Solvent Extraction Research Articles

In-depth mechanistic insights into Au nanoparticles based polyurethane foams as a selective and efficient dispersive solid phase microextractor for textile dyes from water: performance and reusability study

ABSTRACT Herein, a simple, superhydrophobic, superoleeophilic and low cost microextractor Au nanparticles (Au NPs) based polyurethane (PUFs) solid platform (Au NPs/PUFs) has been developed as a promising sorbent for removal and recovery of Congo red (CR) textile dye from water bodies. The sorbent was characterised using UV-visible and SEM techniques. The procedure relied complete dye retention from the aqueous solution at pH 5.0–5.5 onto an Au NP/PUF extractor. Analytical assessments revealed that the Au NPs/PUFs combination significantly improves mass transfer of dye and enhances creation of active sites for CR retention. CR sorption by the sorbent fitted well with intra-particle diffusion and pseudo first-order kinetic models (R2 = 0.990). The enthalpy change, ΔH (37.8 kJ mol−1) indicates that dye extraction is endothermic whereas the entropy change, ΔS0 (116.6 J mol−1K−1), reveals a significant change in the entropy during dye uptake. The free energy change ΔG (3.12 kJ mol−1 at 298 K) of CR sorption indicated that the dye retention was not spontaneous at all temperatures. A twofold sorption mechanism involving absorption accompanying ‘solvent extraction’ and/or ‘weak ion exchange’, combined with surface adsorption of dye is proposed. Sorbent packed mini column demonstrated effective percent removal and recovery (101.8%) of CR from water samples using acetone or NaOH as an eluting agent. The study expands the utility of Au NPs/PUFs for reusability and spectrophotometric sensing of trace levels of CR in water. The key attention also includes integrating PUFs utility by improving the selectivity and sensing properties towards textile dyes.

Optimization of ultrasound-assisted anthocyanin extraction from agricultural waste purple corn silk for multifunctional hemp finishes

The utilization of agricultural wastes for textile dyeing has gained popularity due to their safe and environmentally friendly properties, as well as the resource sustainability. Natural dye extraction is usually achieved through solvent extraction, which is time-consuming, requires a lot of solvent, and degrades desired compounds at high temperatures. Thus, this study investigated ultrasound-assisted anthocyanin extraction from agricultural waste purple corn silk as natural functional colorants for hemp finishes, given the numerous health benefits associated with anthocyanin. In order to optimize the extraction processes and evaluate the synergistic impact of these conditions, response surface methodology was implemented. The optimum conditions were 1:15 material-liquid ratio, 47% ethanol concentration, 60°C, and 20 min, yielding 240.25 mg·L‒1 anthocyanin. The extracted anthocyanin was used for dyeing hemp fabrics and demonstrated satisfactory colorfastness, antibacterial action on both S.aureus and E.coli, with E.coli being more effective, and strong antioxidant (>80%). The dyed fabrics also exhibited their great UV shield (UPF value > 40+). Anthocyanin derived from purple corn silk could therefore be utilized as a natural functional color for medical and health products. Also, purple corn silk contains more anthocyanin than other natural sources, making it a promising natural anthocyanin resource in textile industry.

Carbon Dioxide as a Sustainable Reagent in Circular Hydrometallurgy.

This review highlights the use of CO2 as a reagent in hydrometallurgy, with emphasis on the new concept of circular hydrometallurgy. It is shown how waste CO2 can be utilised in hydrometallurgical operations for pH control or regeneration of acids for leaching. Metal-rich raffinate solutions generated after removal of the valuable metals can serve as feedstocks for mineral carbonation, providing alternative avenues for CO2 sequestration. Furthermore, CO2 can also be used as a renewable feedstock for the production of chemical reagents that can find applications in hydrometallurgy as lixiviant, as precipitation reagent or for pH control. Mineral carbonation can be combined with chemical reactions involving metal complexation reagents, as well as with solvent extraction processes for the concurrent precipitation of metal carbonates and acid regeneration. An outlook for future research in the area is also presented.

