In the electroplating industry, large volumes of water are used, which are polluted at various stages in the process. Waste water containing transition metal ions is not only a dangerous source of environmental pollution, but also valuable waste. Taking into account the problems associated with the ecology and the rational use of natural resources, it is necessary to create low- and non-waste production, in particular, to develop new technological processes and appropriate equipment, to introduce water-circulation cycles. This paper presents the results of a study of the sorption of copper (II) and nickel (II) cations by the FIBAN X-1 ion exchange fiber. Calorimetric studies of the thermal effects of the interaction of FIBAN X-1 fiber with solutions of copper (II) and nickel (II) nitrates were carried out. It is shown that the power, thermal effect and time of the process depend on the nature and concentration of metal ions in the solution. Based on the experimental data, the enthalpy of the process was calculated. The endothermic effect of the process is explained by the energy costs associated with dehydration effects and changes in the conformation of the polymer fiber chains. Sorption isotherms of these ions were obtained. It has been established that at all concentrations studied, Ni2 + ions under these conditions are absorbed by ion exchange fibers better than Cu2 + cations. The calculated sorption constants for copper (II) and nickel (II) are greater than 1. It is shown that the Langmuir equation describes the sorption isotherm better than the Freundlich equation. For deep purification of waste water from metal ions, it was proposed to use the fibrous sorbent FIBAN X-1.
Очистка технологических газов от аммиака является актуальной проблемой в химической промышленности. Целью работы было изучение сорбции аммиака из газовоздушной среды модифицированными волокнистыми сорбентами. В качестве сорбента аммиака использовали карбоксильное волокно ВИОН КН-1 в медной, никелевой и цинковой формах. Исследование поглощения аммиака проводили на воздушно-сухих и влагонасыщеных образцах волокнистого сорбента. Для изучения сорбции в эксикаторах создавали атмосферы с объемной концентрацией аммиака от 10 до 300 мг/м3. Предельно допустимая концентрация содержания аммиака в воздухе рабочей зоны составляет20 мг/м3. Модифицированные волокнистые сорбенты после сорбции аммиака приобретали цвета, характерные для аминокомплексов. Волокно с поглощенным аммиаком обрабатывали раствором соляной кислоты с концентрацией 0.1 моль/дм3 в статических условиях при температуре 293 К в течение 90 минут. Концентрацию ионов аммония определяли на иономере И-130 с ионоселективным электродом. Фотометрический метод применяли для определения концентрации ионов металлов в растворах после десорбции. Установлено, что медная форма поглощает наибольшее количество аммиака. При низких значениях давления газа наблюдается резкое поглощение аммиака модифицированным волокном. Не модифицированное волокно обладает меньшей сорбционной способностью, что объясняется различным механизмом сорбции молекул аммиака на протонированной и ионных формах волокнистого сорбента. Для количественного описания равновесного процесса сорбции аммиака модифицированными волокнами были использованы уравнения Ленгмюра и Фрейндлиха. Коэффициенты корреляции для уравнения Ленгмюра близки к единице. При высоких давлениях происходит полное насыщение сорбента и повышение давления уже не влияет на абсорбцию газа. Полученные результаты по сорбции аммиака согласуются с квантово-механическими расчетами в программном модуле Hyper Chem об образовании на карбоксильном волокне, содержащем как медь, так и никель, комплексов, в состав которых входят от 1 до 3 молекул аммиака. Кинетические зависимости сорбции аммиака на образцах медной и никелевой форм волокна ВИОН КН-1 были получены при концентрации аммиака в газовой фазе 10 мг/м3. Показано, что более высокой скоростью сорбции характеризуется медная форма волокнистого сорбента. Насыщение модифицированных карбоксильных волокон парами воды ухудшает их сорбционные свойства на 8-10 %.
The relationship between the characteristics of hydration and the selectivity of the fibrous carboxyl sorbent is established. Using the isopiestic method and thermal analysis, the hydration of the carboxyl fiber ion exchanger VION KN-1 in sodium, calcium and magnesium forms was studied. The quantity of absorbed water was determined, including the ratio of kinetically unequal water in the sorbent phase. The amount of water absorbed form of magnesium ion exchanger is greater than calcium, the molar proportion of water distribution varying in the degree of hydration of the magnesium and calcium forms fibers substantially equally. The changes in Gibbs energy of hydration and enthalpy of dehydration of ion-exchange fiber are calculated. The increase in Gibbs energy is due to the absorption of near- hydration water, and water farthest hydration is adsorbed at a constant value of the energy. Its highest values are determined for the magnesium form of the sorbent, and the least-for calcium, which corresponds to the ratio of the absorbed solvent of both forms in the first step of hydration. The exchange isotherms of calcium and magnesium ions on the sodium form of VION KN-1 fiber were obtained. The Gibbs energy of solvent interface transfer was calculated, which represents the difference between the Gibbs energies of ion exchange sorption and the direct exchange of cations, and describes the contribution of the change in sorbent hydration during the transition from one ionic form to another. It is found that the selectivity of extractable fiber ion exchanger to metal cations depending on the change in the sorbent during the hydration of ion exchange, which is energetically favorable process and promotes ion-exchange sorption. Carboxyl cation exchanger is more selective for magnesium ions than calcium ions, as confirmed by phase transfer energy high values solvent and less water released during the transition from the sodium form to the magnesium than during the transition to the calcium.
The aim of this work is to study the characteristics of the electrodialysis of a sodium sulphate solution with experimental bipolar membranes based on the MA-41 anion exchange membrane and a liquid sulphonated cation-exchanger modified with bentonite clays. The conversion of sodium sulphate was conducted by electrodialysis with bipolar membranes obtained by applying a liquid sulphonated cation-exchanger containing particles of bentonite clay to the MA-41 anion-exchange membrane.To increase the performance of membranes in terms of hydrogen and hydroxyl ions, we carried out organomodifications of bentonite with alkyldimethylbenzylammonium chloride and stearic acid at various concentrations. The bipolar membrane with the addition of bentonite modified with alkyldimethylbenzylammonium chloride (2 wt%) showed a higher performance in terms of H+-ions. The bipolar membrane with bentonite modified with stearic acid (3 wt%) added to its cation-exchangelayer is the most effective in terms of obtaining a flux of OH--ions. It was shown that a combination ofalkyldimethylbenzylammonium chloride (2 wt%) and stearic acid (3 wt%) used to modify bentonite can increase the performance of the bipolar membrane during the conversion of sodium sulphate, both in terms of the acid and alkali.
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