The results of the study of the efficiency of heat treatment of samples of glauconite are presented. Estimated ability of the sorbent to water absorption and retention of petroleum products. It was established by the method of differential scanning calorimetry that thermally activated glauconite samples are practically not saturated with water vapor. Oil capacity decreases after heat treatment of glauconite at 600°C and increases at 1000°C compared with the original sample, which is explained by various structural changes.

The key point of 3D printing by selective laser sintering is the necessity of complete filling of the working chamber of the printer with a powder material. Since the powder is not completely consumed during the printing process, 25 – 30 wt.% of secondary (unused in the previous cycle) power is added to the primary material in each cycle. Repeated recirculation leads to degradation of the properties of the working powder mixture and increases the probability of rejects. We present the results of a colorimetric study of aging of polyamide-12 powder used in 3D printing by the method of selective laser sintering. Scanning and computer processing of digital images of primary and secondary polyamide powders obtained by colorimetry were performed using MathLab program package. Colorimetric analysis included the expression of the sample color using the parameters of color models applied in digital technologies for synthesizing colored images. The number of cycles before the onset of intensive destruction is no more than three, which is consistent with the practical experience in printing by selective laser sintering. The results characterizing change in the color of the secondary powder depending on the duration of thermal exposure and the gas medium are presented. It is shown that long-term storage of the powder for subsequent use is not advisable, since the initiators of destruction are already present in the material. Thermal oxidative destruction is shown to be a critical factor limiting the use of secondary powder along with changes in the crystallinity and fractional composition of particles. Computer processing of images of polymer powder obtained by the colorimetric method can be used to control the aging process of consumables and to predict the probability of rejections in 3D printing.

Разработан способ извлечения никотиновой кислоты из водных растворов с применением водорастворимого полимера в качестве экстрагента. Исследовано комплексообразование в экстракционных системах с применением жидкостной экстракции. В качестве экстрагента синтезирован поли-N-винилформамид молекулярной массой 25 ∙ 103 г/моль. Для экстракции никотиновой кислоты применены высаливатели сульфат и хлорид аммония. Рассчитаны коэффициенты распределения – от 36 до 215 и степень извлечения аналита – от 87,8 до 98,8%. Эксперимент проводили при рН 6–7, в этих условиях никотиновая кислота находится в растворе в виде биполярного иона. Методом ИК спектроскопии изучено комплексообразование в экстракционных системах. Установлено, что цвиттер-ионы никотиновой кислоты образуют прочные комплексы с водой. На основании результатов ИК спектроскопии предложен механизм взаимодействия никотиновой кислоты с водой и поли-N-винилформамидом, позволяющий объяснить результаты межфазного распределения витамина в экстракционных системах. Установлены условия, при которых достигается практически полное извлечение никотиновой кислоты: рН водно-солевого раствора 6–7, концентрация полимера 0,2 г/см3 и высаливателя 20% масс. Проведено сравнение экстракционных характеристик, полученных с поли-N-винилформамидом и другими полимерами. Установлено, что применение в качестве экстрагента поли-N-винилформамида обеспечивает практически 99%-е извлечение никотиновой кислоты, что превышает этот показатель по сравнению с другими полимерами до 96% и органическими растворителями до 45%. Определение никотиновой кислоты в водном растворе проведено методами УФ спектрофотометрии по собственному поглощению при 262 нм или капиллярного электрофореза. A method for extracting nicotinic acid from aqueous solutions using a water-soluble polymer as an extractant has been developed. Complex formation in extraction systems using liquid extraction is investigated. Poly-N-vinylformamide with a molecular weight of 25 ∙ 103 g/mol was synthesized as an extractant. For the extraction of nicotinic acid, salting agents (ammonium sulfate and chloride) were used, distribution coefficients and the degree of analyte extraction were calculated. The distribution coefficients – from 36 to 215 and the degree of analyte extraction – from 87,8 to 98,8% were calculated. The experiment was performed at pH 6–7, under these conditions, nicotinic acid is in solution as a bipolar ion. Complex formation in extraction systems has been studied by IR spectroscopy. It was found that the zwitterions of nicotinic acid form strong complexes with water. Based on the results of IR spectroscopy, a mechanism for the interaction of nicotinic acid with water and poly-N-vinylformamide is proposed, which allows us to explain the results of interphase distribution of vitamin in extraction systems. The conditions under which almost complete extraction of nicotinic acid is achieved (the 6–7 pH of the water-salt solution, the polymer concentration are 0,2 g/cm3and the salting agent is 20% by weight) are established. The extraction characteristics obtained with poly-N-vinylformamide and other polymers were compared. It was found that the use of poly-N-vinylformamide as an extractant provides almost 99% recovery of nicotinic acid, which exceeds this indicator in comparison with other polymers by up to 96% and organic solvents by up to 45%. Determination of nicotinic acid in an aqueous solution was performed by UV spectrophotometry based on self-absorption at 262 nm and capillary electrophoresis.