Microwave-Assisted Enzymatic Green Solvent Technology for the Extraction and Characterization of Sesame Seed Oil

Traditional methods of extracting oil with organic solvents raise issues related to health, safety, and the environment. Microwave-assisted enzymatic green solvent extraction (MAEGSE) technology is environment friendly because it involves less hazardous chemical synthesis, utilizes renewable feedstock, and decreases the chemical load and emissions produced by organic solvents. The solvents methanol, ethanol, and various cell wall degrading enzymes such as hemicellulose, viscozyme L, pectinase, xylanase, and cellulase were used in this study. The MAEGSE process of sesame oil was conducted, and the results indicated that, unlike the controlled group, no enzymes were used during the process. Among all the combinations a higher oil extraction efficiency was obtained with combination of pectinase and ethanol (37.27%) followed by the xylanase with ethanol (36.75%) from sesame seed without compromising the quality of oil. Among the enzymes tested, pectinase resulted in the highest oil extraction efficiency, followed by xylanase. Use of pectinase improved the oil extraction efficiency in both ethanol and methanol mediums. The outcomes suggested that the application of pectinase enzymes plays a significant role in increasing the oil yield in comparison with the control without compromising quality of oil. Oil extracted without the use of enzyme (control) had a lower free fatty acid (FFA) concentration than the oils extracted with MAEGSE. Even though the specific gravity (SG) and refractive index (RI) of extracted oils were not significantly different in the solvents, the saponification value (SV), peroxide value (PV), iodine value (IV), and free fatty acid (FFA) were found to have minor differences among the extraction techniques.

Comediating Adsorption and Electron Transfer via Dual‐Active Site Catalyst Construction for Improving the Treatment of Extraction Wastewater

Solvent extraction is widely applied, while extraction wastewater treatment remains a huge challenge because of the stability of extractants. Heterogeneous Fenton‐like catalysis is a promising method, but the short half‐life of hydroxyl radicals (•OH) generated by hydrogen peroxide (H2O2) activation results in unsatisfactory •OH utilization and organics removal. Herein, an efficient strategy for treating extraction wastewater based on comediating adsorption and electron transfer by fluorine and nitrogen co‐doped carbon (FNC) catalyst with dual‐active site was developed. Specially, N sites adsorb organics and F sites activate H2O2, shortening the migration distance of •OH. Theoretical calculation and di(2‐ethylhexyl) phosphoric acid (D2EHPA) extraction wastewater degradation experiment showed that F site with electron acquisition can transfer electrons provided by electron‐rich D2EHPA enriched at N sites to H2O2, facilitating the continuous generation of •OH through lowering the energy barrier for H2O2 activation. As a result, 96.49% D2EHPA in simulated wastewater and 90.26% total organic carbon in real extraction wastewater were removed. Moreover, FNC catalyst exhibited excellent reusability and ionic adaptability, and can be extended to the removal of various extractants. The proposed dual‐active site catalyst provides an effective strategy for Fenton‐like reaction to treat refractory extraction wastewater, promoting sustainable development of solvent extraction industry.

Comediating Adsorption and Electron Transfer via Dual-Active Site Catalyst Construction for Improving the Treatment of Extraction Wastewater.

Solvent extraction is widely applied, while extraction wastewater treatment remains a hugechallengebecause of the stability of extractants.Heterogeneous Fenton-like catalysis is a promising method, but the short half-life of hydroxyl radicals (•OH)generated by hydrogen peroxide (H2O2)activation results in unsatisfactory •OH utilization and organics removal.Herein, an efficient strategy for treating extraction wastewater based on comediating adsorption and electron transfer by fluorine and nitrogen co-doped carbon (FNC) catalyst with dual-active site was developed. Specially, N sites adsorb organics andFsites activateH2O2, shortening the migration distanceof •OH. Theoretical calculation and di(2-ethylhexyl) phosphoric acid (D2EHPA)extraction wastewater degradation experimentshowed that F sitewith electron acquisition can transfer electrons provided by electron-rich D2EHPA enriched at N sites toH2O2,facilitating the continuous generation of •OH through lowering the energy barrier for H2O2activation.As a result, 96.49% D2EHPA in simulated wastewaterand 90.26% total organic carbonin realextraction wastewaterwere removed. Moreover, FNC catalystexhibited excellent reusability and ionic adaptability, and can be extended to the removal of various extractants. The proposed dual-active site catalyst providesan effective strategyforFenton-likereactiontotreatrefractory extraction wastewater, promotingsustainable development of solvent extraction industry.

