Deep eutectic solvents (DESs) have received considerable attention in recent years due to their low cost, low toxicity, and biodegradable properties. In this study, a sequential pretreatment comprising of a DES (choline chloride:urea in a ratio of 1:2) and divalent inorganic salt (CuCl2) was evaluated, with the aim of recovering xylose from oil palm fronds (OPF). At a solid-to-liquid ratio of 1:10 (w/v), DES alone was ineffective in promoting xylose extraction from OPF. However, a combination of DES (120°C, 4h) and 0.4mol/L of CuCl2 (120°C, 30min) resulted in a pretreatment hydrolysate containing 14.76g/L of xylose, remarkably yielding 25% more xylose than the CuCl2-only pretreatment (11.87g/L). Characterization studies such as FE-SEM, BET, XRD, and FTIR confirmed the delignification of OPF when DES was implemented. Thus, the use of this integrated pretreatment system enabled xylose recoveries which were comparable with other traditional pretreatments.
Diacylglycerol (DAG) and monoacylglycerol (MAG) are two natural occurring minor components found in most edible fats and oils. These compounds have gained increasing market demand owing to their unique physicochemical properties. Enzymatic glycerolysis in solvent-free system might be a promising approach in producing DAG and MAG-enriched oil. Understanding on glycerolysis mechanism is therefore of great importance for process simulation and optimization. In this study, a commercial immobilized lipase (Lipozyme TL IM) was used to catalyze the glycerolysis reaction. The kinetics of enzymatic glycerolysis reaction between triacylglycerol (TAG) and glycerol (G) were modeled using rate equation with unsteady-state assumption. Ternary complex, ping-pong bi-bi and complex ping-pong bi-bi models were proposed and compared in this study. The reaction rate constants were determined using non-linear regression and sum of square errors (SSE) were minimized. Present work revealed satisfactory agreement between experimental data and the result generated by complex ping-pong bi-bi model as compared to other models. The proposed kinetic model would facilitate understanding on enzymatic glycerolysis for DAG and MAG production and design optimization of a pilot-scale reactor.
Pretreatment with pure, mixed, and diluted deep eutectic solvents (DESs) was evaluated for its effect on Napier grass through compositional and characterization studies. The morphological changes of biomass caused by pretreatment were analyzed by FTIR and XRD. The cellulose and hemicellulose content after pretreatment using mixed DES increased and decreased 1.29- and 4.25-fold, respectively, when compared to untreated Napier grass. The crystallinity index (CrI. %) of mixed DES sample increased due to the maximum removal of hemicellulose (76 %) and delignification of 62 %. The material costs of ChCl/FA and ChCl/LA for a single run are ≈2.16 USD and ≈1.65 USD, respectively. Pure DES showed that ChCl/LA pretreatment enhanced delignification efficiency and that ChCl/FA increased hemicellulose removal. It was estimated that a single run using ChCl/LA:ChCl/FA to achieve maximum hemicellulose and lignin removal would cost approximately ≈1.89 USD. Future work will evaluate the effect of DES mixture on enzyme digestibility and ethanol production from Napier grass. HYPOTHESES: Deep eutectic solvent (DES) pretreatment studies on the fractionation of lignocellulosic biomass have grown exponentially. The use of pure and diluted DES has been reported to improve saccharification efficiency, delignification, and cellulose retention (Gundupalli et al., 2022). These studies have reported maximum lignin removal but also a lower effect on hemicellulose removal from lignocellulosic biomass. It was hypothesized that mixing two pure DESs could result in maximum removal of hemicellulose and lignin after pretreatment. To our knowledge, no studies have been performed to investigate the efficiency of pretreatment using a DES mixture and compared the outcome with pure and diluted DESs. Furthermore, it was hypothesized that using two pure DESs in a mixed form could lower the material cost for each experimental run. Process efficiency was determined by compositional, XRD, and FTIR analysis. Avenues for future research include determining glucose and ethanol yields during the enzymatic saccharification and fermentation processes.
