Abstract
Silica microballoons about 1.5 μm in diameter were prepared from sodium silicate solution by the ultrasonic spraying dry and spray dry methods. Sodium ions were removed with 0.01 N HCl solution, using 1–3 1 g −1. The prepared balloons were characterized with the aid of scanning electron microscopy (SEM), thermal analyses, electron probe X-ray microanalyses, Fourier transform-infrared, and nitrogen and water adsorptions. The SEM observation showed the formation of silica balloons about 1.5 μm in diameter whose shell thickness is about 0.1 μm. Thermogravimetry showed that microballoons prepared by these two methods have different types of silanol groups. The nitrogen adsorption isotherms were of Type II; the α s plots suggested the presence of micropores. The surface area of washed samples is greater than that of unwashed samples. However, the water adsorption isotherms of washed microballoons show a large uptake in the lower relative pressure region and were rather close to Type I. The surface area of washed samples from water adsorption measurements was much greater than that from nitrogen adsorption, indicating the presence of narrow micropores accessible only to water molecules.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Colloids and Surfaces A: Physicochemical and Engineering Aspects
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
