کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
638472 | 1456166 | 2007 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effects of molecular shape on osmotic reflection coefficients
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
تصفیه و جداسازی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
The effects of molecular shape on the osmotic reflection coefficient (Ï0) for rigid macromolecules in porous membranes were analyzed using a hydrodynamic model. In this type of model, employed first by Anderson and Malone [1], steric exclusion of the solute from the periphery of the pore induces a concentration-dependent drop in pressure near the pore wall, which in turn causes the osmotic flow. Results were obtained for prolate spheroids (axial ratio, γ > 1) and oblate spheroids (γ < 1) in cylindrical and slit pores. Two methods, one of which is novel, were used to compute the transverse pressure variation. Although conceptually different, they yielded very similar results; the merits of each are discussed. For a given value of a/R, where a is the prolate minor semi-axis or oblate major semi-axis and R is the pore radius, Ï0 increased monotonically with increasing γ. When expressed as a function of aSE/R, where aSE is the Stokes-Einstein radius, the effects of molecular shape were less pronounced, but still significant. The trends for slits were qualitatively similar to those for cylindrical pores. When Ï0 was plotted as a function of the equilibrium partition coefficient, the results for all axial ratios fell on a single curve for a given pore shape, although the curve for cylindrical pores differed from that for slits. For spheres (γ = 1) in either pore shape, Ï0 was found to be only slightly smaller than the reflection coefficient for filtration (Ïf). That suggests that Ï0 can be used to estimate Ïf for spheroids, where results are currently lacking.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Membrane Science - Volume 306, Issues 1â2, 1 December 2007, Pages 116-124
Journal: Journal of Membrane Science - Volume 306, Issues 1â2, 1 December 2007, Pages 116-124
نویسندگان
Gaurav Bhalla, William M. Deen,