Liquid-liquid Extraction Process Research Articles

Reactive liquid-liquid extraction of lactic acid from microfiltered sweet sorghum silage press juice in an agitated extraction column using a hydrophobic natural deep eutectic solvent as modifier

Downstream processing of carboxylic acids from fermentation broths is cost-intensive and environmentally harmful, which makes methods such as reactive liquid-liquid extraction attractive separation technologies. To enhance the sustainability of liquid-liquid extraction processes, research focuses on sustainable solvents like hydrophobic natural deep eutectic solvents. However, the application of hydrophobic natural deep eutectic solvents in agitated extraction columns for continuous processing has never been investigated. This is essential to facilitate their use in industrial processes, promoting cleaner production. In this study, the application of a thymol-menthol-based deep eutectic solvent as a modifier (with the extractant tri-n-octylamine) in an agitated extraction column is evaluated for reactive liquid-liquid extraction of lactic acid from microfiltered sweet sorghum silage press juice. In addition, three-stage cross-current extractions were performed. The thymol-menthol-based deep eutectic solvent showed efficient phase separation, stable operation, and chemical stability in the agitated extraction column. In three-step cross-current operation, the extraction efficiency for lactic acid was increased from 37.0 ± 0.4 % without feed pH adjustment to 76.2 ± 0.9 % with continuously adjusting the pH value to 2.05 ± 0.02. The thymol-menthol-based deep eutectic solvent shows great potential for application in agitated extraction columns. This is highly promising because natural deep eutectic solvents can enhance the sustainability of extraction processes and reduce the reliance on fossil-based solvents.

Impacts of synthesis variables on spectroscopics evaluation of biobased fatty amide as alkylammonium salt’s precursor for perovskite

Ammonium salts are widely used in chemical industries as additives in cement industries, phase change materials in thermal cooling, ionic materials in electrochromic window and multifunction medium/precursor/catalyst in solar cells to improve the efficiency and stability. This work introduces a procedural enhancement by incorporating a liquid-liquid extraction purification process, resulting in a high-purity biobased fatty amide (FA) with tri-substitution and high-purity biobased tetraalkylammonium ammonium salt (TAS). Biobased FA derived from renewable sources was synthesized via an amidation reaction between fatty acids from vegetable oil with tris(3-aminopropyl)amine under reflux conditions, producing a precursor for TAS used in perovskite solar cell (PSC). This study aimed to optimize and determine the reaction condition of biobased FA at various key synthesis variables by investigating the effects of solvent selection, reaction and crystallization, temperature, catalyst, mole ratio, and dehydrating agent on synthesis yield. A multiple liquid-liquid extraction process was employed to enhance the purity of biobased FA by tunning the selection of solvent based on its relative polarity of the reactant and products. Response surface methodology (RSM) and central composite design (CCD) were utilized to optimize the total yield and the three key variables (reaction time, crystallization time, catalyst amount) respectively. The experimental model developed in this study demonstrated a high degree of fitness with the experimental data (F-value = 27.34), p-value < 0.05) and nonsignificant lack of fit. The model predicted a maximum synthesis yield percentage of 52.62 % under optimal conditions (reaction and crystallization time of 12 and 28 hours), respectively with 4.47 % catalyst). The coefficient of determination of R2 = 0.98 shows a high correlation with the predicted values and in good agreement with the experimental values. Physicochemical properties analysis using spectroscopies techniques, confirmed improved purity with 100% abundance yield of tri-substitution biobased FA and enhanced TAS’s purity up to 60%. The optimization study sheds light on the impact of key synthesis variables on the synthesis yield and percentage abundance (purity), advancing the development of more efficient and tailored sustainable construction materials. These findings highlight the potential of using biobased FA as a sustainable source for TAS production, contributing to a more environmentally friendly approach in PSC development.

Mineral Acid Co-Extraction in Reactive Extraction of Lactic Acid Using a Thymol-Menthol Deep Eutectic Solvent as a Green Modifier.

