In this study, the classification, composition, preparation methods, and performance parameters of deep eutectic solvents (DESs) and their recent applications in natural product extraction, drug delivery systems, trace metal determination, nanomaterial synthesis, and electrochemistry are systematically summarised through the literature of recent decades, using DESs and applications as keywords. The hydrogen bond acceptors (HBA) of DESs are mainly quaternary ammonium salts (e.g., choline chloride) or amphoteric ions (e.g., betaine); the hydrogen bond donors (HBD) are mostly compounds such as urea, polyols, and sugars. Their melting points are related to hydrogen bonding, their polarities are higher than most ionic liquids, and their viscosities are generally in the range of 0.01−5 Pa·s. Compared with traditional organic solvents and conventional ionic liquids, DESs have higher solubility, with their ability to dissolve metal oxides and insoluble drugs, and have good biodegradability. DE... [more]

At present, soil arsenic contamination is one of the prominent environmental problems. The arsenic concentration in honeysuckle exceeds the standard levels, thus affecting the quality of traditional Chinese medicine. In this study, the hydroponic method was employed to explore the effect of organic arsenic (dimethyl arsenic) and trivalent inorganic arsenic (NaAsO2) on the growth of honeysuckle plants. The study demonstrated that low concentrations of inorganic arsenic (10−20 mg/L) and 10−50 mg/L organic arsenic had a stimulating effect on the growth of honeysuckle plants. The activities of antioxidant enzymes (peroxidase and catalase) increased correspondingly. However, the antioxidant system in honeysuckle plants was damaged under high concentrations of inorganic arsenic (20−40 mg/L) and 50−70 mg/L organic arsenic. On exposure to 30 mg/L NaAsO2 or 50 mg/L dimethyl arsenic acid for 10 days, the activities of peroxidase and catalase, as well as the malondialdehyde content, increased wit... [more]

The architecture of hydrogel composites results in not only synergistic property enhancement but also superior functionality. The reaction−diffusion (RD) process is acommon phenomenon throughout nature which induced ordered structure on a length scale from microscopic to macroscopic. Different from commonly used inorganic salts or oppositely charged nanoparticles for the RD process, a modified RD process was used for layered chitosan hydrogel (L-CH) and layered magnetic chitosan hydrogel (L-MCH). During the modified RD process reported in this paper, the protonated chitosan (CS-NH3+) with iron ions (Fe3+ and Fe2+) was used as an inner-reactant and hydroxide ion (-OH−) was used as an out-reactant. The protonated chitosan (CS-NH3+) not only played the role of an inner-reactant but also the reaction medium which controlled the diffusion behavior of the out-reactant (-OH−). A series of ordered layers were constructed and the ordered layers were parallel with the longitudinal axis. The laye... [more]

This study evaluated the effects of dielectric barrier discharge (DBD) plasma technology on some physicochemical and structural properties of corn starch. Amylose content, solubility, water absorption index, turbidity, structural relationships, and surface morphology were measured at 100, 200, and 300 Hz excitation frequencies and at 10 and 20 min exposure times. The plasma treatment at 200 Hz and 20 min promoted the most significant modifications in amylose content, solubility, the water absorption index, and surface morphology. Turbidity did not change significantly. The surface of the granule became smoother with the presence of pores. Slight changes were observed in the ordered structure of starch. Plasma changed several physicochemical properties, significantly decreasing the amylose to amylopectin ratio. Plasma treatment at 200 Hz is recommended to increase the amylopectin content in starches.

