While quasi‐2D perovskite is often used in inverted perovskite solar cells (PSCs) to improve the interfacial carrier transfer, the development of pure 2D perovskite with superior stability is rarely ...seen and the corresponding carrier‐extraction kinetics remains unclear. Here, a variety of hexatomic ring cations including piperidine, pyridine, and cyclohexane are introduced to modify the perovskite/electron transport layer interface. The Dion–Jacobson phase 2D cladding (n = 1) based on 3‐(aminomethyl) piperidinium is proved to form a coordinated energy landscape and homogeneous surface potential distribution, and effectively prolong the electron diffusion length (≈1.58 µm) and accelerate the hot‐carrier extraction rate (2.5 times that of Control at 400 K). Furthermore, the quasi‐2D treatment (n ≈ 3,4) demonstrated a slight escalation in short‐circuit current, but failed to inhibit the interdiffusion of Ag, Pb, and I under illumination. Finally, one of the state‐of‐art power conversion efficiency (PCE) for MA‐free inverted PSCs is achieved at 23.62% with increased open‐circuit voltage (≈1.15 V) and fill factor (≈82.8%). Most importantly, 89% and 93.6% of initial PCE are retained after 720 h under 85 °C heating and 1000 h under maximum power point tracking, illustrating satisfactory thermal and operational stability with pure 2D perovskite capping layer.
The pure Dion–Jacobson phase 2D capping layer (n = 1) based on 3‐(aminomethyl) piperidinium is demonstrated to form a coordinated energy landscape and homogeneous surface potential distribution at the upper surface of inverted perovskites, effectively reducing the severe interfacial recombination and accelerating the extraction of electrons at the perovskite/PCBM interface before hot‐carrier cooling.
•Ultrasound-assisted extraction using clean, green solvents.•Mechanism of ultrasound-assisted extraction.•Design and development of ultrasound-assisted extraction systems.
The objective of this ...review is to discuss the ultrasound-assisted extraction (UAE) of various compounds using clean, green solvents. We also outline fundamental mechanisms and factors associated with the design and the development of clean, green UAE systems. Growing consumer demands for greener alternatives and natural ingredients that do not involve toxic chemicals and the environmental and health risk associated with the use of chemical solvents have attracted the interest of industries to sustainable, non-toxic routes of extraction. UAE can benefit the chemical industry in multiple ways:
•enhancing extraction yield;•enhancing aqueous extraction processes without using solvents;•providing the opportunity to use alternative clean and/or green solvents by improving their extraction performance; and,•enhancing extraction of heat-sensitive components under conditions that would otherwise have low or unacceptable yields.
•Black chokeberry pomace is valorized as a source of anthocyanins.•A novel extraction method based on an aqueous solution of citric acid is considered.•The extraction is performed in continuous mode ...to enhance the yields.•Pressurized liquid fluid extraction assisted ultrasound extraction was chosen as method.•The extraction yield was increased 19% compared to the correspondent batch process.
This work aimed to investigate the optimum conditions of pressure, temperature, ultrasound intensity, solvent concentration and solvent flowrate of ultrasound-assisted pressurized liquid extraction of anthocyanins from Aronia melanocarpa pomace. The novel setup operates with an aqueous solution of citric acid as extraction solvent. The optimization was performed in order to maximize the total anthocyanins content extracted from the pomace. The optimized conditions of 70 °C, 180 bar, a solvent concentration of 1.5 % wt. citric acid, in a 200 W ultrasound bath were obtained. These conditions resulted in 88.0 % wt. extraction of anthocyanins in 45 min. A kinetic study was performed to study the influence of the temperature on the total anthocyanin yield obtained at the optimal extraction conditions.
Moreover, the component stability was assessed to prove that the system could successfully operate at 80 °C. Compared to classical batch extraction using the same solvent concentration and feedstock, the total anthocyanin content of the extract was increased by 19%.
•DESs were firstly developed as green media for the extraction of caffeine from CDT.•The major factors influencing the extraction were optimized by RSM.•The Kamlet-Taft polarity parameters for the ...DESs solution were measured.•The extraction kinetics model was established using the Fick’s Second Law.