Phytochemical Screening of Seaweed Flour (Eucheuma cottonii) Using Various Organic Solvents and Its Application in Tilapia Feed (Oreochromis niloticus)

This study aims to qualitatively analyze the bioactive compounds in Eucheuma cottonii seaweed flour extract and its application in commercial feed for tilapia (Oreochromis niloticus). The methodology employed is experimental and consists of two phases. Phase 1 involves the extraction of E. cottonii flour using three different organic solvents with varying polarity (ethanol, ethyl acetate, and a combination of ethanol + ethyl acetate). The testing parameters include qualitative phytochemical tests for alkaloids, steroids/triterpenoids, saponins, flavonoids, and tannins. Phase 2 consists of the application of the extract to tilapia over a 30-day rearing period with four treatments: control/commercial feed (P0), commercial feed + ethanol extract (P1), commercial feed + ethyl acetate extract (P2), and commercial feed + combined ethanol and ethyl acetate extract (P3). The parameters tested include absolute weight, specific growth rate, survival rate, and water quality. Phytochemical and water quality data are presented in table format. Meanwhile, growth and survival data are analyzed using ANOVA, followed by Duncan’s test for significant differences. The results of the researches carried out, it can be concluded that the phytochemical analysis of E. cottonii extract in ethanol and the ethanol + ethyl acetate combination yielded similar compounds: alkaloids, steroids/triterpenoids, and flavonoids. The ethyl acetate extract contained triterpenoids and flavonoids. Both saponins and tannins returned negative results across all organic solvent treatments. All treatments with the addition of E. cottonii seaweed extract in various organic solvents demonstrated better growth in tilapia compared to the control treatment.

Experimental Study of the Accumulation Mechanism of Styrene in Activated Carbon with the Aid of Supercritical Solvent Extraction

Experimental Study of the Accumulation Mechanism of Styrene in Activated Carbon with the Aid of Supercritical Solvent Extraction

Antioxidant Potential Evaluation at Various Stages of Black Cumin Oil Production

Nigella sativa L. seeds and their industrial process products, oils, cake, and meal, are valuable sources of bioactive compounds with antioxidant properties. In this work, the effect of technological processes on the antioxidant capacity (AC) and total phenolic content (TPC) in the black cumin oils obtained by cold pressing and solvent extraction, as well as the by-products, were evaluated. The AC values of black cumin seeds (BCS), cold-pressed black cumin oil (BCCPO), black cumin oil extracted from seeds (BCEO-S), black cumin oil extracted from cake (BCEO-C), black cumin cake (BCC), and black cumin meal (BCM) were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and cupric reducing antioxidant capacity (CUPRAC) assays, whereas TPC in these samples was analyzed by the Folin–Ciocalteu (FC) method. Two applied conventional oil extraction methods, screw pressing and solvent extraction, significantly affected the AC and TPC in the obtained black cumin oils and by-products. The solvent-extracted black cumin oils revealed higher antioxidant properties (DPPH = 4041–16,500 μmol TE/100 g, CUPRAC = 1275–4827 μmol TE/100 g) than the cold-pressed black cumin oil (DPPH = 3451 μmol TE/100 g and CUPRAC = 3475 μmol TE/100 g). In addition, the oil yield (20.92–48.86%) and antioxidant properties of BCCPO (DPPH = 2933–5894 μmol TE/100 g and TPC = 135–199 mg GAE/100 g) and BCC (DPPH = 1890–2265 μmol TE/100 g and TPC = 284–341 mg GAE/100 g) closely depended on the nozzle diameters (5, 8, and 10 mm) mounted in a screw press. Although both by-products were a rich source of antioxidants, BCM had significantly lower CUPRAC (1514 μmol TE/100 g) and TPC (92 mg GAE/100 g) values than BCC (CUPRAC = 3397 μmol TE/100 g and TPC = 426 mg GAE/100 g). Nevertheless, acid hydrolysis and alkaline hydrolysis of BCM extracts significantly increased their antioxidant potential. However, the DPPH (35,629 μmol TE/100 g), CUPRAC (12,601 μmol TE/100 g), and TPC (691 mg GAE/100 g) results were higher for the BCM extract after acid hydrolysis than those for alkaline hydrolysate (DPPH = 2539 μmol TE/100 g, CUPRAC = 5959 μmol TE/100 g, and TPC = 613 mg GAE/100 g). Finally, the generated AGREEprep metrics highlighted the sustainability and the greenness of the cold pressing of oil from BCS.