A special study on the interaction mechanism between flow and soil is of great significance for revealing the macro breaching mechanism of barrier dams. To study the scouring characteristics of wide-graded sediment under different flow conditions, flume scour tests were conducted regarding the grading curve of dam material and the discharge process of the Tangjiashan barrier dam. The results show that: (1) The scouring process of narrow-graded or uniform sediments is the formation and movement of the sand wave, while the scouring mode of wide-graded sediment is mainly the formation, expansion, and movement of the scouring pit. (2) Under the condition of weak unsteady flow, the surrounding and shielding effect of coarse particles on fine particles is obvious, and the erosion resistance of the material is strong. However, under the condition of strong unsteady flow, the erosion resistance is weak. (3) The erosion of wide-graded sediment is mainly caused by slope angle collapse at the ini... [more]

During the production of deep oil and gas, scaling, waxing, hydrate ice plugging and other problems easily occur. To solve these problems, reducing the temperature loss of oil pipelines is a feasible method. In order to protect the outer wall coating from being damaged and losing its thermal insulation performance, this paper proposes a developed technology for a novel inner wall coating-insulated oil pipeline. A new temperature-resistant and heat-insulating material aerogel was optimized and developed, and it has an extremely low thermal conductivity of less than 0.055 W/m·K. The influence of different coating processes on the thermal insulation coefficient was analyzed, and a novel inner wall coating-insulated oil pipeline was developed. A testing and evaluation platform for its thermal insulation effect was built, and a finite element model was established to analyze the temperature field distribution. When the thickness of the inner coating was 0.5 mm, the thermal insulation effect... [more]

This Special Issue, entitled “Advances in deep eutectic solvents: New green solvents”, was organized to collect original research articles on the latest developments in the new green solvents, deep eutectic solvents (DESs), and their applications [...]

The study of microfractures in shale is mainly based on qualitative description. Conversely, quantitative description of the parameters of shale microfractures can provide a quantitative basis for shale fracture characterization and shale physical properties. Nine shale reservoir samples of the Wufeng−Longmaxi Formation in the Jiaoshiba area were studied, using the backscattered two-dimensional multiscale resolution imaging technology, combined with high-resolution map imaging technology (MAPS), and thousands of images were obtained using scanning electron microscopy. Gray image analysis was used to extract microfracture information from images (2 × 2 cm multiresolution). The “maximum circle method” was used to calculate the length and aperture characteristics of the fractures. Parameters such as the area of the bedding fractures, the surface rate of the fractures, and the linear density of the fractures were obtained by the integration of apertures. The fracture length was between 2~7... [more]

Waste fluorescent powder contains a large amount of rare earth elements, which have a high value for recovery and utilization. In order to achieve the rapid and efficient leaching of rare earth elements in these waste phosphors, microwave-assisted leaching of rare earth elements Y and Eu from the waste phosphor with hydrochloric acid was studied. The maximum leaching rates of Y (99.84%) and Eu (89.82%) were obtained at 600 W microwave power, 60 min microwave radiation time at 60 °C. The leaching kinetics showed that the microwave leaching process of Y and Eu conforms to the chemical reaction control model, and the apparent activation energy is 25.30 kJ/mol and 24.78 kJ/mol. Compared with the conventional heating method, the microwave leaching process can obviously reduce the reaction activation energy, shorten the reaction time, and achieve the rapid and efficient leaching of rare earth elements in the waste phosphors.

The effects of powder formulation, including elemental mixed powder (EMP) and alloy mixed powder (AMP), and energy density on the nitrogen content and microstructural characteristics of high-nitrogen steel prepared by selective laser melting were investigated. The results reveal that the samples prepared with EMP had more nonfusion flaws and a relatively low density, with a maximum of only 92.36%, while samples prepared with AMP had fewer defects and a relative density of up to 97.21%. The nitrogen content and microstructural characteristics were significantly influenced by the laser energy density. The relative density of the EMP samples increased from 88.29% to 92.36% as the laser energy density increased from 83.3 J/mm3 to 125 J/mm3, while the relative density of the AMP samples rose from 93.31% to 97.21%, and the number of defects and the nitrogen content decreased. The mechanical properties of the AMP samples were superior to those of the EMP samples when the energy density rose,... [more]

The integration of spray drying and agglomeration offers significant advantages, such us continuous production with lower energy consumption. However, it is a knife-edge process with a narrow operating window and limited degrees of freedom that decide between successful agglomeration and fluidized bed blockage due to excessive moisture. In this contribution, factors influencing the spray-through agglomeration process of skim milk powder as a model system were investigated via a design of experiments. Three in-line monitoring methods were applied and tested to observe the most important parameters in the agglomeration process—the product moisture and particle size distribution. Regarding the moisture content, a capacitive moisture sensor was calibrated with linear regression and a near-infrared sensor with partial least squares regression. Near-infrared spectroscopy was found to be the suitable method for determining the moisture content, while the capacitive moisture sensor mainly prov... [more]

