The effects of particle sizes of goethite on the adsorption and photocatalytic reduction of Cr(VI)

本研究主要探討不同粒徑之針鐵礦與環境中的毒性陰離子六價鉻之交互作用。針鐵礦的製備採用ferrihydrite熱轉變法、硝酸鐵酸式法和硫酸鐵法分別合成22、139和449 nm三種不同粒徑針鐵礦，另外也以Schwertmann合成法來進行較大粒徑的針鐵礦(849和1207 nm)。合成的針鐵礦樣品利用雷射粒徑儀分析和穿透顯微鏡(TEM)觀測其粒徑及外部型態，以X光粉末繞射儀(XRD)鑑定針鐵礦結晶，以及利用BET比表面積儀和等電位點(ZPC)儀器量測各種粒徑之表面積和表面電位。不同粒徑之針鐵礦對六價鉻的吸附，分別符合Elovich動力模式和Langmuir等溫模式，針鐵礦對六價鉻的吸附量(qmon)介於0.0707-0.207 mmol/g之間，隨針鐵礦粒徑大小之降低而增加，此增加與比表面積之大小有關且其與粒徑大小呈線性關係。隨pH值升高，各粒徑之針鐵礦對六價鉻的吸附均在pH 6-8間有明顯的下降，此與六價鉻之物種轉變為CrO42-或與針鐵礦表面負電荷及氫氧離子之增加有關。針鐵礦對六價鉻的吸附熱隨粒徑之降低而增高，此可能與被吸附的六價鉻從小粒徑針鐵礦的脫附能力較低有關。小粒徑針鐵礦對六價鉻催化還原為三價鉻的能力較高，此可能與小粒徑針鐵礦對六價鉻的吸附能力高，且電子在其表面轉移的能力較快有關。This study mainly investigates the interactions of Cr(VI), a toxic anion in the environment, with goethite with different particle sizes. Several methods were used for goethite syntheses, including ferrihydrite heat transformation, ferric nitrate acidification, and ferric sulfate, which gave particle sizes of 22, 139, and 449 nm, respectively. In addition, a method adopted from Schwertmanm was employed for preparing goethite with greater particle sizes of 849 and 1207 nm. The results of powder X-ray diffraction (XRD) conformed the goethite structures for each synthesized samples. The particle sizes and morphologies of these goethite samples were further verified using a laser scattering particle size distribution analyzer and a transmission electron microscopy (TEM). Surface areas and pHzpc (zero point charge) for each particle were measured using a BET surface area meter and Zeta meter. Cr(VI) adsorption on goethite complied with Elovich kinetic model and Langmuir adsorption isotherm, and the adsorption behaviors was indifferent with the particle sizes of goethite. The maximum adsorption of Cr(VI) on goethite was in the range 0.0707-0.207 mmol/g, depending on the particle size of goethite. A liner relationship existed between the amount of Cr(VI) adsorption and the goethite particle sizes and the smaller goethite particle exhibited higher adsorption ability, corresponding to its higher surface area. A significant declination of Cr(VI) adsorption on goethite was observed at pH 6-8, related probably to the change in Cr(VI) species (i.e., converting from HCrO4- to CrO42- at the specific pH) or/and an increase of surface negative charges and OH ion concentrations. An apparent endothermic reaction was observed while adsorbing Cr(VI) on goethite. Cr(VI) adsorption on smaller particle size of goethite had higher absorption heat which may lead to a decrease of Cr(VI) desorption from the surfaces of small particles. Small particles revealed a higher efficiency for photo-catalytic reduction of Cr(VI) on goethite, attributing to the higher adsorption ability of Cr(VI) and rapid electric transferring on the surfaces of small goethite particles.目　次 中文摘要 英文摘要 目次 表目次 圖目次 壹、 前言………………………………………………………………………………1 貳、 文獻回顧…………………………………………………………………………3 一、環境中的針鐵礦…………………………………………………………………3 二、針鐵礦的結構……………………………………………………………………4 三、針鐵礦的表面特性………………………………………………………………4 四、粒徑大小對礦物吸附的影響……………………………………………………6 五、針鐵礦的粒徑與合成方法………………………………………………………6 六、針鐵礦對污染物的吸附…………………………………………………………8 七、鉻汙染與自然界中的鉻…………………………………………………………12 八、鉻毒性……………………………………………………………………………14 九、鉻的化學性質……………………………………………………………………15 十、光催化還原………………………………………………………………………17 参、材料與方法………………………………………………………………………18 一、針鐵礦的合成……………………………………………………………………18 二、性質分析…………………………………………………………………………20 三、吸附實驗…………………………………………………………………………21 肆、試驗流程簡圖……………………………………………………………………27 伍、結果與討論………………………………………………………………………28 一、針鐵礦性質分析…………………………………………………………………28 二、吸附實驗…………………………………………………………………………36 陸、結論………………………………………………………………………………65 柒、參考書目…………………………………………………………………………6

The Adsorption and Photocatalytic Transformation of Cr(VI) on Mn or Al Substituted Goethite

