Modeling Of Extraction Kinetics Research Articles

Ultrasound-assisted polyphenols extraction with deep eutectic solvent and ethanol-based from Baccaurea macrocarpa pericarp and kinetic model

In this study, the extraction of polyphenols from the Baccaurea macrocarpa pericarp using ultrasonic-assisted deep eutectic solvents (DES-UAE) of 15 different types and ethanol (EtOH-UAE) was investigated. It was found that choline chloride-lactic acid (1:2) is the optimal choice for polyphenol extraction due to its highest extraction efficiency. Subsequently, extraction parameters were optimized using the response surface methodology. The highest total polyphenolic content (TPC) for DES-UAE was achieved with a solvent concentration of 70.2 %, an extraction time of 31.8 min., a temperature of 44.5 °C, and a solvent-solid ratio of 25.1 mL/g. For EtOH-UAE, the optimal solvent concentration was 81.1 %, with an extraction time of 40.4 min, a temperature of 45.5 °C, and a solvent-solid ratio of 20.4 mL/g. Additionally, the second-order extraction kinetic model was found to best describe the extraction behavior for both DES-UAE and EtOH-UAE. This study suggests that DES-UAE is a viable, sustainable, and efficient technique for obtaining polyphenols from Baccaurea macrocarpa pericarp. DES-UAE also presents a promising tool for exploring the commercial feasibility of polyphenol extraction.

Mathematical modeling of extraction kinetics from black chokeberries enhanced by cold plasma pretreatment

The application of cold plasma as a pretreatment for extraction process is a recent development. This research investigates the impact of cold plasma (CP) treatment on the extraction process of bioactive compounds from black chokeberry samples. Utilizing a 12-h maceration process, various analyses, including total phenolic content (TPC), antioxidant capacity (DPPH, ABTS+, CUPRAC assays), total monomeric anthocyanin content (TMA), color parameters, and comprehensive mathematical modeling, were employed to assess the effectiveness of CP treatment. The kinetic modeling with Peleg, Power Law, Elovic's, and Two-site Kinetic Models emphasized the critical role of CP treatment duration in the extraction process. This study indicates that the power-law kinetic model provided the best fit for the experimental data from CP-treated samples, suggesting that this model most accurately describes the extraction kinetics under the conditions tested. In summary, this investigation underlines the crucial role of mathematical modeling in understanding the dynamics of bioactive compound extraction under CP treatment.

Elevated temperature extraction of β-carotene from freeze-dried carrot powder into sunflower oil: Extraction kinetics and thermal stability.

β-Carotene, a precursor of vitamin A, can alleviate the deficiency of this vitamin prevalent worldwide. Earlier research studies have addressed the extraction of β-carotene at relatively low temperatures (up to 70°C) due to its perceived instability at higher temperatures, as a result of which extraction rates recorded are relatively low. This study models the net rate of β-carotene extraction by considering both extraction and degradation kinetics. The model developed, which accounts for degradation occurring in solid and extract phases, has been experimentally validated for the extraction of β-carotene from freeze-dried carrot powder into sunflower oil over a range of temperatures 90-150°C. This study also gives insights into the application of sunflower oil as a carrier for β-carotene during cooking and food processing, by monitoring and modeling the thermal degradation and isomerization of β-carotene at temperatures up to 220°C. The modeling of extraction kinetics shows that it is possible to achieve viable extraction rates by employing temperatures in the range (90-150°C) for relatively short times (<5min). The degradation kinetics shows that almost 75% of the β-carotene can survive heating at 180°C for 10min-indicating the possibility of using β-carotene enriched edible oils for frying. This study also reports on the formation of three isomers of β-carotene identified using HPLC: trans-, 9-cis, and 13-cis. The reaction network model developed in this study was able to account for the transient variation of the concentration of all three isomers. PRACTICAL APPLICATION: β-Carotene is a precursor of vitamin A and its consumption can potentially alleviate the deficiency of this vitamin prevalent worldwide. This study validates a model for the extraction of β-carotene in sunflower oil, which takes into account extraction as well as degradation occurring during extraction, so that a rational method is available for the design of efficient extractors for this purpose. This paper also establishes the thermal stability of β-carotene under frying conditions by quantifying its thermal degradation as well as isomerization.

