Reactive Extraction Research Articles

Upgrading AquaSolv Omni (AqSO) biorefinery: access to highly ethoxylated lignins in high yields through reactive extraction (REx)

Ethanol-mediated reactive extraction is a green and simple process to simultaneously extract and functionalize lignin from wood. Ethoxy groups were incorporated in up to 40.8/100 Ar and the lignins were found suitable for adhesive formulations.

Highly selective separation of tetravalent plutonium from complex system with novel phenylpyridine diamide ligands.

In this study, three phenylpyridine diamide ligands, namely, 2,2'-((pyridine-2,6-diylbis(3,1-phenylene))bis(oxy))bis(N,N-diethylacetamide) (PPEA, L1), 2,2'-((pyridine-2,6-diylbis(3,1-phenylene))bis(oxy))bis(N-ethyl-N-phenylacetamide) (PEPA, L2), and 2,2'-(((4-phenylpyridine-2,6-diyl)bis(3,1-phenylene))bis(oxy))bis(N,N-dioctylacetamide) (PPOA, L3), were synthesized and explored for the solvent extraction of Pu(iv) in a HNO3 medium using 1-(trifluoromethyl)-3-nitrobenzene as the diluent. The effects of HNO3 concentration, extractant concentration, and temperature on the Pu(iv) extraction efficiency were studied. All three extractants displayed high selectivity for Pu(iv) over other metals such as U(vi), Np(v), Am(iii), and various fission elements. At 3 M HNO3, the distribution ratio for Pu(iv) reached 27.18, in contrast to 1.11, 0.3, and 0.03 for U(vi), Np(v), Am(iii), respectively. Slope analysis and UV titration revealed the formation of 1 : 1 Pu(NO3)4/ligand complexes during extraction. The extraction reactions had negative Gibbs free energies, indicating the spontaneous nature of Pu(iv) extraction at room temperature. Furthermore, the extractants demonstrated good stripping ability and reusability, and their radiolytic stability was reasonable up to an absorbed dose of 100 kGy, underscoring their potential for practical applications. Overall, this study broadens our understanding of actinide-diamide ligand coordination and actinide chemistry during coordination, paving the way for the design and synthesis of new extractants.

Recovery of valuable metals from spent lithium-ion batteries through an ecofriendly catalytic approach

The rapid growth of lithium-ion batteries (LIBs) used in electric vehicles is amplifying the importance of recycling valuable materials from spent batteries. Current recycling technologies utilize extractive metallurgical processes to recover metals, particularly from cathode materials. However, pyrometallurgy requires high temperatures for smelting, while hydrometallurgy relies on toxic chemical reagents for leaching. Here, we present a catalytic strategy designed to overcome the energy and environmental challenges associated with metallurgical processes. The extraction reaction is conducted using an HxRuO2 catalyst in the presence of HNO3, H2, and CO2. Extraction is achieved through the selective hydrogenation of nitrate to ammonia, followed by the carbonation of leached metal species. The catalytic process successfully achieves nearly complete recovery of Co and Li as carbonates from LiCoO2. Furthermore, we demonstrate the versatility of this catalytic approach in recovering metals from various cathode materials, including spent LIBs. This newly developed one-pot method offers a promising industrial process for recycling valuable metals from spent batteries in an atom-efficient and environmentally friendly manner, without generating waste.

Extracting structured data from organic synthesis procedures using a fine-tuned large language model.

The popularity of data-driven approaches and machine learning (ML) techniques in the field of organic chemistry and its various subfields has increased the value of structured reaction data. Most data in chemistry is represented by unstructured text, and despite the vastness of the organic chemistry literature (papers, patents), manual conversion from unstructured text to structured data remains a largely manual endeavor. Software tools for this task would facilitate downstream applications such as reaction prediction and condition recommendation. In this study, we fine-tune a large language model (LLM) to extract reaction information from organic synthesis procedure text into structured data following the Open Reaction Database (ORD) schema, a comprehensive data structure designed for organic reactions. The fine-tuned model produces syntactically correct ORD records with an average accuracy of 91.25% for ORD "messages" (e.g., full compound, workups, or condition definitions) and 92.25% for individual data fields (e.g., compound identifiers, mass quantities), with the ability to recognize compound-referencing tokens and to infer reaction roles. We investigate its failure modes and evaluate performance on specific subtasks such as reaction role classification.