Carboxylic acids can be isolated from fermentation broths using reactive liquid-liquid extraction, offering an alternative to the environmentally harmful state-of-the-art process of precipitating calcium lactate. To enhance the sustainability of liquid-liquid extraction processes, greener solvents, such as natural deep eutectic solvents, are investigated. However, fermentation broths often exhibit pH values unsuitable for carboxylic acid extraction, which can be adjusted using mineral acids, though mineral acids may be co-extracted. In this study, we systematically examine the co-extraction of hydrochloric, nitric, sulfuric, and phosphoric acid during extraction and back-extraction of lactic acid. The solvent phase consisted of tri-n-octylamine, trioctylphosphine oxide, or tributyl phosphate diluted in a thymol-menthol deep eutectic solvent. The back-extraction was conducted using a diluent swing with p-cymene as the antisolvent and water as the receiving phase. Tri-n-octylamine showed the highest efficiency for lactic acid (up to 29.8%) but also the highest co-extraction of mineral acids (up to 50.9%). In contrast, trioctylphosphine oxide exhibited a lower but more selective lactic acid extraction (5.94%) with low mineral acids co-extraction (0.135%). Overall, the highest co-extraction was observed for phosphoric acid and the lowest for nitric acid. In conclusion, the selected solvent phase composition and mineral acid influence the co-extraction and, thus, final product purity. The successful application of the natural deep eutectic solvent as the modifier enhances the sustainability of liquid-liquid extraction processes.

Technoeconomic analysis and feasibility of co-solvent mixtures in the liquid-liquid extraction of aromatics

It is desired to improve the efficiency of liquid-liquid extraction processes in the fuel industry by reducing energy consumption and operational costs as well as reducing risk to health, safety and the environment. Co-solvent mixtures for extraction consisting of butane-1,4-diol, propane-1,2,3-triol (glycerol), and 2-methylpentane-2,4-diol (hexylene glycol) were assessed in terms of capital costs, operating costs and total annual costs relative to a baseline process that is employed for the liquid-liquid extraction of toluene from n-heptane. Commercial solvents such as sulfolane, morpholine-4-carbaldehyde (NFM), and dimethyl sulfoxide (DMSO) were used for the baseline processes that were simulated in ASPEN Plus V10. The capital costs ranged between 5.8–6.2 million US dollars, while the energy intensity ranged between 1000 - 1400 kJ/kg. The total annual costs for all solvents studied varied between 2.4 - 2.6 million dollars. The results highlighted that these co-solvent mixtures may offer some benefits in terms of total annual cost when the impact of solvent choice is holistically considered.

Anthropogenic determination and risk assessment of total petroleum hydrocarbons of ground water within Orji auto repair workshops, Owerri, Imo State, Nigeria.

The research determined the anthropogenic source and risk evaluation of total petroleum hydrocarbons of some ground water sources within Orji auto repair workshops, Owerri, Imo State, Nigeria. The concentrations of total petroleum hydrocarbons in different groundwater samples within this vicinity were determined by selecting samples from five sampling locations using the liquid-liquid extraction process and gas chromatography fitted with a flame ionization detector. The concentrations of TPHs were determined with C15 (Pentadecane) and C30 (Triaconate) having the highest total concentrations in all sample locations of 29.67μg/mL and 23.17 μg/mL respectively while C13 (Tridecane) had the lowest combined concentration of 0.13 μg/mL with the presence of both low molecular weight and high molecular weight TPHs, an indication that the water samples had significant levels of carcinogens. Diagnostic ratio and correlation analyses of the samples analyzed showed contamination of the groundwater sources were both of petrogenic and pyrogenic sources. TPHs concentrations found in this study also revealed considerable amount of pollution with respect to contamination factors, pollution load index and degree of contamination. Elevated hazard index was equally observed for adults and children indicating a potential harm to the health of children and adults suggesting a higher risk of cancer from interaction with the polluted water. These results indicate that in remediation actions needs to be carried out before consumption to avoid fatal long term heath consequences.