Optimization and Kinetics Extraction of Natural Dyes from Henna Leaves (Lawsonia inermis L.) with Ultrasonic Assistance

The Lawson dye contained in the leaves of Lawsonia inermis L. has a red-orange color, which can be used as a fabric dye. The solvent is ethanol because it can attract flavonoid compounds bound to Lawson. The ultrasonic-assisted extraction method is employed to enhance the extraction process by breaking down cell walls, thereby facilitating a more rapid extraction of the desired solute. This study investigated the effects of material-to-solvent ratio, ethanol concentration, and extraction time. The research results were analyzed using a UV-Visible spectrophotometer to determine the yield of Lawson extract. The Face-Centered Composite Design (FCCCD) method was applied to this study to obtain optimal analysis results and extraction conditions. The independent variables in this study were the ratio of ingredients to solvent (0.02-0.06 g/g), ethanol concentration (20-60%), and extraction time (5-15 minutes). The optimal extraction conditions were obtained at a ratio of 0.02 g/g, an ethanol concentration of 60%, and an extraction time of 15 minutes, with a predicted model yield of 15.417%. The actual yield under these conditions was found to be 15.4934%. Furthermore, the extraction kinetics model was analyzed to study and predict the optimal Lawson extraction results. Extraction kinetics calculations were carried out using first-order and second-order based on the Lagergren equation. The most suitable extraction kinetic model is second-order with a determinant coefficient value, or the value of R2 is 1, which indicates that the order kinetic model equation represents the actual conditions.

Extraction and Emulsification of Carotenoids from Carrot Pomaces Using Oleic Acid.

This study aimed to use oleic acid-based ultrasonic-assisted extraction (UAE) to recover carotenoids from carrot pomace and emulsify the enriched-carotenoid oleic acid using spontaneous and ultrasonic-assisted emulsification. The extraction performance of oleic acid was compared with traditional organic solvents, including hexane, acetone, and ethyl acetate. The one-factor experiments were employed to examine the impact of UAE conditions, including liquid-to-solid ratios, temperature, ultrasonic power, and time, on the extraction yield of carotenoids and to find the conditional ranges for the optimization process. The response surface methodology was employed to optimize the UAE process. The second-order extraction kinetic model was used to find the mechanism of oleic acid-based UAE. After that, the enriched-carotenoid oleic acid obtained at the optimal conditions of UAE was used to fabricate nanoemulsions using spontaneous emulsification (SE), ultrasonic-assisted emulsification (UE), and SE-UE. The effect of SE and UE conditions on the turbidity of nanoemulsion was determined. Then, the physiochemical attributes of the nanoemulsion from SE, UE, and spontaneous ultrasonic-assisted emulsification (SE-UE) were determined using the dynamic light scattering method. The extraction yield of carotenoids from carrot pomace by using sonication was the highest. The adjusted optimal conditions were 39 mL/g of LSR, 50 °C, 12.5 min, and 350 W of ultrasonic power. Under optimal conditions, the carotenoid content attained was approximately 163.43 ± 1.83 μg/g, with the anticipated value (166 μg/g). The particle sizes of nanoemulsion fabricated at the proper conditions of SE, UE, and SE-UE were 31.2 ± 0.83, 33.8 ± 0.52, and 109.7 ± 8.24 nm, respectively. The results showed that SE and UE are suitable methods for fabricating nanoemulsions. The research provided a green approach for extracting and emulsifying carotenoids from carrot pomace.