Abrasive blasting, sometimes known as sandblasting, is a method used to change the surface condition of materials, clean surfaces, and prepare surfaces for applications such as paint, bonding, coating, etc. The abrasive materials used in abrasive blasting are applied to the surface with compressed air or water and vary according to the purpose of application. The abrasive materials used have negative effects on the environment and human health. So far, organic materials have been used in limited applications in abrasive blasting. However, these materials have a high potential of usage since they are environmentally friendly, safe for human health, and have non-toxic and sustainable properties. In this study, the usability of three different organic wastes (walnut shell, olive pomace and mussel shell) recovered by recycling in abrasive blasting was investigated. In addition, the effect of blasting distance (5, 10 and 15 mm), blasting time (10, 20 and 30 s), powder type (mussel shell, ol... [more]

The present study concerned the production of glucose-based porous carbon materials by a one-step acid-catalyzed HTC. The samples were characterized by elemental analysis (EA), scanning electron microscope (SEM), Brunauer−Emmett−Teller (BET), Fourier transform infrared (FTIR) and point of zero charge (pzc). Experimental results showed that the addition of sulfuric acid (SA) with different dosages in the HTC system could improve the yield of products and reduce chemical oxygen demand (COD) of the process water. When the glucose and acid was at a mass ratio of 1:4 (glucose: SA = 1:4), the hydrochar obtained (H-G9) had a larger specific surface area (SBET = 296.71 m2/g) and higher abundance of functional groups on the surface than that of other samples, such as sulfur-containing functional groups and carboxylic groups, belonged to the mesoporous material with highly negatively surface charged. H-G9 exhibited the optimum adsorption for methylene blue (MB). H-G9 adsorbed MB with an initial... [more]

The paper presents an innovative concept of the fluidization of an adsorption bed carried out under low-pressure conditions. Additionally, different bed mixes were used to test the effects of the bed composition on fluidization. Fluidization was caused by the pressure difference and the velocity of the flowing water vapor. These features make the research presented in this article significantly different from other studies known in the literature and constitute the main novelty of the paper. Silica gel with a particle diameter of 200−250 µm (Geldart group B) with aluminum and carbon nanotube additives was fluidized under reduced pressure (10−25 mbar). The pressure difference results in the flow of water vapor and, consequently, induces fluidization. The pressure in the evaporator was approx. 10 mbar, while in the reaction chamber it was approx. 25 mbar. The pressure difference of about 10−15 mbar allows for a flow of water vapor between the evaporator and the reaction chamber. During t... [more]

The remarkable technological development observed in recent decades has led to an exponential increase in the production of electrical and electronic devices. Regardless of their field of application or the type of device, electronic boards are a common feature of all these devices. For this reason, electronic boards represent a constant in electrical and electronic equipment waste. Knowing their composition and intrinsic economic value is essential for identifying sustainable disposal and valorization processes. In the literature, several articles report typical compositions of electronic boards, but it is rare to find a component-by-component characterization. This procedure is important to determine the components that need to be removed to increase the recovery yields of materials or to identify components with high concentrations of hazardous substances. For this reason, in this scientific article, we propose to examine the chemical composition of all the components of the Arduino... [more]

The temperature or maturity limit of methane (CH4) cracking is very useful for the determination of the most depth or the highest maturity in natural gas exploration owing to the composition of over mature gas. In this work, three series of CH4 cracking experiments were conducted under different conditions of N2 + CH4, N2 + CH4 + montmorillonite and N2 + CH4 + shale, respectively, in a gold tube system. The experimental results show that some heavy gas with negative carbon isotope composition could be generated in the three series experiments and that shale has more intense catalysis for CH4 cracking than montmorillonite. The catalysis of metal elements distributed in the minerals of shale is attributed to CH4 cracking acceleration. The shale catalysis makes the maturity threshold of CH4 substantial cracking decrease from 6.0%Ro under no catalysis, to 4.5%Ro under a shale system in a geological setting. Nevertheless, we suggest not to lightly practice natural gas exploration in shale w... [more]

