Adsorption and desorption of 2,4,6-trichlorophenol onto and from ash as affected by Ag+, Zn2+, and Al3+

详细信息    查看全文

• 作者：Guangcai Chen (1)
  Yusheng Wang (2)
  Zhiguo Pei (2)
  
• 关键词：Adsorption ; Ash ; 2 ; 4 ; 6 ; Trichlorophenol ; Ag+ ; Zn2+ ; Al3+
• 刊名：Environmental Science and Pollution Research
• 出版年：2014
• 出版时间：February 2014
• 年：2014
• 卷：21
• 期：3
• 页码：2002-2008
• 全文大小：360 KB
• 作者单位：Guangcai Chen (1)
  Yusheng Wang (2)
  Zhiguo Pei (2)
  
  1. Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang, Zhejiang, 311400, China
  2. State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
  
• ISSN：1614-7499

文摘

Metal cations and organic pollutants mostly co-exist in the natural environment. However, their interactions in adsorption processes have yet to be adequately addressed. In the current study, the effect of inorganic cations with different charges (Ag+, Zn2+, and Al3+) on the adsorption and desorption of 2,4,6-trichlorophenol (TCP) onto and from processed ash derived from wheat (Triticum aestivum L.) straw was investigated. The adsorption and desorption of TCP were both nonlinear; the isotherm and kinetics curves fitted well using the Freundlich equation and a pseudo-second-order model, respectively. The presence of Ag+ promoted TCP adsorption, while Zn2+ and Al3+ reduced TCP adsorption onto ash. The desorption of TCP from ash showed obvious hysteresis, and the presence of Ag+, Zn2+, and Al3+ caused the desorption to be less hysteretic. The suppression of TCP adsorption by Zn2+ and Al3+ was ascribed to the partial overlapping of adsorption groups between TCP and metal ions. Al3+ had a stronger inhibition effect than that of Zn2+ due to its higher binding capacity and larger hydrated ionic radius than those of Zn2+. Enhanced adsorption of TCP onto ash by Ag+ was ascribed to its ability to reduce the competitive adsorption of water molecules on ash surface by replacing the original ions, such as Na+ and Ca2+, and compressing the hydrated ionic radius of these metal ions. In addition, Ag+ was able to bind with the aromatic organic compounds containing π-electrons, which resulted in a further increase of TCP adsorption by ash.