OPTIMIZATION EXTRACTION OF COFFEINE AND THEOBROMINE FROM VARIOUS VARIETIES OF TEA WITH PLURONIC BLOCK COPOLYMER

Контроль содержания алкалоидов в пищевых продуктах и напитках в соответствии с нормируемыми показателями – актуальная задача для биотехнологии. Рассмотрена экстракция кофеина и теобромина из растительного сырья – чая черного и зеленого с использованием в качестве экстрагента блок-сополимера плюроник, представляющего собой чередующиеся фрагменты этиленоксида (20 мономерных звеньев) и пропиленоксида (70 мономерных звеньев). Экстракционные системы на основе водорастворимых полимеров отвечают всем требованиям «зеленой» экстракции и могут применяться в технологических процессах, связанных с контролем качества исходного сырья. Исследованы условия процесса извлечения пуриновых алкалоидов, установлены его оптимальные параметры: концентрация экстрагента 0,25 г/см3, температура процесса 95°С, степень измельчения для черного и зеленого чая 0,4 и 0,8 мм соответственно, соотношение водной и органической фаз 10 : 1 соответственно. По результатам экстракции рассчитаны коэффициенты распределения и степень извлечения кофеина и теобромина, которая составляет 95–99% в зависимости от сорта чая. Содержание кофеина и теобромина в фазе органического растворителя после экстракции определяли методом капиллярного электрофореза по электрофореграммам образцов черного и зеленого чая. На основании разработанной экстракционно-электрофоретической методики определения кофеина и теобромина в различных сортах чая предложен механизм взаимодействия пуриновых алкалоидов с экстрагентом плюроник. Наличие в цепи полимера концевых НО-групп, а также в основной цепи атомов кислорода способствует взаимодействию полимера с аналитами с образованием водородных связей. Представленные схемы образования Н-связей подтверждают эффективность применения блок-сополимера плюроник в качестве экстрагента пуриновых алкалоидов. Monitoring the content of alkaloids in food and beverages in accordance with the normalized indicators is an urgent task for biotechnology. The extraction of caffeine and theobromine from vegetable raw materials – black and green tea using the pluronic block copolymer as an extractant is considered. The pluronic block copolymer consists of alternating fragments of ethylene oxide (20 monomer units) and propylene oxide (70 monomer units). Extraction systems based on water-soluble polymers meet all the requirements of «green» extraction and can be used in technological processes related to quality control of feedstock. The conditions of the purine alkaloid extraction process have been investigated, its optimal parameters have been established: the extractant concentration is 0,25 g/cm3, the process temperature is 95°C, the degree of grinding for black and green tea is 0,4 and 0,8 mm respectively, the ratio of aqueous and organic phases is 10 : 1 respectively. According to the extraction results, the distribution coefficients and the degree of extraction of caffeine and theobromine, which is 95–99%, depending on the tea variety, are calculated. The content of caffeine and theobromine in the organic solvent phase after extraction was determined by capillary electrophoresis from electrophoregrams of black and green tea samples. The presence of terminal HO-groups in the polymer chain, as well as in the main chain of oxygen atoms, promotes the interaction of the polymer with analytes with the formation of hydrogen bonds. The presented schemes for the formation of H-bonds confirm the effectiveness of using the pluronic block copolymer as an extractant of purine alkaloids.

Demulsification Behavior of Alkali and Organic Acid in Zinc Extraction

Alkali agents could be used to enhance the extraction of zinc from solution of high concentration, but excess alkali can sensitively lead to emulsification of the solution. In this paper, the emulsification in the extraction process, demulsification, and extraction with different additives and its action mechanism were studied. The results indicate that the associated addition of alkali and organic acid could eliminate emulsification and improve zinc extraction. The extraction ratio of zinc reached 99.61% under the conditions of 104 mL/L organic acid, 80 g/L alkali, and 40% extractant concentration. Zinc hydroxide formed from hydroxyl and zinc ion at sensitively increased pH was the cause of emulsification during extraction. Associated addition of alkali and organic acid could contribute to the control solution pH in the range of 3.0–4.0, which is lower than that of the formation of zinc hydroxide, and therefore, improve zinc extraction.