Pore and permeability are distributed discontinuously and unevenly in the dominant sedimentary model of the lateral accretion body inside the meandering river point bar of the Fuyang reservoir of the Yushulin oilfield. Based on the water flooding experiments of field core samples, the influence of pore permeability conditions on residual oil distribution type and water cutting rate was studied by using the microscopic visualization technology enabled through a photolithographically fabricated glass model. It is found that the residual oil in samples shows five discontinuous types, which are cluster, columnar, oil droplet, membrane, and blind end. In the stages with low, medium, and high water cutting rates, the proportion of clustered residual oil in the samples with different permeability is high, reflecting the situation that it is difficult for injected water to spread widely in tight oil reservoirs. With the decrease of permeability, the proportion of membrane and blind end residua... [more]

The soft surrounding rock of deep roadways is in the state of “micro-fracture and low permeability”. In order to solve the problem of grouting reinforcement of micro-fractures surrounding rock in deep roadways, the influence characteristics of auxiliary materials and additives on slurry flow were analyzed, and the composition and proportion of superfine cement-based composite grouting materials were determined: superfine cement accounted for 89.4%, superfine coal ash accounted for 5%, ultrafine mineral powder accounted for 5%, naphthalene water reducing agent accounted for 3~5‱, and lignin sulfonate calcium accounted for 1~3‱. The effects of water−cement ratio and water reducer content on slurry viscosity and water bleeding rate were tested by laboratory experiments. Based on the fracture characteristics of surrounding rock and the “Liu Jiacai Formula”, the influence law of fracture opening, grouting pressure and slurry viscosity on the slurry diffusion radius was analyzed. The results... [more]

Polyhydroxyalkanoates (PHAs) are aliphatic polyesters synthesized intracellularly by microorganisms as a carbon-storage substance. Among the various PHAs, 3-hydroxybutyrate (3HB)-based copolymers are crystalline polymers widely used as biodegradable plastics. Recently, PHAs containing α-carbon-methylated monomers, such as 3-hydroxy-2-methylbutyrate (3H2MB) and 3-hydroxy-2-methylvalerate (3H2MV), have been synthesized and characterized. However, a binary copolymer of 3HB and 3H2MV, P(3HB-co-3H2MV), had not yet been synthesized, and its material properties had not been investigated. In this study, P(3HB-co-11 mol% 3H2MV) (PHBMV11) was synthesized with recombinant Escherichia coli LSBJ, using trans-2-methyl-2-pentenoic acid as the 3H2MV precursor. The thermal properties of PHBMV11 were characterized using differential scanning calorimetry (DSC), and the results were compared with those of P(3HB-co-12 mol% 3-hydroxyvalerate) (PHBV12) to explore the effect of α-carbon methylation in the com... [more]

A series of mesoporous NiO catalysts with high specific surface area were prepared by a simple hydrothermal method and modified by cetyltrimethylammonium bromide (CTAB) as the crystal structure directing regent. The characterization with SEM, XRD, BET, and H2-TPR results demonstrated that the introduction of CTAB effectively improved the dispersion, specific surface area, and pore volume and redox ability of NiO, and thus exposed more active sites. Meanwhile, the NiO catalyst with a CTAB/NiSO4·6H2O molar ratio of 2/3 exhibited the better catalytic ozonation performance of toluene, formaldehyde, methanol, and ethyl acetate than NiO. The in-situ DRIFTS elucidated the reaction path of catalytic ozonation of toluene and indicated that the introduction of CTAB facilitated the complete oxidation of by-products into CO2 and H2O.