摘要 鉻在自然界中主要以三價[Cr(III)]及六價[Cr(VI)]兩種形式存在，其中Cr(VI)為致癌性物質，屬於陰離子，其吸附極易受環境中pH值的影響，由於移動性高，易造成環境污染，而Cr(III)在環境中主要以氫氧化物或氧化物形式存在，移動性低，且對作物的毒性較低，因此藉由礦物將Cr(VI)固定或是將其還原成Cr(III)，可降低Cr(VI)對環境的危害。土壤中的針鐵礦可增進光催化Cr(VI)還原為Cr(III)的能力，而錳氧化物卻可氧化Cr(III)成Cr(VI)，但自然界中錳取代型針鐵礦對鉻的吸持甚至氧化還原反應的影響，仍屬未知。因此，本實驗使用錳取代針鐵礦，並以鋁取代型針鐵礦作為佐證，研究其在光照下對鉻物種轉變的影響。結果顯示，由於錳取代型或鋁取代針型鐵礦的比表面積均比純針鐵礦高，因此錳取代或鋁取代型針鐵礦對於Cr(VI)的吸附能力比純針鐵礦高，最高可達0.1 mmol g-1，而純的針鐵礦對Cr(VI)僅有0.04 mmol g-1的吸附量；在光催化還原Cr(VI)方面，純的針鐵礦具有良好的光催化還原Cr(VI)的效果，在實驗經過12小時後純針鐵礦依舊對六價鉻具有光還原的能力，在實驗進行12小時後，已將0.07 mmol g-1的Cr(VI)還原，而取代型的針鐵礦，在實驗經過12小時後光還原的效果逐漸減弱，高取代量的錳取代型針鐵礦甚至沒有還原的現象。經萃取實驗及氧化實驗證明，將Cr(III)加入錳取代型針鐵礦懸浮液後，以磷酸二氫鉀將吸附在錳取代型針鐵礦表面上的吸附物萃取出後，發現有Cr(VI)吸附在錳取代型針鐵礦的表面，由此可知，錳取代型針鐵礦具有將Cr(III)氧化為Cr(VI)的能力，且每克的10 %錳取代型針鐵礦在12小時內，能氧化出0.02 mmol的Cr(VI)，因此會造成抑制光還原的現象，但是鋁取代型針鐵礦並沒有氧化Cr(III)的能力，故不會隨反應時間，降低光還原Cr(VI)之能力。因此抑制光還原Cr(VI)的現象並非只因錳將Cr(III)氧化為Cr(VI)的關係，由於光催化還原反應僅發生在吸附在針鐵礦表面的Cr(VI)，所以當針鐵礦中的鐵被其他離子取代後，會減少活化鐵的光還原位置，且被光還原的Cr(III)沈澱在吸附劑表面時，亦會減少吸附及光活化位置，由此可知，取代型的針鐵礦對六價鉻的吸附量雖然較純針鐵礦多，但是其光催化Cr(VI)的能力卻會因為離子的取代反應造成針鐵礦表面性質的改變（例如：表面位的變化與表面光活化位置的降低等），而造成光還原能力的抑制。Abstract Chromium exists in the environment as two major forms, Cr(VI) and Cr(III). Chromium(VI) is a Class A human carcinogen by inhalation and an anion with a strong oxidizing ability. It can be adsorbed on minerals; however, the adsorption is greatly influenced by the pH. The characteristic makes Cr(VI) mobile and may cause environmental problems. In contrast, Cr(III) is non-toxic and an essential element for human health. It is found predominantly in insoluble forms in soils, such as Cr(OH)3 or Cr2O3. Thus, the fixation or the reduction of Cr(VI) using specific minerals may lead to an elimination in ecological hazards of such element. Goethite has been confirmed capable of enhancing Cr(VI) reduction in the presence of light. On the other hand, Mn oxides are well known oxidizers for Cr(III). Nevertheless, it is unclear for the redox/adsorption reaction of Cr on Mn-substituted goethite. Therefore, the objective of this study is to investigate the transformations of Cr on Mn-substituted goethite under illumination. Al-substituted goethite was also used in the study for comparisons. The results showed that metal-substitution in the goethite structures could increase Cr(VI) adsorption probably due to an increase in the surface area. Up to 0.1 mmol Cr(VI) was adsorbed on 1 g metal-substituted goethite but only was 0.04 mmol Cr(VI) adsorbed on the same amount of pure goethite. Cromium(VI) could be photo-reduced on goethite and the photo-catalytic reaction continued for at least 12 h. Around 0.07 mmol Cr(VI) was reduced after 12 h reaction. Metal-substituted goethite showed different behavior in the photo-redox reaction. The rate of photo-reduction of Cr(VI) on Mn-goethite gradually decreased as a function of time. There was even no photo-reduction of Cr(VI) observed on high Mn-substituted goethite. The occurrence and the inhibition of photo-reduction of Cr(VI) were further examined by extraction and oxidation techniques on the goethite/metal substituted goethite. A significant decrease in the amount of Cr(VI) extracted by phosphate was observed for light treated samples experienced light which evidenced that Cr(VI) can be reduced on goethite. Through oxidation experiments, we observed that Mn-goethite could oxidize Cr(III). For instance 0.02 mmol Cr(VI) was produced within 12 h when Cr(III) was added to 1 g Mn-substituted goethite. The oxidation of Cr(III) explain the decrease in the amount of Cr(VI) being photo-reduced because a portion of reduced Cr were re-oxidized. We believe that Mn in the goethite proceeded this oxidation reaction because Cr(III) oxidation did not occur in Al-goethite system. Moreover, metal-substitution may decrease the “active site” on goethite, and these sites contribute largely to Cr(VI) reduction. In general, metal-substitution can enhance Cr(VI) adsorption on goethite. In contrast, the substitution may decrease the efficiency for the photo-reduction of Cr(VI), particularly in the presence of Mn.目 錄 中文摘要．．．．．．．．．．．．．．．．．．．．．．．．．I 英文摘要．．．．．．．．．．．．．．．．．．．．．．．．．II 目錄．．．．．．．．．．．．．．．．．．．．．．．．．．．V 表次．．．．．．．．．．．．．．．．．．．．．．．．．．． VII 圖次．．．．．．．．．．．．．．．．．．．．．．．．．．VIII 壹、前言．．．．．．．．．．．．．．．．．．．．．．．．．1 貳、文獻回顧．．．．．．．．．．．．．．．．．．．．．．．2 一、自然界的鉻．．．．．．．．．．．．．．．．．．．．．． 2 二、鉻的毒性及其主要汙染源．．．．．．．．．．．．．．．．2 三、鉻的化學性質．．．．．．．．．．．．．．．．．．．．． 3 四、光催化還原六價鉻反應．．．．．．．．．．．．．．．．． 7 五、金屬取代型針鐵礦及其對六價鉻吸附與轉變之影響．．．．． 9 六、錳氧化物對三價鉻的氧化作用．．．．．．．．．．．．．． 12 參、材料與方法．．．．．．．．．．．．．．．．．．．．．．14 一、吸附物的合成及特性分析．．．．．．．．．．．．．．．．16 二、六價鉻吸附實驗．．．．．．．．．．．．．．．．．．．．16 三、施用光能對錳或鋁取代型針鐵礦之六價鉻的吸附還原反應試驗 ．．．．．．．．．．．．．．．．．．．．．．．．．．．．．17 四、還原反應之印證試驗．．．．．．．．．．．．．．．．．．18 五、比色法—DPC法之測定．．．．．．．．．．．．．．．．19 肆、試驗流程簡圖．．．．．．．．．．．．．．．．．．．．．20 伍、結果與討論．．．．．．．．．．．．．．．．．．．．．．21 一、錳和鋁取代型針鐵礦結構及比例．．．．．．．．．．．．．21 二、錳和鋁取代型針鐵礦之基本吸附特性．．．．．．．．．．．28 三、光催化六價鉻還原動力學．．．．．．．．．．．．．．．．37 四、三價鉻的氧化．．．．．．．．．．．．．．．．．．．．．50 五、鹼性環境下錳和鋁取代型針鐵礦對六價鉻的吸附與光催化還原影響．．．．．．．．．．．．．．．．．．．．．．．．．．．．53 陸、結論．．．．．．．．．．．．．．．．．．．．．．．．．57 柒、參考文獻．．．．．．．．．．．．．．．．．．．．．．．58 表 次 表一、六價鉻化合物及其溶解度一覽表．．．．．．．．．．．．4 表二、針鐵礦中取代Fe(III)的陽離子及其取代性質．．．．．．．10 表三、錳和鋁取代型針鐵礦中所含錳鐵比例與鋁鐵比例．．．．．27 表四、錳取代型針鐵礦吸附六價鉻之等溫吸附結果帶入Elovich動力模式．．．．．．．．．．．．．．．．．．．．．．．．．．．30 表五、錳取代型針鐵礦吸附六價鉻之等溫吸附結果帶入Langmuir等溫吸附方程式所得之吸附方程式．．．．．．．．．．．．．．．32 表六、以磷酸二氫鉀萃取錳取代型針鐵礦吸附六價鉻動力學：照光與無照光之比較．．．．．．．．．．．．．．．．．．．．．．．4

Adsorption of lead, cadmium, copper, zinc, and nickel, by surfactant modified goethite.

