Extraction Kinetics Research Articles

Kinetics of titanium extraction at hydrometallurgical fluoridation of titanomagnetite ore

Kinetics of titanium extraction at hydrometallurgical fluoridation of titanomagnetite ore

Kinetics Extraction of Arabica Coffee Bean (Coffea Arabica)

Coffee beans are the seeds of the coffee plant and a source of coffee beverages. Arabica coffee beans contain oil which has many benefits. The process of extracting oil (solute) in coffee can be done through solvent extraction (leaching). The coffee bean oil extraction process uses n-hexane as a solvent because it can dissolve compounds that have the same properties. The purpose of this research was to study the extraction of essential oil from Arabica coffee beans and to determine the kinetic model of extraction of essential oil from Arabica coffee beans by leaching. The process of separating coffee oil and solvent using thermogravimetric analysis with a temperature of 80℃ until the sample mass is constant. The variables used were temperature and time. The extraction time is 2 hours with retrieval time every 10 minutes. The temperature used is 30°, 40°, and 50℃ with a ratio of material and solvent 1:10. The results showed that the kinetics of arabica coffee extraction followed the second-order extraction kinetics model. The second-order kinetic parameter values of arabica coffee essential oil extraction namely extraction capacity (Cs) at 30°, 40°, and 50℃ were 5.45836, 5,46, and 5.46001 g L-1, respectively, the rate of the initial extraction (h) was 0,00762718, 0,00756716, and 0,0104452 gL-1minute-1, the extraction rate constant (k) was 0,000256, 0,000254, and 0,00035 g-1L-1minute-1, and determination values of 0,9965, 0,9967 and 0,9983.

Synergistic Behavior and Kinetics of Yttrium Extraction from Nitric Acid Using a Binary System of Cyanex 572 and Cyanex 302

This study explores the extraction of Y(III) from nitric acid solutions using a kerosene-based blend of Cyanex 572 (H₂B₂) and Cyanex 302 (H₂A₂). Slope analysis suggests that the extracted species formed in the presence of this mixture is likely YH₄A₃B₄. Separation factors for Y(III) relative to other rare earth elements, specifically Nd(III) and La(III), demonstrate the effectiveness of the Cyanex 572 and Cyanex 302 mixture for selective separation. To gain deeper insights into the extraction mechanism, a kinetic study was conducted using a Lewis cell. The extraction kinetics of Y(III) from the nitric acid medium were analyzed by applying pseudo-first-order rate constants. Results indicate that the process is diffusion-controlled and involves an interfacial reaction. This conclusion is supported by investigating the effects of stirring speed, temperature, extractant concentration, and nitrate and hydrogen ion concentrations on the extraction rate. From the experimental data, a rate equation was derived, and the rate-determining step was identified using interfacial reaction model predictions. Additionally, an extraction model is proposed to elucidate the underlying mechanisms.

Efficient and fast recovery of indium with phosphate-functionalized polyaniline porous carbon self-supported electrode by electrosorption-deposition strategy

Extraction of indium, that an important strategic resource, is limited by the low extraction capacity in the acidic environment, and sluggish adsorption kinetics. Electrodes and adsorption technologies can be combined to improve extraction capacity and kinetics, having high exploitation in metal recovery. A novel phytic acid-doped polyaniline/porous carbon (PA-PANI/PC) carbon cloth self-supported electrode is developed for extracting In(Ⅲ) from aqueous solutions by electrosorption-deposition strategy in this work. A series of characterization analysis show that PA-PANI/PC exhibits electrics double-layer capacitance and pseudocapacitance as well as abundant specific binding sites for In(Ⅲ) and improved hydrophilicity, which all conducive to the extraction of In(Ⅲ). As expected, PA-PANI/PC-2 exhibits the maximum extraction capacity of 284.67 mg/g within 60 min at pH 2.5, which represents the highest reported capacity for the extraction of In(Ⅲ), to date. Benefiting from complexation with phosphate groups, In(Ⅲ) can be directly recovered in the form of precipitation, avoiding backwashing with concentrated acid. Furthermore, the adsorbent maintains great affinity and selectivity for In(Ⅲ) even in multi-component simulated system. The low-cost adsorbent PA-PANI/PC based on simple and low-energy electrosorption-deposition process shows potential in terms of effectively recovering In(Ⅲ) from practical ore fluid.

