enables the production of stable dispersions with uniform nanoparticle sizes (50-200 nm) without forming large aggregates.
4Ease of manufacture
If solvent-shifting method is used with THF-water mixture, then colloidal particles can be formed, but a large amount of organic solvent is required (THF/water ratio at least 3/1)
Solution Approach 1:
The patent optimizes the solvent-to-antisolvent ratio parameter, using water as the antisolvent in volume ratios ranging from 1:4 to 1:10 (organic solvent:water). This optimized ratio significantly reduces organic solvent consumption compared to conventional methods requiring at least 3:1 THF-water ratios, while still achieving effective nanoparticle formation and maintaining process simplicity through controlled precipitation.
5Manufacturing precision
If rapid nanoparticle formation is achieved, then smaller sizes (below 100 nm) can be obtained, but controlling uniformity and avoiding coalescence becomes more difficult
Solution Approach 1:
The patent applies multiple parameter changes simultaneously: maintaining pH between 2-9 to prevent premature precipitation, controlling temperature between 0-50°C for stable dissolution and controlled nucleation, and using specific organic solvents (acetone, acetonitrile, ethanol, methanol) with appropriate water ratios (1:4 to 1:10). These coordinated parameter optimizations enable rapid nanoparticle formation achieving sizes below 100 nm while maintaining uniformity and preventing coalescence through stable dispersion conditions.
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 approach enables the production of Kraft lignin nanoparticles with sizes ranging from 9 nm to 200 nm, offering improved uniformity, dispersion, and industrial scalability, with enhanced safety and recyclability due to reduced organic solvent use and the use of water as a green antisolvent.
Implementation Method 1
dissolving Kraft lignin in a high concentration of organic solvent
Implementation Method 2
incorporating an anti-solvent in the solution that has been formed under different conditions. Thus, nanoparticles are generated due to their decreasing solubility in the medium
Implementation Method 3
leveraging π-π stacking, van der Waals interactions, and electrostatic repulsions to form small, spherical nanoparticles
Implementation Method 4
leveraging π-π stacking, van der Waals interactions, and electrostatic repulsions to form small, spherical nanoparticles
Implementation Method 5
leveraging π-π stacking, van der Waals interactions, and electrostatic repulsions to form small, spherical nanoparticles
Data Source
AI summary
The disclosure relates to a method for manufacturing a colloidal dispersion of Kraft lignin (KL) nanoparticles, said method comprising the steps of (a) providing KL; (b) dissolving said KL into a solvent, to obtain a solution having a concentration of Kraft lignin of at least 15 mg/ml; and (c) mixing said solution with an antisolvent under mixing conditions, to provide a colloidal dispersion of nanoparticles. Said method is remarkable in that the solvent used in step (b) of dissolving said KL is one or more organic solvents, and in that step (c) of mixing is performed by the addition of the solution of step (b) into an antisolvent being or comprising water. The disclosure also relates to spherical KL nanoparticles with an average diameter size ranging from 9 nm up to 70 nm. The disclosure further relates to various uses of said spherical KL nanoparticle.