Optimization of extraction of bioactive compounds with antiproliferative activity from goji berry and assessment of kinetic models

AbstractBACKGROUNDThis work aims to optimize the extraction of bioactive compounds with antiproliferative activity from goji berry (Lycium barbarum) and assess the extraction kinetic models. The extraction was performed by varying the proportion of ethanol/water solvent.RESULTSThe antioxidant activity determination tests indicated a significant difference for the proportion of 60:40 ethanol/water. Conditions for the highest levels of antioxidant activity were 45 °C and 6.71 min for ultrasound and 45 °C and 23.30 h for shaker.CONCLUSIONThe quantification of phenolic compounds, flavonoids, carotenoids and anthocyanins showed that the ultrasound method led to the highest concentrations of these compounds. The extraction kinetics was evaluated, and the So and MacDonald's and second‐order models showed the best fit, with a global maximum deviation lower than 10.0%. High concentrations of extracts produced showed cytotoxic effects for human hepatoma cells by the MTT test. The extract produced by ultrasound reached a cell viability of 37.71%. © 2023 Society of Chemical Industry.

Kinetic Modelling of Liquid-Solid Extraction of Bioactive Compounds from Ginger Waste using Subcritical Water

Kinetic modelling played a key role in the development of subcritical water extraction for bioactive compounds such as: shogaol and gingerol from ginger waste. Liquid-solid extraction kinetics could predict the extraction phenomenon and increase the efficacy of extraction process. The aim of this study was to develop a mathematical model of leaching kinetics and determine the rate constant of extraction process (k) of shogaol and gingerol in ginger pulp which is in the subcritical water phase. The research was carried out in two work stages, namely modeling and experimentation. The modeling was done by comparing three extraction kinetic models, namely pseudo first order, pseudo second order and the distribution coefficient. The model was postulated and validated with experimental data using Matlab. The subcritical water extraction process of shogaol and gingerol in ginger waste was occurred at 140 ℃ with a pressure of 3.5 bar. The extracts had been separated from raffinate and further analyzed using HPLC-MS. The results showed that the pseudo first order kinetic model described well the phenomenon of subcritical water extraction with regression values was 0.9882 for gingerol and 0.9682 for shogaol respectively. The rate constant of extraction process (k) for gingerol and shogaol were 0.1101 and 0.3130 , respectively. This showed that the shogaol extraction rate was higher than the gingerol extraction rate.

Response surface methodology guided process optimizations, modeling and biofunctional analysis of phytochemicals from Nigella sativa seeds as a potential antifungal agent

Nigella sativa L. or black cumin is rich in several bioactives, exhibiting excellent biofunctional properties; hence could be exploited for providing protection against storage fungi. Response surface methodology driven ultrasonic assisted extraction (UAE) and microwave assisted extraction (MAE) variables were optimized to get maximum yield of bioactive phytochemicals from N. sativa seeds. -. The optimal extraction conditions were determined as: amplitude 32.02 kHz, extraction time 13.12 min, solvent to solute ratio 35.88 mL/g for UAE; and microwave power 674.18 W, time 168.21 s, solvent to solute ratio 70.09 mL/g for MAE. Extraction kinetic models demonstrated the initial increasing rate of mass transfer, depending upon individual extraction variable. Microstructural analysis clearly confirmed the influence of ultrasonic cavitation acoustic and microwave energies on the matrix wall, resulting intense rupture and disintegration to release phyto-constituents immediately. Ultra Performance Liquid Chromatography-Quadrupole-Time of Flight–Mass Spectrometric (UPLC-QTOF- MS) analysis of ethanolic concentrate (ENS) revealed fifty-seven diverse phytochemicals, dominated by thymoquinol-β-glucopyranoside, kaempferol-3-O-pentoside, nigellimine, nigellimine-N-oxide, nigellamine A1, thymoquinol, thymoquinone, dithymoquinone and nigellidine-4-O-sulfite. ENS exhibited excellent antifungal action against A. flavus 2838 (27.6 μg/mL) followed by A. flavus 2547 (34.8 μg/mL) and A. flavus 837 (46.3 μg/mL). Antifungal action was further confirmed through the inhibition of fungal ergosterol content (%), correlating with the in silico analysis pertaining to the ligand protein interaction between individual component and sterol 14-α-demethylase. Nigellamine A1, kaempferol-3-O-pentoside and nigellidine-4-O-sulfite were found to be promising as they exhibited favourable interactions like H-bonds, electrostatic bonds, hydrophobic bonds and with weak van der Waals bonds with the target protein.

