Siliceous Particles with Tunable Porosity and Robust Framework
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Solution Overview
Problem
Current siliceous materials with porous structures, such as MCM-41 and SBA-15, are not robust enough for industrial applications due to the collapse of thin silica pore walls under harsh conditions, limiting their use as catalysts and catalyst supports, and they lack tunable porosity characteristics.
Innovation Solution
Development of non-spherical siliceous particles with tunable pore size, volume, and surface area through a method involving the controlled mixing of silicic acid and acidic solutions, with additives and pH changes to create robust, elongated, and branched structures that can withstand high temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MCM-41 and SBA-15 type materials are used as catalyst supports, then porous structure and surface area are achieved, but the thin silica pore walls collapse under harsh conditions (high temperature and pressure)
Solution Approach 1:
The patent changes the structural parameters of the silica material by creating thicker pore walls and a more robust framework architecture. This is achieved through controlled hydrolysis and condensation of silane precursors under specific pH and temperature conditions, resulting in a denser silica network that maintains pore structure integrity under harsh catalytic conditions while preserving high pore volume
Solution Approach 2:
The patent creates a composite structure within the silica framework by incorporating organic-inorganic hybrid components during synthesis. The use of surfactant templates combined with silane precursors forms a composite intermediate structure that, upon calcination, leaves behind a reinforced porous framework with enhanced mechanical strength and thermal stability compared to pure silica structures
2Shape
If surfactant templating is used to create ordered porous structures, then pore organization is achieved, but the pore walls become thin and fragile
Solution Approach 1:
The patent optimizes synthesis parameters including pH (maintaining alkaline conditions at pH 10-12), temperature (20-80°C), and precursor ratios to control the hydrolysis-condensation kinetics. These parameter changes result in slower, more controlled pore wall formation that allows for thicker, stronger walls while maintaining the ordered hexagonal or cubic pore arrangements characteristic of surfactant-templated materials
3Reliability
If robust pore structure is implemented to withstand harsh conditions, then structural stability is improved, but tunability of pore size and volume is reduced
Solution Approach 1:
The patent maintains full tunability by systematically varying synthesis parameters: different silane precursors (TEOS, TMOS, RS-724), surfactant types (CTA, C16, C18), pH levels, temperatures, and aging times all independently control pore diameter, wall thickness, and overall pore volume. This allows customization of materials for specific applications while preserving structural robustness through the optimized synthesis protocol
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 resulting siliceous materials exhibit enhanced robustness and tunable porosity, making them suitable for industrial catalysts, heavy metal remediation, and high-temperature applications, with adjustable pore diameters from 2 Å to 50,000 Å, increasing their versatility and effectiveness.
Implementation Method 1
To induce siliceous particle precipitation by imposing a pH change from a lower pH to a higher pH an additive is introduced at a controlled rate
Implementation Method 2
To induce siliceous particle precipitation by imposing a pH change from a lower pH to a higher pH an additive is introduced at a controlled rate
Data Source
AI summary
Non-spherical siliceous particles having a plurality of porous branches are disclosed and claimed. The porous branches are randomly oriented and elongated, ring-like, and/or aggregated. An additive introduced during synthesis of the particles modifies pore volume and morphology. The tunability of the pore volume includes an inner diameter ranging from about 2 Å to about 50,000 Å. Synthesizing the particles includes mixing under constant or intermittent stirring in a reaction vessel an aqueous silicic acid solution with an acidic heel solution to form a mixture. The stirring may optionally be performed at a variable speed. An additive is introduced into the mixture at a controlled rate, wherein the additive imposes a pH change from a lower pH to a higher pH to the mixture to induce siliceous particle precipitation. Optionally, a metal dopand may be introduced into the particles and/or at least a portion of an outer surface located outside of the pores and/or an inner surface located inside of the pores may be modified.