| Adsorption of Pentachlorophenol onto Oxide and Clay Minerals： Surface Reaction Model and Environmental Implications |
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| 作者姓名： | WU Daqing DIAO Guiyi YUAN Peng PENG Jinlian |
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| 作者单位： | Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640 |
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| 基金项目： | 中国科学院资助项目;广东省博士启动基金 |
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| 摘 要： | The adsorption of pentachlorophenol （PCP） onto quartz, kaolinite, illite, montmorillonite and iron oxides has been investigated by batch equilibrium techniques. The pH-dependent isotherms are curves with peak values, the position of which is at about pH = 5-6 depending on the mineral species. Based on distribution of both speciation of surface hydroxyls on minerals and PCP in solution a surface reaction model involving surface complexation and surface electrostatic attraction is presented to fit the pH-dependent isotherms, and both reaction constants are calculated. The results show that on quartz and phyllosilicate minerals the predominant adsorption reaction is surface complexation, meanwhile both of surface electrostatic attraction and surface complexation are involved on the iron oxide minerals. The reaction constants of surface electrostatic adsorption are usually one to three orders in magnitude, larger than that of surface complexation. The concentration-dependent isotherms can be well fitted by Langmnir equation with the correlation coefficient R〉0.93 for kaolinite and iron oxides. The maximum adsorption is found in the order： hematite 〉 lepidocrocite 〉 goethite 〉 kaolinite 〉 quartz 〉 montmorillonite ≈ illite, which can be interpreted by consideration of both reaction mechanism and surface hydroxyl density. The significant adsorption of PCP onto mineral surfaces suggests that clay and iron oxide minerals will play an important role as HIOCs are adsorbed in laterite or latertoid soil, which is widespread in South China.
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| 关 键 词： | 五氯苯酚 吸附作用 石英 高岭石 蒙脱石 离子氧化物 表面反应模型 |
| 收稿时间： | 2005-07-14 |
| 修稿时间： | 2006-02-17 |
Adsorption of Pentachlorophenol onto Oxide and Clay Minerals: Surface Reaction Model and Environmental Implications |
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| Authors: | WU;Daqing;DIAO;Guiyi;YUAN;Peng;PENG;Jinlian |
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| Abstract: | Abstract The adsorption of pentachlorophenol (PCP) onto quartz, kaolinite, illite, montmorillonite and iron oxides has been investigated by batch equilibrium techniques. The pH‐dependent isotherms are curves with peak values, the position of which is at about pH = 5–6 depending on the mineral species. Based on distribution of both speciation of surface hydroxyls on minerals and PCP in solution a surface reaction model involving surface complexation and surface electrostatic attraction is presented to fit the pH‐dependent isotherms, and both reaction constants are calculated. The results show that on quartz and phyllosilicate minerals the predominant adsorption reaction is surface complexation, meanwhile both of surface electrostatic attraction and surface complexation are involved on the iron oxide minerals. The reaction constants of surface electrostatic adsorption are usually one to three orders in magnitude, larger than that of surface complexation. The concentration‐dependent isotherms can be well fitted by Langmuir equation with the correlation coefficient R>0.93 for kaolinite and iron oxides. The maximum adsorption is found in the order: hematite > lepidocrocite > goethite > kaolinite > quartz > montmorillonite = illite, which can be interpreted by consideration of both reaction mechanism and surface hydroxyl density. The significant adsorption of PCP onto mineral surfaces suggests that clay and iron oxide minerals will play an important role as HIOCs are adsorbed in laterite or latertoid soil, which is widespread in South China. pentachlorophenol (PCP), adsorption, quartz, kaolinite, montmorillonite, illite, iron oxides, surface reaction model |
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| Keywords: | pentachlorophenol (PCP) adsorption quartz kaolinite montmorillonite illite iron oxides surface reaction model |
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