Optimization of ultrasonic-assisted extraction model of Pinus koraiensis seed scales oil induced by tea saponin

Tea saponin was used for UAE of oil from Pinus koraiensis seed scales for the first time, and the extraction kinetic model was fitted and compared with that of traditional SE. Considering the relationship among the oil yield, proanthocyanidins content and solvent properties, ethanol was selected as the optimum extraction solvent. PBD and BBD were used to determine the optimal conditions: 63% aqueous ethanol solution, liquid-to-material ratio was 11:1 mL/g, ultrasonic power was 100 W, ultrasonic duration was 15 min, temperature was 45 °C, and the dose of tea saponin was 0.3%. Under the optimal conditions, the oil yield and proanthocyanidins content from P. koraiensis seed scales were 22.73 ± 0.42% and 3.04 mg/g ± 0.08%, respectively. The actual operating value was consistent with the theoretically predicted value. Comparison of the extraction kinetics model, oil components, physical and chemical properties, antioxidants, microstructure of oil residue, energy consumption and ecological emission characteristics of UAE and SE shows that UAE is a more advantageous technique.

Mathematical, fuzzy logic and artificial neural network modeling of extraction kinetics of essential oil from aerial parts of yarrow (Achillea millefolium L.) using ohmic-assisted hydrodistillation

Mathematical, fuzzy logic and artificial neural network modeling of extraction kinetics of essential oil from aerial parts of yarrow (Achillea millefolium L.) using ohmic-assisted hydrodistillation

Comparative analysis of three kinds of extraction kinetic models of crude polysaccharides from Codonopsis pilosula and evaluate the characteristics of crude polysaccharides.

In this study, the second-order model, Fick’s second law of diffusion, and the Peleg model were used to evaluate the extraction kinetic model of polysaccharide (CPP) from Codonopsis pilosula. The characteristic functional groups, surface structure, and physical and chemical properties of CPP were analyzed by multi-spectroscopic and microscopic techniques. The results showed that the extraction process agreed well with the second-order model, Fick’s second diffusion law, and Peleg model. Rheological tests showed that CPP exhibited different viscosity changes under different conditions (Solution viscosity was inversely proportional to temperature, time, etc.; proportional to polysaccharide concentration, Na+ content, etc.). CPP was composed of molecular aggregates composed of small particles, with more pore structure and basically completely decomposed at 130 °C. The hypoglycemic study showed that CPP had a strong inhibitory effect on α-glycosidase than α-amylase. The morphology and subsequent structural features, anti-diabetic potential, and rheological properties of CPP were revealed to provide a theoretical basis for the development of pharmaceutical preparations or health food and functional food for the treatment of diabetes.Graphic Supplementary InformationThe online version contains supplementary material available at 10.1007/s13399-022-02518-w.

Extraction kinetic model of polysaccharide from Codonopsis pilosula and the application of polysaccharide in wound healing

The crude polysaccharide (CPNP) of Codonopsis pilosula was obtained by hot-water extraction technology. The extraction kinetic model established according to Fick’s first law of diffusion and related parameters of polysaccharide was studied. CPNP microcapsules were prepared by blending with sodium alginate, Ca2+ ions and crude CPNP. The quality control (drug loading rate, embedding rate and release rate, etc) of CPNP microcapsules were analyzed by pharmacopeas standards. The structure feature of CPNP microcapsules also were determined with various methods. The wound healing ability of CPNP microcapsules loading with different concentration of CPNP was evaluated using the rat wound model. The activity of various enzymes and the expression levels of pro-inflammatory factors in the model skin tissue also were determined by enzyme linked immunosorbent assay (ELISA). Hematoxylin-eosin staining (HE), Masson, immunohistochemistry were used to investigate the external application effect of CPNP microcapsules on skin wound repair. The extraction kinetics of CPNP was established with the linear correlation coefficient (R2) of 0.83–0.93, implied that the extraction process was fitted well with the Fick’s first law of diffusion. The CPNP has good compatibility with sodium alginate and Ca2+ ions by SEM and TEM observation, and the particle size of CPNP microcapsules was 21.25 ± 2.84 μm with the good degradation rate, loading rate (61.59%) and encapsulation rate (55.99%), maximum swelling rate (397.380 ± 25.321%). Compared with control group, the redness, and swelling, bleeding, infection, and exudate of the damaged skin decreased significantly after CPNP microcapsules treatment, and the CPNP microcapsules groups exhibited good wound healing function with less inflammatory cell infiltration. The pathological structure showed that in the CPNP microcapsules group, more newborn capillaries, complete skin structure, and relatively tight and orderly arrangement of collagen fibers were observed in the skin of rats. CPNP microcapsules could effectively inhibit the high expression of pro-inflammatory factors in damaged skin, and significantly increase the contents of related enzymes (GSH-Px, T-AOC, LPO) and collagen fibers. The relative expression levels of genes (VEGF and miRNA21) in the CPNP microcapsules group were higher than those in the model group and the negative group. The above results suggested that the CPNP microcapsules could controlled-release the CPNP to the wound surface, and then played a better role in antibacterial, anti-inflammatory and skin wound repair.