In recent years, more and more attention are paid to the green media in the extraction field. Deep eutectic solvents (DESs) are considered as excellent substitutes to traditional organic solvents and ionic liquids (ILs). In this work, DESs were used to extract caffeine from Chinese dark tea (CDT), then caffeine was recovered from the crude DES extract using macroporous resins. The factors affecting the solid-liquid extraction, including DES concentration, liquid-solid ratio, extraction time, extraction temperature, and system pH were studied in the single factor experiments. The Kamlet-Taft polarity parameters of DESs were determined to analyze the proper hydrogen-bond interaction between DESs and caffeine. Then the major factors of DES concentration, liquid-solid ratio, and extraction time were optimized by response surface methodology (RSM). The results showed that the maximum extraction yield of 26.78 mg/g were obtained using the DES choline chloride-lactic acid (ChCl-LA) as extractant under the optimized conditions. Moreover, the kinetics model of caffeine extraction was established using the Fick’s Second Law, the experimental results were well fitted by this model. This extraction of caffeine from CDT using DESs is much simpler and environmentally friendly with low cost and high extraction efficiency.
•The extraction equilibrium of mixed acid in the nitric acid-hydrochloric acid–potassium chloride system with tributyl phosphate shows that the extractant can efficiently separate nitric acid and ...hydrochloric acid.•The nitric acid extraction process in the nitric acid- hydrochloric acid–potassium chloride/TBP-sulfonated kerosene system has been systematically investigated.•A mixed control mathematical model is established to reasonably describe the overall extraction rate of nitric acid in the system.
The preparation of potassium nitrate from nitric acid and potassium chloride is considered a promising process. It is essential to efficiently separate nitric acid and hydrochloric acid from the crystallization mother liquor containing nitric acid, hydrochloric acid, and potassium salt. This article explored the thermodynamic equilibrium of nitric acid extracted from the nitric acid-hydrochloric acid–potassium chloride system by tributyl phosphate. It was discovered that nitric acid and tributyl phosphate are combined through TBP·HNO3. A constant interfacial area cell was adopted to investigate the extraction kinetics of nitric acid by tributyl phosphate dissolved in sulfonated kerosene. The most obvious finding to emerge from this study is that the extraction of nitric acid in this system occurs at the organic-aqueous interface. Which is jointly controlled by the diffusion of organic phase substances and interfacial chemical reactions. Finally, the mathematical model was established to reasonably describe the overall rate equation of nitric acid extraction, and the corresponding mass transfer coefficient and reaction rate constant were obtained.
Pectin as a hydrocolloid has countless functional applications in food and related industries. The extraction techniques considerably influence the composition, characteristic and extractability of ...the target compound, hence there is an ongoing effort to understand the extraction process using theoretical approaches. This review aims to provide a comprehensive overview of different mathematical approaches reported for describing the solid-liquid extraction process for pectin. As the major source of pectin is citrus waste, the extraction techniques described in this review article have considered citrus processing waste as a major substrate. Chemical rate law, empirical models and mechanistic approaches have been considered in the study. The modelling approaches are based on the hydrolysis, diffusion and degradation of pectin in a homogenous medium, and have been described either as a single or combination of more than one phenomenon. The application of models has been critically reviewed with respect to the influence and interdependencies of the parameters on the extraction kinetics with reference to advance green techniques such as subcritical water, microwave and ultrasonic-assisted extraction processes. Understanding of these models can be used to successfully to predict the properties of extraction systems at a phenomenological scale.
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•Reviewing mathematical approaches to describe batch extraction mechanism of pectin.•Interpretation of empirical model, chemical rate law and mechanistic model.•Modelling included hydrolysis, diffusion and degradation steps in homogenous medium.•Critical comparison of the application of models with respect to green techniques.•Robust model building would need coextraction of multiple compounds.
A transient and one-dimensional mathematical model with two partial differential equations is developed to simulate the extraction of de-oiled rosemary plant in a vertical fixed-bed reactor. The ...effect of the dimensionless numbers which appear in the final governing equations (Peclet and Damköhler numbers) is studied. The influence of solvent composition, solid particle size and temperature is also investigated. The process is controlled by internal diffusion effects, with the smallest particle size exhibiting the smallest internal diffusion coefficient. Among the different solvents, 80% ethanol shows the highest total phenolics recovery. The antiradical activity is also enhanced by increasing the temperature and the smaller particle size leads to an improvement in the extraction selectivity. Peclet number has a small effect on the results, while Damköhler number strongly affects the process. An increase in bed porosity causes a significant increase in the internal diffusion time.