Formation of ketoprofen methyl ester artifact in GC–MS analysis of basic drugs in horse urine using alkaline liquid-liquid extraction

This study investigates the unexpected formation of ketoprofen methyl ester (KME) during the routine alkaline liquid–liquid extraction (LLE) process for analyzing basic drugs in horse urine samples using GC–MS analysis. An unidentified peak in the GC–MS chromatogram was observed in certain horse urine samples, identified as KME through mass spectral comparison with in situ synthesized KME. Since the KME is not a metabolite of ketoprofen present in urine, it is proposed that its formation occurs during the LLE process due to the reaction between ketoprofen contained in the urine and methanol used as the solvent of the spiked internal standard. Surprisingly, no artifact was detected when negative quality control horse urine samples (absence of ketoprofen) even when spiked with standard ketoprofen and methanol. Further investigation indicated that the presence of lipase enzymes from bacteria in specific urine samples is the key factor in the formation of the KME artifact. This hypothesis was confirmed when negative quality control horse urines were spiked with ketoprofen, methanol, and a lipase enzyme and the KME artifact was detected. Additionally, the formation of a methyl ester artifact was also detected for flunixin, a carboxylic acid NSAID drug, when negative quality control horse urines were spiked with the drug, methanol, and lipase enzyme. These findings will be valuable for scientists analyzing drugs in urine.

The Role of Sargahydroquinoic Acid and Sargachromenol in the Anti-Inflammatory Effect of Sargassum yezoense.

The anti-inflammatory effect of the ethanol extract of Sargassum yezoense and its fractions were investigated in this study. The ethanol extract exhibited a strong anti-inflammatory effect on lipopolysaccharide-stimulated RAW 264.7 macrophages and effectively suppressed the M1 polarization of murine bone-marrow-derived macrophages stimulated by lipopolysaccharides and IFN-γ (interferon-gamma). Through a liquid-liquid extraction process, five fractions (n-hexane, chloroform, ethyl acetate, butanol, and aqueous) were acquired. Among these fractions, the chloroform fraction (SYCF) was found to contain the highest concentration of phenolic compounds, along with two primary meroterpenoids, sargahydroquinoic acid (SHQA) and sargachromenol (SCM), and exhibit significant antioxidant capacity. It also demonstrated a robust anti-inflammatory effect. A direct comparison was conducted to assess the relative contribution of SHQA and SCM to the anti-inflammatory properties of SYCF. The concentrations of SHQA and SCM tested were determined based on their relative abundance in SYCF. SHQA contributed to a significant portion of the anti-inflammatory property of SYCF, while SCM played a limited role. These findings not only highlight the potential of the chloroform-ethanol fractionation approach for concentrating meroterpenoids in S. yezoense but also demonstrate that SHQA and other bioactive compounds work additively or synergistically to produce the potent anti-inflammatory effect of SYCF.

Method Development and Validation in Water Matrix Employing Tandem Mass Spectrometry: Quantitative Analysis of 76 Multiclass Pesticides in Groundwater Samples Collected from Delhi Ncr Region by Quechers Based Liquid-liquid Extraction Method

