EPA-098-U1U4-04-002

098

1,408 千元

2009/04/02

2010/01/30

謝子陽

永續發展室(停用)

林燕柔

中國科技大學

水質保護

混合矩陣，幾丁聚醣，銅離子

Mixed matrix, chitosan, copper ions

王大銘

謝學真

謝子陽

02-29313416#2503

tyhsien@cute.edu.tw

本研究為結合對重金屬離子具有離子交換能力之離子交換樹脂(Amberjet 1200H, Styrene divinylbenzene copolymer, Rohm & Haas, ID: 0.78 mm)以及中分子量之幾丁聚醣粉末，以製備出多孔隙度幾丁聚醣混合矩陣式立體結構的吸附基材，並探討其對廢水中銅離子之移除能力。經由氮氣吸附法量測出混合矩陣基材具有良好的比表面積(78 m2/g)，另外經由電子顯微鏡照片清楚觀測出離子交換樹脂可均勻分布於幾丁聚醣立體結構中，有利於銅離子質傳進入基材內部，並與幾丁聚醣官能基發生螯合作用，以及與離子交換樹脂進行離子交換反應。經由循環式吸附管柱試驗發現，在吸附過程中銅離子溶液之酸鹼值最終達到6.0，表示在吸附過程中銅離子與水溶液中的氫離子同時對吸附官能基(幾丁聚醣的氨基以及離子交換樹脂的磺酸基)產生競合現象，造成銅離子溶液的酸鹼值上升。另外經由量測銅離子平衡濃度以及混合矩陣式基材於不同銅離子初始濃度下的銅離子平衡吸附量，可得到兩階段式的等溫吸附曲線，表示銅離子吸附於混合矩陣式基材的過程是屬於多層吸附方式，在低濃度銅離子初始濃度下，銅離子可能會阻塞於多孔隙結構之孔徑之中形成第一階段的平衡吸附曲線，而在高濃度銅離子初始濃度時，會形成較高的質傳趨勢，銅離子也更有機會深入高孔隙度幾丁聚醣基材的內部，形成第二階段的平衡吸附曲線。另外在批次搖瓶試驗中使用PVA交聯幾丁聚醣混合矩陣式基材進行銅離子吸附試驗，可得到單層吸附的吸附曲線，可使用Langmuir吸附模式進行模擬；而在低銅離子初始濃度進行PVA交聯幾丁聚醣混合矩陣式基材的吸附及脫附程序，結果顯示銅離子脫附率高達97.9%，隨著銅離子初始濃度提高，其脫附率下降。

混合矩陣，幾丁聚醣，銅離子

98環保署計畫期末報告定稿本.pdf

5MB

2010/5/1 上午 12:00:00

Mixed matrix scaffolds were synthesized by uniformly distribution of ion exchange resins (H+ form Amberjet, ID 780 µm) into the stereo-structural chitosan matrix prepared by chitosan powder with middle molecular weight and then applied for the removal of copper ions from waste water. Specifically, ion exchange resin particles suspending in a 1 wt% of viscous chitosan solution were filled with cylindrical aluminum containers to prepare chitosan mixed matrix scaffolds through the freeze-gelation process. The internal surface area of mixed matrix scaffolds is 78 m2/g by the measurement of N2 adsorption/desorption processes. The uniform distribution of ion exchange resins embedded in the stereo structure of chitosan matrices can clearly be seen in the scanning electron micrograph which will facilitate the adsorption of chitosan as well as ion exchange resins. The adsorption processes were performed by adsorption copper ions of waste water onto the amine functional groups (-NH2) exposed to the external and porous stereo-structural surfaces of chitosan matrix as well as the sulfonate functional groups at the outer surface of ion exchange resins respectively. Results of continuous well-mixed adsorption experiments showed that both copper ions and hydronium ions compete for available adsorption sites on the ion exchanger particles as well as chitosan by adsorption mechanism. Adsorption isotherms at 25 ℃ and pH 6.0 over the concentration ranging from 50 to 1500 mg Cu2+/L performed distinct stepped shape. As copper ions penetrate the porous structure of mixed matrix scaffolds and adsorb on the exposed amines of chitosan and sulfonic sites of ion exchange resins near the outer surface, the formation of adsorbed copper clusters may constrict pores. These effects would be more pronounced when the behavior of adsorption isotherms was observed at its first step. The maximum adsorption capacity for mixed matrix scaffolds were 190 mg Cu2+/g-adsorbents at the initial copper ion concentration of 1500 mg Cu2+/L. The stepped shape of the isotherm revealed that a pore-blockage mechanism may occur along the adsorption processes. Results of well-mixed batch adsorption experiments of PVA-chitosan mixed matrix scaffolds revealed that adsorption isotherms at 25 ℃ and pH 6.0 over the concentration range 200 ~ 3000 mg Cu2+/L could be simulated by a Langmuir adsorption model. The desorption ratio of copper ions of PVA-chitosan mixed matrix scaffolds was 97.9% at low initial copper ion concentrations. As desorption ratio decreased, the initial copper ion concentrations increased.

Mixed matrix, chitosan, copper ions