類別:

黃銅水錶於自來水中腐蝕之機制與鉛、銅、鋅釋出之評估

Sat, 01 Jan 2022 00:00:00 GMT

標題: 黃銅水錶於自來水中腐蝕之機制與鉛、銅、鋅釋出之評估; Corrosion and release of lead, copper and zinc from brass water meter in drinking water 作者: Ching-Hsuan Hsu; 徐靖軒摘要: 腐蝕對於住戶管線系統有很大的影響，可能會造成管線滲漏、管線堵塞以及管件微量物質的釋出。此研究的目的是要了解黃銅水錶在不同的自來水水質條件下腐蝕的情形。本研究藉由感應耦合電漿質譜儀(ICP-MS)偵測鉛、銅、鋅的釋出，並結合表面分析以及電化學方法來觀察黃銅水錶在自來水中腐蝕及腐蝕產物生成的情形。結果顯示因局部電化腐蝕，大量的鉛及鋅會自黃銅水錶釋出。在實驗初期(0-5天)，根據能量色散X射線光譜分析(EDS)，黃銅水錶表面的鉛及鋅的百分比含量有明顯的下降，伴隨著腐蝕電流密度的上升以及表層電阻阻抗的下降，這些結果能夠說明實驗初期有劇烈的腐蝕現象發生；在實驗後期(>10天)，根據金屬釋出及EDS結果進行分析，可以發現含銅及鉛的腐蝕產物在黃銅表面生成，而抑制了腐蝕反應，電化學的檢測亦證實此項結果。當自來水pH值降低，會促進鉛、銅、鋅的釋出，相反的pH值的上升能抑制金屬自黃銅水錶釋出。自由餘氯能夠稍微減少鉛的釋出，然而自由餘氯會大大提升銅及鋅的釋出。; Corrosion has adverse impacts on household plumbing systems, which may lead to water leak, pipe clogging and metal release. In this study, corrosion of brass water meter was investigated using batch experiments with various tap water conditions. The release of lead, copper and zinc was monitored using inductively coupled plasma mass spectrometry (ICP-MS) and electrochemical tests. Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) was used to investigate the change of surface morphology and elemental composition of the corrosion processes. The results showed that high levels of lead and zinc were released from brass water meter due to localized galvanic corrosion among lead, copper and zinc. During the early stage of corrosion (0-5 d), the weight percentage of lead and zinc on the brass water meter surfaces decreased substantially as evidenced by the EDS results. The corrosion current density (Icorr) increased and film resistance (RF) decreased during that period. These results illustrated that severe corrosion occurred. During the later stage (> 10 d), according to the ICP-MS and EDS results, copper and lead corrosion products formed on the brass water meter surfaces, which retarded the corrosion process. The release of lead, copper and zinc was enhanced by a lower pH. Free chlorine was found to slightly reduce the release of lead while promote the release of copper and zinc.