Selective separation of rare earth, Sr, Mo, and Zr from simulated raffinate of uranium/plutonium co-purification process

Spent fuel contains many elements including those that are radioactive. Separation and recovery of these substances have been challenging. This paper presents an efficient strategy for stepwise separation of the rare earth, strontium, molybdenum, and zirconium from the simulated raffinate of a uranium/plutonium co-purification process. This strategy employed three extractants with different metal ion selectivity, and cyclohexanediamine tetraacetic acid (CDTA) was introduced as a complexing agent to inhibit the extraction of Zr(IV) and precious metals. The recovery efficiency of all the rare earth elements was more than 97 % through the three-stage extraction, with N,N,N′,N′-tetranoctyl-diglycolamide (TODGA) as the extractant and N,N-dibutyloctanamide (DBOA) as the phase modifiers. Sr(II) was selectively recovered using N,N,N′,N′-tetracyclohexyl-diglycolamide (TCHDGA). A bisphosphonic acid extractant, N,N-hexadecylamine bis (methylene phenylphosphonic acid) (HADMPPA), was designed and synthesized for the selective separation of Zr(IV) and Mo(VI). The separation conditions of the recovered elements from other elements in each step were systematically examined. Moreover, the mechanism of the extraction reaction was investigated using FTIR spectroscopy, the slope method, and the equimolar series method. To our knowledge, this is the first time that four groups of major elements have been sequencially separated from the simulated high-level waste liquid in one process. This work could contribute to nuclear fuel reprocessing as well as the sustainable development of nuclear energy.

Lithium Dendrite Propagation in Anode-Free Lithium Metal Batteries: An in-Operando Scanning Electron Microscopic Study

In the current technological landscape, lithium metal batteries have significantly surpassed the energy density of conventional lithium-ion batteries. Therefore, The advent of anode-free lithium metal batteries (AFLMBs) offers higher energy densities.. They also provide advantages such as reduced process complexity and lower costs due to their design that eliminates the need for anode materials. Unlike the lithium-ion insertion and extraction reactions in traditional lithium-ion batteries. This makes them easier to lithium dendrite formation, which can puncture the separator or solid electrolytes, among other issues. In this work, we developed anin-operando electron microscopic technique with a unique vacuum square-cell design to ensure air-tight transfer of in-operandocells with vacuum protection into the SEM chamber. We significantly improved the imaging resolution with a windowless design, enabling the direct electron beam to focus on the electrode interfaces. Thus, real-time imaging of Li growth could be achieved via a stable current supply and controlled temperature. we systematically analyzed the Li growth and dendrite propagation behavior in AFLMBs using solid polymer electrolyte (SPE). In particular, we used polyethylene oxide (PEO)-based SPEs containing different lithium salts, namely 25wt% Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), Lithium difluoro (oxalateo)borate (LiDFOB), and Lithium bis(oxalate)borate (LiBOB), within a LiFePO4||Cu anode-free cell configuration. Under a fixed current density, Li deposition and stripping were conducted, in which the PEO-LiTFSI SPE exhibited uniform deposition with a mossy lithium dendrite morphology. In the subsequent deposition process, some branching lithium dendrites were observed. Meanwhile, PEO-LiBOB showed uneven Li deposition with needle-like dendritic formation, potentially disrupting the SPE/electrode interface and leading to safety hazards. Lastly, PEO-LiDFOB initially showed mossy lithium deposition. In contrast, a few dendritic lithium structures appeared as the deposition process continued into the intermediate and later stages. The study successfully established a novel in-situ electron microscopy observation platform isolating water and oxygen. This platform recreated the actual battery operating environment, enhancing the credibility of experimental results. Additionally, we successfully elucidated the growth mechanisms of lithium dendrites in SPE with different lithium salts in the LFP||Cu configuration. This in-situ microscope technology aims to observe the relevant mechanisms behind dynamic deposition. Understanding how this deposition affects battery performance and safety and combining it with advanced operational and ex-situ characterization techniques can further promote the development of all-solid -state batteries in the future.

