陽離子界面活性劑對birnessite型錳氧化物污染物吸附之影響

Effects of cationic surfactants on the sorption of contaminants on birnessite

王南惠(Nan-Hui Wang)

指導教授 ： 駱尚廉

國立臺灣大學/工學院/環境工程學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.11172

摘要

水鈉錳礦為一種層狀型錳氧化物，因具特殊含水層間結構使得離子易於在層間結構間進出。為增加其與有機污染物之親和性，可藉由將birnessite表面增加有機成分之改質來達成，本研究以水熱法將界面活性劑插層birnessite進行材料改質，合成CTMA-birnessite及birnessite，並應用於苯甲酸及甲基橙之去除。
合成之CTMA-birnessite及birnessite材料，以X射線繞射儀、穿透式電子顯微鏡、掃描式電子顯微鏡、傅立葉紅外線光譜儀、和X射線光電子能譜儀等儀器進行材料特性分析，結果顯示，合成之birnessite層間距為0.71 nm，而CTMA-birnessite之層間距增為3.28 nm；而合成之birnessite材料表面，Mn(II)、Mn(III)、及Mn(IV)之比例為22.1%、56.4%、及21.5%、CTMA-birnessite之材料表面則為9.5%、62.4%、及28.1%。
將合成材料用於吸附苯甲酸及甲基橙，結果CTMA-birnessite較birnessite高出37%之苯甲酸去除效能；CTMA-birnessite 在pH 3時對苯甲酸有較高的去除效率，而去除率會隨著pH增高而下降；CTMA-binessite吸附苯甲酸之反應速率較birnessite為高，無論CTMA-birnessite對苯甲酸或甲基橙之吸附動力曲線，均符合擬二階動力方程式；CTMA-birnessite對苯甲酸的等溫吸附曲線符合亨利方程式，對甲基橙的等溫吸附曲線則符合Freundlich等溫吸附模式。
由實驗結果顯示界面活性劑之插層改質後能提昇錳氧化物之吸附能力，且CTMA+插層至birnessite後，會提昇其對有機物質之吸附效率。本研究並提出苯甲酸或甲基橙分配在CTMA+上及吸附在birnessite表面上之作用機制。

關鍵字

吸附 ； 苯甲酸 ； 甲基橙 ； 界面活性劑 ； 水鈉錳礦

並列摘要

Birnessite is a layered manganese oxide mineral. The hydrated layer structure of birnessite allows for the cations transporting in the interlayer region. To enhance the sorption performance for the organic contaminants, birnessite needs to be first surface modified by organic moieties. Inserting hydrocarbon chain into layers can increase the interlayer distance and hydrophobic property, resulting in higher affinity toward organic substances. Cetyltrimethylammonium modified birnessite (CTMA-birnessite) is prepared by a simple hydrothermal method for removing benzoic acid and methyl orange.
The synthetic birnessite materials are characterized by a number of characterization techniques, including powder X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier transforminfrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results indicate that the prepared birnessite has a basal spacing of 0.71 nm and CTMA-birnessite has a basal spacing up to 3.28 nm. The relative contents of Mn(II), Mn(III) and Mn(IV) on the sample surfaces are about 22.1%, 56.4% and 21.5% for birnessite, and 9.5%, 62.4% and 28.1% for CTMA-birnessite.
The CTAB modified birnessite was used to remove benzoic acid and methyl orange in aqueous solution. CTMA-birnessite has a high removal efficiency of benzoic acid at pH 3, while the uptake of benzoic acid decreased with increasing pH values. The reaction rate of benzoic acid sorption increases with the incorporation of CTMA. The pseudo-second-order kinetic equation provides a good description of the benzoic acid and methyl orange sorption on CTMA-birnessite. Benzoic acid sorption on CTMA-birnessite was well interpreted by Henry isotherm model. Instead, methyl orange sorption on CTMA-birnessite was well interpreted by Freundlich isotherm model.
The results show that the modification of birnessite by intercalation of the surfactant can enhance the sorption capacity of manganese oxides. The intercalation of CTMA+ to birnessite will enhance the efficiency on the sorption of organic substances. The mechanism of benzoic acid or methyl orange partition to CTMA+ and adsorption on the birnessite surface were also proposed in this study.

並列關鍵字

partition ； adsorption ； benzoic acid ； methyl orange ； surfactant ； birnessite

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