Water pollution and depletion of natural resources have motivated the utilization of green organic solvents in solvent extraction (SX) and liquid membrane (LM) for sustainable wastewater treatment and resource recovery. SX is an old and established separation method, while LM, which combines both the solute removal and recovery processes of SX in a single unit, is a revolutionary separation technology. The organic solvents used for solute removal in SX and LM can be categorized into sole conventional, mixed conventional-green, and sole green organic solvents, whereas the stripping agents used for solute recovery include acids, bases, metal salts, and water. This review revealed that the performance of greener organic solvents (mixed conventional-green and sole green organic solvents) was on par with the sole conventional organic solvents. However, some green organic solvents may threaten food security, while others could be pricey. The distinctive extraction theories of various sole green organic solvents (free fatty acid-rich oils, triglyceride-rich oils, and deep eutectic solvents) affect their application suitability for a specific type of wastewater. Organic liquid wastes are among the optimal green organic solvents for SX and LM in consideration of their triple environmental, economic, and performance benefits.
Searching for green and ecofriendly solvents to replace classical solvents for industrial scale extraction of coconut oil is of great interest. To explore these possibilities, this study performed comprehensive comparative analyses of lipid profiles and phytosterol compositions in coconut oils obtained by extraction with n-hexane, absolute ethyl alcohol, deep eutectic solvent/n-hexane, dimethyl carbonate (DME) and cyclopentyl methyl ether (CPME) using a foodomics approach. Results indicated that CPME (64.23 g/100 g dry matter) and DME (65.64 g/100 g dry matter) showed comparable capacity for total lipid extraction of total lipids to classical solvents (63.5-65.66 g/100 g dry matter). Considering the phytosterol yield, CPME (644.26 mg/kg) exhibited higher selectivity than other solvents (535.64-622.13 mg/kg). No significant difference was observed in the fatty acid composition of coconut oil by the different solvents assayed. Additionally, total 468 lipid molecules were identified in the samples. For glycerolipid and sphingolipid, the five solvents showed comparable extraction capabilities. However, CPME exhibited higher extraction efficiency of polar lipids (glycerophospholipid and saccharolipid) than other solvents. Overall, these results may be a useful guide for the application of green solvents in industrial production of coconut oil.
Using natural deep eutectic solvents (NDES) for green extraction of lentinan from shiitake mushroom is a high-efficiency method. However, empirical and trial-and-error methods commonly used to select suitable NDES are unconvincing and time-consuming. Conductor-like screening model for realistic solvation (COSMO-RS) is helpful for the priori design of NDES by predicting the solubility of biomolecules. In this study, 372 NDES were used to evaluate lentinan dissolution capability via COSMO-RS. The results showed that the solvent formed by carnitine (15 wt%), urea (40.8 wt%), and water (44.2 wt%) exhibited the best performance for the extraction of lentinan. In the extraction stage, an artificial neural network coupled with genetic algorithm (ANN-GA) was developed to optimize the extraction conditions and to analyze their interaction effects on lentinan content. Therefore, COSMO-RS and ANN-GA can be used as powerful tools for solvent screening and extraction process optimization, which can be extended to various bioactive substance extraction.
Ficus deltoidea was known for its potent antioxidant, anti-melanogenic and photoprotective skin barrier activities. These properties are contributed by its biomarkers which are vitexin and isovitexin. This study aims to optimize the yield of methanolic extraction of Ficus deltoidea leaves (EFD) and evaluate their effects on skin barrier function and hydration. For optimization, Box-Behnken design was utilized to investigate the effects of methanol concentration, sonication time, and solvent-to-sample ratio on the yields of vitexin and isovitexin in EFD. The optimal yields obtained were 32.29 mg/g for vitexin and 35.87 mg/g for isovitexin. The optimum extraction conditions were 77.66% methanol concentration, 20.03 min sonication time, and 19.88 mL/g solvent-to-sample ratio. The quantitative real-time polymerase chain reaction was utilized to measure variant marker genes of transglutaminase-1, caspase 14, ceramide synthase 3, involucrin, and filaggrin of EFD-induced keratinocyte differentiation by in vitro study. Exposure to EFD has elevated the mRNA levels of all tested marker genes by 0.7-9.2 folds. Then, in vivo efficacy study was conducted on 20 female subjects for 14 days to evaluate skin biophysical assessment of hydration. EFD topical formulation treatment successfully increased skin hydration on day 7 (43.74%) and day 14 (47.23%). In silico study by molecular docking was performed to identify intermolecular binding interactions of vitexin and isovitexin with the interested proteins of tested marker genes. The result of molecular docking to the interested proteins revealed a similar trend with real-time PCR data. In conclusion, EFD potentially enhanced the skin barrier function and hydration of human skin cells.
