UV Blocking by Mg鈥揨n鈥揂l Layered Double Hydroxides for the Protection of Asphalt Road Surfaces

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• 作者：Guirong Wang ; Deming Rao ; Kaitao Li ; Yanjun Lin
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：March 19, 2014
• 年：2014
• 卷：53
• 期：11
• 页码：4165-4172
• 全文大小：646K
• 年卷期：v.53,no.11(March 19, 2014)
• ISSN：1520-5045

文摘

Mg_aZn_bAl_c鈥揅O₃ layered double hydroxides (LDHs) with varying magnesium/zinc ratios have been synthesized by a method involving separate nucleation and aging steps. The resulting LDHs were analyzed by powder X-ray diffraction, laser particle size analysis, scanning electron microscopy, and diffuse reflectance UV spectroscopy. The results show that the UV blocking properties of Mg_aZn_bAl_c鈥揅O₃鈥揕DHs depend on both the proportion of zinc and the particle size distribution. The UV absorbing properties of Mg_aZn_bAl_c鈥揅O₃鈥揕DHs increase with the content of zinc, which can be ascribed to the decrease in the band gap energy, as has been observed experimentally and confirmed by density functional theory calculations. The UV screening properties of Zn₄Al₂鈥揅O₃鈥揕DHs were found to increase with increasing particle size, which can be explained by Mie scattering theory. Moreover, in accelerated UV light irradiation aging tests, LDH-modified asphalt samples showed excellent resistance to UV aging, with the efficacy of the LDH increasing with increasing zinc content.