In situ DRIFTS study of hygroscopic behavior of mineral aerosol.
In situ diffusion reflectance infrared Fourier transform spectroscopy was used to study the water adsorption on mineral oxides (SiO2, alpha-Al2O3, MgO, Fe2O3, TiO2). The results showed that all the water adsorption isotherms were well fitted with the Brunauer-Emmett-Teller (BET)-III type equation, with the calculated monolayers occurring at 24%-30% relative humidity. It showed that about 1-5 layers of water adsorbed on oxides surfaces in ambient relative humidity (20%-90%). The measured deliquescence relative humidity of NaCl was (74 +/- 1)%, which demonstrated that DRIFTS is a useful method for the study the hygroscopic behavior of mineral dust. In addition, the limits of DRIFTS were also discussed.
Ma
Qingxin
Q
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. 5237027@rcees.ac.cn
He
Hong
H
Liu
Yongchun
Y
D000327:Adsorption; D000336:Aerosols; D000393:Air Pollutants / Q000737:chemistry; D008903:Minerals / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D014867:Water / Q000737:chemistry*
D000336:Aerosols; D000393:Air Pollutants; D008903:Minerals; D010087:Oxides; D014867:Water