The potential for the transformation of lignocellulosic biomass into valuable commodities is rapidly growing through an environmentally sustainable approach to harness its abundance, cost-effectiveness, biodegradability, and environmentally friendly nature. Ionic liquids (ILs) have received considerable and widespread attention as a promising solution for efficiently dissolving lignocellulosic biomass. The fact that ILs can act as solvents and reagents contributes to their widespread recognition. In particular, ILs are desirable because they are inert, non-toxic, non-flammable, miscible in water, recyclable, thermally and chemically stable, and have low melting points and outstanding ionic conductivity. With these characteristics, ILs can serve as a reliable replacement for traditional biomass conversion methods in various applications. Thus, this comprehensive analysis explores the conversion of lignocellulosic biomass using ILs, focusing on main components such as cellulose, hemicellulose, and lignin. In addition, the effect of multiple parameters on the separation of lignocellulosic biomass using ILs is discussed to emphasize their potential to produce high-value products from this abundant and renewable resource. This work contributes to the advancement of green technologies, offering a promising avenue for the future of biomass conversion and sustainable resource management.
Cellulose nanocrystals (CNC) conventionally involve highly concentrated sulphuric acid, which typically resulted in the formation of undesirable by-products. Although less corrosive mineral acids have been explored as alternatives, high concentrations are still required. In this study, CNC was successfully isolated from Leucaena leucocephala wood using mild sulphuric acid with acetic acid as protic solvent, and it was further studied with the addition of Lewis acids in the form of multivalent transition metal salts as co-catalyst. Selected divalent and trivalent transition metal salts including (Cr(NO3)3, Fe(NO3)3, Co(NO3)2, and Ni(NO3)2) were investigated. The morphology, chemical structure, particle size, and physicochemical properties of the CNCs were determined. Controlled depolymerization of cellulose was observed using transmission electron microscopy (TEM). Rod-like morphology for all CNCs was obtained during the hydrolysis process with the smallest CNC particles found at an average length of 278.1 ± 35.1 nm and a diameter of 13.4 ± 3.0 nm. The results showed that higher valence state metal ions resulted in better cellulose hydrolysis efficiency. In addition, the use of transition metal salt as a co-catalyst improved production efficiency and minimised carbonization of CNC while maintaining desired crystallinity and thermal properties.
Electrospinning has been acknowledged as an efficient technique for the fabrication of continuous nanofibers from polymeric based materials such as polyvinyl alcohol (PVA), cellulose acetate (CA), chitin nanocrystals and others. These nanofibers exhibit chemical and mechanical stability, high porosity, functionality, high surface area and one-dimensional orientation which make it extremely beneficial in industrial application. In recent years, research on chitin - a biopolymer derived from crustacean and fungal cell wall - had gained interest due to its unique structural arrangement, excellent physical and chemical properties, in which make it biodegradable, non-toxic and biocompatible. Chitin has been widely utilized in various applications such as wound dressings, drug delivery, tissue engineering, membranes, food packaging and others. However, chitin is insoluble in most solvents due to its highly crystalline structure. An appropriate solvent system is required for dissolving chitin to maximize its application and produce a fine and smooth electrospun nanofiber. This review focuses on the preparation of chitin polymer solution through dissolution process using different types of solvent system for electrospinning process. The effect of processing parameters also discussed by highlighting some representative examples. Finally, the perspectives are presented regarding the current application of electrospun chitin nanofibers in selected fields.
Emerging contaminants (ECs) originated from different agricultural, biological, chemical, and pharmaceutical sectors have been detected in our water sources for many years. Several technologies are employed to minimise EC content in the aqueous phase, including solvent extraction processes, but there is not a solution commonly accepted yet. One of the studied alternatives is based on separation processes of emulsion liquid membrane (ELM) that benefit low solvent inventory and energy needs. However, a better understanding of the process and factors influencing the operating conditions and the emulsion stability of the extraction/stripping process is crucial to enhancing ELM's performance. This article aims to describe the applications of this technique for the EC removal and to comprehensively review the ELM properties and characteristics, phase compositions, and process parameters.