針鐵礦因為實驗室合成的便利性及良好的結晶特性，已成為研究各種界面（或表面）吸附現象與機制以及水體污染物之移除時備受廣泛使用的吸附材質之一。但是受制於其表面電荷之特性，常使得針鐵礦在一般水體環境條件下吸附正電性金屬物種（微量金屬或重金屬）的功效受到限制。界面活性劑是一種兩性分子，分子組成中各有極性端（或稱親水端，為頭部）與非極性端（或稱疏水端，為尾部），經常用於土壤或地下水有機污染物復育的實驗室研究及現地場址之試驗；界面活性劑藉由覆蓋表面或插入層間，為固體吸附劑增加疏水性甚至轉變表面電性所構成的修飾性吸附材料則屬於另一種應用方式。本研究即是利用陰離子性界面活性劑（SDS）修飾針鐵礦表面，以希望提高表面負電荷來增加金屬吸附量為出發，探討修飾對針鐵礦吸附重金屬的影響。研究結果說明了金屬吸附量確實受表面負電荷增加而有所提升，而且推論負電荷及其於金屬吸附量之效應乃透過界面活性劑於表面之局部雙層結構所貢獻。各樣品對金屬的等溫吸附結果與Langmuir model有良好的配適，數據顯示SDS修飾提高了針鐵礦吸附重金屬的最大吸附容量（qmax），以Cd、Zn尤甚；對Cd、Zn之吸附親和力（KL）亦從無到有，最高對Pb可提升將近5倍之多，對Cu提升約79 %，對Ni則提升約95 %。DRIFT光譜分析之結果，則幫助我們更加確認針鐵礦表面修飾結構之存在。由本研究的實驗成果加上其他眾多的研究文獻，相信此類吸附劑之修飾技術於環境污染復育上應尤有可為。Because of well crystalline and ease for synthesis in laboratory, goethite has become one of the most widely used adsorbents for researching phenomena and mechanisms of varied adsorbates adsorbed on the surface/interface, and also for removing contaminant in aquifers. In general condition of the aqueous environment, however, goethite is usually limited to adsorb trace metal or heavy metal species by its characteristic of surface charge. Surfactants with both polar (hydrophilic) and nonpolar (hydrophobic) group in molecular constitution has been used in the remediation of soil or groundwater organic contamination in laboratory scale as well as in situ trial works. It was also shown that solid adsorbents are able to become more hydrophobic and to reverse the surface charge through the surfactant modification. In this study, our intent is to promote the adsorption for heavy metals by goethite via such kind of modification. We took advantage of the negatively charged anionic surfactant (sodium dodecyl sulfate, SDS) to modify the surface of goethite, and investigated the effect of different proportional modifications on the capability of adsorption for heavy metals by goethite. The amount of metals adsorbed on the solid sample was significantly promoted by the SDS modification. It could be speculated that the partial bilayer structure of surfactant on goethite surface was responsible for additional negative charges and its influence on metal adsorption as well. Adsorption isotherm data were well fitted with Langmuir model. It showed that the SDS modification raised the maximum adsorption capacity (qmax) of goethite for heavy metals, especially for Cd and Zn. The adsorption affinity (KL) was also enhanced by modification, up to five times in increase for Pb, 79% and 95% in increase for Cu and Ni respectively, and Cd was helped to grow out of nothing as well as Zn. According to the DRIFT analysis, we were convinced of the existence of the modification arrangement. By plenty of previous research coupled with this study, one can believe that such technique of modified adsorbents will get an advance in the remediation of environmental contaminations.謝誌---------------------------------------------------------------- i 摘要-------------------------------------------------------------- iii 英文摘要------------------------------------------------------------ v 目錄--------------------------------------------------------------- vi 表目錄----------------------------------------------------------- viii 圖目錄------------------------------------------------------------- ix 第壹章 前言--------------------------------------------------------- 1 一、 針鐵礦與重金屬吸附-------------------------------------------- 1 二、 界面活性劑基本性質與分類--------------------------------------- 2 三、 界面活性劑與土壤及地下水污染----------------------------------- 6 四、 界面活性劑修飾性材料之發展與應用-------------------------------- 8 五、 等溫吸附模式------------------------------------------------ 12 六、 Visual Minteq程式------------------------------------------ 15 七、 研究目的---------------------------------------------------- 16 第貳章 材料與方法----------------------------------------------------17 一、 鐵礦之合成---------------------------------------------------17 二、 合成樣品之鑑定與特性分析---------------------------------------18 三、 針鐵礦之表面修飾----------------------------------------------20 四、 重金屬等溫吸附實驗--------------------------------------------23 五、 pH對重金屬吸附之效應------------------------------------------24 第參章 結果與討論----------------------------------------------------26 一、 針鐵礦與界面活性劑（SDS）之吸附--------------------------------26 二、 合成針鐵礦之基本特性------------------------------------------32 三、 pH對重金屬吸附之效應------------------------------------------45 四、 重金屬之等溫吸附實驗------------------------------------------55 五、 修飾針鐵礦之FTIR分析------------------------------------------74 第肆章 結論-------------------------------------------------------81 第伍章 參考文獻----------------------------------------------------83 附錄----------------------------------------------------------------8

Reactions of hexavalent chromium with black carbon when co-existing with iron or manganese hydrous oxides