麻瘋樹籽油渣之焙燒

Sun, 01 Jan 2012 00:00:00 GMT

標題: 麻瘋樹籽油渣之焙燒; Production of Bio-char from Jatropha-seed Cake via Torrefaction 作者: Tsung-Chi Hsu; 許聰吉摘要: 本研究利用焙燒程序處理麻瘋樹種籽搾油後油渣，以提升其燃料性能。生質廢棄物有水分含量高、熱值低以及運輸貯存上的問題，若透過熱處理程序，雖然有部份質量損失，但仍能保存大部份熱能，可達到熱值提升，以及能量密度增加，並且焙燒產物具疏水性之效果。本研究先進行熱重分析(thermagravimetric analysis, TGA)，決定油渣與脫脂油渣較合適之焙燒溫度(Tr)，與決定焙燒時間(tr)。依TGA結果擇定以260、280、300 °C及時間10-60 min進行焙燒，觀察兩種樣本於各操作條件下之焙燒反應情形。實驗結果顯示油渣在260、280、300 °C能量密度提升之最高值分別為1.25、1.29、1.30，脫脂油渣則分別為1.28、1.37、1.39，兩者焙燒產物之平均乾基熱值(high heating value in dry basis, HHMD)在5,000-6,000 kcal kg-1。焙燒產物固定碳比例上升，顯示更具燃煤特性。結果經迴歸分析後可歸納出熱值與固定碳之間呈現高度相關性質。與台電燃煤採購標準(STP)作為比較，油渣及脫脂油渣之焙燒產物之含硫量、灰分含量均在STP標準D之規範值以內。本研究綜合各項產物特性分析以作為最適操作條件之評估，結果顯示Tr = 280 °C，tr = 40 min之焙燒產物濕基高位熱值(high heating value in wet basis, HHMW)為5,700 kcal kg-1，符合STP標準D (HHMW ≧ 5000 kcal kg-1)之規範。; Torrefaction is a thermal treatment used to enhance the properties of fuels. In this study, Jatropha curcas L. seed cake after mechanically expelling ectraction of oil (denoted as Jatropha pressed cake or JPC) and the de-oiled JPC after further solvent extraction of residual oil using n-hexane (symboled as JDPC), were examined for their torrefaction performances. The thermogravimetric analysis (TGA) were employed to elucidate the thermal decomposition behaviors of JPC and JDPC. Temperatures with acceptable mass loss of 5-10% of JPC in TGA were in the range of 260-310 °C, suggesting the further tests of the torrefaction at 260, 280 and 300 °C. The torrefaction temperature (Tr) and time (tr) play important roles on the production yield of bio-char. The tr employed were 10 to 60 min. During the torrefaction at a setting temperature Tr, the biomass further lost its mass. The characteristics of torrefied products were measured and assessed. Proper torrefaction conditions were elucidated, considering the balance of enhancing the energy density (ED) while retaining the yield (Ym). The results indicate that at Tr= 260, 280 and 300 °C, ED values of torrefaction products of JPC are 1.25, 1.29 and 1.30, while those of JDPC are 1.28 1.37 and 1.39, respectively. The high heating values per mass in dry basis (HHMD) for the cases using JPC and JDPC are about 5,000-6000 kcal kg-1. The fixed carbon content (MFC) increases after torrefaction, enhancing its coal-alike property. The MFC is highly and positively correlated with HHMD. Employing the appropriate conditions of Tr = 280 °C and tr = 40min, the torrefied products containing negligible sulfur, ash of 9.27 wt.% and HHMW of 5700 kcal kg-1 meet the D quality of coal standards of Taiwan Power Co. with sulfur < 1.1 wt.%, ash < 16 wt.% and HHMW >5000 kcal kg-1.

