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Vol. 56 (2020), Issue 3-4, p. 95-102
https://doi.org/10.5281/zenodo.3970433
Термическая стабилизация поверхностного слоя композитной мембраны ультрафильтрации
Abstract
УДК 66.081.6-278, 66.040.22
Исследована стабильность динамического слоя мембраны состоящего из микрочастиц полистирола (ПС). С целью повышения стабильности мембрану нейлон-ПС подвергали термической обработке при температурах от 50 до 100°С в течение 10 минут. Влияние температуры на поверхность динамической мембраны исследовалось методами сканирующей электронной микроскопии и измерением краевого угла смачивания мембран. Стабильность динамического слоя достигается при обработке в течение 10 минут и температуре 50°С, стабильность динамического слоя повышается в 4 раза, масса мембраны после обратной промывки раствором анионных поверхностно-активных веществ не уменьшается, когда у исходной мембраны нейлон-ПС масса сократилось на 0,84%. Также в результате термической стабилизации динамического слоя мембраны повышается степень разделения водомасляной эмульсиис 97 до 99%.
Ключевые слова: водомасляная эмульсия, ультрафильтрация, динамические мембраны, нейлон, полистирол, термическая обработка, стабилизация, мембранные структуры, композитные мембраны.
To increase the stability of the dynamic layer of a membrane that consists of the polystyrene (PS) microparticles, a nylon-PS membrane was heat treated at temperatures from 50 to 100°C within 10 minutes. Increasing the temperature from 50 to 100°С leads to a decrease of the weight up to 0.86%. Temperature impacts on a surface of the dynamic membrane was investigated by the scanning electronic microscopy and the measurement of a wetting contact angle of the studied samples of membranes. The heat treatment of nylon-PS membranes at temperature of 50°С during 10 minutes lead to a decrease of their wetting contact angle from 136° to 129°. Increasing hydrophily of membranes is associated with a decrease of roughness of a blanket and the formation of the open areas acting sites consisting of hydrophilic "nylon 66". Besides, the molten sites were formed on the surface of a membrane. In addition, the intensities of IR spectra were reduced. However, after heat treatment at a temperature of 70°C, the intensities of IR spectra increased. The specific capacity of the dynamic membrane is reduced by 1.5 times after heat treatment at a temperature of 50°C, but at higher temperatures, the membrane permeability increased up to 4.5 times. A decrease of the specific capacity of the membrane is related to the compaction and connection of PS particles under the action of temperature. Heat treatment at temperatures above 50°C leads to an increase in stiffness and brittleness of the dynamic layer of PS, as a result the cracks are formed on the surface of the layer and the membrane permeability increases. The stability of the dynamic layer is achieved by processing for 10 minutes at a temperature of 50°C, it is increased by 4 times, while the mass of the membrane after backwash with anionic surfactants solution did not decrease when the initial nylon–PS membranes mass decreased by 0.84%. The rate of separation of the water-oil emulsion increases from 97% to 99% as a result of thermal stabilization of the dynamic layer of the membrane.
Keywords: water-oil emulsion, ultrafiltration, dynamic membranes, nylon, polystyrene, heat treatment, stabilization, membrane structures, composite membranes.
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