In situ growth of hierarchical porous covalent organic framework coating for enhanced solid-phase microextraction of phenolic compounds

Covalent organic frameworks (COFs), when utilized as solid-phase microextraction (SPME) coating materials, exhibit remarkable abilities to concentrate phenols by thousands-fold owing to their vast surface area and exceptional stability. However, the prevalent micropores inherent in COFs can impede rapid mass transfer of target molecules, prolonging SPME extraction times. To addresses this limitation, this work introduces a novel approach by integrating hierarchical porous structures into COFs, leveraging polystyrene microspheres as hard templates during the in situ growth process of the SPME coating. Due to the presence of a hierarchical porous structure derived from the template, the resulting hierarchical porous TpBD coating, termed HP-TpBD, demonstrated enhanced extraction efficiency, accelerated extraction kinetics, and notably shortened extraction times for phenolic compounds. Coupled with gas chromatography-mass spectrometry, a highly sensitive method featuring a low limit of detection (0.20–0.28 ng L-1), a broad linear range (1.0∼1.0 × 104 ng L-1), and excellent precision (RSD < 8.5 %) was established. This methodology enables accurate quantitative analysis of phenols in water and soil samples. This work provides valuable insights into developing COF-based SPME coatings for the efficient extraction of volatile contaminants, paving the way for more efficient and sensitive analytical procedures.

A novel ternary hydrophobic deep eutectic solvent over a wide pH range for lithium recovery

Owing to the crucial role of lithium (Li) in green technology and energy storage, the global demand for Li is constantly increasing. This article provides a new strategy for recovering Li using ternary hydrophobic deep eutectic solvent (HDES). The novel HDES was composed of 2-thiophenyltrifluoroacetone (HTTA), trioctylphosphine oxide (TOPO), and N,N-diethyldecanamide (DDA), and exhibited high efficiency and selectivity for extracting Li from aqueous solutions. This study systematically evaluated the effect of the initial aqueous pH on the Li extraction efficiency, revealing the stable performance of HDES in the pH range 3–13. Compared to the highly alkaline environment required for Li extraction, the pH characteristics of the HDES provide a wider range of applications and a more environmentally friendly alternative. The HDES exhibited rapid extraction kinetics, achieving equilibrium within 10 min and maintaining phase stability without emulsification. The main mechanism of selective Li extraction is the electrostatic interaction between Li(I) and TTA. The interactions between Li(I) and both TOPO and DDA were confirmed by Fourier transform infrared (FT-IR) spectroscopy, thereby improving the selectivity and extraction efficiency. The countercurrent extraction process demonstrated an impressive Li extraction rate of 98.704 % and a Li(I)/Na(I) separation factor of 10643.14 with industrial Li2CO3 mother liquor, highlighting the application potential of the ternary HDES. The excellent performance of the HDES over a wide pH range provides more opportunities for its application, and its high efficiency, selectivity, and environmental characteristics may promote Li recovery.

Biocompounds recovery from purple corn cob by-product: extraction kinetics, thermal and physicochemical stability of liquid and powdered anthocyanin-rich extract