鹼性條件下臭氧去除水中全氟辛酸

Fri, 01 Jan 2010 00:00:00 GMT

標題: 鹼性條件下臭氧去除水中全氟辛酸; Perfluorooctanoic acid ozonation in alkaline condition 作者: Cheng-Yi Chang; 張丞毅摘要: 全氟碳化物(perfluorinated compounds，PFCs)常被半導體與光電產業用來酸洗電子零件或晶圓表面，或當作光版程序的界面活性劑。PFCs因其強大的碳-氟鍵結(C-F bond)，在自然界中不易被光解、水解或生物降解，也導致其在環境中有持久性與生物累積性的特質。許多文獻已證實PFCs具有致突變腫瘤與致癌性，因此利用工程方法去除PFCs為近年來熱門的研究議題。其中，全氟辛酸(perfluorooctanoic acid，PFOA)為一種最被廣泛應用的人造全氟碳化物，且比起許多其他的PFCs更具毒性、更難以分解。 PFOA無法在中性或酸性環境下使用臭氧直接降解，因此本研究嘗試使用臭氧在鹼性條件下，產生氫氧自由基(hydroxyl radical，OH•)降解水中PFOA。實驗中改變之參數有：pH (5~6, 11)、臭氧濃度(0 wt%, 2 wt%, 2.5 wt%, 7 wt%, 9.5 wt%, 10.5 wt% (ozone/oxygen))，PFOA初始濃度(50 ppb, 5 ppm)、過氧化氫(H2O2/O3 =5, 10, 20 molar%)、腐植酸(15 mg/L)與外加超音波場源震盪影響。當在鹼性條件(pH=11)下，使用臭氧能有效降解PFOA。使用2.5 wt%之臭氧可得到最佳處理效率(90 %)；若添加過氧化氫增加氫氧自由基之穩定態濃度，可使去除效率增加15 %~ 56 %；添加腐植酸抑制氫氧自由基之穩定態濃度，會使去除效率減少15 %~44%；外加超音波場源震盪則增加2 %去除效率，顯示降解機制為氫氧自由基攻擊目標污染物。此方法可將PFOA降解成毒性較低的中間產物如：全氟庚酸(PFHpA)、全氟己酸(PFHxA)、全氟戊酸(PFPeA)、全氟丁酸(PFBA)與氟離子，以減少PFOA在環境中的危害。此外，本研究亦嘗試將最佳操作條件用於處理全氟辛烷磺酸(Perfluorooctanesulfonic acid, PFOS)與實廠廢水，結果顯示PFOS去除效率可達84 %，用於處理實廠廢水6小時可去除92 %之PFOA、4小時即可去除99 %之PFOS。; Perfluorinated compounds (PFCs) have been widely used as surfactants in photolithographic processes in semiconducting and optoelectronic industry. The highly stabilities in photodegradation, hydrolysis, and biodegradation of perfluorinated compounds is attributed to their strong C-F bond, resulting in persistence and bioaccumulation in the environment. PFCs have been proved to be a carcinogen to human. Perfluorooctanoic acid (PFOA), one of human-made PFCs, is more toxic and difficult to be degraded than many other PFCs. PFOA can not be degraded by direct ozone reaction in acidic/neutral condition. Consequently, this study aimes to investigate PFOA ozonation in alkaline condition due to the generation of hydroxyl radical to degrade PFOA. The degradation efficiency of PFOA varied with pH values (5~6, 11), ozone concentrations (0 wt%, 2 wt%, 2.5 wt%, 7 wt%, 9.5 wt%, 10.5 wt% (ozone/oxygen)), the initial PFOA concentrations (50 ppb, 5 ppm), the molar ratio of hydrogen dioxide to ozone (H2O2/O3 =5, 10, 20 molar%), presence of humic acid (15 mg/L) and with the assistant of ultrasound. In alkaline condition (initial pH=11), ozonation can effectively degrade PFOA and exhibits the best efficiency with 2.5 wt% (ozone/oxygen). Adding hydrogen dioxide to enhance the steady concentration of hydroxyl radical (OH•) increases 15~56% of the conversion. Adding humic acid to restrain the steady concentration of OH• decreases 15~44% of the conversion. Combining ultrasonic vibration increases 2% of the conversion. Those phenomena illustrate that the hydroxyl radical attacking the target compound is the main mechanism of degradation. In this study, PFOA can be degraded to the-lower-toxic intermediates such as PFHpA, PFHxA, PFPeA, PFBA, and fluoride ion. In addition, this technology was also applied in treating perfluorooctanesulfonic acid (PFOS) and industrial wastewater under the optimum operating condition. Result shows that 84% PFOS can be degraded, and 92% PFOA and 99% PFOS in the industrial wastewater can be degraded within 6 hours and 4 hours, respectively.