•The Damköhler number strongly affects the process.•Internal mass transfer is the controlling step.•Increasing bed porosity augments internal diffusion time.•Grinding and increasing temperature reduce mass transfer limitations.
•Ultrasonic-microwave technique combined with ethanol, as green solvent, was used to extract oil from green coffee beans.•The extraction process was optimised using response surface methodology (RSM) ...and central composite design (CCD).•Extraction kinetics for green coffee oil during ultrasonic-microwave extraction was established.•Evidence of structural changes caused by ultrasonic-microwave treatment in residue coffee was observed by scanning electron microscopy (SEM).
This study was designed to integrate ultrasonic-microwave assisted extraction (UMAE) with ethanol, a green solvent, to extract green coffee oil (GCO) from green coffee beans. Response surface methodology was utilised to maximise the efficiency of GCO extraction. Structural changes occurring in the coffee residue were explored using scanning electron microscopy, and extraction kinetics was established. Results indicated that the yield of GCO obtained by UMAE under optimum conditions (microwave power 350 W; extraction time 10 min; and liquid-solid ratio 28:1 mL/g) was 10.58 ± 0.34%. Extraction kinetics revealed that UMAE exhibited higher efficiency and took less time (10 min vs 5 h with solvent extraction) compared with conventional process. The highest contents of kahweol and cafestol found in the UMAE extract were 12.00 and 22.28 mg/g oil, respectively. This study demonstrated that UMAE with ethanol is a rapid, efficient, and environmentally friendly green technique for the extraction of green coffee oil.
► Improvement of polyphenols extraction from black chokeberry with ultrasound assistance. ► Evaluation of the effect of main process parameters on the extraction efficiency. ► Correlation between ...antioxidant activities and polyphenols in the extracts. ► Potential replacement of synthetic antioxidants by extracts from black chokeberry.
Ultrasound assisted extraction (UAE) of antioxidant polyphenols from Aronia melanocarpa berries was studied. The influence of various parameters (time and temperature of extraction, solvent composition, solid–solvent ratio, particle size, and ultrasonic irradiations) on the extraction kinetics and yields was evaluated. Very clear effect of ultrasound was observed (up to 85% increase of the yield of extracted polyphenols). High temperature and the presence of ethanol in the solvent improved also greatly the extraction process. The high antioxidant activity of the extracts determined by DPPH tests confirmed suitability of UAE for the preparation of antioxidant-rich plant extracts. A very good correlation between the concentration of polyphenols in the extracts and the corresponding antioxidant activity was observed.
In this study, the deep eutectic solvent based ultrasound-assisted extraction (DES-UAE) was investigated for the efficient and environmentally friendly extraction of Selaginella chaetoloma total ...biflavonoids (SCTB). As an extractant for optimization, tetrapropylaminium bromide-1,4-butanediol (Tpr-But) was employed for the first time. 36 DESs were created, with Tpr-But producing the most effective results. Based on response surface methodology (RSM), the greatest extraction rate of SCTB was determined to be 21.68 ± 0.78 mg/g, the molar ratio of HBD to HBA was 3.70:1, the extraction temperature was 57 °C, and the water content of DES was 22 %. In accordance with Fick's second rule, a kinetic model for the extraction of SCTB by DES-UAE has been derived. With correlation coefficients 0.91, the kinetic model of the extraction process was significantly correlated with the general and exponential equations of kinetics, and some important kinetic parameters such as rate constants, energy of activation and raffinate rate were determined. In addition, molecular dynamics simulations were used to study the extraction mechanisms generated by different solvents. Comparing the effect of several extraction methods on S.chaetoloma using ultrasound-assisted extraction and conventional methods, together with SEM examination, revealed that DES-UAE not only saved time but also enhanced SCTB extraction rate by 1.5–3 folds. SCTB demonstrated superior antioxidant activity in three studies in vitro. Furthermore, the extract could suppress the growth of A549, HCT-116, HepG2, and HT-29 cancer cells. Alpha-Glucosidase (AG) inhibition experiment and molecular docking studies suggested that SCTB exhibited strong inhibitory activity against AG and potential hypoglycemic effects. The results of this study indicated that a Tpr-But-based UAE method was suitable for the efficient and environmentally friendly extraction of SCTB, and also shed light on the mechanisms responsible for the increased extraction efficiency, which could aid in the application of S.chaetoloma and provide insight into the extraction mechanism of DES.
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