The Natural Ficus carica L. (fig) Extract as an Effective Prophylactic Antibacterial Agent for Inflammation-Related Infections.

Klebsiella pneumoniae (K. pneumoniae) is a multidrug-resistance Gram-negative organism responsible for carbapenem-resistant infections. These challenges have inspired studies on the use of natural products as alternatives to conventional drugs. The aim of this study was to analyze the antibacterial and antioxidant effects of Ficus carica L. (fig) branch extracts and to perform in vivo animal experiments to better understand the absorption mechanisms of the antibacterial components during the digestion process after oral administration. The antibacterial components of the fig branch extracts were analyzed via gas chromatography-mass spectrometry (GC-MS). An in vivo animal study and liquid chromatography-triple quadrupole-tandem mass spectrometry (LC-QQQ-MS/MS) analyses were performed to analyze the deacetylation reactions of the fig extracts after oral administration in mice. Ultimately, the antibacterial effects of the fig extracts increased with the fractional distillation time. The fig extracts showed excellent antibacterial effects against K. pneumoniae, as well as Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa). The three antibacterial and antioxidant components of the fig extracts were revealed to be eugenol, acetyleugenol, and psoralen. Interestingly, in this study, we identified acetyleugenol in the phenolic compounds of the fig extract for the first time. Through in vivo animal testing, we observed the deacetylation reaction of acetyleugenol to eugenol in the fig extract as digestion proceeded in the internal organs of the mice after oral administration. The results of this study suggest the use of natural fig extract as an effective therapeutic and prophylactic antibacterial agent for inflammation-related infections with a wide variety of biomedical applications.

Roles of Cyt-c/Caspase-9/Caspase-3/Bax/Bcl-2 pathway in Cd-induced testicular injury in rats and the protective effect of quercetin

Cadmium (Cd) exposure causes oxidative damage to mitochondria, which would adversely affect rat testicular tissue. Quercetin (Que) is a natural antioxidant with anti-inflammatory, antioxidant and anti-apoptotic effects. However, the mechanism by which Que inhibits Cd-induced apoptosis of testicular cells remains unclear. The purpose of this study was to investigate the role of mitochondrial apoptosis pathway (Cyt-c/Caspase-9/Caspase-3/Bax/Bcl-2 pathway) in inhibiting Cd-induced apoptosis of testicular cells by Que. We used SD rats to simulate Cd chloride exposure by treating all sides of the rats with CdCl2 and/or Que. The levels of GSH and MDA in rat testis were detected using reagent kits. The effects of CdCl2 and/or Que on tissue damage, apoptosis, and gene and protein expression of the Cyt-c/Caspase-9/Caspase-3/Bax/Bcl-2 pathway in rat testis were examined by HE, TUNEL, RNA extraction and reverse-transcriptase polymerase chain reaction (RT-PCR), and Western blot (Wb). The results show that Cd significantly increased the contents of GSH and MDA in rat testis (P < 0.01); conversely, Que significantly reduced the contents of GSH and MDA (P < 0.01). Cd inflicted damage to testicular tissue, and Que addition significantly reduced the damage. Cd increased the number of apoptosis of testicle cells, and Que inhibited testicle-cell apoptosis. In addition, the results of reverse transcription PCR and Wb assays confirmed that, as expected, Cd increased the expression levels of Cyt-c, Caspase-9, Caspase-3, and Bax mRNAs as well as proteins. And at the same time decreased the expression of the anti-apoptotic factor Bcl-2 in the cells. Surprisingly, these effects were reversed when Que was added. Therefore, Que can play an antioxidant and anti-apoptotic role in reducing the testicular tissue damage caused by Cd exposure. This provides a conceptual basis for the later development and utilization of Que as well as the prevention and treatment of tissue damage caused by Cd exposure.