Purification of recovered phosphoric acid by extracting aluminium with di-2-ethylhexyl phosphoric acid

The extraction of aluminium from dilute phosphoric acid with di-2-ethylhexyl phosphoric acid (DEHPA) was optimized using response surface methodology. The optimization was based on the experimental three-level central composite face-centred design (CCF) and was conducted on real-life samples. The three variables included were pH, extractant concentration and aqueous to organic phase ratio (AO). Under the optimized conditions (pH 2.5, 0.6 M DEHPA and AO ratio 1:2), extraction efficiency of 99% for aluminium in four extraction stages is achieved. The purified phosphoric acid solution can then be utilized by the fertilizing industry. Stripping tests for organic phase loaded with aluminium were conducted with sulphuric acid. Extremely high stripping efficiency was obtained with 0.9 M sulphuric acid resulting in the recovery rate of 88% in one stage. After stripping, the aluminium sulphate solution can be reused as a precipitation agent for phosphorus in the wastewater treatment process.

Computational simulation and modelling of uranium extraction using tributylphosphate through membrane extractor

Non-disperse solvent extraction is an effective technique for the extraction of metal ions from aqueous solution. In this study, uranium extraction using n-dodecane solvent containing tributylphosphate extractant in a membrane contactor was investigated. A 2D mathematical model was developed for the fluid flow and mass transfer in the hollow fibre membrane extractor. The equations of the created model were solved using the finite element method. The uranium concentration distribution in the extractor at different extractant concentrations as well as feed acidity was studied. The results showed that there is reasonable good agreement between experimental uranium extraction and modelling outputs at different extractant concentrations. Increasing extractant concentration from 5 to 30% led to the enhancement of uranium extraction from 2.60 to 34.13%. Also, there was an increase in the uranium extraction with increasing feed acidity in the range of 1–3 M. Furthermore, based on the radial uranium concentration distribution, it was found that the main mass transfer resistance in the system was microporous membrane section. Finally, it was obtained that the uranium extraction efficiency could be improved significantly by increasing porosity-to-tortuosity ratio. It was concluded that the membrane specification plays the most important role as the dominant mass transfer resistant was in the membrane subdomain.

Influence of Electrolyte Impurities from E-Waste Electrorefining on Copper Extraction Recovery

In order to reflect possible issues in future sole e-waste processing, an electrolyte of complex chemical composition reflecting system of sole e-waste processing was obtained by following a specially designed pyro-electrometallurgical method. The obtained non-standard electrolyte was further used for the purpose of comprehensive metal interference evaluation on the copper solvent extraction (SX) process. Optimization of the process included a variation of several process parameters, allowing determination of the effect of the most abundant and potentially the most influential impurities (Ni, Sn, Fe, and Zn) and 14 other trace elements. Moreover, comparing three commercial extractants of different active chelating groups, it was determined that branched aldoxime reagent is favorable for Cu extraction from the chemically complex system, as can be expected in future e-waste recycling. The results of this study showed that, under optimal conditions of 20 vol.% extractant concentration, feed pH 1.5, O/A ratio 3, and 10-min phase contact time, 88.1% of one stage Cu extraction was achieved. Co-extraction of the Fe, Zn, Ni, and Sn was under 8%, while Pb and trace elements were negligible. Optimal conditions (H2SO4 180 g/L, O/A = 2, and contact time 5 min) enabled 95.3% Cu stripping and under 6% of the most influential impurities. In addition, an impurity monitoring and distribution methodology enabled a better understanding and design of the process for the more efficient valorization of metals from e-waste.

Study Of The Stability Of Water-In-Oil Emulsion Intended for the Extraction of Heavy Metals Application: Copper Ions

This work aims to optimize the parameters that affect the stability of a W/O emulsion to exploit it in the extraction of heavy metals contained in the liquid effluents. The study of the emulsion stability shows that; an emulsification time of 10 minutes, a surfactant concentration of Span80 equal to 3% (w/w), an extractant concentration of Triethylamine N(CH2CH3)3 equal to 5% (w/w), an internal phase concentration of phosphoric acid (H3PO4) of 0.75M, a volume ratio of membrane phase to internal phase of 1, a volume ratio of external phase to the emulsion of 20 and a stirring speed of 180 rpm; lead to the formation of a very stable emulsion with a very low rupture rate of around 1.92% after one hour of contact time. The results of extraction of copper ions revealed that under the best operational conditions, the extraction yield was closed to 93.33% for 20% extractant content, a contact time of 12 minutes, and an initial concentration of copper ions of 400 ppm. The application of this new membrane matrix based on phosphoric acid used as inner phase, sorbitan monooleate as a surfactant, and Triethylamine as extractant has been proven effective for extracting copper ions in water.

