The hydrophobic silica aerogel(SiO2 aerogel) was prepared by in situ polymerization sol-gel method and ethanol supercritical drying,with tetraethoxysilane(TEOS) as silica source,phenyltriethoxysilane(PTES) as modifier,ethanol as solvent and ammonia as catalyst.The effects of n(PTES)/n(TOES) were investigated on gel time,structure,and hydrophobicity.The SiO2 aerogel was measured by Fourier transform infrared spectroscopy(FT-IR) and scanning electron microscopy(SEM).The effects of n(PTES)/n(TOES) were also studied on adsorption property of pentane,hexane,heptane,octane,benzene,toluene,o-xylene,nitromethane,nitroethane,and nitrobenzene.The adsorption intensity of SiO2 aerogel was compared with that of activated carbon.The results show,with the increasing of n(PTES)/n(TOES),the surface area,pore volume,and pore size of SiO2 aerogel decreased,gel time and hydrophobicity increased,and the contact angle could be 154° with n(PTES)/n(TOES)=0.7.The adsorption intensity of SiO2 aerogel with n(PTES)/n(TOES)=0.5 was bigger than that of activated carbon with an average 5.84 times of 10 organic liquid.The adsorption intensity of aerogel with n(PTES)/n(TOES) =0.1 was the best one in all samples with the average 8.33 times compared with that of activated carbon.
以六钛酸钾晶须(PTW)为遮光剂,掺入SiO_2气凝胶中降低气凝胶的热导率。研究偶联剂的种类和添加量、PTW掺入量对气凝胶热导率、密度和比表面积等性能的影响。采用X线衍射仪(XRD)、傅立叶红外光谱仪(FT-IR)、扫描电子显微镜(SEM)对气凝胶进行表征。结果表明:0.5 mL KH550对10 g PTW进行表面改性后,将PTW按照质量分数28.57%掺入SiO_2气凝胶中可使其热导率降至0.023 55 W/(m·K)。PTW在气凝胶中保持原有的晶体结构,SiO_2仍保持无定形网络结构。
The adsorption properties of nitrobenzene from wastewater by hydrophobic silica aerogels were investigated.The effects of adsorption intensity by pH value,adsorption temperature,adsorption time and the amount of the silica aerogels were studied.The adsorption principle and mechanism of silica aerogels adsorbing nitrobenzene were discussed along with the Freundlich equation.The results showed that the adsorption intensity of the hydrophobic silica aerogels could reach 68.76% at better adsorption conditions of adsorption temperature 25°C,pH value 8.35,the amount of SiO2 aerogels dosage 3.33 g/L,and adsorption time of 30 min,and that the adsorption properties were related to the hydrophobility of aerogels,surface area of organic solution,structure of aerogels.
CUI Sheng1,LIU XueYong2,LIU Yu2,SHEN XiaoDong1,LIN BenLan1,3,HAN GuiFang1 & WU ZhanWu1 1 College of Material Science and Engineering,Nanjing University of Technology,Nanjing 210009,China