This study evaluated the thermal degradation kinetics of total monomeric anthocyanins (TMA) from in-natura purple corn cob and the recovery of bioactive compounds from their by-products. The TMA and antioxidant capacity (AC) extraction kinetics were evaluated by conventional (CE) and ultrasound-assisted extraction (UAE, 25°C, 40kHz, 32W/L) methods. The stability of liquid and powdered extract by using maltodextrin (M) [M(2%)] and corn starch (C) [M(1.5%) + C(0.5%)], was evaluated. Thermal degradation kinetics (65-90°C) showed that TMA are relatively stable at high temperatures, with a half-life of 5.3h at 90°C and an activation energy of 949.2J·mol-1. The TMA and AC extraction kinetics from corn cob by-product, described by the Peleg model, showed that the UAE had the highest extraction rate (<k1) and equilibrium yield (<k2), reducing CE times by up to 58% and 67%, for TMA and AC respectively. Furthermore, the stability of this extract was greater at pH ≤ 3, decreasing at neutral and alkaline pH. On the other hand, the water adsorption isotherms modeled by GAB model showed that the powder [M(1.5%) + C(0.5%)] had greater stability (Xm = 5.97g/100g d.m.) compared to the powder [M(2%)] (Xm = 3.71g/100g d.m.). Additionally, significant differences were observed between treatments in terms of color density, polymeric color, and % tannin contribution, where the powder [M(1.5%) + C(0.5%)] demonstrated greater stability. These results highlight the effectiveness of the UAE method for recovering TMA and AC from purple corn cob by-products and the importance of storage conditions and pH in the stability of anthocyanin-rich extracts and powders with potential applications in food and non-food industries.

An emulsion extraction system composed of hydrophobic deep eutectic solvent and water for synchronous extraction of oil and phenolic compounds from U.S. pecans [Carya illinoinensis (Wangenh.) K. Koch]

U.S. pecan nuts are rich in oil and phenolic compounds with important biological functions. At present, the reports about simultaneous extraction of oil and phenolic compounds are limited, and the traditional procedure is complicated and the yield is low. In this study, a new emulsion formed by hydrophobic deep eutectic solvent (DES) and water was used as extractant for synchronous extraction of oil and phenolic components from U.S. pecans, and subsequently the two were recovered from the upper and lower phases based on the incompatibility of DES and water, respectively. The oil and phenolic compounds obtained by the optimization of extraction conditions were 615.29 mg/g and 82.11 mg/g, respectively, which were higher than those obtained by conventional methods. At the same time, the extraction mechanism is discussed through the extraction kinetics and thermodynamics. The extraction process conformed to the Fick’s second law, and it was an endothermic process. After directional recovery by macroporous resin and back-extraction, the effectiveness of the method was proved by the analysis of fatty acid composition of oil, spectral characterization of phenolic compounds and antioxidant activities.

Mechanisms of Cd immobilization in contaminated calcareous soils with different textural classes treated by acid- and base-modified biochars

Acid or base modification of biochars has shown promise for enhancing the immobilization of potentially toxic elements (PTEs) such as cadmium (Cd) in contaminated soils. However, limited information is available on the interaction between soil textural classes and modified biochar application for Cd stabilization in contaminated calcareous soils. Therefore, the objective of the study was to examine the extent of Cd immobilization in contaminated calcareous soils with diverse textural classes, utilizing both acid (HNO3) and alkali (NaOH) modified and unmodified biochars derived from sheep manure and rice husk residues. The modified or unmodified biochars were applied at a rate of 2% (w/w) to Cd-contaminated silty clay loam, loam, and sandy loam soils, followed by a 90-day incubation at field water capacity. Sequential extraction and EDTA-release kinetics studies were used to assess the effect of the treatments on the extent and mechanisms of Cd immobilization. Among the treatments, acid-modified manure biochar was most effective at reducing water soluble and exchangeable Cd fractions (-20.5%), by converting them into metal oxide and organic matter bound fractions. This effectiveness was primarily attributed to the significant increase in surface oxygen functional groups in the acid-modified biochar which could promote Cd complexation. However, the acid-modified manure biochar released more immobilized Cd during EDTA extraction than the base-modified manure biochar, suggesting that EDTA extraction of R-O-Cd complexes was easier than extracting Cd associated with insoluble compounds. This difference was likely due to the acidic pH and lower ash content of the acid-modified biochars compared to the base-modified manure biochars. Additionally, the extent of Cd immobilization was lower in sandy loam soil, highlighting the importance of immobilizing Cd in light-textured soils to prevent its transfer to organisms.

