應用零價鐵結合過氧化氫程序(ZVI/Fenton、ZVI/H2O2)降解壬基苯酚聚乙氧基醇之研究

Nonylphenol Polyethoxylate Degradation by Fenton Oxidation with Zero Valent Iron

李明憲(Ming-Hsien Li)

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(2009年)

摘要

壬基苯酚聚乙氧基醇(NPnEO)廣泛應用於各種工業製程當中，導致出流水COD值上升無法符合放流水標準，實場以生物處理作為出流水主要處理程序，對於高分子有機物的NPnEO不僅操作時間過長，且效率不彰。以零價鐵結合過氧化氫程序處理NPnEO廢水不僅可解決傳統方法的問題，並可將生物難分解的高分子有機物分解成較易分解的小分子，提高NPnEO廢水的生物可分解性。
本研究系統根據過氧化氫加藥位置分為ZVI/Fenton及ZVI/H2O2兩部份，首先ZVI/Fenton在固定NP9EO濃度(200 mg/L)及H2O2/Fe2+比值1.7條件下，控制不同亞鐵(2.2、5.1、7.6、10.4、16.6 mM)、pH值(2、3、4)及氧化時間(5、10分鐘)下進行探討；ZVI/H2O2同樣固定NP9EO濃度(200 mg/L)條件下，探討不同pH值(1.5、2、3、4)、H2O2劑量(11.8、23.5、35.3及47.1 mM)及水力停留時間(0.75、1.5、3分鐘)等實驗參數之影響，並探討其反應動力學、TOC去除效率及生物可分解性。
根據實驗結果顯示以ZVI/Fenton處理200 mg/L NP9EO，在H2O2/Fe2+=1.7、亞鐵量5.1 mM，氧化pH 3，氧化時間5分鐘條件下，可去除60%之TOC，反應速率常數0.30 min-1，反應後BOD5/COD比值提升至0.37。TOC去除效率及反應常數，隨著系統pH值、初始亞鐵量改變而有所增減。而ZVI/H2O2系統，受到同存於反應槽內的零價鐵影響，TOC去除效率明顯下降。ZVI/H2O2在水力停留時間3分鐘，H2O2 加藥量23.5 mM，pH 4條件下，可去除50 %之TOC，反應速率常數0.33 min-1，反應後出流水BOD5/COD比值提升至0.29。TOC去除效率及反應速率常數會隨著系統中pH值、水力停留時間、過氧化氫劑量改變而變化。經ZVI/Fenton及ZVI/H2O2處理後，NP9EO廢水之生物可分解性，可有效提升至中度至生物易分解的範圍。
在最適操作條件下，ZVI/Fenton不僅TOC去除效率較ZVI/H2O2高出6 %，BOD5/COD比值為0.37也高於ZVI/H2O2之0.29，除此之外ZVI/Fenton使用的過氧化氫劑量只有ZVI/H2O2的1/3左右。ZVI/H2O2系統出流水仍含有大量的亞鐵造成去除效率下降的主要原因。

關鍵字

NPnEO ； Fenton ； 零價鐵 ； 流體化床 ； H2O2 ； 兩段式

並列摘要

This research was investigated for the degradation of nonylphenol ethoxylates in aqueous solution by integrated techniques that hydrogen peroxide combined zero valent iron process, and observed the biodegradability(BOD5/COD). Integrated techniques were included ZVI/Fenton and ZVI/H2O2. Therefore, this research would discuss the difference between ZVI/Fenton and ZVI/H2O2.
NP9EO was degraded completely by both systems. In the ZVI/Fenton system, the greatest TOC removal of NP9EO was 60 % and the biodegradability was 0.37 under optimal condition (NP9EO 200 mg/L, pH 3, H2O2/Fe2+ ratio 1.7, Fe2+ 5.1 mM). The TOC removal efficiency increased with ferrous iron concentration, but the TOC removal efficiency was reduced when ferrous iron concentration was in excess of 5.1 mM. In the ZVI/H2O2 system, the TOC removal of NP9EO was 54 % and the biodegradability was 0.29 under optimal condition (NP9EO 200 mg/L, pH 4, HRT 1.5 min, H2O2 dosage 23.5 mM). The TOC removal efficiency was also reduced with ferrous iron concentration increased. TOC removal was increased with oxidant dosage, but the TOC removal efficiency was reduced when oxidant dosage was in excess of 23.5 mM.
Obviously, ZVI/Fenton system was more efficient than ZVI/H2O2 in TOC removal of NP9EO and biodegradation of effluent. The difference in TOC removal of NP9EO and the biodegradability between ZVI//Fenton and ZVI/H2O2 was 6 % and 0.08, respectively. ZVI/H2O2 system had to use more oxidant dosage and more ferrous iron in effluent than ZVI/Fenton system.

並列關鍵字

NPnEO ； Fenton ； Zero valet iron ； Fluidized bed ； H2O2 ； Two-stage

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