Acid Solvent Research Articles

Stability trend analysis of light lanthanide complexes with a fluorophenyl-dipicolinamide: A quantum chemical study

Extracting lanthanides (Ln) from actinides (An) is a crucial step in reprocessing spent nuclear fuel, and the interaction between ligands and Ln inevitably deserves careful study. In this study, we employ density functional theory (DFT) calculations to analyze the stability trend of trivalent light lanthanides (Ln (III), from La(III) to Eu(III)) complexes with N,N'‑diethyl-N,N'-di(para)fluorophenyl-2,6-dipicolinamide (FDPA), which has emerged as a promising ligand in Ln-An separation. The bond length, nature of bonding and electronic energy density properties of Ln-N and Ln-O bonds have been investigated. The quantum theory of atoms in molecules calculation shows that Ln(III)-FDPA complexes are stable, via closed-shell interactions. The Gibbs free energy changes (∆G) of La(III), Pr(III), Pm(III), Sm(III), and Eu(III) complexes with FDPA are approximately -0.07 Kcal/mol. In contrast, the ∆G values of Ce(III) and Nd(III) complexes with FDPA are 1.534 and 0.781 Kcal/mol, respectively. These findings indicate that La(III), Pr(III), Pm(III), Sm(III), and Eu(III) can be excellently extracted by FDPA from acidic solvents, whereas Ce(III) and Nd(III) do not. Our study contributes to a better understanding of the mechanism of lanthanide complexes and provides guidance for the design of ligands that can effectively discriminate lanthanides in nuclear waste reprocessing.

Integrated acetic acid and deep eutectic solvent pretreatment on poplar for co-production of xylo-oligosaccharides, fermentable sugars and lignin antioxidants/adsorbents

Efficient fractionation of lignocellulosic biomass in usable forms of hemicellulose, cellulose and lignin is very important for the sustainable lignocellulosic biorefinery. Herein, poplar sawdust was pretreated with an integrated process composed of acetic acid pre-hydrolysis (170 °C, 60 min) for xylo-oligosaccharides (XOS) production and mild deep eutectic solvent (90–130 °C, 60 min) post-delignification for recovering lignin fractions, resulting in easily hydrolyzed cellulose fraction. Results showed that, after integrated pretreatment and enzymatic hydrolysis, 51 % of xylan and 92 % of glucan in raw biomass could be converted to XOS (DP 2–6) and glucose, respectively, while 71 % of the original lignin could be recovered in DES solvent. The resulting XOS were proven to ensure the growth of probiotics, Bifidobacterium adolescentis. Besides, the lignin macromolecules recovered from DES solvent showed high-purity (around 95 %), low-molecular weight (Mw around 2000), small particle size (270–170 nm) and high-PhOH (3.08 mmol/g) content, which were likely relevant to the excellent antioxidant activity (RSI = 15.16) and adsorbent activity (Pb(II) 461.89 mg/g lignin). Finally, mass balance and energy analysis revealed that the integrated pretreatment could be used as a promising approach for the production of bio-based chemicals and materials from woody biomass.

An Efficient Extraction and Selective of Alumina from Lapindo Mud

Lapindo mud, a soft clay soil found in Sidoarjo, East Java, has a high water and mineral content. It contains 16% alumina (Al2O3), making it a potential source of aluminum metal. The high content of silica oxide in Lapindo mud is of particular interest to separate the oxide from the alumina oxide. Silica oxide is insoluble in acid while aluminum oxide is soluble in acid. The alumina extraction process was carried out using acid solvent. The dried mud with a size of ≤100 mesh was extracted using HNO3 and HCl solvent with concentration of 4, 6, and 8 M at temperatures of 60℃, 70℃, and 80℃ for 100, 200, and 300 minutes. The extraction results were filtered, then the pH of the filtrate was adjusted to 12 with 6 M NaOH. The filtrate was filtered, thus Fe3+ was obtained as a residue. The filtrate was neutralized to pH 8 using 6 M HCl. The filtrate was filtered to obtain NaAlO2. The precipitate formed was washed using distilled water and dried in an oven to obtain Al(OH)3. Al(OH)3 was then calcined at 600℃ for four hours to form Al2O3. The results showed that acid solvent concentration, extraction temperature, and heating time affected the mass of Al2O3 obtained. Increasing acid solvent concentration, extraction temperature, and heating time, increases the mass of Al2O3 obtained. The mass of Al2O3 obtained was 1.19 grams for HNO3 solvent and 1.63 grams for HCl solvent with concentration of 8 M, extraction temperature of 80℃, and heating time of 300 minutes. The results of XRF characterization show that the Al3O3 purity level is 42.8% and 27.3%with HNO3 and HCl solvent, respectively.