Cr(VI)具有高毒性和致癌性，工業排放為Cr(VI)進入環境造成污染的主要來源。土壤中的有機質和黑炭為Cr(VI)主要的還原劑之一，已被證實能還原Cr(VI)成毒性和危害較低的Cr(III)。然而，卻仍有Cr(VI)被淋洗至較深土層甚至污染地下水的情況，推測是由於土壤組成複雜，其他組成與Cr(VI)的反應可能會延緩Cr(VI)的還原速率和減少Cr(VI)的還原量。因此本研究選擇黑炭為Cr(VI)還原劑的代表，探討氧化鐵和氧化錳與黑炭共存時，對黑炭與Cr(VI)的吸附和還原轉化之影響。結果顯示，針鐵礦與黑炭共存系統中，針鐵礦會與黑炭競爭吸附溶液中的Cr(VI)，且因為遲滯效應導致吸附於針鐵礦上的Cr(VI)不易脫附釋出，而限制了黑炭對Cr(VI)之還原反應。但長時間反應後，Cr(VI)仍逐漸被黑炭所還原，所生成的Cr(III)則鍵結於黑炭表面。氧化錳與黑炭共存系統中，則分別探討Cr(III)和Cr(VI)的吸附和氧化還原反應。黑炭雖然可吸附Cr(VI)並將其還原為Cr(III)，但氧化錳會氧化溶液中Cr(III)成Cr(VI)，而抑制了Cr(VI)在黑炭表面的還原轉化。隨著反應時間的增加，氧化錳本身會逐漸被還原溶解，因此，反應產物最終仍以鍵結於黑炭上的Cr(III)物種為主。另外，黑炭與Cr(III)反應的系統中，在低pH時，黑炭表面具有淨正電荷而不利於吸附Cr(III)，氧化錳將Cr(III)氧化成Cr(VI)的型態後，反而可藉由黑炭對Cr(VI)的還原反應，促進溶液中整體鉻的移除，將Cr(III)固定於黑炭上而降低其再被氧化成毒性較高的Cr(VI)之風險。總結本研究之結果，土壤中其他組成與Cr(VI)的反應，會對土壤中還原劑還原Cr(VI)之反應產生抑制的影響，因此可能會提高進入土壤中的Cr(VI)之移動性和有效性，進而增加其造成污染的風險。本研究結果亦顯示過去藉由了解單一土壤組成和Cr(VI)或其他污染物反應來推估其環境宿命有其不足之處，必須考慮不同組成共存之相互作用的影響，以及此相互作用如何決定鉻或其他污染物的物種轉化和傳輸過程，才有助於提供污染處理和評估上有效的資訊。Cr(VI) is one of the pollutants of major concern in the environment due to its high toxicity and carcinogenicity. In oxic soils, organic matter (OM) and black carbon (BC) are the predominant reductants that can reduce toxic Cr(VI) to less toxic Cr(III). However, Cr(VI) still can be leached to deeper layers of soil or even into groundwater. The low reduction rate of Cr(VI) is presumably attributed to the reactions of other soil constituents with Cr(VI) that inhibit the reduction of Cr(VI) by OM and BC. Thus, in this study, the influences of hydrous oxides of Fe and Mn on the Cr(VI) reduction of BC were investigated. The results showed that the co-existence of goethite with BC inhibited the Cr(VI) reaction of BC due to the fast adsorption rate and strong desorption hysteresis of Cr(VI) on goethite. Nonetheless, the prolonged reaction of Cr(VI) with BC and goethite removed Cr(VI) from solution through the adsorption of Cr(VI) and the subsequent reduction of adsorbed Cr(VI) to Cr(III). The resulting Cr(III) is either released back into solution or bound on BC. When MnO2 coexisted with BC, the aqueous Cr(III) were oxidized to Cr(VI) by MnO2. The Cr(III) oxidation and releasing back into solution occur as coupled reactions. The oxidation of aqueous Cr(III) by MnO2 inhibited the Cr(VI) reduction by BC when MnO2 coexisted with BC. At lower pH, the net positive charge on the surface of BC resulted in electrostatic repulsion between Cr(III) and BC. On the other hand, the oxidation of Cr(III) by Mn oxide led to the formation of Cr(VI) in solution, which was subsequently reduced by BC and consequently enhanced the removal of total Cr by BC at lower pH when BC coexisted with MnO2. In summary, the presence of Fe and Mn oxides inhibited the reduction of Cr(VI) by BC, leading to an increasing risk of Cr(VI) contamination in soil. Thus, the interactions between different soil consitutents need to be considered in order to have better understanding of the environmental risks of Cr contamination in soil.