Theoretical insights into the extraction behaviors of neptunium(VI) and plutonium(IV) based on the structure of organophosphorus ligands

Organophosphorus ligands such as TBP, TiAP, and DMHMP have exhibited excellent performance in recovering actinides from spent fuel. In this work, the molecular geometries and properties of TBP, TiAP and DMHMP were investigated using density functional theory calculations. Furthermore, the extraction mechanism of ligands for actinides (Np(Ⅵ), Pu(Ⅳ)) was further elucidated by simulating the microstructures and extraction reactions of metal–ligand complexes. The results demonstrate that the complexation ability of the three ligands on actinide cations (NpO22+ and Pu4+) follows the order of DMHMP > TiAP > TBP. The electrostatic potential (ESP) analysis indicates that the nucleophilic ability of DMHMP is stronger than that of the other two ligands. The frontier molecular orbital analysis of the three ligands represents that DMHMP has the highest HOMO energy, suggesting that it has the strongest electron-donating capability and is more likely to bond with metal ions. The values of Wiberg bond indices (WBI) suggest that the MO bonds in DMHMP complexes have more covalency. According to the QTAIM analysis, the interactions between actinide cations and the ligands are predominantly ionic in nature. The molecular orbital analysis of the complexes shows that the M(NO3)n·2DMHMP (MNpO22+ and Pu4+) complexes are more stable, which is supported by thermodynamic energy analysis. This work has clarified the complexing properties of actinide cations with three ligands, shedding light on the extraction mechanisms of organophosphorus ligands for actinide cations. It is anticipated to lay the theoretical foundation for the efficient recovery of critical actinide elements in spent fuel reprocessing, which will also provide innovative approaches for the design and development of related separation processes.

Effect of CH4 Addition on Soot Formation in C2H4 Diffusion Flame

Abstract Studying the effect of co-combustion of multiple fuels on soot formation has become a hot spot in the investigation of soot particles. In this paper, the influence of methane blending on soot formation in ethylene flame combustion is studied experimentally and numerically. The visible spectrum of flame image processing technology was used for the in situ measurement of laminar flame temperature and carbon smoke volume points in the experiment. The effects of different methane blending ratios on particle nucleation, coalescence, surface growth, and oxidation process of soot were analyzed based on the piecewise particle dynamics soot model of polycyclic aromatic hydrocarbons (PAHs) using CoFlame Code. Results indicate that the synergistic effect promoted the increasing rate of nucleation and addition reaction of hydrogen extraction at a low methane blending ratio, and the increase in the total mass of soot was mainly due to the PAH condensation rate. The total amount of soot generation gradually decreases with increasing blending ratio. The overall trend of condensation, surface growth rate, and soot nucleation in the flame decreases with increasing blending ratio. And the nucleation rate gradually shifts from a single peak to a double peak and increases slightly at the initial stage of the flame combustion reaction. It is worth mentioning that the change of three PAH precursors (secondary benzo(a)pyrenyl, benzo(a)pyrene, and benzo(ghi)fluoranthene) and the temperature explains the change of nucleation rate from unimodal to bimodal.

Pengaruh Variasi Waktu dan Kecepatan Pengadukan Terhadap Difusivitas dan Konstanta Reaksi Dengan Proses Ekstraksi Reaktif

