E. V. Kruchinina

Deep desalination of water by evaporation through polymeric membranes

Transport properties and structural features of a number of already known and new types of polymeric membranes in desalination of aqueous salt solutions by membrane distillation and pervaporation were studied. The possibility of obtaining distilled water in a single stage by pervaporation from dilute or concentrated aqueous salt solutions was examined for the example of membranes fabricated from celluloses of varied origin (wood, cotton, bacterial).

Study of polyelectrolyte complexes of chitosan and sulfoethyl cellulose

The complexing of polycation chitosan and polyanion sulphoethyl cellulose during the formation of polyelectrolyte simplex membranes using the layer-by-layer deposition of a solution of one polyion on a gel-like film of another one has been studied. The structural characteristics of the multilayer composites and their components have been analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray microanalysis. A technique is proposed for studying the structure of surface layers of thin polymer films (15–20 μm) using a portable DIFREI-401 diffractometer. It is shown that the sequence of layer deposition during the formation of membrane films does not affect their structural characteristics. The interaction between positively charged chitosan groups (-NH3+) and negatively charged sulfoethyl cellulose groups (-SO3−) during the growth of polyelectrolyte complexes results in a packing of chitosan chains in the multilayer film.

Aromatic polysulfone imides and membranes based on them

Aromatic polyimides containing diphenyl sulfone fragments in the backbone were prepared. Asymmetric microporous films of the synthesized polymers were prepared by wet forming under the conditions of a phase-inversion process. The morphologies and the mechanical and transport properties of nonporous and phase-inversion films as materials for pervaporation membranes were studied. Multilayer composite membranes with diffusion layers of an aromatic polyether imide were prepared on the basis of microporous polyamido imide films. These membranes showed high performance in pervaporation separation of ethanol-cyclohexane mixtures of various compositions.

Pervaporation Membranes for Separating Mixtures of Methanol and Methyl tert-Butyl Ether

Transport characteristics of new types of bi- and multilayer composite polymer pervaporation membranes and asymmetrical membranes in separating mixtures of methanol and methyl tert-butyl ether were studied. The principles of design of the membranes and their mass-exchange characteristics are treated in terms of the Henis-Tripodi resistance model.

Dehydration of Organic Solvents by Evaporation through Membranes Based on Polyelectrolytic Complexes

Evaporation of binary aqueous-organic mixtures through composite membranes with coatings based on polyelectrolytic complexes including different combinations of polyelectrolytic polycations and polyanions was studied. The possibility of efficient dehydration of organic solvents by their pervaporation was demonstrated.

Prediction of separating characteristics of pervaporation membranes by inverse gas chromatography

The potentiality of inverse gas chromatography to predict separating properties of pervaporation membranes is studied for the example of a membrane composed of a mixture of polyvinyl alcohol and polyacrylic acid. Correlation relationships between the retention time of substances and relative rate of their mass transfer across the membrane were derived. A comparative method for assessment of the membrane selectivity was suggested proposed, and its consistency was checked for pervaporation separation of methanol-methyl acetate-water-acetic acid, methanol-toluene, and ethanol-ethyl acetate mixtures, including those with an azeotropic composition.

Structure and Transport Properties of Films of Mixed Cellulose Esters

Cellulose acetomyristates of varied composition were studied. The sample volume abnormally increases in high-temperature stretching and after swelling in benzene. Cellulose acetomyristates can be used as membranes for separating aromatic and aliphatic hydrocarbons.