摘要i Abstractii 目錄iii 表次v 圖次vi 第1章 前言1 第2章 前人研究與文獻回顧3 2.1 鉻的污染來源與毒性3 2.2 鉻的環境化學4 2.2.1鉻的水溶液化學4 2.2.2土壤有機質7 2.2.3 黑炭8 2.2.4 氧化鐵9 2.2.5 氧化錳11 2.3研究目的14 第3 章 材料與方法17 3.1 樣品製備17 3.1.1 纖維素黑炭17 3.1.2 針鐵礦17 3.1.3 二氧化錳17 3.2 纖維素黑炭、針鐵礦和二氧化錳之基本性質分析17 3.2.1 C、H、O組成17 3.2.2 比表面積18 3.2.3 零電點18 3.3 纖維素黑炭、針鐵礦和二氧化錳對鉻的吸附實驗18 3.3.1 實驗試劑18 3.3.2反應動力學實驗19 3.3.2.1動力學實驗步驟19 3.3.2.2磷酸萃取六價鉻步驟19 3.3.2.3 鉻的定量分析19 3.3.2.4 總Fe的定量分析21 3.3.2.5 總Mn的定量分析21 3.3.2.6 反應動力學實驗之變因21 3.3.2.7動力學模式22 3.4 連續稀釋脫附實驗23 第4 章 結果與討論24 4.1材料基本性質24 4.1.1黑炭元素分析24 4.1.2比表面積及零電點測定24 4.2 針鐵礦與纖維素黑炭之六價鉻吸附實驗26 4.3氧化錳與纖維素黑炭之鉻吸附實驗39 4.3.1氧化錳與纖維素黑炭之六價鉻吸附實驗39 4.3.2氧化錳與纖維素黑炭之三價鉻吸附實驗57 第5 章 結論71 第6 章 參考文獻75 表次 表2-1 台灣環保署規定鉻之汙染管制標準4 表2-2 氧化錳的等電點(pHpzc)12 表2-3 地下水中之Cr(VI)濃度15 表4-1 纖維素黑炭之C、H、O含量24 表4-2 纖維素黑炭、針鐵礦與氧化錳之比表面積和孔隙體積25 表4-3 pH 2、4和6下，纖維素黑炭有無添加氧化錳對移除溶液中Cr(VI)的反應速率常數53 表4-4 pH 2、4和6下，纖維素黑炭與氧化錳1：1混合對移除溶液中Cr(VI)與Cr(III)的反應速率常數67 圖次 圖2-1 不同Eh-pH下，鉻的物種分布圖5 圖2-2 不同pH值與Cr(VI)濃度下，Cr(VI)的物種分布圖5 圖2-3 針鐵礦與Cr(VI)的吸附反應機制10 圖2-4 Cr(VI)於針鐵礦表面三種不同錯合物種之結構11 圖2-5 鉻的水溶液化學反應16 圖4-1 纖維素黑炭、針鐵礦及氧化錳之零電點測定25 圖4-2 (a) pH 2 (b) pH 4 (c) pH 6，3 g L-1 ●針鐵礦▼黑炭 ■針鐵礦＋黑炭 □針鐵礦＋黑炭(計算值) 對Cr(VI)初始濃度為10 mg L-1 之動力學吸附實驗，溶液中Cr(VI)濃度隨反應時間的變化33 圖 4-3 pH 4下，黑炭(3 g L-1)與10 mg L-1 Cr(VI)吸附後以及標準品的XANES圖譜34 圖4-4 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●針鐵礦▼黑炭 ■針鐵礦＋黑炭 對Cr(VI)初始濃度為10 mg L-1 之固體上Cr(VI)萃取實驗結果35 圖4-5 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●黑炭 ▽針鐵礦＋黑炭 對Cr(VI)初始濃度10 mg L-1之動力學吸附實驗，固體上Cr(III)濃度隨反應時間的變化 36 圖4-6 針鐵礦＋黑炭(3g L-1)與初始濃度10 mg L-1的Cr(VI)之長時間動力學吸附實驗(pH 4) 37 圖4-7 針鐵礦(3g L-1)與反應初始濃度為5~50 mg L-1的Cr(VI)之連續稀釋脫附實驗(pH 4)37 圖4-8 不同pH下，總Fe溶出濃度隨動力學反應時間的改變情形，黑色符號部分吸附劑為針鐵礦(3g L-1)；白色部分符號吸附劑為針鐵礦+黑炭(各3g L-1)與Cr(VI)反應之結果38 圖4-9 (a) pH 2 (b) pH 4 (c) pH 6，M:氧化錳 B:黑炭 B+M:氧化錳＋黑炭，與10 mg L-1 Cr(VI)於3g L-1、反應時間48 hr後溶液中Cr(VI)物種的轉變百分率44 圖4-10 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●氧化錳 ▼黑炭 ■氧化錳＋黑炭 對Cr(VI)初始濃度為10 mg L-1 之動力學吸附實驗，溶液中Cr(VI)濃度隨反應時間的變化。45 圖4-11 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●氧化錳▼黑炭 ■氧化錳＋黑炭 對Cr(VI)初始濃度為10 mg L-1 之固體上Cr(VI)萃取實驗46 圖4-12 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●氧化錳 ▼黑炭 ■氧化錳＋黑炭 對Cr(VI)初始濃度為10 mg L-1 之動力學吸附實驗，固體上Cr(III)濃度隨反應時間的變化47 圖4-13 纖維素黑炭與10 mg L-1 的Cr(VI)吸附反應48小時後，於0.01M KCl中的脫附動力學實驗(pH4)48 圖4-14氧化錳與10 mg L-1的Cr(III)之動力學吸附實驗49 圖4-15 纖維素黑炭與初始濃度為5~15 mg L-1 之Cr(VI)吸附反應48小時後，以pH4之0.01M KCl連續稀釋脫附之結果50 圖4-16 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●氧化錳 ▼黑炭 ■氧化錳＋黑炭 對Cr(VI)初始濃度為10 mg L-1 之動力學吸附實驗，溶液中Cr(III)濃度隨反應時間的變化。51 圖4-17 反應時間(a) 8 hr (b) 24 hr (c) 48 hr (3g L-1、pH 4) M:氧化錳 B:黑炭 B+M:氧化錳＋黑炭 對Cr(VI)初始濃度為10 mg L-1吸附實驗之鉻物種分佈結果52 圖4-18 pH 2、4和6下，纖維素黑炭有無添加氧化錳對移除溶液中Cr(VI)的一階動力學模式53 圖4-19 不同pH下，於反應時間5分鐘、3g L-1時，氧化錳與初始濃度為10 mg L-1Cr(III)吸附實驗之結果54 圖4-20 (a)氧化錳＋黑炭 (b) 黑炭對Cr(VI)初始濃度為10 mg L-1 之動力學吸附實驗結果55 圖4-21 不同pH下，於反應時間48 hr、3g L-1的(a)黑炭(b)氧化錳＋黑炭與濃度為10 mg L-1的Cr(VI)反應後之鉻物種分佈結果56 圖4-22 (a) pH 2 (b) pH 4 (c) pH 6 氧化錳(3g L-1)與10 mg L-1 Cr(III)動力學吸附實驗，鉻的物種分佈隨時間改變之情61 圖4-23 (a) pH 2 (b) pH 4 (c) pH 6，M:氧化錳 B:黑炭 B+M:氧化錳＋黑炭，與10 mg L-1 Cr(III)於3g L-1、反應時間48 hr後溶液中Cr(III)的物種轉變百分率62 圖4-24 不同pH下，纖維素黑炭有無添加氧化錳(3g L-1)與10 mg L-1 Cr(III)反應48小時，固體上Cr(III)的含量之差異63 圖4-25 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●黑炭▼氧化錳＋黑炭與10 mg L-1Cr(III)之動力學吸附實驗，溶液中Cr(III)濃度隨反應時間改變之情形64 圖4-26 不同pH下，黑炭(3g L-1)與10 mg L-1 Cr(III)反應48小時後，鉻的物種分佈結果65 圖4-27 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●氧化錳 ▼黑炭 ■氧化錳＋黑炭與10 mg L-1 Cr(III)之動力學吸附實驗，溶液中Cr(VI)濃度隨反應時間改變之情形66 圖4-28 pH 2、4和6下，纖維素黑炭有無添加氧化錳對移除溶液中Cr(VI)的一階動力學模式67 圖4-29 (a) pH 2 (b) pH 4 (c) pH 6，3g L-1 ●氧化錳 ▼黑炭 ■氧化錳＋黑炭 與10 mg L-1 Cr(III)反應之磷酸萃取結果68 圖5-1氧化鐵、黑炭與Cr(VI)反應示意圖73 圖5-2 氧化錳與Cr(III)/Cr(VI)氧化還原反應7