Optimization of ultrasound-assisted deep eutectic solvent extraction, characterization, and bioactivities of polysaccharide from Plantaginis Semen

Plantaginis Semen (PS) are the dried mature seeds of Plantago asiatica L. or Plantagodepressa Willd. in the Plantago family. Its polysaccharides are important components of PS. Response surface methodology was used to optimize the ultrasonic-assisted deep eutectic solvent (DES) extraction process of PS polysaccharides (PSP). The results showed that the optimal extraction parameters were a solid-liquid ratio of 1:35 g/mL, an extraction time of 73 min, and a molar ratio of 2:1. The yield of PSP was 0.64% and 1.20% by water immersion and ultrasonic water extraction, respectively, indicating that the DES extraction method (2.21 ± 0.06%) is superior to these two methods, and the optimization effect is good. Through the α-glucosidase and α-amylase inhibition activities experiment, it was found that the IC50 values of PSPs-1 were 1122 and 220.5 μg/mL. DPPH·and ABTS+ scavenging activity experiments showed that the IC50 values of PSPs-1 were 19.2 and 4.3 μg/mL, respectively. Its molar ratio of monosaccharide composition is rhamnose: galactose: galacturonic acid: glucose: glucuronic acid: arabinose: mannose: xylose = 33.6:13.3:6.5:3:2.6:2:1.4:1. Therefore, this study can provide an experimental basis for the establishment of an industrialized production process of polysaccharides and the study of their biological activities.

Towards realism in hazard assessment of plastic and rubber leachates – Methodological considerations

While plastic chemicals are key drivers of observed effects to aquatic species, there remains a lack of standardized and fit-for-purpose approaches for experimentally deconvoluting the effects of plastic chemicals from particle effects. This study investigated differences in chemical composition determined using two different organic solvents for extractions (dichloromethane-ethyl acetate, methanol) and by thermal desorption applied to 51 thermoplastic and elastomer products. The composition of natural water leachates of four select elastomers was also investigated. The number of chemical features in each material varied according to the extraction method, with solvent extracts exhibiting the most chemicals, and only 19 compounds commonly identified by all three methods. The number of chemical features in leachates was generally similar to the corresponding chemical extracts, but strong differences in relative composition were detected. While turbulence had minimal impact on leachate composition, particle loading strongly influenced leachate composition, temperature and salinity influenced the leachate concentration for some chemicals, and leaching time depended upon chemical mobility. Leachate composition cannot be readily predicted from particle characterization and multiple parameters are drivers of compositional variance in aquatic leachates. Recommendations for performing leaching studies that are relevant for hazard characterization in a realistic aquatic environment risk assessment scenario are suggested, with a particular focus on particle loading.

The effects of sample preparation on the interpretation of pyrolysis-based organic matter analysis in immature oil shale

Oil shale as well as shale oil and shale gas are significant energy resources with huge reserves present in different parts of the world. Various geochemical proxies have been applied to assess the petroleum potential of oil shales with samples pre-treated in various ways, e.g. as whole rock or demineralized sample or as solvent extracted rock/kerogen. In this respect, it is important to understand and quantify, how achieved geochemical parameters are influenced by pre-treatment. In this study, a systematic comparison is presented based on a study on i) whole rock, ii) extracted whole rock, iii) kerogen concentrate, and iv) extracted kerogen concentrate obtained after solvent extraction of demineralized shales. In total, seven immature, organic matter-rich samples from the Miocene lacustrine sediments of the Nördlinger Ries impact crater, Germany, were pretreated in this way leading to overall 28 samples. A set of elemental analysis (C, H, N), Rock-Eval pyrolysis, and Curie Point-pyrolysis–gas chromatography–mass spectrometry measurements were performed on these pretreated samples. Mineral matter removal leads to significant increase of total organic carbon, but also thermally evaporable and pyrolytically cracked organic matter (Rock-Eval S1 and S2 peaks). To some extent, labile organic matter represented in the original S2 peak can be destructed by mineral removal with hydrochloric and hydrofluoric acid, as shown by elevated values of PI [S1/(S1 + S2)] after demineralization. The organic matter type tends to be more petroleum-prone with raised hydrogen index (HI) and aliphaticity values after demineralization, while Rock-Eval Tmax values commonly applied as parameters for thermal maturity tend to decrease, though not for all samples.Reduced TOC, S1, S2 and PI values of extracted samples suggest that both thermally evaporable and additionally some non-evaporable but soluble organic matter hidden in the original S2 peak can be lost after solvent extraction. Increased values of HI, H/C and N/C of extracted samples indicate more oil-prone organic matter types than unextracted samples. Typical maturity-related parameters such as aliphaticity and Rock-Eval Tmax decrease. Smectite and zeolites, which are abundant in the samples, are suggested to protect organic matter to some extent against solvent extraction, influencing a variety of geochemical proxies and the occurrence of metal cation-containing minerals. Zeolite invigorates the protection effect.