A miniaturized, QuEChERS based, liquid–liquid extraction method followed by tandem gas chromatography–mass spectrometry determination was developed and validated for 76 pesticide residues determination in water using European SANTE/11312/2021 guideline and monitored the 70 ground water samples collected from Delhi NCR, India region for the determination of pesticide residues. The accuracy, precision, specificity, linearity, recovery, repeatability, reproducibility, robustness, limit of detection and limit of quantification of the method were evaluated. Uncertainty measurement was calculated for each analyte. The samples were extracted with dichloromethane using liquid-liquid extraction process. Each Pesticide was optimized in terms of different MS parameters and chromatographic conditions by GC-MS/MS using Multiple Reaction Monitoring (MRM) mode. In linearity regression co-efficient (R2) value of each pesticide was determined in the range of 0.9856-0.9997. The percent average recoveries were found from 87.98—119.99 at 1, 5 and 10 LOQ spiking level. The method performance complied with the regulatory requirements, and thus, can be implemented. LOD and LOQ of the pesticides were found 10µg/L and 30µg/L respectively. Expanded Measurement of uncertainty of all pesticides was below ±50 percent of mean recovery value as per SANTE 11312/2021. Organophosphorous, fungicides, and pyrethroids were the group of pesticides most frequently found. In this study, 12 pesticides were found above the MRL (EEC Council Directive 1980/778/EEC). Additionally, dieldrin, which is now banned by law in India, was found in samples of ground water. The method provided a high throughput analysis of multi-class pesticides with satisfactory selectivity, sensitivity, accuracy, and precision.

MARALIXIBAT IN RAT PLASMA AND ITS PHARMACOLOGICAL STUDIES (BIO-ANALYTICAL METHOD DEVELOPMENT AND VALIDATION BY LC-MS)

The bio-analytical method development of Maralixibat using Elobixibat as an internal standard is a convenient, fast, accurate, and consistent new LC-MS technique and was validated. The present work explains the development of the LC-MS/MS bio-analytical method by RP-18(150x4.6 mm, 3.5µ) column and a binary mixture(0.1% formic acid &amp; methanol) of organic mobile phase in the ratio 60:40. By using liquid-liquid extraction process, these drugs are removed from rat plasma. The linearity in the standard curve was observed under the experimental concentration range. 10%-200% (6-12ng/ml) of Maralixibat. The calibration plots were linear with a regression coefficient of R2&gt; 0.999. Precision, Accuracy, Stability results, and Matrix effect were observed within the acceptable limit. The method is more accessible and effective for analyzing the sample in the body fluids. The work represents that Specificity, Suitability, Accuracy, and linearity parameters ideally agree with the USFDA guidelines and are efficiently practiced in rat plasma for pharmacokinetic studies

Pertechnetate/perrhenate-capped Zr/Hf-Dihydroxide Dimers: Elucidating Zr-TcO4 Co-Mobility in the Nuclear Fuel Cycle.

Spent nuclear fuel contains heavy element fission products that must be separated for effective reprocessing for a safe and sustainable nuclear fuel cycle. 93 Zr and 99 Tc are high-yield fission products that co-transport in liquid-liquid extraction processes. Here we seek atomic-level information of this co-extraction process, as well as fundamental knowledge about ZrIV (and HfIV ) aqueous speciation in the presence of topology-directing ligands such as pertechnetate (TcO4 - ) and non-radioactive surrogate perrhenate (ReO4 - ). In this context, we show that the flat tetrameric oxyhydroxyl-cluster [MIV 4 (OH)8 (H2 O)16 ]8+ (and related polymers) is dissociated by perrhenate/pertechnetate to yield isostructural dimers, M2 (OH)2 (XO4 - )6 (H2 O)6  ⋅ 3H2 O (M=Zr/HfIV ; X=Re/TcVII ), elucidated by single-crystal X-ray diffraction. We used these model compounds to understand the pervasive 93 Zr-99 Tc coextraction with further speciation studies in water, nitric acid, and tetrabutylphosphate (TBP) -kerosene; where the latter two media are relevant to nuclear fuel reprocessing. SAXS (small angle X-ray scattering), compositional evaluation, and where experimentally feasible, ESI-MS (electrospray ionization mass spectrometry) showed that perrhenate/pertechnetate influence Zr/HfIV -speciation in water. In Zr-XO4 solvent extraction studies to simulate fuel reprocessing, we provide evidence that TcO4 - enhances extraction of ZrIV , and compositional analysis of the extracted metal-complexes (Zr-ReO4 study) is consistent with the crystallized ZrIV 2 (OH)2 (ReVII O4 - )6 (H2 O)6 ⋅dimer.