The effect of hydroxypropyl methylcellulose (HPMC) concentration on β-cyclodextrin (β-CD) solubilization of norfloxacin was examined. The solubility and dissolution of norfloxacin/β-CD and norfloxacin/β-CD/HPMC inclusion complexes were studied. The presence of β-CD increased significantly the solubility and dissolution of norfloxacin. The addition of HPMC until 5% (w/w) improved the solubilization of norfloxacin but further addition above 5% (w/w), decreased norfloxacin solubilization. Fourier transformed Infra-red (FTIR) showed that norfloxacin was successfully included into β-CD. Differential scanning calorimetry (DSC) showed that the norfloxacin endothermic peak shifted to a lower temperature with reduced intensity indicating the formation of inclusion complex. The addition of HPMC reduced further the intensity of norfloxacin endothermic peak. Most of the sharp and intense peaks of norfloxacin disappeared with the addition of HPMC. In conclusion, the concentration of hydrophilic polymer used to enhance β-CD solubilization of poorly soluble drugs is very critical.
Superglue in the ear as a foreign body is an uncommon presentation. We report the case of a lady who accidentally instilled superglue directly onto her tympanic membrane and presented five days later. We successfully removed the glue with acetone and managed to preserve the integrity of the tympanic membrane.
The catalytic activity of free laccase and a novel sol-gel laccase (SOLAC) in ionic liquids and organic solvents was demonstrated by using 2,6-dimethoxyphenol (2,6-DMP) as a substrate. The enhancement of the catalytic activity of the SOLAC was observed and compared to the free laccase in both media. The oxidative biodegradation of o-chlorophenol as a model of phenolic environmental pollutants in organic media shows that the degradation was observed only when using water pre-saturated organic solvents or reverse micelle system. The SOLAC gave higher biodegradation rate in either aqueous or organic solvents, in which the optimum temperature was observed at 40 °C for the reverse micelle system as a reaction medium. All results demonstrated the potential use of the SOLAC for biodegradation of phenolic environmental pollutants in non-conventional media.
Solvolysis of oil palm empty fruit bunches (EFB) fibres using different solvents (acetone, ethylene glycol (EG), ethanol, water and toluene) were carried out using an autoclave at 275°C for 60 min. The solvent efficiency in term of conversion yield was found to be: EG>water>ethanol>acetone>toluene. The liquid products and residue obtained were analyzed using Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass selectivity. The obtained results showed that the chemical properties of the oil product were significantly affected by the type of solvent used for the solvolysis process. The higher heating value (HHV) of oil products obtained using ethanol is ∼29.42 MJ/kg, which is the highest among the oil products produced using different solvents. Water, ethanol and toluene yield major phenolic compounds. While EG favors the formation of alcohol compounds and acetone yields ketone and aldehyde compounds.
Various types of vegetable oil-based organic solvents (VOS), i.e. vegetable oils (corn, canola, sunflower and soybean oils) with and without extractants (di-2-ethylhexylphosphoric acid (D2EHPA) and tributylphosphate (TBP)), were investigated into their potentiality as greener substitutes for the conventional petroleum-based organic solvents to extract Cu(II) from aqueous solutions. The pH-extraction isotherms of Cu(II) using various vegetable oils loaded with both D2EHPA and TBP were investigated and the percentage extraction (%E) of Cu(II) achieved by different types of VOS was determined. Vegetable oils without extractants and those loaded with TBP alone showed a poor extractability for Cu(II). Vegetable oils loaded with both D2EHPA and TBP were found to be the most effective VOS for Cu(II) extraction and, thus, are potential greener substitutes for the conventional petroleum-based organic solvents.