Acid–solvent cluster-catalyzed general and regioselective Friedel–Crafts arylation of alcohols

An acid–solvent clusters-catalyzed general and regioselective Friedel–Crafts alkylation has been described.

Effect of chloride salts and microwaves on polyethylene terephthalate (PET) hydrolysis by iron chloride/acetic acid Lewis/Brønsted acidic deep eutectic solvent

Iron(iii)-based deep eutectic solvents were demonstrated to be active solvents for the hydrolysis of poly(ethylene terephthalate), especially under microwave irradiation.

Development of eco-friendly pretreatment processes for high-purity silicon recovery from end-of-life photovoltaic modules.

This study examines the efficacy of photovoltaic (PV) recycling processes and technologies for the recovery of high-purity silicon powder from waste solar modules. In order to facilitate the simplification of complex processes, such as the conventional nitric acid dissolution, solvent and ultrasonic irradiation, and solvent dissolution, a variety of mechanical separation processes have been established. These processes are designed to enhance the efficiency and effectiveness of the aforementioned processes. And a novel method for separating EVA from recycled Si powder was devised, which studied the WGS process using aqueous solutions of H2O, HNO3, and NaCl with different specific gravities. The WGS process using NaCl solution demonstrated superior performance, removing over 94% of the EVA, requiring less energy input and producing 73% less CO2 emissions compared to the thermal process. These technologies facilitate the transition towards a circular economy and bolster the implementation of carbon-neutral initiatives.

DRGD-linked charged EKKE dimeric dodecapeptide: pH-based amyloid nanostructures and their application in lead and uranium binding.

Peptides have been reported to undergo self-assembly into diverse nanostructures, influenced by several parameters, including their amino acid sequence, pH, charge, solvent, and temperature. Inspired by natural systems, researchers have developed biomimetic peptides capable of self-assembling into supramolecular functional structures. The present study explored a newly designed peptide sequence, EKKEDRGDEKKE, where E = glutamic acid, K = lysine, D = aspartic acid, G = glycine, and R = arginine, with a metal binding DRGD sequence incorporated between the exclusively charged EKKE peptide. We investigated the formation and the potential of the EKKEDRGDEKKE peptide in retaining the structure and morphology adopted by the individual EKKE peptide. According to a combination of experimental techniques such as thioflavin T fluorescence, field emission-scanning electron microscopy, atomic force microscopy, and circular dichroism, it was evident that the EKKEDRGDEKKE peptide displayed a pH-dependent propensity to adopt amyloid-like structures. Furthermore, the self-assembled entities formed under acidic, basic, and neutral conditions exhibited morphological variations, which resembled that observed for the exclusively charged EKKE peptide. Furthermore, the incorporation of the functional DRGD motif resulted in promising binding to two toxic metal ions, lead (Pb) and uranium (U), as evidenced by a range of spectroscopic techniques, including UV-visible spectroscopy, atomic absorption spectroscopy, fluorescence spectroscopy, and X-ray photoelectron spectroscopy. The use of the amyloid-forming EKKEDRGDEKKE scaffold can also be extended to potential biomedical applications.

