連續流NTFC 光催化反應器再生回收之研究

Abstract

奈米級零價鐵及二氧化鈦為近年來被廣泛研究與應用於還原及氧化 有機污染物。本研究室目前已發展出以新穎的方式合成奈米級二氧化鈦/ 零價鐵複合材料(nanoscale TiO2/Fe0 composite, NTFC)，先前之研究顯示 NTFC 在批次式實驗中找到當pH 3 時，能有效脫色及去除有機碳來降解 偶氮染料及硝酸鹽等污染物，且改善二氧化鈦及零價鐵於應用上之限制。 本研究將進一步建立連續流NTFC 光催化再生回收之系統，以偶氮染料為 目標污染物，進行效能測試及找出最適化條件，將連續流NTFC 光催化再 生回收之系統利用pH-可程式控制器(pH-Programmable Logic Controller, pH-PLC)反饋系統進行全自動化。效能測試先以連續流試驗調整不同觸媒 劑量、水力停留時間、染料濃度、攪拌速率及不同再生藥劑添加為操作參 數；最後則以最適操作條件及再生點時的pH 值為依據進行全自動化，實 驗結束則以強力磁鐵進行觸媒顆粒的收集，進行再生試驗。反應同時進行 溶液監測、分析污染物之降解。結果顯示，NTFC 在不同的操作條件下均 能有效脫色及去除有機碳，並找出再生點pH 5；在全自動pH-PLC 反饋系 統中，使用鹽酸來調整pH 值並進行奈米顆粒再生及光催化反應。本研究 證實此反應系統能使用NTFC 顆粒於酸性條件下有效處理高色度廢水，並 能利用過氧化氫和鹽酸有效進行奈米顆粒之再生，而回收使用的NTFC 依 然可以有效脫色及去除有機碳。

Nano-zero-valent iron (nZVI) and titanium dioxide (TiO2) are commonly applied to degrade the organic pollutants in the wastewater. In our laboratory, a novel TiO2/Fe0 composite (NTFC) material has been prepared and its effective decompositions of azo-dye and nitrates have been demonstrated in batch tests. The aim of this study was to explore the feasibility of a continuous flow catalytic reactor on pollutants, focusing on the regeneration and recycling of the NTFC. The study was comprised of two parts: the optimization of the continuous flow system operation for azo-dye degradation and the evaluation of the automatic pH-programmable logic controller (pH-PLC) feedback system. The operation parameters include the dosage of NTFC, hydraulic retention time, concentration of pollutant, and the stirring rate, as well as the regeneration point of pH for automatic pH-PLC feedback system. After the completion of each continuous flow cycle, the remaining composite catalyst was collected using the magnet. The decolorization and TOC removal by the continuous system under acidic condition were satisfactory. The automatic pH-PLC feedback system by using HCl also proved that the catalyst can be regenerated, and the recycled NTFC can be reused in the continuous flow reactor for pollutants degradation.