| 摘要: | 薄膜液晶螢幕 (Thin Film Transistor Liquid Crystal Display, TFT-LCD) 的開發製造於台灣已是一個重要的產業，以台灣目前的總產值已經位居世界第一，成為全球主要供應國，預計總產值可達1.3兆元，相對地有機廢水量也相當可觀。TFT製程有機廢水殘留了許多未反應完之藥劑、溶劑等，如未妥善處理將造成放流水體優養化污染及許多環境問題。
流體化床芬頓法 (Fluidized-bed Fenton process, FBF) ，此程序進行Fenton反應時，不僅可以將有機污染物降解，於反應時所產生的鐵氧化物會在觸媒擔體上結晶，而且觸媒擔體上所形成之鐵氧化物也具異相催化效果，以減少亞鐵離子添加量，並減少化學汙泥處理及處置成本。而流體化床結晶程序 (Fluidized-bed crystallization process, FBC) 是新一代的處理技術，對於一些無法氧化的無機物，利用結晶方式達到去除以及回收的效果，避免使用傳統的混凝產生汙泥或是生物處理的缺陷，最終達到資源化以及去除的目標。
本研究亦以Box-Behnken之實驗設計法針對影響研究中的各個因子進行規劃，其目的在於以較少的實驗組合進而的到合理、準確的分析結果，並採用統計學上之變異數分析方法說明實驗因子對響應值之影響及因子間之交互作用關係，找出最佳化實驗參數的可能方向，然後應用反應曲面法來評估其主因子、水準範圍內所呈現的去除效率特性，求出降解污染物可能的最佳參數。
在磷酸鹽去除方面，由結果得知，在條件Phosphorus = 10mM、pH = 7、P/Fe2+ = 1.3、HRT = 120 min 的時候，總磷去除效果可以達到58.3% 結晶效率亦有41.6%，此時可得到實驗設計法中最高的去除效率。其次在乙醇胺去除方面，在條件MEA = 5mM、pH = 3、Fe2+ = 3、H2O2 = 50mM 的時候，乙醇胺最高降解效果可達到98.9%。在結合應用系統中，總磷去除效率45.13% 結晶效率可達到30.5%，在第二部份氧化試驗時乙醇胺去除率可達到76.15%。
對於礦化作用，乙醇胺總有機碳(TOC)去除效率且結果中顯示乙醇胺甚至可以從水樣中完全去除，不過TOC還是很高，是由於中間產物很可能在反應中發生，應用離子層析儀(IC)鑑定中間產物發現流體化床反應中，有形成醋酸及其他酸類。
The mass production value of thin film transistor liquid crystal display (TFT-LCD) in Taiwan, which is second in the world next to Korea, will reach one trillion NT dollars yearly in the near future. However, the resulting wastewater will also increase to approximately 200,000 m3/day. The main component of this wastewater is ethanolamine(MEA) and phosphorus(P).
Advanced oxidation processes (AOPs) are efficient methods for degrading toxic chemicals. One of these processes, the Fluidized-bed crystallization and Fenton process, was used for the treatment of the TFT-LCD wastewater to remove the monoethanolamine and phosphorus.
In the design of experiment, the Box-Behnken design was used to optimize the operating conditions. The selected factors were initial pH, P/Fe2+ and HRT with the phosphorus removal as the response function. As a result of the degradation of this wastewater by Fluidized-bed crystallization process. The selected factors were initial Fe+2 concentration, H2O2 concentration and pH with the MEA removal as the response function. As a result of the degradation of this wastewater by Fluidized-bed Fenton process.
In Fluidized-bed crystallization process removal efficiency of 58.3% for 10mM phosphorus was achieved after 2 hours under optimal conditions of pH = 7, [P/Fe2+] = 1.3 and [HRT] = 120min; A removal efficiency of 98.9% for 5mM MEA was achieved after 2 hours under optimal conditions of pH = 3, [Fe2+] = 5mM and [H2O2] = 50mM on Fluidized-bed Fenton process. Then used Fluidized-bed crystallization Fenton processes in TFT-LCD Synthetic wastewater treatment, the total removal and Crystal efficiency were 45.13% and 30.5%, respectively, the MEA removal efficiency can still reach 76.15%.
For the mineralization, MEA and TOC removal efficiencies were examined and the results show that even MEA could completely remove from the solution, however, TOC was still very high. This is probably due to the intermediates that might occur in the reaction. IC was used to identify intermediates in the reaction and the results reveal that during Fluidized-bed Fenton process, there are formation of Acetic acid. |
