title: Adsorption of diethyl phthalate ester to clay minerals.
abstract: Phthalate esters are a group of plasticizers, which have been widely detected in China's agricultural and industrial soils. In this study, batch adsorption experiments were conducted to investigate the environmental effects on the adsorption of diethyl phthalate ester (DEP) to clay minerals. The results showed that DEP adsorption isotherms were well fitted with the Freundlich model; the interlayer spacing of K(+) saturated montmorillonite (K-mont) was the most important adsorption area for DEP, and di-n-butyl ester (DnBP) was limited to intercalate into the interlayer of K-mont due to the bigger molecular size; there was no significant effect of pH and ionic strength on DEP adsorption to K-mont/Ca-mont, but to Na-mont clay. The adsorption to kaolinite was very limited. Data of X-ray diffraction and FTIR spectra further proved that DEP molecules could intercalate into K-/Ca-mont interlayer, and might interact with clay through H-bonding between carbonyl groups and clay adsorbed water. Coated humic acid on clay surface would enhance DEP adsorption at low concentration, but not at high concentration (eg. Ce>0.26 mM). The calculated adsorption enthalpy (ΔHobs) and adsorption isotherms at varied temperatures showed that DEP could be adsorbed easier as more adsorbed. This study implied that clay type, compound structure, exchangeable cation, soil organic matter and temperature played important roles in phthalate ester's transport in soil.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, No. 71. East Beijing Road, Nanjing 210008, PR China; School of Resources and Environment, Anhui Agricultural University, Hefei 230036, PR China. Electronic address: 860330009@qq.com.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Wu
authors.affiliation: School of Resources and Environment, Anhui Agricultural University, Hefei 230036, PR China. Electronic address: youbinsi@ahau.edu.cn.
authors.forename: Youbin
authors.initials: Y
authors.lastname: Si
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, No. 71. East Beijing Road, Nanjing 210008, PR China. Electronic address: dmzhou@issas.ac.cn.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, No. 71. East Beijing Road, Nanjing 210008, PR China. Electronic address: juangao@issas.ac.cn.
authors.forename: Juan
authors.initials: J
authors.lastname: Gao
mesh_terms: D004952:Esters / Q000737:chemistry; D006801:Humans; D007616:Kaolin / Q000737:chemistry*; D010795:Phthalic Acids / Q000737:chemistry*; D018570:Risk Assessment; D017640:Silicates / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D004952:Esters; D010795:Phthalic Acids; D017640:Silicates; D012989:Soil Pollutants; D007616:Kaolin; C033214:Smectite
keywords: Adsorption; Clay mineral; Interlayer; Montmorillonite; Phthalate ester; Thermodynamic