Influences of Zn(II), Cu(II) and Al(III) on tetracycline antibiotics adsorption by iron hydroxide

四環類抗生素(TC)為世界上廣泛使用之抗生素，其被使用於預防人類疾病、獸醫用藥及當作動物的生長促進劑使用。但由於極少量的TCs可經由新陳代謝被動物的腸胃道所吸收，而大部分的TC會以原結構經由動物的尿液以及排泄物排至動物體外。當TC被釋放到環境中，土壤中常見的礦物如鐵氧化物對TC的吸附行為便為一個控制環境中TC的移動性及生物有效性的重要角色。由於TC可與雙價及三價金屬離子產生很強的錯合能力，此錯合反應會改變TC的帶電特性而影響TC與吸附劑表面之交互作用，進而改變其在環境中的傳輸。在本研究中，TC在鐵氧化物例如水合鐵礦及針鐵礦上的吸附反應，會受溶液pH值及不同的金屬錯合比例所影響，水合鐵礦及針鐵礦皆在pH 6時有最大的TC吸附量，當溶液中出現金屬離子(Zn2+、Cu2+及Al3+)時，金屬離子會經由同時與鐵氧化物及TC產生錯合而形成鐵氧化物及TC間的陽離子橋接，即其會與鐵氧化物和TC產生三元複合體而增進TC在鐵氧化物表面的吸附量。金屬離子與TC間不同的錯合比例亦會影響TC與鐵氧化物間的交互作用，TC-Zn及TC-Al在莫耳比為1:1而TC-Cu在莫耳比為1:3時會有最大的TC吸附量。此外，經金屬修飾過後的鐵氧化物表面，其對於TC的吸附能力沒有TC-金屬錯合物的吸附能力強。Tetracyclines(TCs) is one of the most widely-used antibiotics in the world, which are commonly used as human infection medicines, veterinary medicines, and animal growth promoters. Because only small amount of TCs are absorbed during metabolism, the majority of TC are excreted via feces and urine as unchanged form. Upon TC release, iron oxide-hydroxides (IOH), common minerals in soils, may play an important role in controlling the behavior and bioavailability of TC in the environment. However, the interactions of TC with IOH may be subject to change while TC forming a strong complex with divalent or trivalent cations. In this report, TC adsorptions on iron oxide-hydroxides, such as goethite and ferrihydride, as influenced by pH and metal cations with various molar ratios, were examined. Results indicated that TC adsorption on ferrihydrite and goethite exhibited relatively fast, and it reached the maximum at pH 6. The presence of metals (Zn2+、Cu2+ and Al3+) would increase TC adsorption on the minerals, attributing probably to the formations of metal bridge and ternary complexes. TC and metal ratios influenced strongly the interactions of TC with the iron minerals. A maximum adsorption of TC was observed for TC-Zn/TC-Al and TC-Cu with a TC-metal ratio of 1:1 and 1:3, respectively. However, an increase of metal concentrations behind the specific ratio would lead to a decrease of TC adsorption Modifications of mineral surfaces by extra metal ions may create an unfavorable local environment for TC or TC-metal complexes adsorptions.摘要…………………………………………………………………………………..i Abstract………………………………………………………………………………..ii 目錄…………………………………………………………………………………...iii 圖目錄………………………………………………………………………………..vii 表目錄………………………………………………………………………………...ix 第一章 前言…………………………………………………………………………1 第二章 前人研究……………………………………………………………………3 2.1 抗生素的發展………………………………………………………………...3 2.2 抗生素的種類及抑菌機制………………………………………………..….3 2.3 抗生素抗藥性…………………………………………….…………………..5 2.4 細菌抗藥性產生的機制…………………………………………………...…6 2.5 世界各國及台灣對畜牧用抗生素的管制情形……………………………...6 2.6 抗生素做為飼料添加物………………………………………………...……8 2.7 四環素……………………………………………………………………….10 2.7.1 四環類抗生素介紹……………………………………………………..10 2.7.2 四環素在環境中的濃度………………………………………………..14 2.8 四環素與環境中物質交互作用…………………………………………….15 2.8.1 環境中物質吸附四環素………………………………………………..15 2.8.2 金屬離子與四環素的交互作用………………………………………..16 2.9 鐵氧化礦物………………………………………………………………….16 2.9.1 針鐵礦…………………………………………………………………..17 2.9.2 水合鐵礦………………………………………………………………..18 2.9.3 鐵氧化物表面化學特性………………………………………………..21 2.9.4 鐵氧化物吸附四環素之研究…………………………………………..23 2.10 金屬作為飼料添加物……………………………………………………...23 2.10.1 銅 (Copper, Cu)……………………………………………………….23 2.10.2 鋅(Zinc, Zn)…………………………………………………………...24 2.10.3 鋁(Aluminum, Al)……………………………………………………..24 第三章 材料與方法………………………………………………………………..25 3.1 藥品…………………………………………………………………………..25 3.2 儀器設備…………………………………………………………………….25 3.3 鐵氧化礦物的合成………………………………………………………….26 3.3.1 針鐵礦的合成…………………………………………………………..26 3.3.2 水合鐵礦的合成………………………………………………………..27 3.4 鐵氧化礦物X光繞射分析………………………………………………..…27 3.5 鐵氧化物界達電位分析…………………………………………………….28 3.6 鐵氧化物粒徑分析………………………………………………………….28 3.7 鐵氧化物比表面積測定…………………………………………………….29 3.8 不同 pH值對鐵氧化礦物吸附TC的影響………………………………….29 3.8.1 不同 pH TC檢量線製作……………………………………………….29 3.8.2 不同pH影響鐵氧化物吸附TC…………………………………………30 3.8.3 鐵氧化礦物在不同 pH下吸附TC之動力試驗………………………..30 3.8.4 鐵氧化礦物在不同pH下對TC之等溫吸附試驗………………………30 3.9 陽離子對於鐵氧化物吸附TC的影響……………………………………....31 3.9.1 TC添加不同陽離子的檢量線製作…………………………………….31 3.9.1.1 TC與金屬1:1莫耳比例之檢量線製作…………………………….31 3.9.1.2 金屬加入先後順序對於鐵氧化物吸附四環素影響試驗………...31 3.9.1.2.1 鐵氧化物先與金屬反應………………………………………31 3.9.1.2.2 金屬先與TC反應……………………………………………...32 3.9.1.3 金屬離子影響鐵氧化礦物在不同pH下吸附四環素……………..32 3.9.2 四環素與不同莫耳比例金屬檢量線之製作…………………………..32 3.9.2.1 動力吸附不同比例的TC-金屬錯合物於針鐵礦…………………..33 3.9.3 金屬的添加對於鐵氧化物等電點的影響……………………………..33 3.10 針鐵礦及TC與金屬反應後之官能基鑑定…………………………….....33 3.10.1 針鐵礦與金屬反應48小時後官能基鑑定……………………………33 3.10.2 TC與金屬反應48小時後官能基鑑定……………………………….....34 3.11 等溫吸附模式 …………………………………………………………….34 3.11.1 Freundlich吸附理論………………………………………………….....34 3.11.2 Langmuir吸附理論…………………………………………….……….35 3.12 動力吸附模式……………………………………………………………...36 3.12.1 擬一階動力方程式 (Pseudo-first-order equation)……………….36 3.12.2 擬二階動力方程式 (Pseudo-second-order equation)……………..37 第四章 結果與討論………………………………………………………………..38 4.1 鐵氧化物基本性質分析…………………………………………………….38 4.1.1 水合鐵礦及針鐵礦X-ray 繞射光譜儀結構分析……………………....38 4.1.2 鐵氧化物界達電位分析………………………………………………..40 4.1.3 鐵氧化物粒徑分析及比表面積………………………………………..40 4.2 不同pH對鐵氧化物吸附TC影響…………………………………………...43 4.2.1 pH影響鐵氧化物吸附TC試驗………………………………………….43 4.2.2 鐵氧化物在不同pH下吸附TC之動力實驗……………………………48 4.2.3 鐵氧化物在不同pH下吸附TC之等溫實驗……………………………48 4.3 金屬離子對鐵氧化物吸附TC的影響…………………………………….....56 4.3.1 金屬Cu與Zn的添加對於鐵氧化物吸附TC的影響………………….....56 4.3.2 金屬Cu添加先後順序對鐵氧化物吸附TC的影響…………………….62 4.3.3 金屬Zn添加先後順序對鐵氧化物吸附TC的影響……………………..65 4.3.4 鐵氧化物吸附TC-Cu及TC-Zn錯合物……………………….………….68 4.3.5 鐵氧化物吸附TC及TC-metal錯合物綜合比較……….………….…….68 4.3.6 針鐵礦吸附不同莫耳比例的TC-metal錯合物…………………..……..70 4.3.7 比較針鐵礦表面的Cu2+與溶液中的Cu2+對針鐵礦吸附TC的影響….82 第五章 結論………………………………………………………………………..86 參考文獻……………………………………………………………………………87 附錄…………………………………………………………………………………9