The world is experiencing a crisis of scarcity of diesel fuel sources. The B30 program is to develop energy sources by utilizing alternative energy sources to prevent petroleum shortages. This program also supports research, namely making biodiesel using non-edible raw materials. Apart from that, another benefit of this research is to determine the effect of time on the yield of biodiesel production, knowing the effect of stirring speed on the diffusivity constant and reaction speed constant of the reactive extraction process. Biodiesel production in this research uses a reactive extraction process. The raw materials used are mahogany seeds, the solvent is methanol, chloroform as a co-solvent, and KOH as a catalyst. This process uses a temperature of 65°C, reaction time of 40 and 80 minutes, and varying stirring speeds of 200 and 300 rpm. The effect of time with a variable stirring speed of 200 rpm the longer the resulting yield increases, while at a stirring speed of 300 rpm the resulting yield decreases. The yield obtained at 200 rpm stirring was 82.363% (40 minutes), 87.6366% (80 minutes), 84.7605% (40 minutes), and 78.7204 (80 minutes). For the methyl ester diffusion constant, the stirring speed of 200 rpm is 8,20 x 10-8 dm2/minute, while the stirring speed of 300 rpm is 8,17 x 10-8 dm2/minute. The reaction rate constant is 1.99 dm3/mol min.

Streamlined instrument-free lysis for the detection of Candida auris

The continued spread of Candida auris in healthcare facilities has increased the demand for widely available screening to aid in containment and inform treatment options. Current methods of detection can be unreliable and require bulky and expensive instruments to lyse and identify fungal pathogens. Here, we present a quick, low-cost, instrument-free method for lysis of C. auris suitable for streamlined sample processing with polymerase chain reaction (PCR) detection. Chemical, thermal, and bead beating lysis techniques were evaluated for lysis performance and compatibility with nucleic acid extraction and downstream PCR reactions. Using only 10 s of manual shaking with glass beads, this method demonstrated a limit of detection (LOD) of C. auris at 500 colony forming units per mL, a 20-fold improvement compared to the LOD without manual shaking, and a 60-fold reduction in time compared to common fungal lysis kits, all while maintaining repeatability and reproducibility across multiple users. This work highlights a simple method for increasing sensitivity and reducing turnaround time of PCR-based C. auris detection and exhibits promise for integration into point-of-care platforms towards real-time triage of colonized patients.

In Situ Transesterification from Soybean Seed Using Mechanochemical Methods toward Producing Biodiesel.

The research and development of new routes of biodiesel synthesis have been increasingly in line with the principles of green chemistry. In this sense, mechanochemistry is a promising technique, able to ally the energetic potential with reductions in the use of solvents and steps of treatment of the sample and the purification of the product. To date, this is the first work using mechanochemistry directly in extracting soybean oil from its seed and the in situ transesterification reaction by applying a reactive soybean oil extraction process. The presence of n-hexane was studied in different molar proportions (relative to the oil content), and a low solvent consumption in a 3:1 ratio was adopted. Mechanochemistry favored oil diffusion in the n-hexane solvent, resulting in a mean triglyceride content equal to 90%, against 66% obtained in the tests without spheres in the planetary ball mill. The catalyst content was also evaluated, and 4% NaOH (weight, concerning the oil) was the concentration that presented less residue of nontransesterified glycerides in the samples for ethyl ester preparation. Additionally, the protein content was determined on the residual soybean cake, with no loss of nutritional potential when subjected to the mechanochemical process.

Sequential Extraction and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy Monitoring in the Biorefining of Brewer's Spent Grain.

The brewing industry plays a significant role in producing a substantial annual volume of by-products, which contributes to the global accumulation of food waste. The primary by-product generated is brewer's spent grain (BSG), a lignocellulosic biomass rich in proteins, fiber, and moisture content. Leveraging biorefining and valorization techniques for BSG represents a promising strategy to enhance sustainability, resilience, and circularity within the brewing chain. To date, most studies have focused on extracting proteins from BSG. Yet, it is crucial to note that the fiber part of BSG also holds considerable potential for biorefining processes. This study introduces a novel sequential extraction method designed to integrally recover the major components of BSG. Notably, it introduces a reactive extraction approach that enables the simultaneous extraction and tuneable functionalization of the hemicellulose component. Additionally, the study assesses the utility of the attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy as a user-friendly tool to monitor and evaluate the effectiveness of the fractionation process. This spectroscopic technique can provide valuable insights into the changes and composition of BSG throughout the extraction process.

Heterocyclic Ligands with Different N/O Donor Modes for Am(III)/Eu(III) Separation: A Theoretical Perspective.

