前驅滲透膜進行碘化鉀廢液的濃縮研究

Concentration of potassium iodide solution from TFT-LCD process by forward osmosis process

翁煜庭(Yu-Ting Weng)

指導教授 ： 陳孝行

國立臺北科技大學/工程學院/環境規劃與管理研究所/碩士(2014年)

摘要

前驅滲透程序（Forward osmosis, FO）是一種利用溶液滲透壓差驅動的薄膜技術，有著無需外加壓力的優點，為一種新興薄膜處理技術。本研究使用 TFT-LCD 廠偏光板製程中所產生之高濃度氫氧化鉀廢液做為驅動溶液，結合 FO 程序，濃縮同樣由偏光板製程中所產生的另一股廢水-碘化鉀廢液，目標將碘化鉀廢液由初始的0.6 %提濃至6%，以回收再利用，同時探討 FO 程序對硼酸及碘離子之去除效率，藉此了解其對後段回收處理之影響。
為提升濃縮效率，實驗以 PRO mode 進行實驗，使用氫氧化鉀及氯化鈉做為驅動液，進行碘化鉀廢液濃縮之研究。實驗結果顯示，以 pH 值 11.5 之氫氧化鉀溶液做為驅動液時，初始水通量可達 11.69 LMH，濃縮後碘化鉀溶液之濃度由原本的 0.6% 提濃至 6.95%，以 100 g/L 氯化鈉做為驅動液時，碘化鉀溶液可濃縮至 5.58%。而 TFC 膜之濃縮效率較 CTA 膜佳，可達 4.20%。在硼酸及碘離子去除率方面，以高 pH 值氫氧化鉀溶液做為驅動液時具有較高之去除率，硼酸去除率可達 43%，碘離子去除率可達 97.0%。硼酸之去除率以 TFC 膜的 8.56% 為較高，對碘離子去除率則以 CTA 膜的 87% 較佳。由實驗結果初步評估，在不包含建設面積、管線、膜沖洗及人事管理所需費用下，FO 程序與現行使用濃縮程序相比，能有效降低操作成本。

關鍵字

前趨滲透 ； 氫氧化鉀 ； 碘化鉀 ； 驅動液 ； 濃縮

並列摘要

Forward osmosis（FO）is a process of water driven by the osmotic pressure difference across the semipermeable membrane without the aid of external energy. In this study, the high concentration of potassium hydroxide and low concentration of potassium iodide solution from Thin film transistor liquid crystal display （TFT-LCD） wastewaster were utilized as draw and feed solution in FO process, respectively. The potassium iodide solution was intended to concentrate ten times to be reused in TFT-LCD process. Meanwhile, the simultaneous rejection of boric acid and iodide was considered as interference of subsequent treatment processes.
In this work, pressure-retarded osmosis（PRO）mode was used to obtain higher concentration efficiency. Potassium hydroxide and sodium chloride were used as draw solution in FO process to concentrate potassium iodide. The results show that the highest water flux was achieved of 11.69 LMH when using potassium hydroxide draw solution at pH 11.5 and potassium iodide concentration was concentrated to reach to 6.95% from the initial concentration of 0.6%. Meanwhile, 100 g/L sodium chloride using as draw solution achieved water flux of 9.02 LMH and potassium iodide concentration was concentrated to reach to 5.58% from the initial concentration of 0.6%. Moreover, Thin-film composite（TFC）membrane was recorded higher efficiency of concentrated potassium iodide 4.2% as compared to cellulose triacetate（CTA）membrane 3.22%. Furthermore, the highest rejection of boric acid（43.0%）and iodide （97.0%.）was achieved when using potassium hydroxide draw solution at high pH .The rejection of boric acid for TFC membrane achieved 8.56% higher than that of 3.4% in CTA membrane but the rejection of iodide for CTA membrane achieved 87.0% higher than that of 83.5% in TFC membrane..The overall performance demonstrates that FO processes are promising technology to concentrate potassium iodide with extremely low cost compared to other methods（i.e., RO, membrane distillation, ion exchange）.

並列關鍵字

Forward osmosis ； Potassium hydroxide ； Potassium iodide ； Concentration

參考文獻

[64] 王清海，有機物質對鍶核種在蒙托土吸附行為影響之研究，博士論文，國立清華大學，新竹，2010。

[3] S. Loeb, "Energy production at the Dead Sea by pressure-retarded osmosis: challenge or chimera?", Desalination, vol. 120, 1998, pp. 247-262.

[4] T.S. Chung, X. Li, R.C. Ong, Q. Ge, H. Wang, and G. Han, "Emerging forward osmosis (FO) technologies and challenges ahead for clean water and clean energy applications", Current Opinion in Chemical Engineering, vol. 1, 2012, pp. 246-257.

[5] H. Bai, Z. Liu, and D.D. Sun, "Highly water soluble and recovered dextran coated Fe3O4 magnetic nanoparticles for brackish water desalination", Separation and Purification Technology, vol. 81, 2011, pp. 392-399.

[6] T.Y. Cath, A.E. Childress, and M. Elimelech, "Forward osmosis: Principles, applications, and recent developments", Journal of Membrane Science, vol. 281, 2006, pp. 70-87.