Method for preparing silicon dioxide aerogel by using bagasse ash

Abstract

The invention provides a method for preparing silicon dioxide aerogel by using bagasse ash. The method is characterized by comprising the following steps: (1) mixing the bagasse ash with a sodium hydroxide solution, carrying out heating boiling, carrying out continuous stirring, and carrying out filtering so as to obtain sodium silicate filter liquor; (2) mixing the sodium silicate filter liquor with acidic ion exchange resin, and carrying out continuous stirring so as to obtain a silicic acid solution; (3) adding trimethylchlorosilane into the silicic acid solution, and carrying out stirringfor 10 to 40 minutes, so as to obtain a primary modified solution; (4) adding hexamethyldisilazane into the primary modified solution, and carrying out stirring for 10 to 40 minutes, so as to obtain asecondary modified solution; (5) adjusting the pH of the secondary modified solution to 4 with an ammonium hydroxide solution, so as to obtain silicon dioxide aquagel; (6) subjecting the silicon dioxide aquagel to standing heat-preserving treatment, so as to obtain gel; (7) drying the gel under ordinary pressure, thereby obtaining the silicon dioxide aerogel.

Description

technical field [0001] The invention relates to a method for preparing silica airgel, in particular to a method for preparing silica airgel by using bagasse ash. Background technique [0002] Bagasse is the cellulose fiber left after extracting sugary juice from sugarcane. It is the main by-product of the sugar industry and is also a rich and utilizable resource. Similar to most other biomass materials, bagasse contains high VOCs. Bagasse is thus an inexpensive potential energy source; most sugar mills, including those in Indonesia, use bagasse as their primary fuel to generate nearly enough energy to process sugarcane. Burning bagasse for energy will result in the production of large amounts of waste ash, which also poses disposal problems. Due to people's increasing concern about environmental issues, there are also requirements for green and safe processing of bagasse ash. [0003] In the prior art, silica aerogels are usually synthesized using organic alkoxides (expen...

AI Technical Summary

Problems solved by technology

The cost of using biomass ash to produce sodium silicate is relatively low, and the operation is relatively easy, but it needs to be dried by supercritical drying, and this method has long process cycle, low output and high cost

While coal fly ash can be processed and dried at ambient pressure to make silica aerogels, coal fly ash often requires high-temperature pretreatment to produce sodium silicate, a process that is energy-intensive

The above factors limit the commercial applications of these materials