電容去離子技術去除水中銦、鎵、鉬之基礎研究

An Investigation of Capacitive Deionization Technology on In、Ga、Mo Removal in Wastewater Treatment

郭湯杰(Tang-Chieh Kuo)

指導教授 ： 莊順興

朝陽科技大學/理工學院/環境工程與管理系/碩士(2014年)

摘要

本研究分別以自組電容去離子技術(Capacitive Deionization Technolgy, CDI)模型廠進行硬度及銦、鎵、鉬去除之研究，探討因子包括電壓、濃度等。研究結果顯示，於硬度去除特性上，在不同電壓條件下 1.0 V 及 1.2 V，隨著電壓增加，吸附能力越好，但在 1.4 V、1.6 V、1.8 V條件下 過大的電壓，造成電解反應使極板發生濃度極化現象進而發生極板結垢，導致吸附能力下降。而在不同濃度操作下，濃度越大去除率越小，濃度為100、150、200、250及300 mg CaCO3/L條件下，硬度去除率分別為 49.7%、31.8%、27.1%、24.3%、22.6%，從各濃度吸脫附循環的 EC 值發現，濃度越高電解現象越強，使得吸附量隨濃度增加更快達到飽和。
在銦、鎵及鉬之電吸附特性上，不同電壓操作下，CDI吸附能力與電壓成正比，但水體中鉬離子主要是因為 Mo7O246-佔大多數，其價數高展現出優勢之離子競爭性，其次為水合半徑較大，對於孔洞的進入效果較差，導致 OH-及 Cl-無法被有效的吸附。在不同濃度下，濃度越高離子吸附量有增加之趨勢，但去除率則反之，代表電吸附能力隨著濃度增加逐漸達到飽和。銦、鎵之離子競爭特性，在相同離子價數的比較下，水合半徑較小的離子擁有較高的吸附容量，顯示出 In3+比 Ga3+容易吸附。鉬離子則因溶液中不同pH與不同濃度形成不同離子型態，雖然NO3-初始莫爾濃度為鉬離子的6倍，但對於鉬離子競爭影響不大，鉬離子去除率均為90%以上。

關鍵字

鎵 ； 銦 ； 硬度 ； 電容去離子技術 ； 鉬 ； 離子競爭

並列摘要

This study discussed the hardness and In, Ga and Mo removal based on the self assembly capacitive deionization technology (CDI) model factory. The factors discussed in this study included voltage, concentration, etc. The results showed that the hardness removal under different voltages, under 1.0 V and 1.2 V, the adsorptive capacity increases with the voltage. However, under overvoltage of 1.4 V, 1.6 V and 1.8 V, the electrolytic reaction causes concentration polarization of plate, resulting in plate fouling, so that the adsorptive capacity declines. In the operation at different concentrations, the removal ratio decreases as the concentration increases. When the concentration is 100, 150, 200, 250 and 300 mg/L as CaCO3, the hardness removal ratio is 49.7%, 31.8%, 27.1%, 24.3% and 22.6% respectively. According to the EC value of adsorption-desorption cycle at various concentrations, when the concentration is high, the electrolysis is strong, so that the adsorbance reaches saturation earlier with the concentration.
In terms of electro-adsorption characteristic of In, Ga and Mo, in the operation under different voltages, the CDI adsorptive capacity is proportional to voltage. However, the Mo7O246- is in the majority of Mo ions in the water and the ions at high valence number show advantageous ion competitiveness. Secondly, the hydrated radius is large, the access of pore is worse, so that the OH- and Cl- cannot be adsorbed effectively. At different concentrations, the adsorbance of ions at higher concentration tends to increase, but the removal ratio is on the contrary. In other words, the electro-adsorption capacity becomes saturated gradually as the concentration increases. In terms of ion competitiveness of In and Ga, according to the comparison at the same ionic valence number, the ion in smaller hydrated radius has higher adsorption capacity, meaning In3+ is easier to be adsorbed than Ga3+. The Mo ion forms different ion partition due to different pH values and different concentrations of solution. Although, the initial molarity concentration of NO3- is six times of Mo ion, but the influence on Mo ion competition is slight, the removal ratio of Mo ion is higher than 90%.

並列關鍵字

Mo ； Ga ； In ； Hardness ； CDI ； Ion Competition

參考文獻

29.朱敬平，「產業廢水污染特性調查及自我污染削減推動計畫」，行政院環境保護署(2008a)。

44.財團法人光電科技工業協進會，「全球光電市場與台灣光電產業回顧與展望」，(2006)

50.簡廷育，「碳纖維布超高電容之應用：電容式去離子裝置及能源儲存模組」，碩士論文，國立臺灣大學工學院化學工程學系，台北(2012)。

58.王清海，「有機物質對鍶核種在蒙托土吸附行為影響之研究」，碩士論文，國立清華大學，新竹(2010) 。

59.蔡裕榮，「以溶膠凝膠法製備透明導電氧化物薄膜的探討」，碩士論文，國立中正大學，嘉義(2002) 。