結合化學還原法及薄膜過濾程序處理含重金屬銅廢水之研究

Combining chemical reduction and membrane filtration for copper-containing wastewater treatment

陳建圳(Chien-Tsun Chen)

指導教授 ： 李奇旺

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2017年)

https://doi.org/10.6846/TKU.2017.00251

摘要

重金屬廢水由於存在如EDTA的螯合反應變得更加復雜化，這些配體在表面處理或印刷電路板行業的水中普遍存在;通過常見的化學沉澱法產生金屬氫氧化物沉澱去除重金屬已不再是可行的。在本研究中，採常用於生產金屬納米粒子的化學還原法來去除和回收銅離子，產生的金屬納米粒子可以做為載體提高還原的效果及速率。在本研究中，將化學還原法和薄膜過濾程序結合在一起處理含銅和配體的電子廢水，並將其稱為“還原結晶”。中空纖維膜浸沒安裝於封閉反應器中，以隔絕減少空氣中的氧氣對還原過程的影響。 pH和ORP為實驗中的主要對照參數。在這項研究中，研究了pH、ORP，對銅去除效率、銅顆粒大小和薄膜阻塞的影響。
結果顯示，在pH值為5〜8，ORP為-400mV和-500mV的條件下，銅的還原/去除率為87-92％。使用連續性Cu（II）還原系統還原含銅和鎳的廢水；可達近90％的銅去除效率，然而鎳去除率僅只有15％。連續還原系統中薄膜於3天操作後TMP迅速增加。可以發現金屬光澤顆粒懸浮在薄膜槽中及中空纖維膜被一層金屬塗層覆蓋。加入銅金屬顆粒做為結晶種子可以提高了還原/回收速率同時減少薄膜阻塞的影響。TMP保持穩定直到實驗結束。從系統收集的固體樣品中可以鑑定出金屬銅和氧化亞銅(Cu2O)。模擬廢水中同時含有重金屬銅及鎳時，可實現幾乎93％的銅去除效率，符合要求台灣EPA對銅的排放標準。但在鎳的去除上僅達到15％的去除效率，未來需進一步處理。

關鍵字

化學還原法 ； 薄膜過濾程序 ； 銅 ； 螯合劑

並列摘要

Treatment of the metal-containing wastewater is complicated by the presence of ligands, such as EDTA, which are ubiquitous in metal-containing wastewaters from surface finishing or printed circuit board industries; the common practice to remove metal through metal hydroxide precipitation is no longer a viable option. Chemical reduction, which has commonly used for the production of metal nanoparticles, was employed to remove and recover copper ions in this study.
In the current study, chemical reduction and membrane filtration are combined to treat electronic wastewater containing copper and ligands, and the process is dubbed as reduction "crystallization process". A closed reactor with submerged type membrane installed was designed to minimize the effect of oxygen from air on the reduction process. Both pH and ORP are used as the control parameters for the treatment process. In this study, effects of pH, hydraulic retention time, solid retention time on copper removal efficiency, the size of copper particles, and membrane fouling were studied. The result shows that 87-92% of copper reduction/ removal was achieved at pH of 5 to 8 and ORP of -400 mV and -500 mV, respectively. The synthetic wastewater containing both copper and nickel ions was treated using the continuous Cu(II) reduction system. Almost 90% of copper removal efficiency is achieved by the system, while it is merely 15% for nickel removal efficiency. In membrane integrated continuous Cu(II) reduction system, the TMP increased rapidly after a 3-day operation. Visually, hollow fiber membranes were covered by a layer of coating and shiny metallic particles suspending in membrane tank can be spotted. Injecting Cu seed particles enhanced the reduction rate of Cu, and the coating of membrane surface can be reduced. TMP remained low and stable until the end of operation. Metallic copper and cuprous oxide (Cu2O) were identified in the solid samples collected from systems. Re-oxidation of metallic copper particles by atmospheric oxygen during sample handling or incomplete reduction of Cu(II) ions during reduction process might also result in the formation of cupric or cuprous oxides.

並列關鍵字

Chemical reduction ； membrane filtration ； copper ； ligands

參考文獻

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