A. Hernández

Pore size distributions in microporous membranes. A critical analysis of the bubble point extended method

Abstract An extended bubble point method has been used to examine the porous morphology of several track-etched microporous polycarbonate membranes with nominal pore sizes ranging from 0.1 to 5.0 μm. The technique has been carefully analyzed and corrected to take into account the diverse non-ideal factors in flow along with the prevalence of Knudsen flow over the Hagen-Poiseuille one in the smaller pores. The pore size distributions were obtained in terms of flow or pore numbers. Bulk porosity and pore densities were in good agreement with nominal and SEM values for each filter. Performancewise, measured water permeabilities agreed well with those obtained from pore density distributions, assuming Knudsen air flow through the narrowest pores.

Contact angles and external protein adsorption onto UF membranes

Abstract Both receding and advancing contact angles of pure water and BSA solutions against the active layers of several retentive ultrafiltration membranes are studied here. In particular, three membranes from desalination systems, whose active layers are made of aromatic polyamides: G5, G20 and G50 have been chosen. It has been shown that these membranes are hydrophilic with equal advancing contact angles against pure water while the receding ones decrease with increasing pore radii. Finally, both the contact angles against the BSA solutions are studied at different pH and concentrations. It is shown that the stationary advancing contact angles correspond to the early adsorption steps while receding ones correspond to the final adsorption level. When analyzed within this frame, the results obtained can easily be explained in terms of the qualitatively known molecule–molecule and molecule–membrane surface interactions.

Reduction of Pb(II) in water to safe levels by a small tubular membrane nanofiltration plant

Abstract Dilute Pb(II) aqueous solutions were nanofiltered through a tubular membrane with good rejections. Retention was modeled using the Modified Spiegler–Kedem theory. The true retention, evaluated from concentration-polarization measurements, was similar to the observed value. The three characteristic parameters of the model: reflection coefficient

Three independent ways to obtain information on pore size distributions of nanofiltration membranes

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Characterisation of nanofiltration membranes: Structural analysis by the DSP model and microscopical techiques

σ, solute permeability

Ceramic membranes from Moroccan natural clay and phosphate for industrial water treatment.

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