Excellent "CHON" compatible ligands based on a heterocyclic skeleton for the separation of trivalent actinides [An(III)] from lanthanides [Ln(III)] have been widely explored, the aim being spent nuclear fuel reprocessing. The combination mode of a soft/hard (N/O) donor upon the coordination chemistry of An(III) and Ln(III) should play a vital role with respect to the performance of ligands. As such, in this work, two typical experimentally available phenanthroline-derived tetradentate ligands, CyMe4-BTPhen (L1) and Et-Tol-DAPhen (L4), and two theoretically designed asymmetric tetradentate heterocyclic ligands, L2 and L3, with various N/O donors were investigated using scalar relativistic density functional theory. We have evaluated the electronic structures of L1-L4 and their coordination modes, bonding properties, and extraction reactions with Am(III) and Eu(III). We found that the Am/Eu-N interactions play a more important role in the orbital interactions between the ligand and Am(III)/Eu(III) ions. Compared with those of L1, the coordinated O atoms of L2 and L4 weaken the metal-N bonds. The Am(III)/Eu(III) selectivity follows the order L1 > L2 > L4 based on the change in Gibbs free energy, reflecting the fact that the Am(III)/Eu(III) selectivity of the ligand is affected by the number of coordinated N atoms. In addition, L3 displays the strongest binding ability for Am(III)/Eu(III) ions and the smallest Am(III)/Eu(III) selectivity among the four ligands, due to its structural preorganization. This work clarifies the influence of the number of coordinated N and O atoms of ligands on Am(III)/Eu(III) selectivity, which provides valuable fundamental information for the design of efficient ligands with N and O donors for An(III)/Ln(III) separation.

Sequential separation and recovery of phosphorus and lithium from lithium phosphate slag by selective extraction-precipitation

The efficient utilization of lithium and phosphate resources from lithium phosphate slag, a byproduct originated from lithium extraction, holds great significance for environmental protection and industrial advancement. Existing methods primarily focus on Li extraction from this slag, while phosphate resources are often overlooked. In this work, we proposed an alternative approach based on impurity extraction, followed by sequential precipitation of FePO4 and Li2CO3, to concurrently recover lithium and phosphate from lithium phosphate slag. The results demonstrated an aluminum separation efficiency of 85 %, effectively reducing the aluminum concentration in the raffinate to below 25.0 mg/L. The extraction reaction, facilitated by saponification, involved cation exchange between Al3+ and Na+. The synthesis process of FePO4·2H2O was predominantly controlled by the chemical reaction with an activation energy of 102.8 kJ/mol. The obtained FePO4·2H2O and Li2CO3 products met the standards for battery-grade materials. Notably, the process achieved a remarkable phosphorus recovery rate of 98.7 % while maintaining a low lithium loss rate of below 2.0 %. This work presents an efficient and environmentally friendly method for achieving comprehensive recovery of lithium and phosphate resources from lithium phosphate slag.

Detection of SARS-CoV-2 variants among travelers crossing the northern international border checkpoint in Duhok province, Iraq

Background: Variants of SARS-CoV-2 have been detected along with the worldwide COVID-19 transmission. Insufficient data exists regarding SARS-CoV-2 variants in Iraq, particularly concerning travelers at Iraqi border crossings. This study aimed to screen SARS-CoV-2 variants among individuals entering Iraq from Turkey through the Ibrahim Khalil international border checkpoint. Methods: A total of 116 (52 females, 64 males) COVID-19-positive cases from June 6, 2021, to July 30, 2021, were randomly selected from the Ibrahim Al-Khalil border crossing point between Turkey and Iraq. The patients were Iraqis tested positive for COVID-19 through nasopharyngeal and oropharyngeal swab collections. The confirmation of SARS-CoV-2 cases involved RNA extraction and real-time reverse transcription polymerase chain reaction (RT-PCR), following the World Health Organization guidelines. All samples were subjected to variant detection using the reverse transcription RT-PCR method. The RNA was extracted using a Zybio nucleic acid extraction kit and the RT-PCR was conducted using SARS-CoV-2 S-gene mutation detection RT-PCR kit. Results: In the 116 patients, we detected variants B.1.1.7, B.1.617.1.2, B.1.617.1.3, and Omicron sub-lineages (B.1.1.529, BA.1) at frequency rates of 13, 16, 45, and 36 cases, respectively. The highest prevalence rate was the delta variant among the tested subjects (38.8%) followed by the Omicron sub-lineages (B.1.1.529, BA.1) at 31%. Conclusion: This finding, which is the first of its kind at the northern Iraqi border checkpoint, suggests that these two variants could be a source of COVID-19 circulating in the Duhok province in Iraq. Additional studies are warranted across the country’s border entry points.