Hierarchically-porous resin for the adsorption of organic matter in raffinate produced by solvent extraction from the vanadium industry

Solvent extraction wastewater contains high concentrations of organic pollutants and metal ions, making it difficult to treat. This paper presents a method of using hierarchically-porous adsorption resin to recover organics from raffinate and regenerate the resin, addressing secondary pollution in extraction processes. The chosen resin, WS6108, removes over 95 % of organics from raffinate, with high metal ion concentrations enhancing its adsorption efficiency. The article conducted an optimization experiment and mechanism study on WS6108 resin for adsorbing organic matter in vanadium raffinate (OIVR), followed by desorption and recycling tests. Results showed WS6108 resin achieved a 96.7 % adsorption efficiency at a solid–liquid ratio of 24 g/L after optimization. The chosen methanol desorbent achieves over 99 % desorption efficiency for the WS6108 cycle under specific conditions. The resin’s performance remains stable for up to 45 cycles. Adsorption isotherms and kinetic experiments indicate that OIVR adsorption by WS6108 resin is endothermic, non-spontaneous and entropy increasing. Moreover, the adsorption kinetics of OIVR by WS6108 resin followed a pseudo-second-order model, based on the activation energy, liquid film diffusion was considered the main rate-controlling step. A column experiment was conducted to verify that WS6108 resin can be used in real vanadium raffinate to remove organics. Density functional theory (DFT) revealed that strong hydrogen bonding, π-π stacking and excellent adsorption diffusion behavior drive OIVR adsorption. This study aims to increase the use of adsorption to treat oily wastewater generated by solvent extraction.

Efficacy of Melia azedarach leaf extract in different solvents against Heterotermes indicola Wasmann (Blattodea: Rhinotermitidae) using non-durable wooden blocks under laboratory and field conditions

Hetertermes indicola Wasman (Blattodea: Rhinotermitidae) is a highly wood-destructive termite species in the urban settings of Pakistan. This study evaluated the biocidal action of Melia azedarach leaf extract in different solvents on H. indicola by conducting choice and no-choice feeding deterrence assays using impregnated palatable wood under field and laboratory conditions. Dose-dependent and time-dependent trends were observed in the leaf extracts of M. azedarach at different concentrations (500, 1000, and 1500 ppm) using solvent water and methanol with 80–100 % termite mortality after 6 days of exposure. A key outcome was the higher termiticidal efficacy of methanolic extract compared to aqueous extract under both field and laboratory conditions. The LC50 values of 358 ppm for methanol and 466 ppm for aqueous extract after 15 days in a laboratory no-choice experiment exhibit a quantitative measure of chinaberry leaf extract toxicity. A significant reduction in mean percent weight loss (8.26 %) of treated wood with 1500 ppm of M. azedarach leaf extract in methanol was observed under field conditions. In conclusion, triterpenoids and phytol present in methanolic leaf extract demonstrated higher efficacy in both lab and field conditions making a solid foundation for the further development of natural wood preservatives. Since they induced rapid lethargic conditions in termites and digestive toxicity which leads to minimum loss of treated wood.