Antimicrobial Cyclic Dipeptides from Japanese Quail (Coturnix japonica) Eggs Supplemented with Probiotic Lactobacillus plantarum.

Fifteen cyclic dipeptides (CDPs) containing proline, one cyclo(Phe-Ala) without proline, and a non-peptidyl DL-3-phenyllactic acid were previously identified in the culture filtrates of Lactobacillus plantarum LBP-K10, an isolate from kimchi. In this study, we used Japanese quail (Coturnix japonica) eggs to examine the effects of probiotic supplementation on the antimicrobial CDPs extracted from quail eggs (QE). Eggshell-free QE were obtained from two distinct groups of quails. The first group (K10N) comprised eggs from unsupplemented quails. The second group (K10S) comprised eggs from quails supplemented with Lb. plantarum LBP-K10. The QE samples were extracted using methylene chloride through a liquid-liquid extraction process. The resulting extract was fractionated into 16 parts using semi-preparative high-performance liquid chromatography. Two fractions, Q6 and Q9, were isolated from K10S and identified as cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro). The Q9 fraction, containing cis-cyclo(L-Leu-L-Pro), has shown significant inhibitory properties against the proliferation of highly pathogenic multidrug-resistant bacteria, as well as human-specific and phytopathogenic fungi. Some of the ten combinations between the remaining fourteen unidentified fractions and two fractions, Q6 and Q9, containing cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro) respectively, demonstrated a significant increase in activity against multidrug-resistant bacteria only when combined with Q9. The activity was 7.17 times higher compared to a single cis-cyclo(L-Leu-L-Pro). This study presents new findings on the efficacy of proline-containing CDPs in avian eggs. These CDPs provide antimicrobial properties when specific probiotics are supplemented.

Solubility of di-(2-ethylhexyl)phosphoric acid (D2EHPA) in aqueous electrolyte solutions: Studies relevant to liquid-liquid extraction

Di-(2-ethylhexyl)phosphoric acid (D2EHPA) is an acidic extractant frequently used in solvent extraction for metal refining. Only limited information is available on the amount and type of impurities present in commercially available D2EHPA and their effect on liquid-liquid extraction. In this paper, these impurities were identified and the importance of pre-conditioning the extractant before carrying out extractions is demonstrated. Furthermore, the solubility of D2EHPA in aqueous solutions was investigated as a function of pH, concentration of extractant and anion present in the aqueous phase (chloride, bromide, iodide, sulfate, methanesulfonate, thiocyanate, and nitrate). The density of the organic phases and the sodium and water uptake in the organic phase were determined as a function of the different anions present in the aqueous phase. The type of anion was found not to have a large influence on the solubility of D2EHPA in the aqueous phases. Low concentrations of salt in the aqueous phase or high pH values resulted in significant losses of D2EHPA to the aqueous phase. A very sharp increase in water content in the organic phase was observed around pH 5 (pH 6 for the nitrate system), accompanied by a significant increase in extraction of sodium ions, which explains the observed increase in density of the organic phase, and the tendency to third-phase formation. The results from this fundamental study help to better understand the behavior of liquid-liquid extraction systems in which D2EHPA is used as extractant and can help to prevent third-phase formation and losses of extractant to the aqueous phase. Moreover, the impurities present in commercially available D2EHPA and their impact on liquid-liquid extraction processes are determined.

The a priori screening of potential organic solvents using artificial neural networks

A QSPR model using artificial neural networks was constructed to estimate the binary interaction parameters for the temperature-dependant form of the NRTL model with the objective of using it as a supplement to assist limitations of group contribution methods in the screening of potential solvents for liquid-liquid extraction processes. Parameters were regressed using experimental LLE and VLE data and checked for consistency. Molecule structures were drawn and descriptors determined with the use of Materials Studio. The QSPR model uses 31 descriptors as input and produced absolute average deviations of 0.23 and 0.19 for each pair of binary interaction parameters respectively. The development of this model is shown to be effective in improving the robustness of solvent screening processes.

