電容去離子技術(capacitive deionization, CDI)為新興海水淡化技術，透過施加低電壓，使擁有儲存離子之能力，並移除施加電壓後即可進行脫附，於水再生領域已是未來發展的趨勢之一。廢污水經生物處理後之出流水，尚包含二級程序未能完全處理之有機物質，然而有機物質會堵塞奈米碳材電極裡之孔洞以導致去離子效果不佳。故本研究開發奈米鈦管(titanate nanotube, TNT)修飾活性碳電極(TNTAC electrode)，透過CDI技術降低水中離子濃度，加上奈米鈦管之電催化效果，於CDI去除離子的同時降低有機物的堵塞。研究中分別利用Ti wt.%為3、5與10 wt.%的TNTAC電極進行去離子試驗，其為5 wt.% Ti含量時，複合電極有最佳的去離子效果。此外，比較水熱溫度120、150與180°C所製備之TNTAC，以150°C製備之TNTAC電極具有最佳的處理效果。接著針對黃腐酸與NaCl混合水樣進行重覆去離子試驗，結果顯示本研究所製備之5-TNTAC-150電極，重覆使用可達9次之多，且去離子效能與吸附黃腐酸之能力皆優於活性碳電極，經X射線光電子能譜(X-ray photoelectron spectroscopy, XPS) 測定重複使用後的電極表面C1s化學態之組成變化，得知TNTAC電極不僅能在吸附黃腐酸之同時，卻不造成電極阻塞，有效降低有機物對電極結垢之問題。;Capacitive deionization (CDI) is a rising technology for water desalination. CDI is based on the electrosorption of ions onto the electrical double layer (EDL) of electrode surface which formed by applying low voltage, and the desorption is processed easily by removing voltage. There has been a dearth of research about the CDI performance when there is organic compounds in wastewater for reuse. The biologically treated still contains dissolved organic matter (DOM) which cannot be treated completely by the secondary process, and it will block the pores of carbon nano-material and make poor deionization efficiency. The titanate nanotube (TNT) modified activated carbon electrode (TNTAC electrode) has been developed in this study to reduce the adverse effect which is from organic compounds in aqueous solution. In this study, TNTAC electrodes with 5 wt.% of Ti and hydrothermal temperature of 150°C has the best deionization efficiency. The adsorption-desorption has been carried out for the mixture of fulvic acid and NaCl. The results show that the TNTAC electrode prepared in this study can be reused up to 9 times, and both the deionization efficiency and the ability of fulvic acid adsorption are superior to the activated carbon electrode. The composition of the chemical state for the surface of electrode after reuse is determined by X-ray photoelectron spectroscopy (XPS). It is found that the TNTAC electrode may decompose fulvic acid and limit the fouling of electrode at the same time, and effectively extend the working time of electrodes.