Primena vodenih eutektičkih rastvarača za hemijsku valorizaciju otpadnog mulja - određivanje mineralnog sadržaja

Sewage sludge is a by-product of municipal wastewater treatment processes with significant soil-forming and fertilizing characteristics. However, if sewage sludge contains heavy metals, it can negatively affect the soil environment. The accumulation of heavy elements in the soil can negatively affect the circulation of elements in the natural environment, regarding plants, animals, and humans. The primary sources of heavy metals in human and animal food are plants, which are also the primary consumers of mineral nutrients from soil and water. Even a very small amount of heavy metals in the body can create metabolic problems, reduced body functions, and compromised immune and enzymatic processes, all of which contribute to various diseases and may even cause death. The aim of this study was to find a suitable system for mineral extraction from the municipal sewage sludge after water purification, collected from the wastewater treatment plant in Vlasotince, so the real composition of sewage sludge could be obtained. For that purpose, different aqueous deep eutectic solvents were applied: choline chloride:lactic acid (ChCl:LA), choline chloride:urea (ChCl:U), choline chloride:glycerol (ChCl:G), choline chloride:propylene glycol (ChCl:PEG), choline chloride:citric acid (ChCl:CA), and choline chloride:ethylene glycol (ChCl:EG).The concentrations of minerals after wet digestion were determined by Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). The results showed that the highest amounts of minerals, especially Ca, P, and Fe, were extracted using aqueous acidic deep eutectic solvent systems (ChCl:LA and ChCl:CA). Also, the mineral composition of sewage sludge indicates the possibility of its use as a significant soil fertilizer supplement.

Isolation and Characterization of Active Alkaloid Compounds from Cinnamomum Verum Cortexes and Proof of their Medicinal Efficacy against Pathogenic Fungus Alternaria Alternate Causing Upper Respiratory Tract Inflammatory Disease

Six alkaloid compounds were isolated (the discovery of a natural drug, which is a combination of the six alkaloid compounds). Alkaloids viz., 1,3,5-Triazine-2-carboxylic acid, 4-amino-6-methyl; 1,2,4-Triazino[5,6-E][1,2,4]-triazine-3,6-dione, hexahydro; 2-(4,5-Dihydro-3-methyl-5-oxo-1-phenyl-4-pyrazole)-5-nitrobenzoic acid; 4-metyl-3,4-dihydro-[1,2,3] trizolo [4,5-d] pyrimidine-5,7-dione; Propanoic acid-3-(perhydro-2,5-dioxo-imidazol [4,5-d] imidazole-1-yl) and 1,2,3-Triazolo[4,5-f] benzotriazole- 4,8(4H,8H)-dione, were isolated from Cinnamomum verum cortexes by using ethanolic acetic acid, sulphuric acid, and ammonia solvents, and they were characterized by using preliminary qualitative tests, gas chromatography-mass spectrumGC-MASS. The medicinal efficacy was studied for these six alkaloidic compounds theoretically by using the Autodock program and the results showed the presence of high efficacy of the compounds. Then the medicinal efficacy was measured biologically for the six compounds mixture in vitro depending on the synergistic interaction principle by using various concentrations (5, 10, 15, 20, and 25 mg/ml) by using of agar diffusion technique. The results showed that the six alkaloidic compounds’ mixture is biologically active against Alternaria alternate fungus, where the inhibition zone diameters were recorded equal to 27, 33, 41, 45, and 49 mm respectively towards the pathogenic fungus. Also, cytotoxicity tests for the different concentrations of six active alkaloid compounds mixture proved there is no toxic effect belonging to them towards red blood cells, and no hemolysis effect appeared in blood cells. Therefore, six alkaloid compounds isolated from Cinnamomum verum cortexes can be used as active drugs for the treatment of various diseases especially those caused by pathogenic fungi represented by Alternaria alternate, without any side effects.

Rationally designed acidic deep eutectic solvent induced catalysis and spontaneous catalyst recycling of Pd-catalyzed ethylene alkoxycarbonylation

Rationally designed DES-induced homogeneous catalysis and heterogeneous separation of alkoxycarbonylation enabled remarkably prolonged catalyst lifespan over homogeneous systems.

Polymerization of α-pinene catalyzed by Lewis acidic deep eutectic solvents

A green and effective catalytic system for α-pinene polymerization using a recyclable Lewis acidic DES catalyst has been developed.