Novel castor oil/water/ethanol Pickering emulsions stabilized by magnetic nanoparticles and magnetically controllable demulsification

A novel castor oil/water/ethanol Pickering emulsion, stabilized by magnetic nanoparticles (NPs), was developed to allow on-demand demulsification by an external magnetic field for the extraction of ethanol from aqueous solution using the castor oil. The emulsion was stabilized by Fe3O4-coated cellulose nanocrystals (CNC@Fe3O4) and lignin-coated Fe3O4 NPs (lignin@Fe3O4). The stability of the emulsions was investigated at various castor oil to ethanol-water ratios (50/50 and 70/30), various NP concentrations, and ethanol concentrations in the aqueous phase. The magnetically controlled demulsification ability of the emulsions was investigated by using a permanent magnet. The results showed that the 70/30 emulsions were more stable than the 50/50 emulsions for all the ethanol concentrations. Moreover, increasing the NP concentration increased the emulsion stability and hence, 1 w/v% NPs concentration provided the more stable systems. However, all the emulsions were successfully broken by the permanent magnet. Yet, the presence of ethanol improves the ability of the external magnetic field to demulsify these dispersions. Furthermore, the used hybrid NPs were recovered and recycled for three cycles. The recycled NPs were characterized with X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) indicating that they retained their saturation magnetization and crystalline structure, demonstrating their lack of degradation over multiple recycling cycles. This study facilitates the exploration of innovative two-phase Pickering emulsions comprising three distinct liquid components and their utilization in liquid-liquid extraction processes.

Microstructural Origin of Selective Water Oxidation to Hydrogen Peroxide at Low Overpotentials: A Study on Mn-Alloyed TiO2

Introduction: Hydrogen Peroxide, H2O2, is a versatile chemical with applications ranging from industrial to household use such as pulp bleaching, wastewater treatment, and sterilization. In addition to these established uses, H2O2 is emerging as a green energy carrier which can release 96 kJ mol−1 of energy via exothermic chemical decomposition with only water and oxygen as by-products. Currently, more than 95% of H2O2 produced globally originates from anthraquinone autoxidation. This process requires precious metal catalysts and expensive liquid-liquid extraction processes that are only feasible for large-scale chemical plants.Electrochemical and photochemical syntheses are promising alternatives for distributed H2O2 production. H2O2 can be produced by 2e- processes both via oxidatively, via water oxidation reaction (WOR) or reductively via oxygen reduction reaction (ORR). These approaches take advantage of abundant energy sources, i.e., renewable electrical or solar energy, and enables the storage of intermittent energy as the free energy of chemical bonds for distributed energy storage. Charge Transfer: H2O2 can be (photo-)electrochemically synthesized via a two-electron (2e−) water oxidation pathway, as shown in equation 1.2H2O → H2O2 + 2H+ + 2e−, E = +1.77 VRHE (1)However, existing catalysts often exhibit low faradaic efficiency (FE) due to the competitive four-electron (4e−) pathway of O2 evolution reaction (OER) equation 2.2H2O → O2 + 4H+ + 4e−, E = +1.23 VRHE (2)The thermodynamic driving force for OER is always at least +0.54 V greater than that of the 2e− H2O2 pathway which can allow the undesired O2 evolution pathway to overcome any kinetic barriers and dominate. In addition, the produced H2O2 can be over-oxidized to O2 at an excess potential of at least +1.09 V equation 3.H2O2 → O2 + 2H+ + 2e−, E = +0.68 VRHE (3)Thus, the partial oxidation of water to hydrogen peroxide presents a model system of a common challenge in catalysis where the desired product is kinetically feasible but thermodynamically unfavorable.In this work, we utilize X-ray Photoelectron Spectroscopy to quantify the presence of Mn(III) defect states within the TiO2 band gap which are energetically aligned to peroxide generating reactive intermediates.During operation, the energy levels of CB and VB of TiO2 are fixed, or “pinned”, at −0.05 and 3.29 VRHE, respectively, yet the empty states of the Mn defect states can precisely align with the energetics of H2O2 producing intermediates. Under a higher applied potential, i.e., +2.3 VRHE, there would exist a moderate overpotential for the 2e− water oxidation, but such a potential also enables the other pathways including 1e− water oxidation to produce radicals, leading to an overall reduction in H2O2 production rates due to the reduced selectivity. Thus, this strategy of defect state tuning is best suited to low overpotentials, <100mV, catalysis. Conclusion: This study presents a new strategy of introducing charge-transport defect states and demonstrates the design of H2O2-producing surfaces that oxidize water to H2O2 with high selectivity at very low overpotentials. Given the growing literature related to H2O2 selective catalysis, this approach is expandable to a range of host oxides that prevent H2O2 disproportionation to favor 2e− H2O2 electrochemistry.Faradaic efficiency of >90% at < 150 mV overpotentials was achieved for H2O2 production, accumulating 2.97 mM H2O2 after 8 hours. Nanoscale mixing of Mn2O3 and TiO2 resulted in a partially filled, highly conductive Mn3+ intermediate band (IB) within the TiO2 mid-gap to transport charge across the (Ti,Mn)Ox coating. This IB energetically matched that of H2O2-producing surface intermediates, turning a wide bandgap oxide into a selective electrocatalyst capable of operating in the dark. Figure 1