Modelling of bioactive components extraction from corn seeds

Corn is the most widely cultivated grain worldwide, due to its employability in human and animal nutrition. This grain has bioactive compounds with high pharmacological benefits. Several traditional techniques for extracting bioactive compounds from plant matrices involve solid-liquid extraction, commonly dynamic maceration. The main factors that can influence the yield and selectivity of this extraction are: solvent, time, temperature, solid-liquid ratio and particle size of material. In this context, extraction kinetic models have been applied to simulation and design studies. The objective of this work was to adjust extraction kinetic models based on experimental data of bioactive compounds extracted from corn seeds. In this way, solvents used were methanol/water 70/30 (v/v), methanol/water 95/5 (v/v), ethanol/water 70/30 (v/v) and ethanol/water 95/5 (v/v) and the extraction times were 1, 4 and 24 h. Extraction efficiency was monitored by the DPPH free radical scavenging test, using gallic acid as a standard. Best results were obtained with the solvent methanol/water 70/30 (v/v) during 1 and 4 h of extraction. Kinetic models that best fitted experimental data were First Order and So and MacDonald’s, while those that could not present good statistical analyzes were Parabolic Diffusion and Power Law.

PRE-TREATMENT TEMPERATURE AND MULTI-RESPONSE SURFACE OPTIMISATION OF ULTRASOUND-ASSISTED EXTRACTION OF ANTIOXIDANTS FROM RED DATES

Ziziphus jujube known as red dates are natural flora, are a rich source of antioxidant bioactive compounds and are widely used in making Chinese traditional medicine. However, the optimization of extraction conditions and demonstration of extraction kinetics of red dates remains a gap. Therefore, the main objective of this research was to enhance the antioxidant activity via DPPH, crude extract yield, and TPC by response surface methodology (RSM). Also, mathematical modeling of the TPC extraction kinetics was performed. Single-factor experiments were adopted to identify the preliminary RSM ranges of four extraction parameters such as liquid-solid ratio (10, 20, and 30 ml/g), extraction temperature (50, 60 and 70°C), time (40, 50 and 60min), and ultrasonic power (70, 80 and 90%). The extraction kinetics based on RSM optimized conditions were modeled into six extraction kinetic models. As result, the highest crude extract yield (4.56 g), highest TPC (0.023 g GAE/g extract), and highest antioxidant activity (85.88%) were obtained at 60ºC. The optimum values were liquid-solid ratio 30ml/g, extraction temperature 60°C, time 60 min, and ultrasonic power 70%. The antioxidant activity of red dates after optimization (90.59%) was higher than that of synthetic antioxidants, Butylated Hydroxytoluene (84.71%), and Butylated Hydroxyanisole (77.73%). Furthermore, the best-fitted kinetic model was the second-order kinetic model due to its coefficient of determination (R2) at 0.9849, being the closest to 1 and its root mean square error (RMSE) was the lowest, 0.001028 among other models.