Efficient Extraction and Analysis of Wheat Straw Lignin by Response Surface Methodology

To enhance the high-value utilization of straw waste and achieve efficient lignin extraction, wheat straw was selected as the feedstock for investigating the effects of reaction temperature, reaction time, solid–liquid ratio, and formic acid concentration on lignin yield using a formic acid/acetic acid solvent system. A single-factor experimental design was initially employed, followed by optimization using the response surface methodology. Additionally, a kinetic model was developed to describe lignin extraction kinetics in the formic acid/acetic acid system. The structural characteristics and thermal stability of the extracted lignin were analyzed via FTIR, UV spectroscopy, and TGA. The findings indicate that increasing reaction temperature, reaction time, solid–liquid ratio, and formic acid content all significantly enhanced lignin extraction yield from wheat straw, with the primary influencing factors being reaction temperature &gt; solid–liquid ratio &gt; reaction time &gt; formic acid content. The optimal extraction conditions were identified at a reaction temperature of 90 °C, a reaction time of 3.5 h, a solid–liquid ratio of 1:16.5, and a formic acid content of 86.2 wt.%, yielding a lignin content of 79.83%. The analytical results demonstrated that the extracted lignin preserved the structural integrity of the original lignin and exhibited good thermal stability.

Study of the extraction kinetics of flavonoids from the fruits of Sophora japonica L. with sunflower oil

Among the large number of biologically active substances contained in the fruits of Sophora japonica L., the extraction of flavonoids, substances of medium polarity, is particularly important. The process of extracting them with vegetable oil from fruits is quite complicated. The object of research is the kinetics of the process of extracting flavonoids from Sophora japonica L. fruits with sunflower oil. The influence of temperature, duration, and hydraulic modulus on the extraction process, as well as on the derivation of the equation of the mathematical model, is studied. Mathematical modeling methods are used in the research. Processing of experimental data for the study of extraction kinetics in the vegetable oil:vegetable raw material system is carried out using the Statistica statistical package. In order to derive the equation of the mathematical model of the process of extracting flavonoids from Sophora japonica L. with sunflower oil, the influence of temperature, duration and hydromodulus on the process of transition of the target component – flavonoids to the extract – is investigated. A mathematical model of the dependence of flavonoids on the hydromodulus (H=10–25), temperature (t=25–45 °С) and the duration of the extraction process of Sophora japonica L. (τ=2–10 h) is obtained, which makes it possible to calculate the content of flavonoids with an average relative with an error within 5 %. On the basis of the conducted experimental studies, basic technological schemes for obtaining unrefined sunflower oil of increased biological value are developed, which includes the following stages: preparation of raw materials, treatment of prepared raw materials with sunflower oil during dilution and mixing, separation of oil from raw materials by filtering. The proposed technology is promising, as its implementation is possible not only in food industry enterprises, but also in restaurant establishments, as it does not require expensive equipment, additional production premises and special training of personnel. The mathematical models of the extraction process of Sophora japonica L. with unrefined sunflower oil proposed in the work allow to select the extraction parameters with a high degree of probability and offer the consumer flavonoid-enriched sunflower oil of increased biological value.

A novel trialkyl phosphate – Ionic liquid mixture for an efficient separation of Lithium ion from its acidic feed solution

Separation of Lithium ion (Li+) using conventional non-crown type ligands through solvent extraction process is a challenging task and can only be feasible by tuning the organic phase with an additional polar environment. In this context, we have projected an extracting system containing a traditional trialkyl phosphate (T(alk)P): Tri-iso-amyl phosphate (TiAP) containing a minimal amount of ionic liquid (IL): [C4mpip][NTf2] (1-butyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide) for the efficient extraction and separation of Li+ from its hydrochloric acid feed. The extraction performances pertaining various experimental parameters were realized to explore the solvent potentiality of TiAP/[C4mpip][NTf2] towards Li+ coordination. Involvement of two ligand molecules in extraction in presence of 10 % (v/v) IL diluent offers fast extraction kinetics and turns the extraction mechanism into a cation exchange pathway, which was further examined by using different classes of ILs in conjunction with TiAP for Li+ uptake. The selectivity of Li+ over other alkali (or alkaline earth) metal ions was investigated to highlight the affinity of the proposed IL system towards Li+. Extraction scenario in TiAP phase was compared with that in TBP phase containing same IL to bring out the efficacy of the proposed IL system. The stripping performance of Li+ from the loaded organic phase was studied using an acid solution to establish the sustainability of the proposed extraction process.