Investigating the effectiveness of the main channel in microfluidic liquid-liquid extraction process

The liquid-liquid extraction method has been one of the most critical chemical engineering processes for many years. The combination of liquid-liquid extraction and microfluidic systems constitutes a significant advancement in this process in recent years. The inherent advantages of microfluidic systems, due to their micro dimensions and the widespread application of liquid-liquid extraction, have made this process more applicable in various industries. This article focuses on microfluidic systems, discussing the effects of changes and modifications made to the main channel of these systems, as well as the resulting improvements in flow type and channel shape, and their applications. The assessment concludes with a discussion of the prospects of this field.

Comparing organic solvents in a combined water precipitation and liquid–liquid extraction process to recover lignin and furanics from a lactic acid: choline chloride deep eutectic solvent used as cooking liquor for cooking of spruce

AbstractExtracting and purifying lignin from wood without compromising cellulose quality is a challenging process. Lactic acid: choline chloride is a deep eutectic solvent (DES) that has been identified as acceptable delignification solvent, producing lignin and hemicellulose as byproducts to the cellulose. Hemicellulose is partly transformed into furanic compounds (such as furfural and 5-HMF). While the larger lignin can be obtained by water precipitation from DES, smaller lignin molecules and furanics can be recovered by liquid–liquid extraction (LLX), either directly or after precipitation of the larger lignin molecules. The presence of water in the DES after water precipitation reduced the mutual miscibility with the solvents, allowing the use of a wider range of solvents in the LLX process. In the precipitation step, all the larger molecular weight lignin (Mw &gt; 5000 Da) can be recovered when adding at least 3.5:1 [g/g] water to DES-black liquor. For the LLX step, guaiacol was found as suitable alternative to the previously published 2-methyltetrahedrofuran (2-MTHF). In addition, here we report the use of 2,2,5,5-Tetramethyl oxolane (TMO), a recent addition to the palette of (potentially) bio-based solvents. The distribution coefficients of smaller lignin molecules and furanics in LLX with guaiacol, TMO and 2-MTHF were compared, revealing that smaller lignin molecules (500–5000 Da) can be recovered with a reasonable distribution coefficient by 2-MTHF and guaiacol. Furfural showed distribution coefficients of at least 1.27 in all three solvents. Guaiacol and TMO both showed a significantly lower lactic acid leaching than 2-MTHF. This makes them potential alternatives for 2-MTHF in this technique. Graphical abstract