Study on extraction kinetics of Salviae Miltiorrhizae Radix et Rhizoma: model establishment and investigation of critical process parameters

In this study, Fick's first law and partition equilibrium were used to represent the internal and external mass transfer processes of Salviae Miltiorrhizae Radix et Rhizoma at the macroscopic level, and a mass transfer model was established. The specific surface area was integrated into the mass transfer resistance, which effectively avoided the irregular shape of medicinal materials and expanded the application scope of the model. Meanwhile, the mass transfer model was further combined with the kinetic model of salvia-nolic acid degradation to establish the extraction kinetic models of salvianolic acid B, lithospermic acid and Danshensu. The model was applied to study the extraction process of Salviae Miltiorrhizae Radix et Rhizoma. According to the sensitivity analysis results, the relative error of the model prediction was within 5% near the maximum extraction rate(320 min), and the prediction performance of the model was good. According to the investigation results of different process parameters, stirring could significantly accelerate the mass transfer rate of salvianolic acid B, while the mass transfer resistance and degradation rate constant were not affected by solvent-to-solid ratio. The linear relationship between the reciprocal of temperature and the logarithm of mass transfer resistance was good(R~2=0.996), indicating that the temperature and mass transfer resistance conformed to Arrhenius formula. In addition, we also found that the concentration changes of lithospermic acid and Danshensu were weakly affected by mass transferwhen the extraction temperature was higher than 358 K. This study has provided the basis for the process optimization and quality control of traditional Chinese medicine extraction.

The Reaction Extraction Combining Crystallization for Growth of Sodium Chloride in a Spray Fluidized Bed Crystallizer

At present, the crystal size of sodium chloride prepared by a traditional crystallization process (such as stirred crystallization) is inhomogeneous, and it has a great quantity of fine grains in crystallizer. This work presents a novel approach for the growth of sodium chloride from supersaturated solutions by reaction-extractive crystallization in a spray fluidized bed crystallizer (SFBC), in which sodium sulfate solution is transformed into potassium chloride and sulphuric acid based on a reactive extraction-crystallization process using triisooctylamine (TOL) in n-octanol as the extraction system. This paper mainly studies the effect of operating conditions (e.g., circulation flow rate, velocity ratio of oil and aqueous phases, crystallization temperature, hydraulic residence time, and feed velocity) on the crystal size distribution (CSD) during the crystallization process of sodium chloride in a SFBC. Experimental results show that the optimum conditions are 1.0362 m/s as the best circulation flow rate, 9.5 : 8.5 as the best velocity ratio of oil and aqueous phases, 313 K as the best temperature, 4320 s as residence time, and 8 mL.min−1 as the best feed velocity. Meanwhile, the proposed extraction kinetic model about extraction rates is developed and validated against data from the SFBC. And it proves that the reactive extraction system is controlled by diffusion and chemical reaction. Analysis of the extraction kinetic model and comparison with experiments reveal that the extraction kinetic model results are in well agreement with experiments. Furthermore, the uniform and large crystals can be obtained in a spray fluidized bed crystallizer without special concentration since extraction and crystallization are carried out in the same equipment. In addition, all of the sodium chloride products prepared under the optimal conditions in SFBC show a better CSD performance than the stirred crystallization. This research demonstrates that this process enables controlling the crystal size in a rather wide range, thus further underlining the potential of this technique for applications in the crystallization industry.

Effect of ultrasound power on extraction kinetic model, and physicochemical and structural characteristics of collagen from chicken lung

The effects of ultrasound power on extraction kinetic model, and physicochemical and structural characteristics of collagen from chicken lung were studied. Ultrasound power caused a significant increase in extraction rate and equilibrium concentration, with the maximum extraction yield (31.25%) at 150 W. The experimental data were consistent with the predicted ones in this empirical equation, in which the percentage error differences was 0.026–4.159%. Besides, ultrasound treatment did not affect their triple-helical structure. The thermal stability of pepsin-soluble collagen by ultrasound pre-treatment (UPSC) was higher, due to the higher imino acid content (20.76%). UPSC also exhibited better solubility and fibril forming capacity. Overall, the kinetic model of UPSC from chicken lung could serve the purpose of obtaining collagen, which displayed a potential alternative source to mammal collagens for application in food, biomaterials and biomedical fields.Graphical abstract

