利用甘胺酸-硝酸鹽程序製備奈米級銅氧化物處理有機污染物之研究

Production of Nanascale Copper Oxide by GNP（glycine-nitrate process）for Organic Pollutant Removal

張良偉(Liang-Wei Jang)

指導教授 ： 陳孝行

國立臺北科技大學/工程學院/環境工程與管理研究所/碩士(2012年)

https://doi.org/10.6841/NTUT.2012.00675

摘要

由於印刷電路板製程中，往往產生大量硝酸銅廢液，而在廢液中，銅含量約 9.5％，因此具極高的回收再利用價值。而 GNP 合成法主要是在金屬硝酸鹽溶液中加入甘胺酸作為燃料，反應完成後之產物即為金屬氧化物。因此本研究係以印刷電路板中硝酸銅廢液為原料，製備光觸媒材料-氧化銅。 甘胺酸在反應中不僅作為燃料，亦為還原劑，因此本研究將探討在不同 G/N（Glycine/Notrate）合成條件下觸媒的改變。因反應過程為離子型態進行，因此產物可趨近奈米等級；而反應過程中會產生大量氣體，因此觸媒具多孔構造，可提升其比表面積。G/N = 0.3 時，所製備出材料利用 XRD 判定其晶相為 CuO，利用 SEM 及 TEM 觀測其粒徑約為 100 nm，利用 BET 測定其比表面積為 167 m2/g。而當 G/N 升高時，因甘胺酸加入量提高，使反應溫度上升，因此使觸媒產生燒結的情況，導致觸媒粒徑變大、比表面積降低的情形發生。G/N = 0.5 時，粒徑約為 1 μm、比表面積為 131 m2/g；G/N = 0.5 時，粒徑超過 1 μm、比表面積為 92 m2/g。而甘胺酸亦為還原劑，因此 G/N 提高時，反應物傾向還原，當 G/N = 0.5 時，其成分為 CuO/Cu2O，而 Cu2O 約為 55％；當 G/N = 0.5 時，其成分為 Cu2O與 Cu，Cu約為 75％。 將本研究 GNP 在不同條件下製備出之銅氧化物應用於光催化系統中降解有機污染物 NP9EO，由空白實驗可看出，NP9EO 之降解可經由 OH• 氧化斷鏈，但僅能將其降解為副產物，仍無法有效礦化；然而本研究之觸媒具較好之吸附能力，可將污染物吸附並過濾去除，因此對於 TOC 去除效果較為理想。當使用 G/N = 0.3 之觸媒時，其觸媒最佳劑量為 0.3 g/L、H2O2 為 0.05 M，其 NP9EO 去除率為而過多的觸媒會導致觸媒間產生遮蔽效應；過量之 H2O2 則會與污染物競爭 OH•。而利用 G/N = 0.5 之觸媒時，由於 Cu2O 之光催化效果較佳，因此提升了 NP9EO 去除率，為 87.7％，但因觸媒比表面積降低，導致吸附污染物能力較差，TOC 去除率降低為 57.6％；同樣的利用 G/N = 0.7 之觸媒時，TOC 去除率降為 57.6％；然而 Cu 可提升觸媒在價帶上電子的傳導能力，因此增強光催化效果，因此 NP9EO 去除率提升為 94.6％。

關鍵字

GNP ； 氧化銅 ； 光觸媒 ； 界面活性劑 ； 有機污染物

並列摘要

A new combustion synthesis method, the glycine-nitrate process, has been used to prepare copper oxide powders. A precursor was prepared by combining glycine with metal nitrates in stoichiometric ratios in an aqueous solution. The precursor was heated to evaporate excess water, yielding a viscous liquid. Further heating to about 145°C caused the precursor liquid to self-propagating combustion. The glycine nitrate process has been successfully employed to prepare nanosized, porous copper oxide powders. Photochemical reactions catalyzed by semiconductors have been investigated extensively in the degradation of organic pollutants. Copper oxide is a photocatalyst. It can decompose the organic pollutant by irradiation under UV light. In some studies . It was demonstrated that “Cu2O/CuO” governs the capability of the heterojunction cascade and Cu does not play a significant role regardless of the heterojunction cascade efficiency. The effects of various key operating parameters and the effect of hydrogen peroxide the degradation rate of organic pollutants were studied. The SEM, TEM studies on these powders confirmed their nanosized nature and porous structure. When g/n molar is 0.3 as-prepared powders were nanosized (∼100 nm) into a spherical shape. The powders showed a very large surface area of 167 m2/g, as determined by BET surface area measurements. Then XRD pattern defines to CuO.But the particle size becomes bigger when the g/n molar increases. Because that increasing g/n molar ratio will increase flame temperature which led to particle sintering. When g/n molar is 0.5 as-prepared powders size closes 1 μm, and When g/n molar is 0.5 the catalyst size more than 1 μm. The glycine also act as reducing agent, so When g/n molar is 0.5 the catalyst includes CuO/Cu2O, and when g/n molar is 0.7 the catalyst contains Cu2O/Cu. The optimum values were 0.03 g/L of photocatalyst, 100 mg/L of NP9EO, 0.05 M of H2O2. An over 80% NP9EO and TOC removal was achieved in this catalytic oxidation.For an efficient photoactivity, low CuO concentration and sufficiently high concentration on Cu2O are requested. So when g/n molar is 0.5 of catalyst, the NP9EO removal efficiency achieved 87.7％. Cu cannot act as photosensitizer, but it can improve the photpcatalytic activity of single semiconductor by the formation of apparent ohmic junction enhancing the charges transfer kinetics.When g/n molar is 0.7 of catalyst, the NP9EO removal was achieved 94.6％. But due to the size increasing with g/n molar, so cause the particle BET decrease. When g/n molar is 0.5, the TOC removal was closed 57.6％. In same reason when g/n molar is 0.7, the TOC removal was achieved 52.8％

並列關鍵字

GNP ； Copper oxide ； photocatalyst ； NPnEO

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