Extraction of Cerium from Nitric Acid Medium using Cyanex 302 and Cyanex 572

In this paper, the extraction of cerium from the synthetic environment ([Ce]=0.04 M) was investigated using the solvent extraction method with a mixture of solvents. Considering that the synergy of extractants can lead to the improvement of cerium extraction, Cyanex 302 solvent was used for synergy with Cyanex 572. The results showed that the combination of Cyanex 572-Cyanex 302 can extract a high percentage of cerium (&gt; 90%). Also, the value of ΔG is equal to 18.61 (kJ/mol), so the extraction reaction of Ce (III) is non-spontaneous.

Selective separation of vitamin C by reactive extraction using ionic liquid: Experimental and modelling

Vitamin C (ascorbic acid), is an important nutrient widely used as a dietary supplement in the food, beverage, cosmetic and feed industries or as a drug in the pharmaceutical industry. It can be produced by a traditional two-step fermentation or a novel one-step process, but its separation from the fermentation broth still needs improvement. This study investigated a reactive extraction method to selectively separate vitamin C from 2-ketogluconic acid using an ionic liquid as the extracting agent and heptane as diluent. The separation efficiency and selectivity factor, as well as the analysis of extraction conditions (type and ionic liquid concentration, pH of the aqueous phase, contact time, temperature) influence and extraction mechanism were discussed. Heptane as the solvent and 100 g/L [P6,6,6,14][Phos] as the extractant were the optimum mixture for reactive extraction, resulting in an extraction yield of 99.98 % for vitamin C. A maximum selectivity factor of 3.5 was obtained for ascorbic acid for 160 g/L [P6,6,6,14][Phos] and pH 3 of the aqueous phase. The process was modeled and optimized using an Artificial Neural Networks (ANNs) and Differential Evolution (DE) algorithm. Based on the performance parameters evaluated and extraction yields obtained, ionic liquids have great potential for vitamin C separation.

Reactive extraction of pyridinedicarboxylic acid (PDCA) with tri-n-octylamine and Aliquat 336 in 1-octanol – A promising approach to access microbially produced PDCA

Pyridinedicarboxylic acids (PDCA) are analogues to terephthalic acid and promising molecules for the production of bio-based plastics. Previous work achieved the microbial production of PDCAs from the renewable resource lignin but an efficient and low cost method to recover PDCA from fermentation broth is still missing. Reactive extraction is commonly applied for the extraction of carboxylic acids from aqueous phase. In this study, we investigate reactive extraction of PDCA with the two extractants tri-n-octylamine (TOA) and Aliquat 336 in the diluent 1-octanol. The extraction and re-extraction were optimized with 2,5-PDCA in an aqueous solution leading to up to 98 % extraction for both extractants. Re-extraction by pH swing resulted in > 95 % re-extracted 2,5-PDCA. A scale-up in liquid–liquid centrifuges enabled continuous extraction and re-extraction in liter scale with a yield of 95 %. A concentration factor of 3.6 was achieved and the organic phase was recycled. The approach also showed transferability to the processing of complex fermentation solution. 2,4-PDCA, microbially produced in a bioprocess, could be recovered by 65 % in one single extraction and re-extraction step from biomass-free fermentation broth.