Diffusive Flux and Magnetic Manipulation of Nanoparticles through Porous Membranes

Citations Over TimeTop 18% of 2010 papers

Abstract

Measurement of transport of nanometer scale particles through porous media is important to begin to understand the potential environmental impacts of nanomaterials. Using a diffusion cell with two compartments separated by either a porous alumina or polycarbonate membrane as a model system, diffusive flux through mesoporous materials is examined. Experiments are performed as a function of particle size, pore diameter, and solvent, and the particle fluxes are monitored by the change in absorbance of the solution in the receiving cell. Using the measured extinction coefficient and change in absorbance of the solution as a function of time, the fluxes of 3, 8, and 14 nm diameter CoFe(2)O(4) particles are determined as they are translocated across pores with diameters 30, 50, 100, and 200 nm in hexane and aqueous solutions. In general, flux decreases with increasing particle size and increases with pore diameter. We find that fluxes are faster in aqueous solutions than in hexane, which is attributed to the hydrophilic nature of the porous membranes and differences in wettability. The impact of an applied magnetic flux gradient, which induces magnetization and motion, on permeation is also examined. For larger membrane pore diameters, applied magnetic fluxes increase the rate of transport of 14 nm CoFe(2)O(4) particles more than that of 3 or 8 nm diameter particles, reflecting their differences in susceptibility. However, larger particles are excluded from membranes with small diameter pores, consistent with magnetic interparticle attractions that reversibly induce magnetic aggregation.

Related Papers

• → A study of gas transport through interfacially formed poly(N,N-dimethylaminoethyl methacrylate) membranes(2009)26 cited
• → Gas permeation of porous organic/inorganic hybrid membranes(1995)41 cited
• → Permeation properties and microstructure of porous inorganic membranes.(2001)10 cited
• [Drug permeation through synthetic lipid membranes. Part 10: The effects of diffusion layers on the permeation process (author's transl)].(1980)
• Determination of the structure parameter of the hydrophobic porous membrane used for membrane absorption(2005)