Optimization of liquefaction process based on global meta-analysis and machine learning approach: Effect of process conditions and raw material selection on remaining ratio and bioavailability of heavy metals in biochar

<abstract> <p>Although liquefaction technology has been extensively applied, plenty of biomass remains tainted with heavy metals (HMs). A meta-analysis of literature published from 2010 to 2023 was conducted to investigate the effects of liquefaction conditions and biomass characteristics on the remaining ratio and chemical speciation of HMs in biochar, aiming to achieve harmless treatment of biomass contaminated with HMs. The results showed that a liquefaction time of 1–3 h led to the largest HMs remaining ratio in biochar, with the mean ranging from 84.09% to 92.76%, compared with liquefaction times of less than 1 h and more than 3 h. Organic and acidic solvents liquefied biochar exhibited the greatest and lowest HMs remaining ratio. The effect of liquefaction temperature on HMs remaining ratio was not significant. The C, H, O, volatile matter, and fixed carbon contents of biomass were negatively correlated with the HMs remaining ratio, and N, S, and ash were positively correlated. In addition, liquefaction significantly transformed the HMs in biochar from bioavailable fractions (F1 and F2) to stable fractions (F3) (<italic>P</italic> < 0.05) when the temperature was increased to 280–330 ℃, with a liquefaction time of 1–3 h, and organic solvent as the liquefaction solvent. N and ash in biomass were positively correlated with the residue state (F4) of HMs in biochar and negatively correlated with F1 or F2, while H, O, fixed carbon, and volatile matter were negatively correlated with F4 but positively correlated with F3. Machine learning results showed that the contribution of biomass characteristics to HMs remaining ratio was higher than that of liquefaction factor. The most prominent contribution to the chemical speciation changes of HMs was the characteristics of HMs themselves, followed by ash content in biomass, liquefaction time, and C content. The findings of this meta-analysis contribute to factor selection, modification, and application of liquefied biomass to reducing risks.</p> </abstract>

Polyamide 66 hybrid TiO2–pectin flat-sheet membrane applied to wetland water ultrafiltration

This article describes a study in which a hybrid, polyamide 66 flat-sheet membrane is fabricated and then used to eliminate turbidity in wetland water in an area of South Kalimantan, Indonesia. The membrane was prepared by the phase inversion technique, using nylon 66, formic acid solvent, titanium dioxide and pectin as additives. Results show that the pure water flux of the membrane produced is extremely high – reaching 418.04 Lm-2h-1 – but decreased to 311.97 Lm-2h-1 with the addition of TiO2–pectin. When applied to wetland water the PA–TiO2–pectin membrane showed 100% turbidity rejection.

Green Synthesis of 2H-Pyrano[2,3-d][1,3]thiazole-6-carbonitriles in Trifluoroethanol as an Efficient Acidic Solvent and Their Biological Activity

Green Synthesis of 2H-Pyrano[2,3-d][1,3]thiazole-6-carbonitriles in Trifluoroethanol as an Efficient Acidic Solvent and Their Biological Activity

Phase Transitions of Naphthalene-2,3-carbonitride Steered by Solvent Effects and Metal Ion Concentration Variation.

The delicate regulation of structural phase transition can provide advanced approaches for fabricating desired and well-organized nanoarchitectures on surfaces. Introduction of metal ions into pure organic systems can facilitate the phase transition from hydrogen-bonded structures to metal-organic structures by coordinating with organic molecules. However, it remains a challenge to attain a phase transition dominated by variable metal coordination configurations through adjustment of the metal ion concentration. Herein, we report the phase transitions of naphthalene-2,3-carbonitride (2,3-DCN) molecules on highly oriented pyrolytic graphite (HOPG) under varying solvents and Cu2+ ion concentrations. By integrating data from scanning tunneling microscopy imaging and density functional theory calculations, it is demonstrated that phase transitions of 2,3-DCN occur through forming diverse coordination configurations where Cu2+ ions can coordinate with 2,3-DCN and 1-nonanoic acid or Cl- ions to form different ligand components with a coordination number of 4 when varying the molar ratios of 2,3-DCN to Cu2+ ion in the 1-nonanoic acid solvent. However, in the case of 1-heptanoic acid as a solvent, the self-assembly structure of 2,3-DCN only changes via the alteration of hydrogen bonding sites and Cu2+ ions do not coordinate with 2,3-DCN molecules. These findings provide valuable insights into the coordination behavior of metal ions in different solvents.