Supramolecular deep eutectic solvents as green media for efficient extraction of tea polyphenols and its application in bio-active film

Ultrasonic-assisted supramolecular deep eutectic solvents (SUPRADESs) extraction of active ingredients from plants is a novel green extraction method. In this study, a series of SUPRADESs combined with cyclodextrins (CDs) and organic acids or polyols were synthesized and used to extract the tea polyphenols (TP). SUPRADESs, consisting of Hydroxypropyl-β-cyclodextrin (HP-β-CD) and L-lactic acid (LA) with a mass ratio of 1:5, contributed to achieving the maximum extraction efficiency of TP. Then, the extraction rate was optimized by different experimental conditions, and the optimal extraction yield of TP was (111.36 ± 2.31 mg/g). Then, the biofilms were successfully prepared using HP-β-CD/LA extract as a plasticizer for polyvinyl alcohol and chitosan. Furthermore, the antioxidant activity of extract and film containing TP was determined using biochemical kits. Finally, the synthesis process of HP-β-CD/LA and the TP extraction were investigated using molecular simulation. The findings indicate that enhanced TP yield could be attributed to an increase in non-covalent bonds between HP-β-CD and TP through the assistance of LA.

Ultrasonic-assisted DES extraction optimization, characterization, antioxidant and in silico study of polysaccharides from Angelica dahurica Radix

In this study, polysaccharides from Angelica dahurica Radix (ADR) were extracted by using ultrasonic-assisted deep eutectic solvent (DES) extraction method. The DES consist of choline chloride (HBA, hydrogen bonding acceptor) and 1, 4-butanediol (HBD, hydrogen bonding donor) with the molar ratio of 1:3 was proved as the best system for polysaccharides extraction. A Box-Behnken design with three factors and three levels was utilized to optimize ultrasonic power, extraction time and temperature for increased polysaccharides yield. The optimal extraction parameters were determined as follows: DES water content of 20 %, liquid–solid ratio of 10:1 mL/g, ultrasonic time of 21 min, temperature at 60 °C, and ultrasonic power of 435 W. These conditions yielded an extraction rate nearly matching the theoretical predicted value of the response surface model, surpassing the traditional hot water extraction method by 1.33 times and requiring less time. The antioxidant polysaccharides was assessed using DPPH,ABTS and Hydroxyl methods, which indicated that ADRP extracted by ultrasound assisted DES had excellent antioxidant capacity and showed a dose–response relationship with drug concentration. Structural analysis identified ADR polysaccharides as a heteropolysaccharide rich in sugar aldonic acids—namely, fucose, rhamnose, arabinose, galactose and glucose—with molar ratios of 0.47:1.99:17.61:64.76:15.17. The polysaccharides’ number-average molecular weight was determined to be 97.422 kDa, with a weight-average molecular weight of 245.678 kDa. Network pharmacology and molecular docking analysis suggest that the monosaccharides Rha and Ara could potentially interact with the proteins GSR and GSTA1, respectively, indicating that ADRP had good antioxidant potential and could be applied in multiple fields with promising development prospects in the future.

Optimization of ultrasound-assisted extraction of astaxanthin from black tiger shrimp (Penaeus monodon) shells using deep eutectic solvent and ethanol as a co-solvent

The study aimed to enhance the extraction of astaxanthin (ASX) from black tiger shrimp shells by combining Deep eutectic solvent (DES) and ultrasound-assisted extraction (UADE). The DES used in the research consisted of choline chloride (Ch) and citric acid (CA) in a 1:2 molar ratio with 20% water. Response surface methodology (RSM) utilizing a Box-Behnken design (BBD) was employed to optimize the UADE conditions, considering ultrasound power (200 – 400 W), ethanol concentration in the DES (5 – 65 %), and extraction time (5 – 45 min). The optimal UADE parameters identified by BBD were 330 W ultrasound power, 35% ethanol content, and 33 min of extraction, resulting in the highest ASX content of 47.42 μg/g, closely matching the predicted value of 48.65 μg/g. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis revealed structural alterations in samples treated with DES-based UAE, setting it apart from soxhlet extraction, maceration, and ethanol-based DES extraction. The outcomes indicated that UADE outperformed traditional extraction methods like soxhlet extraction, maceration, and ultrasound-assisted ethanol extraction (UAET) regarding ASX yield and antioxidant activity, while also needing shorter extraction durations. These results underscore UADE as a productive and eco-friendly approach for extracting ASX from shrimp shells.