Desferrioxamine B 對磷吸附後針鐵礦之溶解機制

Desferrioxamine B(DFOB) is one of microbial trihydroxamate siderophores, which is excreted by soil microbes and plant rootunder iron (Fe) deficientconditions.It can dissolveFe oxide minerals and increase the Fe availability in soil.Phosphate (P) is well known to be easily fixed by Fe minerals in soil. Because P and DFOB may compete the same surface binding sites, it is unclear whether P availability is increased when Fe oxide minerals are dissolved by DFOB. The aim of this research is to investigate the effects of DFOB on the releasing rates of P and Fe from P-adsorbedgoethite. P-adsorbed goethites were prepared with 0, 40 and 100% P loading amountsat pH 5 and 9. DFOB-promoted dissolution experiments were conducted at pH 5 and at different temperatures (5, 25 and 45℃). The corresponding dissolution rate constants were obtained and subsequently used to calculate the pre-exponential factor (A) and activation energy (Ea) through Arrhenius equation. The results showed that the calculated activation energyfor the dissolution reaction increased with the P adsorptionincrease, as there was stronger bonding interaction between Fe and P. Although theactivation energy increases , the dissolution rate of Fe is also increased. It is because more P adsorbed on goethite, Eap become lower than EaFe and thus Fe dissolution is chemically controlled by P. The complex species of P also control Fe dissolution. Fe dissolution is more significantly enhanced by mononuclear bidentate complex. The enhancement of Fe dissolution with more adsorbed P can be explained by increased A value, which means that DFOB was more accessible to the surface of goethite. The increase in the accessibility of DFOB to the goethite surface with increasing P adsorptionresults from the increasing negative charge of goethite surface. Moreover, the dissolution-readsorption mechanism may play a significant role in enhancement of Fe and P dissolution.Desferrioxamine B (DFOB)是一種由微生物分泌的載鐵物質，它含有三個醯基羥胺官能基。鐵是生物生表的重要元素之一，但在土壤環境中，微生物和植物根系常處於缺乏鐵的情況下。為了攝取足夠的鐵元素，它們會分泌對鐵親和力高的載鐵物質，把鐵礦物上的鐵溶解，增加土壤中的有效鐵。除了鐵之外，土壤磷的有效性很低，它很容易被固定在鐵礦物上。由於磷酸鹽和DFOB會競爭針鐵礦上相同的反應位置，目前還不瞭解磷的吸附對DFOB溶解鐵的影響。因此，本研究的目的是探討DFOB對針鐵礦上磷和鐵 溶解的影響，從而了解DFOB對土壤中磷及鐵有效性的影響。實驗中先準備在pH5 和pH9 下不同含量( 0，40，100％磷 ) 磷吸附的含磷針鐵礦，並 在pH 5 下加入DFOB在不同溫度下（5，25 和 45℃）進行溶解實驗。計算出的溶解速率常數，隨後通過Arrhenius equation來計算指前因子A和活化能Ea。結果顯示，磷會阻擋DFOB吸附在針鐵礦上。由於鐵和磷之間的鍵結強度增加，活化能也隨磷吸附增加而增加。然而，鐵的溶解速率卻隨磷吸附增加而增加。當磷吸附增加，由於溶解鐵之活化能較溶解磷之活化能高，磷成為鐵溶解的控制因子。磷在針鐵礦上的鉗合型態對鐵溶解也有影響，單核雙配位的鉗合型態有促進鐵溶解的效果。另外，磷的吸附導致表面負電荷的增加，讓DFOB更容易跟針鐵礦的表面鐵反應，進一步促進鐵溶解。磷的重新吸附機制亦為促進鐵和磷溶解的原因之一。Acknowledgments............................................i Abstract................................................ ii 摘要......................................................iv Contents ..................................................v Figure List ............................................viii Table List...............................................xii 1.INTRODUCTION.............................................1 2.LITERATURE REVIEW .......................................3 2.1 Fe oxides..............................................3 2.1.1 Fe in soil ..........................................3 2.1.2 Fe oxide dissolution.................................4 2.1.3 Rate Laws of Fe oxide dissolution ...................6 2.2 Siderophores...........................................7 2.2.1 Definition of siderophores...........................7 2.2.2 Desferrioxamine B (DFOB).............................9 2.3 DFOB-induced Fe oxides dissolution....................11 2.3.1 Ligand-promoted dissolution by DFOB.................11 2.3.2 Reductive dissolution by DFOB.......................12 2.3.3 DFOB-induced dissolution in presence of other ligands...................................................14 2.4 Interactions between Fe oxide and phosphate ..........15 2.4.1 Introduction of phosphate...........................15 2.4.2 Bonding between goethite surface and phosphate..... 17 2.4.3 Retention of phosphate on goethite .................20 2.5 Arrhenius equation....................................22 3. MATERIALS AND METHODS .................................23 3.1 Materials.............................................23 3.2 Sample preparation....................................23 3.2.1 DFOB purification...................................23 3.2.2 Minerals synthesis..................................24 3.2.2.1 Goethite synthesis.000............................24 3.2.2.2 Ferric phosphate synthesis........................25 3.2.2.3 Mineral identification and post processing........25 3.2.3 Phosphate adsorption on goethite....................27 3.2.3.1 Phosphate adsorption isotherm ....................27 3.2.3.2 Preparation of phosphate-adsorbed goethite samples ..........................................................29 3.3 Dissolution of minerals in the presence of DFOB.......30 3.3.1 Dissolution in batch experiment.....................30 3.3.2 Determination of dissolved Fe and P.................31 3.3.3 Determination of DFOB concentration ................31 3.4 Zeta potential determination..........................33 3.5 X-ray absorption near edge structure (XANES) spectroscopic study.......................................34 4. RESULT AND DISCUSSION..................................35 4.1 Zeta potential of minerals............................35 4.2 DFOB adsorption.......................................37 4.3 Fe dissolution .......................................38 4.4 Relation between phosphate and Fe dissolution.........40 4.5 Rate coefficients and Arrhenius parameters........... 41 4.6 XANES spectroscopic result ...........................46 5. CONCLUSION............................................ 67 6. REFERENCES............................................ 69 Figure List Figure 2.1 a) The structure of goethite. b) The schematic model of goethite – water interface: A – crystalline bulk structure, B–crystalline surface structure, and C – semi-ordered physisorbed water or sorbates......................4 Figure 2.2 The scheme of Fe acquirement by organisms via siderophore excretion......................................9 Figure 2.3 a) Chemical structure of the fully protonated DFOB; b)Structure of metal-DFOB complex...................10 Figure 2.4 Adsorption of acetohydroxamic acid (aHA) through ligand exchange reaction..................................12 Figure 2.5 Structures of (a) monoclinic FePO ‧2H2O and (b) orthorhombic FePO4‧2H2O. Blue corresponds to FeO6 octahedra in hydrated P, and yellow corresponds to PO4 tetrahedra. (a) and (b) are shown along a axis, b axis across, c axis up. Stucture of (c) FePO4‧2H2O with water molecules located. Purple represents FeO6 octahedra in hydrated P, blue represents PO4 tetrahedra, orange represents hydrogen atom and red represents oxygen atom. ..........................16 Figure 2.6 Speciation of orthophosphate ions in solution as a function of pH..........................................17 Figure 2.7 (a) Models of ligand coordination to the Fe oxide surface; (b)Depicted PO4 surface-complexes on goethite....19 Figure 2.8Relative surface P speciation on goethite for two fixed P concentration: (a) 10-7 M and (b) 10-4 M, in 0.01 M NaNO3 as function of pH. Dotted line represents the monodentate species (FeOPO3);Solid lines depict the bidentate species (Fe2O2PO2 and Fe2O2POOH)................20 Figure 2.9 Scheme of surface precipitation mechanism. Step 1, adsorption of P on the surface. Step 2, dissolved Fe adsorbs on the surface P. Step 3, goethite dissolves to refill the consumed Fe. Step 4, P adsorbs to the surface-bound Fe..................................................21 Figure 3.1 XRD patterns of synthesized goethite...........26 Figure 3.2 XRD patterns of synthesized ferric phosphate (FePO4‧2H2O)..............................................27 Figure 3.3 a) Isothermal experiment of P adsorption on goethite; b) Linear Langmuir equation fitting for P adsorption................................................29 Figure 3.4 The influence of P, Fe(II) and Fe(III) concentration on DFOB determination. .....................32 Figure 3.5 The wavelength scanning spectra of DFOB in presence and absence of P.................................33 Figure 4.1 Zeta potential of intact goethite and P-goethites as a function of P loading................................48 Figure 4.2 Zeta potential at pH 5 of pH 5 and pH 9 P goethites as a function of P loading. ....................49 Figure 4.3 DFOB adsorption on pH 5 P-goethites and FePO4‧2H2O at 5 ℃, 25℃ and 45℃. ..............................50 Figure 4.4 DFOB adsorption on pH 9 P-goethites and FePO4‧2H2O at 5 ℃, 25℃ and 45℃. ..............................51 Figure 4.5 Fe dissolution of pH 5 P-goethites at 5℃, 25℃ and 45℃..................................................52 Figure 4.6 Fe dissolution of pH 9 P-goethites at 5℃, 25℃ and 45℃..................................................53 Figure 4.7 P dissolution of pH 5 P-goethite at 5℃, 25℃ and 45℃. ....................................................54 Figure 4.8 P dissolution of pH 9 P-goethite at 5℃, 25℃ and 45℃. ....................................................55 Figure 4.9 Comparison of Fe and P dissolution of pH 5 100% P-goethite at 5℃, 25℃ and 45℃. .........................56 Figure 4.10 The P/Fe ratio of 40% and 100% P-goethites and FePO4‧2H2O. ..............................................57 Figure 4.11 Fe dissolution fitting of all goethites and FePO4‧2H2O at 5, 25and 45℃................................58 Figure 4.12P dissolution fitting of pH 5 100% P-goethite and FePO4‧2H2O mineral at 5℃, 25℃ and 45℃...................59 Figure 4.13 Fe dissolution fitting of pH 5 P-goethites by Arrhenius equation........................................60 Figure 4.14 Fe dissolution fitting of pH 9 P-goethites by Arrhenius equation........................................60 Figure 4.15 Fe dissolution fitting of FePO4‧2H2O mineral by Arrhenius ................................................60 Figure 4.16 P dissolution fitting of pH 5 100% P- goethite and FePO4‧ 2H2O by Arrhenius equation....................61 Figure 4.17 XANES spectra of pH 5 100% P P-goethite at 0, 1 and 72 hr. dissolution times..............................62 Figure 4.18 XANES spectra of pH 9 100% P P-goethite at 0, 1 and 72 hr.dissolution times...............................63 Table List Table 3.1The N, C, S, H element amount of DFOB determined by elemental analysis. ......................................24 Table 4.1 Zeta potential determination of all minerals at pH 5. ...................................................... 48 Table 4.2 Rate coefficients of Fe dissolution in presence of DFOB at 5℃,25℃ and 45℃. ................................64 Table 4.3 Arrhenius parameters of Fe dissolution in presence of DFOB ..................................................65 Table 4.4 Rate coefficients and Arrhenius parameters of P dissolution of pH 5 100% P-goethite and FePO4‧2H2O mineral in presence of DFOB at 5℃, 25℃ and 45℃. ................6

