Silica Aerogel Preparation Using Solid Silicon Sources
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Solution Overview
Problem
Current methods for preparing silica aerogels using organic silicon sources result in significant organic waste gas production, while methods using inorganic sources lead to excessive sodium ions and subsequent waste water generation, affecting product quality and environmental sustainability.
Innovation Solution
The use of a solid silicon source, such as white carbon black or silica powder, mixed with an alkaline solution to form an aerogel precursor, which is then dried to produce a silica aerogel, reducing organic waste and sodium ion contamination, and allowing for controlled gelation reactions to enhance specific surface area and thermal insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If organic silicon sources (tetramethoxy-silicane, tetraethyl orthosilicate) are used as raw material, then silica aerogel can be prepared through sol-gel process, but a large amount of volatile organic compounds will be produced and emitted during mixing and drying
Solution Approach 1:
The invention changes the chemical composition parameter of the silicon source from organic compounds to inorganic compounds (solid silicon source + alkaline solution), fundamentally altering the reaction system to eliminate volatile organic compound emissions while maintaining the sol-gel process capability for silica aerogel formation
Solution Approach 2:
The invention uses readily available solid silicon sources (white carbon black, silica powder, diatomite) that can be easily disposed of after reaction, replacing expensive and environmentally problematic organic silicon sources, aligning with the principle of using simple, replaceable materials
2Quantity of substance
If sodium silicate solution is used as silicon source, then silica aerogel can be prepared, but excessive sodium ions remain in the product causing metal corrosion
Solution Approach 1:
The invention extracts and removes the harmful sodium ions from the reaction system by using solid silicon sources instead of sodium silicate solution, eliminating the source of metal corrosion while preserving the ability to form silica aerogel through alternative silicon sources that do not introduce excessive sodium
Solution Approach 2:
The invention converts the harmful effect of sodium ion contamination into a benefit by selecting silicon sources that naturally avoid sodium ion introduction, thereby eliminating the need for complex purification steps and directly producing high-quality aerogel suitable for metal applications
3Quantity of substance
If dimethylchlorosilane is used as raw material, then silica aerogel can be prepared through hydrolysis, but a large amount of chloride ions are produced which are highly corrosive
Solution Approach 1:
The invention changes the chemical parameter of the silicon source from chloride-containing compounds to chloride-free solid silicon sources, fundamentally altering the reaction system to eliminate chloride ion generation and the associated corrosion and waste liquid problems
Solution Approach 2:
The invention uses simple, inexpensive solid silicon sources (white carbon black, silica powder, diatomite) that can be easily disposed of, replacing complex and environmentally problematic dimethylchlorosilane, aligning with the principle of using simple, replaceable materials that minimize environmental impact
4Object-generated harmful factors
If solid silicon source is used with alkaline solution, then organic waste gas and sodium ion contamination are minimized, but the preparation process requires controlled gelation reactions
Solution Approach 1:
The invention implements feedback control in the gelation process by monitoring and adjusting parameters such as pH, temperature, and mixing rate to achieve optimal gel formation, ensuring consistent product quality while maintaining environmental benefits of the solid silicon source approach
Solution Approach 2:
The invention performs preliminary preparation of the alkaline solution and solid silicon source mixture before the actual gelation reaction, ensuring proper stoichiometry and mixing conditions are established in advance, which simplifies the subsequent gelation process and reduces the need for complex real-time adjustments
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 minimizes organic waste and sodium ion-related issues, producing silica aerogels with larger specific surface areas and lower thermal conductivity, thus improving product quality and environmental friendliness.
Implementation Method 1
The solid silicon source reacts with the alkaline solution under certain conditions to form an aerogel precursor
Implementation Method 2
nanoclusters with different structures are formed in the solution by controlling reaction conditions of hydrolysis and condensation. The clusters adhere to each other, so as to form a gel
Implementation Method 3
During drying, the earlier-formed gel is not only dehydrated, but also ensured that the gel does not collapse, so that the air is allowed to enter the network in the gel to replace those water in the original gel
Implementation Method 4
The preparation of aerogels are usually consisted of sol-gel process and supercritical drying treatment
Implementation Method 5
Silica aerogel solid, containing 99% of gas, shows blue under Rayleigh scattering
Data Source
AI summary
A preparation method for a silica aerogel, comprising the following steps: A) raw material containing a solid silicon source and an alkaline solution is used to produce an aerogel precursor after mixing; and B) the aerogel precursor is dried to obtain a silica aerogel. An improved silica aerogel preparation method, comprising the following steps: A) a cation exchange resin and a silicate solution are used as raw materials and mixed; B) the mixed material is allowed to stand to obtain an aerogel precursor; and C) the aerogel precursor is dried to obtain a silica aerogel.