Determining the efficient mass ratio of the extractant and the object of extraction and the equilibrium concentrations of the target components in them

The caviar and lecithin complex of freshwater fish can be widely used for the production of various food products, including those of functional orientation. The main technological operations in lecithin technology should include the processes of extraction of the initial caviar raw material and raffinate obtained after the first stage of selective extraction. The purpose of the study is to identify the rational mass ratio of extractant and raw material (module), on which the extraction efficiency depends, as well as the final concentration of extracted substances in the extract to determine its current value in the process of mass transfer to study the kinetics of extraction. The object of the study is the caviar-anchovy complex of fathead carp, carp, pikeperch and catfish, as well as the extract and raffinate from it. Summarizing the experimental data on revealing the rational module, as well as the final concentration of extracted substances in the extracts obtained, we can conclude that for caviar of the fish species under study, the rational hydromodule for its extraction with acetone is the ratio of dry caviar : extractant 1 : 4, and for its extraction with ethyl alcohol is the ratio of dry caviar : extractant 1 : 8. If the mass ratio refers to the fresh caviar of the studied fish species, then its rational indicator at its extraction with acetone is the ratio of fresh caviar : extractant 1 : 1.5, and at its extraction with ethyl alcohol is the ratio of fresh caviar : extractant 1 : 3. The average final concentration of extracted substances from dry caviar of the studied fish species in the extracts obtained, if acetone was used as a solvent under rational conditions of mass transfer, corresponds to the value of 1.3 %, and if ethyl alcohol was used as a solvent under rational conditions of mass transfer, corresponds to the value of 1.0 %.

Isoflavone-rich extracts from okara using supercritical fluid extraction: Kinetic modeling and characterization

The lipid fraction and bioactive compounds from okara, a by-product of soybean processing, have been extracted by supercritical fluid extraction. The effect of operating parameters, pressure (20–40 MPa), temperature (40–80 ºC), and cosolvent usage (0–10 %wt. ethanol), on the extraction kinetics has been investigated, satisfactorily correlating the experimental data to the Sovová’s model. Extraction yield by SFE ranged from 0.1014 g extract/g insoluble solid (IS) at 20 MPa and 80 ºC to 0.1081 g extract/g IS at 30 MPa and 60 ºC (from 9.2 to 9.8 g extract/100 g okara, respectively), similar to Soxhlet extraction with n-hexane (9.2 ± 0.2 g extract/100 g). Pressure positively affected the initial extraction rate, which also increased with temperature except for the lowest pressure of 20 MPa, exhibiting a typical cross-over behavior. The use of ethanol as cosolvent promoted the extraction of phenolic compounds and isoflavones, and was less important in the extraction of tocopherols. Extraction yield using ethanol increased up to 0.1100 g extract/g IS at 40 MPa and 40 ºC. As expected, the higher content of bioactive compounds in the sc-CO2 + ethanol extracts positively affected the antioxidant capacity, with the maximum found at 20 MPa, 40 ºC and 10 %wt. ethanol.

