多重功能改質黏土之吸持與催化特性研究;The multiple functions of the modified clay sorption and catalytic properties

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题名:	多重功能改質黏土之吸持與催化特性研究;The multiple functions of the modified clay sorption and catalytic properties
作者:	林芳伃;LIN,FANG-YU
贡献者:	環境工程研究所
关键词:	Koc;BTEX;改質土壤;催化;分佈介質;catalytic;modified clay;BTEX;Koc;partition medium
日期:	2012-07-17
上传时间:	2012-09-11 18:17:49 (UTC+8)
出版者:	國立中央大學
摘要:	在自然環境下通常為無機與有機污染物同時存在，一般土壤攜帶負電，故對金屬陽離子具有高親和力，但於水溶液中對有機污染物則不具吸附性；傳統土壤改質劑可增加土壤有機質含量，並增加其對有機污染物之吸持能力，但卻對金屬離子不具親和力。本研究藉由不含有機質之鈉蒙特石與四種具特殊官能基之改質劑，以靜電作用力及接枝改質方式製備含人造有機質之改質土壤，利用其特殊結構可同時吸持無機重金屬與非離子有機污染物，並探討利用吸附之重金屬催化分解有機污染物之可行性。實驗結果發現，改質劑提供之未共用電子對與金屬離子發生錯合反應，且對Cu2+ 之親和力較高，主因為Cu2+ 電負度較大易與有機質結合。改質土壤對BTEX的吸持以土壤有機相之分佈為主，而有機吸附質的水溶解度與其分佈常數呈反比。不同改質方式之改質土壤對重金屬的飽和吸附量以及有機物之分佈作用皆為靜電作用力大於接枝方式。相同有機吸附質( BTEX )於不同改質土壤的Koc 與改質土壤的有機碳含量呈負相關性，可能導因於BTEX之分佈行為受到改質土壤之改質劑結構與疏水性分佈環境所影響。本研究使用之有機改質劑所形成的分佈介質良好且具較少極性官能基影響BTEX之分佈行為。改質土壤對重金屬為無機相吸附作用而對非離子性有機化合物(NOCs)則為有機相分佈作用，研究證實在同時吸持作用下因吸附機制不同，故沒有發生相互競爭之行為。因催化活性之不同，Pd2+金屬於20秒即可將污染物降解60％左右，顯示過渡金屬具有良好之催化效果。In the natural environment, the soil that carry negative charge has affinity for the metal ions, but not for organic pollutants in aqueous solution. Conventional soil modifier can increase soil organic matter content and increase their sorption capacity for organic pollutants but does not have affinity for metal ions. In this present study, a new approach to modify soil using the specific modifier is focused. By excluding organic matters sodium montmorillonite with four special functional groups as the modifier, van der waals force, grafting method for modification of soil, and using its special structure which can absorb heavy metals and nonionic organic compounds (NOCs) simultaneously were carried out. Finally, using adsorbed heavy metal modified clay, decomposed nonionic organic were adsorbed. The results showed that ligand of modifier offer lone pair to the heavy metal to form complex reaction. The affinity for Cu2+ is better, which would be because Cu2+ has more electronegativity and binding to the ligand and hence increased adsorption. In addition, alkyl chain on the soil surface can be regarded as a partition medium. Modified clay sorption of BTEX in the distribution of soil organic-based and water solubility of organic adsorbate is inversely proportional to its distribution constant. Among different modified methods, modified clay saturation adsorption capacity of heavy metals, as well as the role of the distribution of organic matter is due to the van der waals force which is greater than the grafted way. For the same organic adsorbate (BTEX) in different adsorbent’s, distribution constant of organic carbon (Koc) and modified clay organic carbon content were negatively correlated, the distribution and behavior of BTEX by the hydrophobic modification of soil affected by the environment and structure. Natural soil by the organic modifier improved the distribution of NOCs better in this study and partition medium has affected less the polar functional groups of the distribution of BTEX behavior. Modification of soil for heavy metals is the inorganic phase of the adsorption and partition of the NOCs is the role of the organic phase. Thus it is confirmed that the role of sorption at the same time is due to the different adsorption mechanism and they do not compete with each other's. Due to different catalytic activity between Pd2+ and Cu2+, 75% of benzene was decomposed by Pd2+ within the first 20 s .It showed that transition metal has a good catalytic effect.
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