高雄都會區PM2.5化學組成、來源貢獻及氧化潛勢與褐碳之機制驅動因素

Thu, 01 Jan 2026 00:00:00 GMT

標題: 高雄都會區PM2.5化學組成、來源貢獻及氧化潛勢與褐碳之機制驅動因素; Chemical composition, source contributions, and mechanistic drivers of oxidative potential and brown carbon in PM2.5 in Kaohsiung urban areas 作者: 廖婕妤; Jie-Yu Liao 摘要: 細懸浮微粒(PM2.5)化學組成與褐碳(BrC)光學特性對PM2.5的氧化潛勢(OP)具有重要影響，然而其交互關係仍未被充分釐清。本研究於高雄都會區楠梓(NZ)與鳳山(FS)進行四季與日夜之PM2.5採樣，結合其化學組成、BrC光學特性、氣膠酸鹼度與OP分析，並透過富集因子(EF)、受體模式正矩陣因子法、逆軌跡模式與雙變量極坐標圖進行來源解析，以探討PM2.5生成機制、毒性特徵及潛在來源。研究結果顯示，二次無機氣膠(SIA)與水溶性有機碳為PM2.5主要成分，其生成受大氣氧化能力與氣膠液態水含量(ALWC)共同影響。而隨著ALWC增加，有利於WSOC和BrC液相反應生成。此外，在365 nm波長下的質量吸收效率(MAE365)與OPm (質量量化之OP)呈正相關，顯示吸光有機物對氣膠氧化活性具有重要貢獻。SIA生成可調控氣膠酸鹼度與ALWC，在酸性相關金屬途徑下，低pH可能增加金屬溶解度；在ALWC相關有機物生成途徑下，高SIA增加ALWC，並促進WSOC與BrC生成，兩者反應途徑間接影響氣膠氧化活性與氣候。來源解析與軌跡分析顯示，兩測站受長程傳輸與本地排放控制，其中OPv (體積量化之OP)主要來自生質燃燒與二次氣膠及逸散性粉塵排放，而OPm則呈現測站差異，NZ受交通與工業排放影響較大，FS則受逸散性粉塵、生質燃燒與二次氣膠來源影響較大。此外，影響BrC光學特性的來源亦與氣膠OP密切相關，凸顯排放源特性、氣膠酸度、ALWC及大氣傳輸過程之交互作用對PM2.5氧化活性的影響。在政策管制上，應加強SIA前驅物、金屬與有機物排放之控制，以降低PM2.5氧化活性和光學作用影響。本研究強調降低氣膠毒性需同時考量PM2.5濃度與其化學組成、BrC光學特性、大氣環境條件與來源排放，並可提供高污染城市之空氣污染管制策略與健康風險評估之重要參考依據。; Fine particulate matter (PM2.5) chemical composition and the optical properties of brown carbon (BrC) play important roles in determining the oxidative potential (OP) of PM2.5; however, their interactions remain insufficiently understood. In this study, PM2.5 samples were collected at two stations in the Kaohsiung urban area, Nanzi (NZ) and Fengshan (FS), across four seasons and under both daytime and nighttime conditions. By integrating measurements of chemical composition, BrC optical properties, aerosol acidity, and OP, and applying enrichment factor (EF) analysis, Positive Matrix Factorization, backward trajectory model, and bivariate polar plot analyses, this study investigates PM2.5 formation mechanisms, toxicity characteristics, and potential sources. The results indicate that secondary inorganic aerosols (SIA) and water-soluble organic carbon (WSOC) are the dominant components of PM2.5, and their formation is jointly influenced by atmospheric oxidative capacity and aerosol liquid water content (ALWC). Increased ALWC facilitated the aqueous-phase formation of WSOC and BrC. In addition, the mass absorption efficiency at 365 nm (MAE365) was positively correlated with OPm (mass-normalized OP), indicating that light-absorbing organic species contribute significantly to aerosol oxidative reactivity. SIA formation regulated both aerosol acidity and ALWC. Under the acidity-associated metal pathway, lower aerosol pH may increase metal dissolution, whereas under the ALWC-associated organic pathway, elevated SIA increased ALWC and facilitated the formation of WSOC and BrC. These two pathways jointly influenced aerosol oxidative reactivity and climate. Source apportionment and trajectory analyses further revealed that both stations were influenced by local emissions and long-range transport. OPv (volume-normalized OP) was primarily associated with biomass burning and secondary sources, as well as fugitive dust. In contrast, OPm exhibited distinct spatial patterns, with NZ being more strongly influenced by traffic and industrial emissions, whereas FS was more strongly affected by fugitive dust, biomass burning and secondary sources. Furthermore, sources influencing BrC optical properties were also closely associated with aerosol OP, highlighting the combined effects of source characteristics, aerosol acidity, ALWC, and atmospheric transport on PM2.5 oxidative reactivity. From a policy perspective, controlling SIA precursors, metal emissions, and organic emissions is essential to mitigate PM2.5 oxidative reactivity and its optical effects. This study emphasizes that effective reduction of aerosol toxicity requires consideration of not only PM2.5 mass but also its chemical composition, BrC optical properties, atmospheric conditions, and emission sources, providing important insights for air pollution control strategies and health risk assessment in highly polluted urban areas.