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題 名 | Adsorption Kinetics of C[feba]E[feb8]at the Air-Water Interface=非離子型界劑C[feba]E[feb8]之吸附動力學研究 |
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作 者 | 林析右; 李雅琪; 邵明建; | 書刊名 | Journal of the Chinese Institute of Chemical Engineers |
卷 期 | 33:6 2002.11[民91.11] |
頁 次 | 頁631-643 |
分類號 | 460.025 |
關鍵詞 | 非離子型界劑; 吸附動力學; Adsorption kinetics; Diffusion; Ninionic surfactant; Surface equation of state; Surface tension; |
語 文 | 英文(English) |
中文摘要 | 本研究以懸垂液低影像數位化測量儀量測兩組動態界面張力變化,以探討聚氧乙烯系非離子型界面活性劑□□的吸附動力學,其一為吸附程序:界劑分子吸附至乾淨界面的張力變化;其二為脫附程序:界劑分子由過度擁擠的界面脫附至溶液本體的張力變化。本研究以兩組平衡數據(分別為平衡張力與溶液濃度之關係γ(C)與平衡張力與界面濃度的關係γ(□))決定吸附等溫模式與參數。Frumkin模式能合理描述□□的平衡張力數據,並且顯示□□屬於anti-cooperative吸附行為。研究結果顯示□□分子的質傳控制機制,就吸附程序而言,為由低濃度的擴散控制轉移到高濃度的混合控制:就脫附程序而言,在本研究之實驗濃度範圍內為混合控制。經由動態張力的模擬,可得到□□的擴散係數與吸、脫附速率常數。最後,亦探討球狀效應對研究界面活性劑動態吸附行為的影響。 |
英文摘要 | A video-enhanced pendant bubble tensiometer was employed for the study of the adsorption kinetics of nonionic surfactant □□. Two dynamic processes in a quiescent surfactant solution were monitored by measuring the relaxation profiles of surface tension: the adsorption onto a clean air-water interface and the desorption out of an overcrowded interface due to sudden shrinkage of pendent bubble. In addition, two equilibrium data, equilibrium surface tension γ(C) and surface equation for state γ(□), were measured and used for the determination of adsorption isotherm and model parameters. The adsorption of □□ was found to be anti-cooperative from the comparison between equilibrium data and the Frumkin isotherm. The controlling mechanism of the adsorption process changes as a function of bulk isotherm. The controlling mechanism of the adsorption process changes as a function of bulk concentration, indicating a shift of mechanism from diffusion-control at dilute concentrations to mixed diffusive-kinetic control at more elevated bulk concentrations. The desorption process for □□ out of an overcrowded interface was also confirmed to be mixed-controlled. Comparison was made for the entire relaxation period of surface tension data and model predictions. Values of the diffusivity and the adsorption/desorption rate constants of □□ were evaluated from these dynamic γ(t) profiles. At the end, the spherical effect on studying surfactant adsorption kinetics was discussed. |
本系統中英文摘要資訊取自各篇刊載內容。