Supercritical CO2 green solvent extraction of Nepeta crispa: Evaluation of process optimization, chemical analysis, and biological activity

This research investigates the extraction of compounds from Nepeta crispa (N. crispa), utilizing supercritical carbon dioxide green solvent, for the first time. Using RSM, the study examines the impact of pressure (15-25MPa), temperature (313-333K), and co-solvent (0.5- 3.5%) on the extraction yield. The antioxidant activity of the essential oil is assessed through Ferric Reducing Antioxidant Power (FRAP) assay, while its antibacterial properties are evaluated against four bacterial strains. The SCFE method achieved a maximum yield of 1.812% at optimum conditions (P= 25MPa, T= 313K and co-solvent= 3.5%). GC-Mass analysis revealed that the primary constituents of N. crispa essential oil which are 1,8-cineol and 4aα,7α,7aα-nepetalactone in both extraction methods. The antioxidant and antibacterial results of N. crispa showed the superiority of SC-CO2 over hydrodistillation method. These observed antioxidant and antibacterial attributes highlight the plant’s potential suitability for applications within the food and pharmaceutical industries.

Preparation of needle coke from low-temperature coal tar pitch based on modification, component separation and component blending

Needle coke is widely used in the production of ultra-high power electrodes, special carbon materials, carbon fibers, and their composites. How to prepare needle coke with excellent performance through directional adjusting of raw material components is a hot research topic. In this paper, coal tar pitch (CTP) was extracted from low-temperature coal tar (Low-coal tar). To further increase the content of quinoline-soluble, CTP was modified by formaldehyde via chemical polymerization. By adjusting the blending ratio of hexane-insoluble toluene-soluble (HI-TS) and toluene-insoluble tetrahydrofuran-soluble (TI-AS) obtained by modified coal tar pitch (HCTP) separation adopting solvent extraction, a series of green needle coke and needle coke were prepared. The physicochemical structures were analyzed using FTIR, TG, Py-GC/MS, XRD, PM, and SEM, and the electrochemical properties were evaluated and analyzed. The results show that the Lc and La of green needle coke and needle coke firstly increase and then decrease with the decrease of TI-AS content, while the ID/IG demonstrated the opposite tendency. When the content of TI-AS is 16.67%, it is favorable to improve the micro-morphology of needle coke and increase the content of the ideal graphite lattice (from 24.47% to 31.88%) and needle coke yield (44.03%). In this paper, the composition distribution of CTP was adjusted, and the effect of the blending ratio of HI-TS and TI-AS on the structure of green needle coke and needle coke was investigated, improving the added value of Low-coal tar and providing data reference for the directional regulation of needle coke.

Optimization of Microwave-Assisted Polyphenol Extraction and Antioxidant Activity from Papaya Peel Using Response Surface Methodology and Artificial Neural Network

The objective of the present study is to determine the optimal conditions of microwave-assisted extraction (MAE) such as microwave power (MWP), irradiation time (I-time), ethanol concentration (EtOH%), and solvent-to-solid ratio (S/S) for maximizing total polyphenol content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity from papaya peel. Box-Behnken design (BBD) was used considering MWP 300–600 W, I-time 60-120 s, EtOH% 30-70%, and S/S 30-70 mL/g. Additionally, response surface methodology (RSM) and artificial neural networks (ANN) were employed for modelling, with cross-validation to enhance reliability. These models were combined with the desirability function (DF) and/or genetic algorithm (GA) optimization approaches. Maximizing TPC and DPPH activity while maintaining MWP, I-time, EtOH%, and S/S within their respective ranges using hybrid optimization approaches (RSM-DF: TPC = 1058 mgGAE/100g, and DPPH = 83%, RSM-GA: TPC = 1064 mgGAE/100g and DPPH = 79%, and ANN-GA: TPC = 1086 mgGAE/100g, and DPPH = 83%,) yielded consistent optimal results. An additional optimization approach (RSM-DF: TPC = 955 mgGAE/100g, and DPPH = 90%), aimed at minimizing MWP, I-time, EtOH%, and S/S while maximizing TPC and DPPH activity, showed a significant reduction of approximately 3 L in ethanol consumption for each 100 g of dry samples. The maximized TPC and DPPH activity in all four approaches showed a significant (p < 0.05) alignment with their corresponding validation tests, demonstrating the better performance of these modelling and optimization processes. In terms of assessing the effectiveness of microwave assistance, conventional solvent extraction was also performed, maintaining a 70 mL/g S/S ratio of 55% ethanol at 60°C for 2 h. This method resulted in lower values of TPC (857 ± 23 g GAE/100g) yield and DPPH activity (72 ± 5%) compared to the optimized condition of MAE.