The natural hydrophilic property of leather makes it a possible growing substrate for microorganisms. Microorganisms such as bacteria, yeasts, and molds frequently grow on shoe lining leather, causing skin diseases, unpleasant odors, and discomfort for the wearers. To address these issues, herein, bio-synthesized silver nanoparticles from Piper betle L. leaf extract were applied as an antimicrobial agent to pig leather via the exhaustion method. The characterization of nanosilver-treated pig leather was performed using colorimetry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic absorption spectroscopy (AAS), and FTIR techniques. Evaluation of antimicrobial efficacy of the nanosilver-treated leather was both qualitatively and quantitatively assessed against two bacteria (Escherichia coli and Staphylococcus aureus) and two fungi (a yeast Candida albicans and a mold Aspergillus niger) in accordance with AATCC TM90, AATCC TM30, and ISO 16187:2013 sta... [more]

In view of the problem that the formation of deepwater wells in the study area leak easily, the mechanism of loss-circulation was studied in depth, and the loss-circulation plugging material SmartGel was developed with guar gum and its derivatives as the main synthetic raw materials. The gel process could be controlled by adjusting the dosage and temperature of gel accelerators. In order to adjust the gelling speed of SmartGel, GelRetarder and GelAccelerant were developed. The extrusion strength of SmartGel increased with the increase in SmartGel dose and decreased with the increase in temperature. As for the plugging performance of SmartGel, the sand bed test confirmed that the pressure capacity of SmartGel in the 80 °C sand bed can reach at least 7 MPa, which can meet the requirements of site construction. The PPT sand tray test and core flow meter simulation pore test showed that SmartGel has good bearing performance. As for the gel-breaking of SmartGel, low-temperature gel-breaking... [more]

Two novel separation methods have been presented for the concurrent assessment of flumethasone pivalate (FP) and clioquinol (CL) in their combinations in ear drop formulations or in the presence of phenoxyethanol preservative (PEP) in their cream formulations. The first method is an innovative thin-layer chromatographic (TLC) method. The optimal separation was accomplished via silica gel aluminum plates F254, with a mixture of benzene, ethyl acetate and formic acid (5:5:0.2, in volumes) as the mobile system. In Method II, a new ultra-high-performance liquid chromatographic method (UHPLC) with a photodiode array detector (PDA) was presented. A reversed-phase inertsil ODS 5 µm C 18 packed column (100 Å, 4.6 mm internal diameter (I.D.) × 50 mm) at 30 °C was employed. Elution was completed in 3 min. Unfortunately, greener solvents were tested as a mobile phase, but an asymmetric peak for CL was noted. In addition, the new UHPLC method has a priority over the old HPLC one by Sayed et al., 2... [more]

The development of oxygen evolution reaction electrocatalysts with a low cost, high activity, and strong stability is of great significance to the breakthrough of energy conversion technology. Herein, a composite material (NiCo(CA)@M) was obtained by growing nickel-cobalt nanoparticles on MIL-88A in situ by a simple two-step solvent thermal method. The results show that NiCo(CA)@M composite has rich active sites, and the formation of the composite induces charge redistribution between NiCo(CA) and MIL-88A, effectively reducing the reaction energy barrier, while growth in situ was conducive to the improvement of material stability. Impressively, the NiCo(CA)@M catalyst achieved a current density of 10 mA cm−2 in alkaline electrolyte required an overpotential of only 270 mV and the Tafel slope was 69 mV dec−1. At the same time, the NiCo(CA)@M catalyst had excellent stability at a current density of 10 mA cm−2, and after the 16 h i-t test, the catalyst still had 91.1% current density rete... [more]

Successfully replacing meat with plant-based options will require not only replicating the texture of muscular fibres, but also imitating the taste, aroma, and juiciness of meat as closely and realistically as possible. This study examines the impact of rapeseed oil on the textural properties of meat analogues. Pea protein and soy protein are chosen as model systems to assess the effect of rapeseed oil. Optical, mechanical, and rheological characterisation tests are conducted to investigate the oil droplet distribution, the gel strength, Young’s modulus, and the length of the LVE region. The hypothesis is that oil droplets will act as active fillers in the protein matrix, and thus, diminish the strength of the protein gel network. The results of this study show that rapeseed oil droplets act as inactive fillers, as they are not bound to both examined protein matrices. Soy protein extrudates display minimal changes, while pea protein extrudates are significantly affected by the addition... [more]