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標題: | 應用新穎吸附劑吸附去除水體中農藥之研究 A Study of Application of Novel Adsorbents on the Removal of Pesticides from Water |
作者: | Guo-En Hsu 許國恩 |
指導教授: | 張慶源 |
關鍵字: | 農藥,納乃得,吸附,超高交聯樹脂,質量傳送,吸附動力, methomyl,activated carbon,hypercrosslinked polymer,adsorption isotherm,adsorption kinetics,adsorption dynamics, |
出版年 : | 2006 |
學位: | 碩士 |
摘要: | 農藥過量使用及使用不當會造成農藥之殘留,且因不易生物降解而在環境中累積進而對水質環境造成嚴重影響。本研究以粒狀活性炭F-400及新穎超高交聯樹脂MN-100、MN-150及MN-500等吸附劑吸附去除水中殘留之農藥納乃得(methomyl,為台灣用量最大之殺蟲劑之ㄧ)。研究內容包含了吸附劑之物理化學特性鑑定及吸附行為之探討(包含:等溫吸附行為和動力吸附行為之探討),並求出與吸附行為相關之各項參數,期對各種吸附劑對納乃得吸附行為做一全盤性了解。
超高交聯樹脂與活性炭F-400均具有相當大之比表面積,其孔隙結構皆以微孔為主,中孔為次,微孔體積均約佔總體積44%-58%。四種吸附劑平均(中數, medium)顆粒粒徑由大而小分別為F-400、MN-100、MN-150及MN-500,粒徑依序為822、677、662及651 μm。超高交聯樹脂之粒徑分佈較活性炭狹窄且均勻。 Langmuir與 Freundlich等溫吸附方程式可以有效地模擬超高交聯樹脂和活性炭F-400之等溫吸附行為。活性炭F-400及超高交聯樹脂MN-100、MN-150及MN-500四種吸附劑之Langmuir等溫吸附單層飽和吸附量qL值分別為145、21.60、24.15及5.07 g kg-1,實驗結果顯示F-400具有最高的吸附容量,且當水中存在有其他有機物質時(humic acid),會因產生競相吸附而導致methomyl吸附量下降。 在完全攪拌反應槽(completely stirred tank reactor, CSTR)之吸附動力學方面,分別以整體性動力(包含假性一階動力方程式、假性二階動力方程式、及Elovich rate equation)、及傳統動力學(包含表面擴散、孔擴散、及分枝孔擴散動力模式)分析進行探討。結果顯示:假性二階動力方程式和Elovich rate equation皆可有效地模擬四種吸附劑對methomyl之吸附動力行為;表面擴散、孔擴散及分枝孔擴散動力模式皆能有效的描述methomyl在四種吸附劑顆粒之內部質量傳送行為,其中以分枝孔擴散模式模擬methomyl在吸附劑內部之質量傳送可得最佳效果。 固定管柱吸附貫穿實驗中,依法規標準來判定,此三吸附劑(F-400、MN-100、MN-150)真正處理methomyl之溶液體積仍有限。而由表面擴散模式所求得之動力學參數結合linear driving force模式可有效的預測MN-100和MN-150之吸附貫穿行為。此外,以Yoon and Nelson方程式可以有效地模擬F-400、MN-100及MN-150三種吸附劑對水中methomyl之吸附貫穿行為。有機溶劑甲醇可以有效地將飽和之超高交聯樹脂完全再生,且不影響其對methomyl之吸附容量。 Activated carbon (F-400) and novel hypercrosslinked polymer (Macronet MN-100, MN-150, and MN-500) were used as the adsorbents for the removal of pesticide (i.e., methomyl) from the aqueous solution. The physicochemical characteristics of adsorbents, and adsorption behaviors including adsorption kinetics and dynamics were investigated. Furthermore, factors affecting the adsorption equilibrium and kinetics were also examined in this study. Marcronet resins and activated carbon F-400 possess high specific surface areas and all are microporous due to the high micropore volume. In addition, Marcronet resins are more uniform and homogeneous than activated carbon F-400. The Langmuir and Freundlich isotherms successfully predicted the adsorption equilibrium behaviors of methomyl onto F-400 and Marcronet resins. Furthermore, the monolayer adsorption capacity (qL) of F-400 for methomyl (145 g kg-1) was higher than that of Marcronet resins. The natural organic matter decreased the adsorption capacity of methomyl onto F-400 and MN-150 because of the competitive adsorption. Regarding the adsorption kinetics of methomyl on various adsorbents from solutions in completely stirred tank reactor (CSTR), global kinetics (pseudo-first-order, pseudo-second-order, and Elovich rate equations) and traditional kinetics (surface, pore, and branched pore diffusion kinetics) models were investigated in this study. The pseudo-second-order, Elovich rate equations and traditional kinetics models can well predict the adsorption kinetics of methomyl onto F-400 and Marcronet resins. The adsorption dynamics of methomyl in the fixed bed showed that the adsorption capacity of methomyl on F-400 was the highest among the adsorbents investigated. The parameters obtained from surface diffusion model combined with linear driving force model, and Yoon and Nelson equation can well describe the breakthrough curve of adsorption of methomyl in the adsorber systems. The organic solvent (i.e., methanol) can completely regenerate the exhausted adsorbent without reducing the original adsorption capacity of methomyl. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/33276 |
全文授權: | 有償授權 |
顯示於系所單位: | 環境工程學研究所 |
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