A green and integrated strategy for enhanced phenolic compounds extraction from mulberry (Morus alba L.) leaves by deep eutectic solvent

Green and tailor-made deep eutectic solvents (DESs) coupled with microwave-assisted extraction (MAE) were performed to extract phenolic compounds from mulberry leaves. Among the twelve DESs prepared, Choline chloride/Glycerol (1:2) with 20% water content was more efficient to get high extraction yields of phenolics. Then, several essential parameters of microwave-assisted deep eutectic solvents extraction (DES-MAE) were optimized by single-factor and Box-Behnken design (BBD) experiments. According to the result of optimization, the total extraction yield of target phenolic compounds reached 8.352 mg/g at microwave temperature 66 oC for extracting 18 min with the liquid/solid ratio of 20 mL/g, which was obviously superior to conventional solvent extraction. In addition, the extraction kinetic models confirmed that microwave-assisted extraction was a more efficient extraction technique than ultrasound-assisted extraction and heat-refluxing extraction. Meanwhile, the macroporous resin was utilized to enrich and separate target compounds from DES extracts, and the recovered DES still exhibited a good solvent effect to be applied for re-extraction. Therefore, DES-MAE followed by macroporous resin column chromatography was a green and integrated strategy for the extraction and preparative separation of active ingredients from plant materials.

In Situ Formation of Ionic Liquid by Metathesis Reaction for the Rapid Removal of Bisphenol A from Aqueous Solutions

In this work we present a rapid and easy method to remove the totality of bisphenol A from aqueous solutions using ionic liquid (IL). Dispersive liquid–liquid microextraction is employed. The IL 1-octyl-3-methylimidazolium bis((trifluoromethane)sulfonyl)imide ([C8C1im] [NTf2]) is formed in situ because of the mixture of 1-octyl-3-methylimidazolium chloride ([C8C1im]Cl) and lithium bis(trifluoromethanesulfonyl)imide (Li[NTf2]) aqueous solutions. A cloud of microdroplets of IL formed by the dispersion generated through the precursors metathesis reaction allows the rapid and total extraction of bisphenol A (BPA). After centrifugation, the formed IL phase is deposited at the bottom of the flask and the total amount of BPA is extracted in the sedimented phase. The volume of IL is very low, in the order of microliters, which enables us to remove all the BPA from the solution. The technique studied is highly efficient, cost-effective, and presents less environmental impact than other extraction techniques, thus becoming an outstanding alternative to the most commonly used methods. BPA concentration is determined by high performance liquid chromatography by injecting the IL phase directly. An extraction kinetic model for the kinetic profile has been tested for this method, which allows to infer the ideal experimental conditions to execute the extraction method.

Empirical kinetic models for the electrochemical extraction of arsenic and heavy metals from clay containing tailings

Three empirical kinetic models for the arsenic, iron and manganese electrochemical extraction from clay containing tailings highly contaminated were analysed: the intraparticle diffusion model, the Elovich model and the two first-order reactions model. Models were chosen regarding their relative simplicity and accuracy of fitting experimental data. Elovich model was the best fitted model for the As extraction data with the lowest average relative error (ARE = 0.320) and the highest coefficient of determination (R2 = 0.986). The intraparticle diffusion model was the most adequate to describe the Fe and Mn extraction (ARE = 0.142, R2 = 0.942 for Fe, and ARE = 0.112, R2 = 0.926 for Mn). The influence of the current intensity, extractant concentration and liquid/solid ratio on the coefficients of the extraction kinetic models was also determined. Arsenic extraction Elovich model coefficients showed a direct linear relationship with the process variables while iron and manganese extraction diffusion model coefficients showed a direct linear relationship with the current intensity and the extractant concentration but an inverse relationship with the liquid/solid ratio. Response surface plots were used for estimating the interactive effect of the four independent variables studied (current intensity, extractant concentration, liquid/solid ratio and time) on the electrochemical extraction.