Efficient ultrasonic extraction of alkaloids and glycosides from Camptotheca acuminata Decne via deep eutectic solvents: Kinetics and mechanisms

The study investigated the extraction of alkaloids and glycosides from the Camptotheca acuminata Decne using deep eutectic solvent (DES). 18 types of deep eutectic solvents (DESs) were prepared, and it was found that the extraction performance of choline chloride (ChCl)-formic acid (FA) was optimal, surpassing traditional solvents such as methanol/70 % methanol. In comparison to methanol, the extracted amount of compounds by DES was 2–3 times higher. The extraction processes involving the molar ratio of ChCl-FA, pH, DES/H2O mass ratio, solid/liquid ratio, as well as ultrasonic power were optimized. A mathematical model for solid/liquid extraction kinetics from Camptotheca acuminata Decne was developed. The extraction mechanism was investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and 1H nuclear magnetic resonance(1H NMR). The results revealed that the DES caused dissociation in Camptotheca acuminata Decne and formed hydrogen bonds with Camptothecin (CPT). Meanwhile, density functional theory (DFT) calculations verified that FA-based exhibited the highest extracted amount for CPT. In addition, this study investigated the recovery rate of DES, and the results showed that after 10 cycles, the DES system remained effective for the extraction of alkaloids and glycosides.

Synergistic ternary deep eutectic solvents: An archetype for sustainable and eco-conscious Li and Co recovery from spent batteries

The development of sustainable materials for energy is a critical challenge in the pursuit of a circular economy. This study presents an innovative approach for recycling lithium-ion batteries (LIBs) using a novel, sustainable deep eutectic solvent (DES) composed of glycine, ascorbic acid, and water. This natural, chloride-free ternary DES leverages the biocompatible and eco-friendly properties of its constituents, achieving exceptional leaching efficiency of 99.1 % for lithium and 97.9 % for cobalt under optimized conditions. A multifaceted methodology integrating advanced factorial design, kinetic modeling, and machine learning was employed to refine the process parameters and enhance leaching efficiency. The extraction kinetics were predominantly governed by endothermic surface reactions, characterized by activation energies of 81.5 kJ/mol for Co and 110.9 kJ/mol for Li. An ensemble neural network model accurately predicted the extraction with an R2 > 0.95, demonstrating the robustness of the computational approach. The DES exhibited excellent recyclability over five cycles, thereby emphasizing its potential for practical industrial applications in the field of sustainable materials management. This approach facilitated the selective recovery of high-purity lithium oxalate and cobalt oxalate, underscoring the efficiency and environmental benefits of the process. DFT calculations provided insights into the extraction mechanism, revealing the crucial role of hydrogen bonding and synergistic effects of the DES components. This pioneering study not only advances LIB recycling but also establishes a comprehensive, quantitatively validated framework, paving the way for future innovations in sustainable materials management and supporting global efforts towards a circular economy in energy storage.

Efficient Electron Injection into Graphullerene Enables Reversible NaC2 Sodium Storage.

Sodium-ion batteries are emerging as promising alternatives to conventional lithium-based technology, offering solutions to challenges in large-scale grid storage. However, the capacity of conventional graphite-based anodes for storing Na-ions is inherently limited by suboptimal thermodynamic interactions and irreversible structural changes that occur in the anode during charge-discharge cycles. Herein, we present a computational design that explores the potential of graphullerene, a two-dimensional framework with interconnected fullerene moieties, for the reversible storage of Na-ions. A unique aspect of this design is the electron injection capacity into the graphullerene anode, reaching 15 electrons per fullerene moiety, which is the highest limit to date. This advancement enables large-scale Na-ion storage up to the stoichiometry of NaC2, exhibiting specific capacity of 551 mAhg-1 and averaged open circuit voltage of 0.18 V vs Na/Na+. In addition, the multilayered arrangement of stored Na-ions enhances the Na-ion diffusivity on the graphullerene surface, leading to rapid insertion and extraction kinetics. Thus, raising the electron injection limit offers a promising strategy to transform carbon-based anodes into suitable candidates for reversible Na-ion storage, without relying on artificial defect introduction or doping.

