檸檬酸在三正辛胺支撐式液膜中之傳送機構

Kinetics of citric acid transport through supported liquid membranes containing Tri-n-octylamine as mobile carriers

陳利君(L.J. Chen)

指導教授 ： 莊瑞鑫

元智大學/工程學院/化學工程與材料科學學系/碩士(1994年)

摘要

本文的目的在於探討檸檬酸（H3A）在三正辛胺(TOA)支撐式液膜中的傳送
，所使用的薄膜是多孔性的聚二氟乙烯膜（PVDF），薄膜溶液是以三正辛
基胺為萃取劑，二甲苯為溶劑，反萃取溶液分別為去離子水或碳酸鈉。本
研究分為二部份討論：一是探討檸檬酸的傳送機構，一是利用 TOA-salt
萃取檸檬酸的效應。為描述檸檬酸在支撐式液膜中的理論質傳現象，本文
應用液-液萃取所得的動力參數及質傳係數（支撐液膜系統所用之裝置與
液液萃取相同），以建立理論傳送模式，其包括檸檬酸的水相擴散，薄膜
擴散及界面化學反應等速率方程式，並比較理論值與實驗值的差異。而水
相擴散、薄膜擴散及界面化學反應的阻力亦合併討論之，以求出本傳送過
程的速率控制步驟；同時探討進料濃度、溫度及TOA 初濃度對傳送的影響
。 此外，對二（2-乙基己基）磷酸（D2EHPA）與 TOA 的混合萃取劑的效
應亦加以討論之。另一方面，應用不同的 TOA-salt ，如 TOA-H3A，TOA-
H2SO4，TOA-HNO3 及 TOA-HCl 萃取檸檬酸，可得到其萃取效果：HNO3>H3
A>H2SO4>HCl（無論以碳酸鈉或去離子水為反萃取液）。另一方面，亦測
試 TOA-salt 所負載酸的程度及 TOA 初濃度等對傳送效果的影響。

關鍵字

支撐式液膜 ； 檸檬酸 ； 傳送機構

並列摘要

he transport of citric acid through a supported liquid embrane
( SLM ) was investigated in this paper.ri-n-octylamine was in
xylene used as mobile carriers thatas adsorbed in a microporous
poly-vinyl difluoride ( PVDF )upport. The strip solution was
either deionized H2O or Na2CO3.he subjects studied in this
paper included （1） the kineticsnd mechaanism of citric aicd
transport through SLMs and （2）he effects of TOA-salt on this
SLM transport.Based On thexperimental data obtained from liquid-
liquid extractionkinetic and equilibria parameters ) and
hydrodynamics of thepparatus (mass transfer coefficients), a
transport modelncluding film diffusion in the aqueous phase,
the membraneiffusion, and the interfacial chemical reaction was
proposedo describe the transport rates. The experiments were
performedn a stirred membrane-based cell. The validity of the
transportodel was compared with the experimental results of
SLM. Also,he rate-controlling steps were estimated from the
resistancesf aqueous diffusion, membrane diffusion, and
interfacialhemical reactions. In addition, the effects of
temperature,nitial TOA concentration, citric feed concentration
on SLM fluxere studied. The effect of a mixture of di(2-
ethylhexyl)hosphoric acid and TOA on transport was also
discussed.our types of TOA-salts extractant such as TOA-H3A,
TOA-H2SO4,OA-HNO3 and TOA-HCl were used as mobile carriers to
transportitric acid of SLM. It was observed that the
transportfficiency decreased in the following orders：H3A>HNO3>
H2SO4>HClwith the strip phase of Na2CO3 or with H2O）.

並列關鍵字

Crtirc acid ； Supported liquid membrane ； Kinetic ； TOA ； TOA-salt