[Ambient pressure synthesis and characterization of silica aerogel as adsorbent for dieldrin].
Hydrophobic silica aerogels were prepared from cheap waterglass precursors via surface modification of wet gels and ambient pressure drying route. Its adsorption capacity of Dieldrin, a typical of persistent organic pollutants (POPs), was examined. It is characterized via BET, FTIR, and DSC-TGA. The silica aerogels were highly hydrophobic with contact angles of 135 degrees-142 degrees, and the hydrophobicity of the aerogels could be maintained up to the temperature of 380 degrees C. The silica aerogels were porous with, pore size distribution of 17.5-23.4 nm, porosity of 94.8%-95.6%, and surface area of 444-560 m2 x g(-1). The results of adsorption experiments indicated that the hydrophobic aerogels could remove 84% of dieldrin from aqueous solution within 4 h; the adsorption process followed the pseudo-second-order kinetics process. Based on the adsorption equilibrium results, the adsorption capacity of silica aerogel was 11 times bigger than by active carbon.
Sha
Wei
W
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. hewsay@gmail.com
Liu
Rui-ping
RP
Liu
Hui-juan
HJ
Qu
Jiu-hui
JH
D000327:Adsorption; D004026:Dieldrin / Q000302:isolation & purification*; D005782:Gels; D057927:Hydrophobic and Hydrophilic Interactions; D011312:Pressure; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification
D005782:Gels; D012997:Solvents; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide; D004026:Dieldrin