H2O2/UV程序結合針鐵礦對於EDTA氧化之研究

[[notice]]補正完畢[[conferencetype]]國內[[conferencedate]]20001201~2000120

陶斯松在茶樹土壤中的吸附及在茶樹葉面上的光降解研究

Chlorpyrifos [O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl), a phosphorothioate ester, is an efficient and commonly used pesticide in tea-growing regions in Taiwan. Due to its toxicity, the residue and transformation of chlorpyrifos on the leaves of tea trees and in soil planted with tea trees need to be investigated for the safety of tea drinkers and proper functioning of the ecosystems. The research was divides into two parts of (1) sorption and desorption of chlorpyritos on goethite and ferrihydrite, representative of the crystal and amorphous forms of Fe oxides, effect of humic acid and two types of soils grown with tea trees; (2) a direct photolysis and the possible photo-oxidation pathways of chlorpyrifos on the tender and old leaves of the tea trees irradiated by sunlight, ultraviolet light (UV) and visible light. Results showed that chlorpyrifos sorption by ferrihydride was greater than that of goethite, and both iron hydr(o)oxides have more adsorption in lower pH. The present of humic acid can promote the adsorption on goethite. However, the red soil, having high iron hydr(o)oxide contents, exhibited a greater sorptive ability of chlorpyrifos even if it contained lower organic matter. Indifferent to the light sources, the rates of photo-decompositions of chlorpyrifos proceeded more rapid on the surface of tender leaves than those of old ones, even if old ones reflect more light with epicuticular wax. The reason may be that the increasing of temperature on old leaves and the wavelength adsorption of chlorpyrifos itself. Under the photolysis, absorption of chlorpyrifos occurred simultaneously on the surfaces of leaves, and these reactions were enhanced with an increase of leaf temperatures. Our preliminary results of LC/MS/MS analyses indicated that the photo-degradations of chlorpyrifos would lead to the production of product of chloro-2-[pyridinyl-O,O-ethyl] thiophosphate through the dechlorination under the photolysis on solid and aqueous phase. Additonally, chlorpyrifos could transform to chlorpyrifos-oxon by the oxidation of P=S to P=O.It cleavaged.into TCP and DEP under the aqueous phase due to hydrolysis. However, under the solid phase, dechlorination of chlorpyrifos-oxon occurred primary.陶斯松，化學式為O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl, chlorpyrifos)，目前為病蟲害防治上常用之高效有機磷殺蟲劑，它的作用是被廣泛認可的。陶斯松的使用在國內的茶樹種植上尤其常見，雖然已被用來替代其他高毒性農藥，但陶斯松的施用給人類健康、土壤和水環境以及生態安全造成的隱患也是不容忽視的。因此，茶樹葉面上與種植茶樹的土壤中，陶斯松的殘留以及環境行為的研究更是顯得重要，研究分為兩部分：一為探討兩種種植茶樹的酸性土壤，與存在於土壤中之鐵氧化物水合鐵礦與針鐵礦，以及腐植酸對吸附陶斯松行為的影響；二為以紫外光、可見光以及太陽光為光源，研究陶斯松分別在茶樹的老葉及嫩葉葉片與不同基質表面上的直接光降解作用，並且探討固相表面上光降解可能產生的產物以及途徑，比較固相基質與其他降解反應如水溶液與微生物性分解途徑之差異。結果顯示水合鐵礦對陶斯松的吸附反應會大於針鐵礦，且環境pH值對於此兩種鐵氧化物並無太大影響，僅會在較高pH值下因鐵氧化物表面離子化造成吸附量些微降低，在鐵氧化物上有腐植酸的存在會因增加表面的疏水性吸附位置使針鐵礦對陶斯松的吸附量增加。但發現即使土壤有機質含量低，桃園茶改場茶園紅土可能因富含鐵氧化物，而對陶斯松的吸附量較多。茶樹上陶斯松光降解的研究，葉面蠟質、光源的種類與葉面的溫度改變會交互對葉面與不同基質表面上的陶斯松光降解造成影響，蠟質含量較多的老葉，其陶斯松光降解應較慢，但相反的結果可能與蠟質造成葉面的溫度上升有關，且溫度的上升，也會使的部分陶斯松可能進入到葉組織或被熱分解。而在陶斯松光降解路徑研究，在照射UV光後，固相與液相情況下皆會發生陶斯松吡啶環的脫氯反應，而不同的是兩相中在產生陶斯松的氧化物後，液相環境下會傾向水解產生產物，固相環境下則會多進行陶斯松氧化物吡啶環的脫氯反應，此途徑是不照光水溶液與微生物分解上沒有發生的；而另一途徑為陶斯松本身藉由脫氯反應慢慢脫去吡啶環上的氯，也是只在有光照降解下才會有的現象。摘要 i Abstract iii 目錄 v 表次 vii 圖次 viii 壹、 前言 1 一、研究緣起 1 貳、文獻回顧 3 一、農藥簡介 3 二、有機磷農藥簡介 4 1.1 有機磷農藥結構及特性 4 1.2 有機磷農藥毒性 8 三、陶斯松 10 3.1 陶斯松簡介 10 3.2 陶斯松於茶樹栽植上的利用 14 3.3 環境中的陶斯松 17 3.3.1 光化學降解 19 四、茶樹生長環境 25 4.1 鐵氧化礦物 26 4.2 針鐵礦 27 4.3 水合鐵礦 27 4.4 鐵氧化物表面化學特性 30 參、材料與方法 31 一、藥品 31 (一) 研究用水 31 (二) 分析藥品及溶劑 31 二、儀器設備 32 三、吸附試驗 36 3.1 土壤採集與處理 36 3.2 土壤基本特性分析 36 3.3 陶斯松吸附試驗 40 四、陶斯松在不同基質表面的光化學降解 44 4.1. 茶葉葉面上陶斯松在不同光源下的光化學降解 44 4.2. 不同材質表面上的陶斯松在不同光源下的光降解動力學 48 4.3.陶斯松的分析條件 49 肆、結果與討論 51 一、陶斯松的吸附作用 51 (一)陶斯松在茶樹土壤中的吸附作用 51 (二)鐵氧化物對陶斯松的吸附作用 62 二、陶斯松的光降解 85 (一)陶斯松在茶樹葉面上的光降解 85 (二)陶斯松在不同材質為基質的表面上之光降解 94 (三)環境溫度對葉面及不同基質表面上殘留陶斯松的影響 100 三、陶斯松之中間產物分析 103 伍、結論 112 陸、參考文獻 11

覆蓋及敷蓋對坡地土壤表面電荷量之影響

本文之目的在探討覆蓋及敷蓋對坡地土壤表面電荷量之影響程度。以覆蓋及敷蓋處 理已達十五年之久的鳳山荔枝園水土保持試驗區土壤為材料，測定土壤之表面淨電 荷、零電點、有機質、有效性磷、陽離子交換能量、比表面積及鑑定所含礦物，所 得結果如下： 1.試驗土樣以X-ray 繞射法鑑定，其結果含有高嶺土（Kaolinite）、 蛭石（ Vermiculite） 、長石（Feldspar）、石英（Quartz）、白雲母（ Muscovite）、 針鐵礦（Goethite）及少量之磷礦石（Apatite） 屬於混合型膠體土壤。 2.土壤之比表面積與其所含之粘粒量有正相關，試驗土樣因處理不同，土壤流失量 亦異，致表土粒粒量略有差異而影響比表面積。表土以百喜草覆蓋區較稻草敷蓋區 及淨耕對照區為高；底土因粘粒含量未變，故比表面積也沒有顥著差異。 3.覆蓋及敷蓋處理可增加土壤有機質及有效性磷含量，致降低土壤零電點，使其表 面電荷量增大，有利於保肥力提高。 4.熱帶、亞熱帶地區土壤測定CEC ，在PH 5．5時，則用中性醋酸銨抽出液交換性陽離子總量即可。 5.試驗土壤為混合型膠體土壤，其表面電荷量之計算尚需要導出另一新數學模式。 #2811806 #281180