Supercritical CO2 Assisted Ni-P Electroless Plating of PET Components with Complex 3D Structures

There is an increasing demand of methodologies to metallize complex polymer materials for application in electronics such as wearable devices and robotic products. In various metallization methods, electroless plating is a powerful and promising approach to meet this demand. The present conventional electroless plating requires pretreatment steps to deposit catalyst onto surfaces of polymer materials, which results in damages to their surfaces and also deformation of their shape because of the usage of strong acidic solvents. Furthermore, the adhesion strength between the polymer material and the metal layer is insufficient. To overcome these problems, a catalyzation step using supercritical carbon dioxide (sc-CO2) as the solvent is proposed.[1] The sc-CO2-assisted catalyzation enables a deep impregnation of catalysts into the polymer material without the pretreatment step, and this enhances the adhesive properties of the deposited metal on the polymer. By the sc-CO2-assisted catalyzation, electroless Ni-P plating of polyethylene terephthalate (PET) is realized. [1] Metallization of polymer materials with complex 3D structures is a more attractive topic, but it is widely accepted to be more difficult than film structures. Also, application the electroless plating via sc-CO2-asssited catalyzation to 3D-structured polymer materials remains unexplored. In this presentation, we report Ni-P plating of PET samples having complex 3D structures by the sc-CO2-assisited catalyzation process.A PET based material with a concavo-convex structure was designed and fabricated by the processing machine as shown in Figs. 1(a)–(b). Sc-CO2-assisted catalyzation process was performed in a high pressure reactor[1] containing palladium (II) hexafluoroacetylacetonate (Pd(C5HF6O2)2) as the palladium catalyst source at 70 °C under 15 MPa for 2 h. After the catalyzation process, the reactor was cooled to room temperature while maintaining the pressure in the reactor, and then the pressure in the reactor was reduced to atmospheric pressure. The collected PET sample from the reactor was kept under ambient atmosphere for two weeks, and then it was subjected to electroless Ni-P plating at 70 ℃ for 10 min.Fig. 1(c) shows the PET sample obtained after the sc-CO2-assisted catalyzation process followed by the post-treatment process. The volume of the catalyzed PET sample was scarcely changed. On the other hand, the post-treatment processes performed under the different conditions were found to cause undesired swelling and white turbidity of the PET sample, presumably because of microbubbles derived from residual CO2 in the PET. Fig. 1(d) shows an image of Ni-P successfully metallized on the PET surface. The electrical resistance of the Ni-P/PET material was 8.7 Ω, which is acceptable for electronic device applications. From these results, we concluded that sc-CO2-assisted catalyzation is applicable to metallization of PET materials with complex 3D structures. Reference [1] P.-W. Cheng, C.-Y. Chen, T. Ichibayashi, T.-F.M. Chang, M. Sone, S. Nishimura, J. Supercrit. Fluids 180 (2022) 105455. Figure 1

The Effect of High Molecular Weight Glutenin Subunit Encoded by Glu-B1k Allele on Bread-Making Quality of Near-Isogenic Lines of Bread Wheat

: In this study, the effect of the 22 glutenin subunit encoded by the Glu-B1k allele on the chromosome B on the quality of wheat was investigated. Nevzatbey and a genotype of Triticum aestivum L. subsp. sphaerococcum were used as parents and produced the near-isogenic lines (NILs) in the generation of BC4F3. Plant morphological traits and protein content, sedimentation volume, lactic acid solvent retention capacity (SRC), and glutenin swelling index (GSI) of the NILs were determined. The mean protein content of the NILs carrying 22 glutenin subunit was higher than that of the NILs carrying the 7+9 glutenin subunit (20.4% and 16.2%, respectively). In contrast, the NILs with 22 glutenin subunit had a lower sedimentation volume than those of the NILs with 7+9 glutenin subunits. The 22 glutenin subunit decreased the sedimentation volume from 19.47 to 13.49 mL. The average GSI value of the NILs carrying 7+9 glutenin subunits was higher than that of the NILs carrying 22 glutenin subunit (3.05 and 2.92). In conclusion, in this study we were able to detect a quality difference between NILs with 22 and 7+9 glutenin subunits in a small amount of samples. These findings suggest that glutenin subunit 22 may be associated with low gluten strength.

