title: [Infrared spectroscopic study of Changbaishan diatomite].
abstract: Changbaishan diatomite was treated under the conditions of temperature from 100 to 1330 degrees C, and examined by infrared spectroscopy applying the KBr-technique. In the range from 250 to 1500 cm(-1), the spectra of the samples at 100 to 1100 degrees C show the same three characteristic broad bands at 1100, 801 and 471 cm(-1), which are similar to amorphous silica. Besides the above three broad bands, the spectra of 1200 and 1330 degrees C treated samples exhibit three new bands at 618, 386 and 301 cm(-1), which indicate that the diatornite transforms into cristobalite. While all of the eleven samples show an asymmetric broad band at 3440 cm(-1) in the range from 3000 to 4000 cm(-1), the spectrum of 500 degrees C treated sample begins to exhibit a 3745 cm(-1) band assigning to isolated Si-OH group stretching vibration. The 3745 cm(-1) band shows the highest intensity at 900 degrees C, and disappears at 1200 degrees C. According to the absorbance of the 3745 cm(-1) band of different temperature treated samples, the H2O content in the form of Si-OH group was calculated semi-quantitatively, which indicates that the Si-OH group exists at the internal structure defects in addition to existing at the surface. The transform mechanism of diatomite into cristobalite was also discussed.
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Wan-sheng
authors.initials: WS
authors.lastname: Xiao
authors.forename: Wen-shi
authors.initials: WS
authors.lastname: Peng
authors.forename: Guan-xin
authors.initials: GX
authors.lastname: Wang
authors.forename: Fu-ya
authors.initials: FY
authors.lastname: Wang
authors.forename: Ke-nan
authors.initials: KN
authors.lastname: Weng
mesh_terms: D003460:Crystallization; D007692:Diatomaceous Earth / Q000737:chemistry*; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D004365:Drugs, Chinese Herbal; D007692:Diatomaceous Earth; C033787:diatomite