Thermodynamic Analysis of Trace Cobalt(II) Extraction from Cobalt Chloride Aqueous Solution Using Cyanex 272 in Kerosene

In this study, it was researched that the extraction of Co(II) from CoCl2 aqueous solutions using Cyanex 272 (bis(2,4,4-trimethylpentyl) phosphonic acid) in kerosene and determined the effects of the equilibrium pH value, extractant concentration and chloride ion concentration on the extraction of cobalt at different temperatures. The results indicate that the distribution ratio of cobalt increases as the equilibrium pH value, extractant concentration and extraction temperature increase. However, the cobalt distribution ratio decreases as the chloride ion concentration increases. We calculated the equilibrium constants (AH9, AG9, and AS9) for a range of temperatures and investigated the relationship between AG9 and T. The extraction reaction of cobalt was determined to be an endothermic reaction; thus, raising the temperature was beneficial to the reaction.

Increasing the depth of apatite processing by extracting rare-earth elements

Currently, most high-technology productions are impossible without rare-earth elements (REE). The heavy rare-earth elements are of great interest as they have the highest market value and are in demand in the vast majority of knowledge-intensive industries. The main recourse of REE in Russia is apatite ore which is used in the production of fertilizers. As a result of its leaching, about 15-20% of REE goes to wet-process phosphoric acid. To enhance the depth of apatite processing, it is necessary to develop a technology which will allow obtaining rare-earth elements as by-products. The method of extraction and concentration of REE discussed in this paper was conducted by using the extractant based on di-(2-ethylhexyl) phosphoric acid (D2EHPA). The mechanism of extraction was studied, as well as the impact of the extractant concentration, phase ratio and the number of stages on the extraction process.

Effect of Different Extractant Concentrations on the Content of Biologically Active Substances in Motherwort Tincture

Introduction. This article considers the ways to optimize the motherwort tincture formulation while reducing the content of ethyl alcohol in the finished product. Qualitative and quantitative tincture test items depending on extraction method used and extractant concentration have been studied.Aim. To study the possibility of reducing the content of ethyl alcohol in motherwort tincture.Materials and methods. Comparison of quantitative and qualitative test items of tincture samples prepared by percolation, maceration, fractional maceration, modified fractional maceration is carried out. Quantitative comparative test items: dry residue, ethyl alcohol content, microbiological purity, quantitation, qualitative reactions – the presence of phenolic compounds, flavonoids in the samples (qualitative reactions, HPLC), iridoids (TLC) was used.Results and discussion. The developed method of modified fractional maceration consists in extracting herb materials with a more concentrated extractant (in the study, 80 %, 60 %, 40 % ethyl alcohol), then the subsequent extraction of herb materials with purified water. Comparison of the presence of different classes of biologically active substances in tinctures obtained by different technological methods and in infusions is carried out.Conclusion. It has been established that the most rational method is to obtain a tincture by modified fractional maceration method with ethyl alcohol content NLT 35 % in the finished product. The obtained results can be used in pharmaceutical industry for drug production by extractive methods, as well as for studies on technology optimization for obtaining extractive drugs from medicinal herb materials.

Selective Recovery of Molybdenum over Rhenium from Molybdenite Flue Dust Leaching Solution Using PC88A Extractant

Selective solvent extraction of molybdenum over rhenium from molybdenite (MoS2) flue dust leaching solution was studied. In the present work, thermodynamic calculations of the chemical equilibria in aqueous solution were first performed, and the potential–pH diagram for the Mo–Re–SO42−–H2O system was constructed. With the gained insight on the system, 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl)-ester (PC88A) diluted in kerosene was used as the extractant agent. Keeping constant the reaction temperature and aqueous-to-organic phase ratio (1:1), organic phase concentration and pH were the studied experimental variables. It was observed that by increasing the acidity of the solution and extractant concentration, selectivity towards Mo extraction increased, while the opposite was true for Re extraction. Selective Mo removal (+95%) from leach solution containing ca. 9 g/L Mo and 0.5 g/L Re was achieved when using an organic phase of 5% PC88A at pH = 0. No rhenium was coextracted during 10 min of extraction time at room temperature. Density functional theory (DFT) calculations were performed in order to study the interactions of organic extractants with Mo and Re ions, permitting a direct comparison of calculation results with the experimental data to estimate selectivity factors in Mo–Re separation. For this aim, PC88A and D2EHPA (di-(2-ethylhexyl) phosphoric acid) were simulated. The interaction energies of D2EHPA were shown to be higher than those of PC88A, which could be due to its stronger capability for complex formation. Besides, it was found that the interaction energies of both extractants follow this trend considering Mo species: MoO22+ > MoO42−. It was also demonstrated through DFT calculations that the interaction energies of D2EHPA and PC88A with species are based on these trends, respectively: MoO22+ > MoO42− > ReO4− and MoO22+ > ReO4− > MoO42−, in qualitative agreement with the experimental findings.