Extraction, foam-mat drying, and physicochemical analysis of Indonesian black glutinous rice (Oryza sativa L. var glutinosa) anthocyanins

Anthocyanins are water-soluble flavonoid that gives a purplish-blue colour to black glutinous rice. Anthocyanins can be degraded by high temperature (>65ᵒC), oxygen, and light during storage. Foam-mat drying is expected to maintain anthocyanins from degradation and prolong their shelf life. This research aimed to obtain the optimum condition for anthocyanins extraction and foam-mat drying with the physicochemical evaluation of anthocyanins extract. The extraction process was done by the maceration method using food-grade solvents, water+citric acid and water, at four different times (6, 18, 24, and 48 hrs). Ethanol+citric acid were used as a control. The results showed that extraction using water+citric acid solvent for 48 hrs yielded higher total anthocyanins content (2.15±0.03 mg/g rice) than using water solvent (0.70±0.01 mg/g rice). Production of anthocyanins powder was carried out using the foam-mat drying method with the variation of maltodextrin (10 and 20%) and egg white (7.5, 10, and 20%) as the encapsulant and foaming agent. The highest anthocyanins content (0.45±0.06 mg/g powder) was obtained from water+citric acid extract mixed with 10% maltodextrin and 7.5% egg white. The solubility of its powder was acceptable (96.23±0.67%), and the water activity fulfilled the water activity standard of the powder drinks (0.33±0.00). In conclusion, the most optimum condition for anthocyanins extraction was using water+citric acid for 48 hrs and foam-mat drying using 10% maltodextrin and 7.5% egg white.

Sustainable upcycling of sugarcane bagasse into nanofibrillated cellulose utilizing novel green solvents and high intensity ultrasonication

Nanofibrillated cellulose (NFC) are versatile materials with applications spanning from advanced composites to water treatment innovations. Production of NFC using biopolymers found in agricultural waste residues holds importance due to their environmentally friendly nature, providing viable substitute for non-renewable petroleum resources. From the perspective of sustainable economy, this article focuses on utilizing agricultural waste, sugarcane bagasse (SCB) for the production of nanofibrillated cellulose using green approach. Here, we synthesized four different types of acidic natural deep eutectic solvents (NADES) and investigated their potential as pretreatment agents synergistically with acetosolv, aiming to enhance cellulose recovery from SCB. The pretreatment step led to significant yield of cellulose (84.4 %) using Gly-CA NADES and acetosolv combination. The yields in case of Xyl-CA (82.2 %), Gly-TA (75.6 %) and Xyl-TA (68.9 %) were relatively lower. Subsequent implementation of high-intensity ultrasonication (HIU) process resulted in rapid nanofibrillation of fibres with minimal cellulose loss. The morphological and particle size analyses of the produced NFC samples using SEM, TEM and DLS revealed that they exhibited heterogeneity with lengths varying from 25 to 80 nm and widths varying from 5 to 10 nm, indicating a high efficiency of disintegration. The qualitative analysis of NFCs was also investigated by employing XRD, FTIR and TGA/DTG that further determined that the structure of NFCs remained unaltered even after subjecting it to various treatment methods. Thus, the study signifies a holistic approach to resource recovery and promoting sustainable and environmentally friendly biomass conversion processes.

Preparation and Characterization of Zinc(II)-Based Lewis/Brønsted Acidic Deep Eutectic Solvents.

Lewis/Brønsted acidic deep eutectic solvents (LBDESs) are a recent class of solvents that combine the two types of acidity. In some cases, this synergy leads to enhanced catalytic properties for many reactions and applications. For this reason, it is important to discover more LBDESs. In this work, we prepared and characterized four different zinc(II)-based LBDESs, mixing ZnCl2 and various Brønsted acids: acetic, glycolic, levulinic, and formic acids. Apart from the latter, for which the corresponding DES is not thermally stable, the samples have been characterized in terms of density, viscosity, and conductivity. Notably, as zinc(II) is a diamagnetic metal, all of them are suitable for NMR spectroscopy, for example, for kinetic and mechanistic studies.