Simultaneous posthydrolysis and liquid–liquid extraction: a SIMPLLE process to detoxify eucalyptus prehydrolysis liquor

AbstractThe prehydrolysis liquor from the prehydrolysis Kraft process is rich in sugars and could thus serve as a sustainable feedstock for the production of various chemicals. However, its industrial utilization is impeded by the presence of fermentation inhibitors and extensive lignin precipitation, the latter receiving only little attention in the literature.In order to provide a feedstock suitable for biotechnological or chemical conversion, the prehydrolysis liquor from eucalyptus wood must be detoxified whilst preventing the precipitation of lignin. To increase the yield of monomeric sugars, acid posthydrolysis should be investigated.Various solvents and solvent mixtures were screened for the high temperature liquid–liquid extraction of isothermally separated prehydrolysis liquor. Their capability to prevent lignin precipitation and to extract fermentation inhibitors was assessed using mass balances and size-exclusion chromatography. Based on the solvent screening, a process for simultaneous posthydrolysis and liquid–liquid extraction of eucalyptus prehydrolysis liquor was proposed and investigated using statistic experimental design.Liquid–liquid extraction using aliphatic alcohols effectively prevents lignin precipitation, and the addition of 25% (w/w) tri-n-octylamine was found to increase the overall inhibitor extraction efficiency. The conditions for the simultaneous posthydrolysis were investigated using a Box-Behnken experimental design, allowing for a maximum monomeric sugar yield of 83.0% at a sugar purity of 91.6%.The simultaneous posthydrolysis and liquid-liquid extraction (SIMPLLE) process thus avoids industrial-level problems associated with lignin precipitation. It provides a carbohydrate-rich stream with low levels of fermentation inhibitors, enabling further conversion to value added products.

Dissolution of Rare Earth Elements Concentrate from Xenotime Sand with Strong Acids

Rare Earth Elements (REE) concentrate from the processing of xenotime minerals still contains a mixture of REE and its impurities, so it requires a further separation process to purify the content of each element. The first step to separating each element of REE is to dissolve the REE concentrate in strong acid as a feed for the liquid-liquid extraction or ion exchange column process. The REE concentrate was dissolved in 3 variations of strong acids, namely hydrochloric acid, nitric acid, and sulfuric acid. XRF and FTIR analyses were done before and after the dissolution process. The results showed that sulfuric acid is the best dissolution reagent for the total rare earth elements (71.75%) but is less selective for separating light REE, heavy REE, and their impurities. Better selectivity for separating light REE and heavy REE is shown by dissolution with nitric acid with dissolution levels of 37.32% and 81.91%, respectively. Meanwhile, hydrochloric acid showed the lowest dissolution results for the total element of REE (63.14%) but had the best selectivity to prevent the dissolving of radioactive elements. The results of the FTIR analysis showed that REE-chloride, REE-nitrate, and REE-sulfate bonds had been formed in each dissolving filtrate.

A Simple yet Efficient Hydrophilic Phenanthroline-Based Ligand for Selective Am(III) Separation under High Acidity.

Highly selective hydrophilic ligands were believed to be an efficient way to overcome the massive amount of hazardous organic solvent used in the liquid-liquid extraction process and stood as a new frontier in the Lns(III)/Ans(III) partition. Current reported hydrophilic ligands suffer from harsh preparation conditions, inferior extraction performances, limited available chemical structures, and inability to carry out extraction under high acidity. In this article, we report a simple yet efficient carboxylic group modified phenanthroline-diimide ligand which displayed unexpected Lns(III)/Ans(III) and Ans(III)/Ans(III) separation capabilities in 1.5 M HNO3. Unique dimeric architectures for Eu(III) complexes were observed, which could be the origin of the outperforming selectivity and acid resistance. We believe this crystal engineering approach could inspire a renaissance in searching for new functional groups and coordination modes for efficient, high-acid-tolerance Lns(III)/Ans(III) separation ligands.