Analysis of the composition of Brazilian black soybean seeds and mathematical modelling of intermittent drying and extraction of antioxidant compounds using fractional calculus

AbstractThe present study aims to analyze the composition of black soybean seeds, evaluate the intermittent drying of black soybean seeds by fractional calculus, optimize the extraction conditions of the antioxidant compounds by varying the solvent ratio and the extraction time, fit traditional models of extraction kinetics, and compare with the fractional order model. Regarding the oil content, it is analyzed that black soybeans have a high lipid content (18.86%), an oil source of interest for research and industrial applications. Regarding drying, it was found that the first order model cannot be used to describe the kinetics of intermittent drying for black soybean seeds and the best kinetic fits were obtained with the Page and fractional order models, which can be applied in simulations of drying and dryer designs. Regarding the extraction process, ethanol/water 45/55 (v/v) solvent proportion obtained the highest antioxidant compound content during 1 h of extraction. So and MacDonald's and hyperbolic kinetic models presented the best fitting to experimental data. About the fractional order model, it is found that for extraction conditions with more significant amounts of water in the ethanolic solution, the α value obtained is less than 1, resulting in the phenomenon of subdiffusion. For the extraction condition with a low amount of water in the ethanolic solution, the α value was greater than 1, depicting a superdiffusion process.

Application of zwitterionic ionic liquid-based capsule phase microextraction for the HPLC-UV determination of doxycycline in human urine samples

Herein, we describe the utilization of an ionic liquid (IL)/Carbowax 20 M−functionalized sol–gel sorbent for the capsule phase microextraction of doxycycline in authentic human urine samples. This green sample preparation method combines stirring and filtration in a single, standalone sample preparation device, streamlining the sample preparation process. Additionally, it provides rapid extraction kinetics and high extraction efficiency. The experimental conditions (i.e. sorbent type, sample pH and volume, extraction time, ionic strength, elution solvent, and volume) affecting the extraction efficiency of the analyte were studied and optimized. The method was linear in the range of 0.1 – 5.0 μg/mL with a coefficient of determination higher than 0.995. The achieved LOD was found to be 0.02 μg/mL while the lower limit of quantitation (LLOQ) was 0.1 μg/mL. The IL/Carbowax 20 M−functionalized microextraction capsules were reusable at least 30 times for urine samples. The relative recoveries (% RR) ranged between 93.4 – 115.9 % while the precision (expressed as % RSD) was better than 8.1 % in all cases. The robustness of the microextraction procedure and the instrumental HPLC method were separately investigated using Plackett-Burman experimental designs. The analytical protocol demonstrated cost-effectiveness, ease of handling, and speed, leading to increased sample throughput. The green character of the developed method was evaluated using the Green Analytical Procedure Index (GAPI) and Blue Applicability Grade Index (BAGI). Finally, the method’s applicability was demonstrated by analyzing authentic human urine samples after oral administration of a doxycycline-containing pharmaceutical formulation.

A Kinetic Study of Silver Extraction from End-of-Life Photovoltaic Panels through Gold-REC1 Process

Recycling materials from end-of-life devices and products is becoming increasingly a fundamental activity for the sustainable development of nations. With the return from the market of immense quantities of photovoltaic panels at the end of their life, it is essential to foresee processes for recovering and valorizing all the raw materials present in them to avoid wasting important flows of raw materials. This research introduces a novel process aimed at the recovery of silver and silicon from end-of-life photovoltaic panels. The leaching efficiency and kinetics of ground cake powder in sulfuric acid, ferric sulfate, and thiourea were investigated in the leaching system. In particular, the influences of significant parameters, including particle size, leaching temperature, and stirring rate, on the extraction kinetics were analyzed using the shrinking core model. The results showed silver dissolving mechanisms, in which more than 90% of silver recovery at 60 min of reaction time and 99% at 120 min was achieved (120 rpm, 53–125 µm, and 40 °C). The significant effect of the leaching temperature suggests that the process is under the control of the chemical reaction. Moreover, these results were confirmed by the regression analysis of the experimental data with the shrinking core model. It can be concluded that this newly proposed process, called Gold-REC1, allows the recovery of Ag and Si (solid residue from the process) with extremely high yields and rapid kinetics. The obtained results can provide fundamental data for developing end-of-life photovoltaic recycling on an industrial scale.