In continuation of investigation for environmentally benign protocol for new solvents termed deep eutectic solvents (DESs), it is herein reported results concerning the toxicity and cytotoxicity of choline chloride (ChCl) based DESs with four hydrogen bond donors including glycerine, ethylene glycol, triethylene glycol and urea. The toxicity was investigated using two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity effect was tested using the Artemia salina leach. It was found that there was no toxic effect for the tested DESs on all of the studied bacteria confirming their benign effects on these bacteria. Nevertheless, it was found that the cytotoxicity of DESs was much higher than their individual components (e.g. glycerine, ChCl) indicating that their toxicological behavior is different. For our best knowledge this is the first time that toxicity and cytotoxicity of DESs were studied. The toxicity and cytotoxicity of DESs varied depending on the structure of components. Careful usage of the terms non-toxicity and biodegradability must be considered. More investigation on this matter is required.
We examined the solubility of simvastatin in water in 0.01 mol·dm(-3), 0.02 mol·dm(-3), 0.04 mol·dm(-3), 0.09 mol·dm(-3), 0.18 mol·dm(-3), 0.36 mol·dm(-3), and 0.73 mol·dm(-3) arginine (ARG) solutions. The investigated drug is termed the solute, whereas ARG the cosolute. Phase solubility studies illustrated a higher extent of solubility enhancement for simvastatin. The aforementioned system was subjected to conductometric and volumetric measurements at temperatures (T) of 298.15 K, 303.15 K, 308.15 K, and 313.15 K to illustrate the thermodynamics involved and related solute-solvent interactions. The conductance values were used to evaluate the limiting molar conductance and association constants. Thermodynamic parameters (ΔG (0), ΔH (0), ΔS (0), and E s) for the association process of the solute in the aqueous solutions of ARG were calculated. Limiting partial molar volumes and expansibilities were evaluated from the density values. These values are discussed in terms of the solute-solvent and solute-cosolute interactions. Further, these systems were analyzed using ultraviolet-visible analysis, Fourier-transform infrared spectroscopy, and (13)C, (1)H, and two-dimensional nuclear overhauser effect spectroscopy nuclear magnetic resonance to complement thermophysical explanation.
Multi-walled carbon nanotubes (CNTs) functionalized with a deep eutectic solvent (DES) were utilized to remove mercury ions from water. An artificial neural network (ANN) technique was used for modelling the functionalized CNTs adsorption capacity. The amount of adsorbent dosage, contact time, mercury ions concentration and pH were varied, and the effect of parameters on the functionalized CNT adsorption capacity is observed. The (NARX) network, (FFNN) network and layer recurrent (LR) neural network were used. The model performance was compared using different indicators, including the root mean square error (RMSE), relative root mean square error (RRMSE), mean absolute percentage error (MAPE), mean square error (MSE), correlation coefficient (R2) and relative error (RE). Three kinetic models were applied to the experimental and predicted data; the pseudo second-order model was the best at describing the data. The maximum RE, R2 and MSE were 9.79%, 0.9701 and 1.15 × 10-3, respectively, for the NARX model; 15.02%, 0.9304 and 2.2 × 10-3 for the LR model; and 16.4%, 0.9313 and 2.27 × 10-3 for the FFNN model. The NARX model accurately predicted the adsorption capacity with better performance than the FFNN and LR models.
Chitosan-deep eutectic solvent (DES) beads were prepared from chitosan and DESs. The DESs used were choline chloride-urea (DES A) and choline chloride-glycerol (DES B). Both chitosan-DES beads were used to remove malachite green (MG) dye from an aqueous solution. The optimum pH for chitosan-DES A was recorded at pH 8.0 while optimum pH for chitosan-DES B was pH 9.0. The maximum adsorption capacity obtained for chitosan-DES A and chitosan-DES B were 6.54 mg/g and 8.64 mg/g, respectively. The optimum conditions for both chitosan-DES beads to remove MG were 0.08 g of adsorbent and 20 min of agitation time. Five kinetic models were applied to analyse the data and the results showed that the pseudo-second-order and intraparticle diffusion model fitted best with R2 > 0.999. For the adsorption capacity, results show that the Freundlich and Langmuir adsorption isotherms fitted well with chitosan-DES A and chitosan-DES B, respectively. The maximum adsorption capacities (qmax) obtained from chitosan-DES A and chitosan-DES B were 1.43 mg/g and 17.86 mg/g, respectively. Desorption indicated good performance in practical applications.