Characteristics Of Dissolution Research Articles

Characteristics of congruent dissolution of silicate minerals enhanced by chelating ligand under ambient conditions

Abstract Natural and anthropogenic chelating ligands play important roles in promoting mineral dissolution during water-rock interactions. To address the remaining issue of how chelating ligands participate in the dissolution of minerals, this study investigated the dissolution characteristics of seven types of silicate minerals in the presence of a chelating ligand, N,N-bis(carboxymethyl)-L-glutamic acid (GLDA), which is a glutamic acid derivative, through batch dissolution experiments. The results showed that the dissolution of all types of silicate minerals, i.e., olivine (nesosilicate), epidote (sorosilicate), tourmaline (cyclosilicate), enstatite (single-chain inosilicate), hornblende (double-chain inosilicate), biotite (phyllosilicate), and anorthite (tectosilicate), can be enhanced by up to two orders of magnitude at both pH 4 and 8. The chelating ligand particularly facilitated the dissolution of minerals with a higher Al content, such as tourmaline and anorthite. Furthermore, the presence of chelating ligands enhanced the leaching of not only metals but also Si from minerals, resulting in a more congruent characteristic of mineral dissolution. A possible mechanism is that the chelating ligand adsorbs onto the negatively charged the mineral surface, which attracts more H+ and polarizes Si-O and Mg-O bonds, thereby dissolving the minerals at a faster rate. These results have significant implications for understanding the dissolution of minerals in nature and for the application of chelating agents in geological and materials engineering.

Synthesis of binder-free hydrated vanadium oxide-polyaniline electrodes via in situ polymerization for high-performance aqueous zinc-ion batteries

Hydrated vanadium oxide, a kind of layered electrode material with high theoretical specific capacity, has great potential for developing high-performance, low-cost, and eco-friendly aqueous zinc-ion batteries. However, its characteristics of poor electronic conductivity, vanadium dissolution, and unstable structure lead to poor electrochemical performance, such as low specific capacity, poor rate performance and short cycle life. Combining PANI with layered hydrated vanadium oxide is expected to overcome the shortcomings and achieve high zinc storage performance. In this work, binder-free hydrated vanadium oxide-polyaniline inorganic–organic hybrid compounds deposited on carbon cloth (VOH-PANI/CC) are developed by combination of layer-by-layer and in-situ polymerization process. Benefiting from synergistic effect between polyaniline and hydrated vanadium pentoxide, the hybrid electrode (VOH-PANI/CC) delivers high capacities of 290 mA h/g at 0.5 A/g and 165 mA h/g at 4 A/g. In contrast, the specific capacities of VOH/CC are only 185 and 70 mA h/g at 0.5 and 4 A/g, respectively. This in-situ polymerization of aniline via layer-by-layer strategy on hydrated vanadium oxide provides a novel synthesis scheme for the use of vanadium oxide as cathode material for aqueous zinc-ion batteries.

Effect of novel surfactant protic ethanolamine based ionic liquids on the aqueous solubility and thermodynamic properties of acetaminophen

The solubility of poorly soluble drugs in aqueous media remains an obstacle in the pharmaceutical development process. Ionic liquids (ILs), with their remarkable solvent properties, have gained considerable attention as potential solubility enhancers for such drugs. In this context, surfactant protic ethanolamine-based ILs have emerged as a particularly promising class of compounds due to their unique dual functionality. This study explores the significant role of these novel solvents in improving drug solubility, focusing on their potential applications in pharmaceutical formulations. Acetaminophen (ACP), a widely used analgesic and antipyretic drug, often encounters solubility limitations that hinder its effective pharmaceutical applications. In the past few years, there has been a growing recognition of the potential of ILs (ionic liquids) as effective solvents. They offer promising prospects for enhancing the solubility of pharmaceutical substances in water-based solutions. This study investigates the enhancement of ACP solubility through the utilization of ILs. The solubilization behavior of ACP in the attendance of mono, bis and tris-(2-hydroxyethylammonium) octanoate systems is explored, highlighting the significant impact of different number of hydroxyethyl groups combinations on its solubility profile. Experimental results reveal that these ILs exhibit a remarkable ability to improve the solubility of ACP, making them attractive candidates for pharmaceutical formulations. The mechanisms underlying this enhancement are discussed, encompassing factors such as the ion-specific interactions, polarity, and hydrogen bonding capabilities of ionic liquids. Furthermore, the potential implications of utilizing ILs for enhancing the bioavailability and formulation versatility of ACP are considered. To accurately correlate the solubility data, various thermodynamic models were employed. Furthermore, to examine the observable thermodynamic characteristics of dissolution in the studied systems Van't Hoff and Gibbs equations were used. The findings indicated that the dissolution process in all co-solvents used was characterized by an endothermic nature and driven by enthalpy.

Predicting carbonate rock dissolution using multi-scale residual neural networks with prior knowledge

The factors that affect carbonate dissolution are complex, and it is crucial to acquire efficient and accurate knowledge of carbonate dissolution characteristics for CO2 capture and storage (CCS) projects. In current research, the most precise outcomes can be achieved through experimental or simulation techniques, but they are frequently computationally demanding and time-consuming. Data-driven machine learning methods can efficiently perform regression prediction tasks. In this paper, we propose a multi-scale hierarchical regression model for the dissolution problem based on residual neural networks, incorporating prior knowledge. We have developed new equations for carbonate rock dissolution and have incorporated the factors that influence this process into 3D image data by introducing Dissolution Degree (Dd) parameters. This allows the image data to include both the pore space structure and dissolution information with physical meaning. We utilize the pore phase and matrix phase grayscale thresholds (Pt, Mt) to eliminate voxel noise in the characteristic maps obtained from the model. This ensures that the predicted characteristics of carbonate rock dissolution are consistent with practical physics knowledge. We selected a total of 5 core samples to test the model. Among them, three samples are from the test set, and the additional two core samples selected have strong and weak correlations with the training set samples, respectively. The predictions were evaluated using semantic segmentation evaluation parameters, porosity, geometrical and topological structure parameters, Péclet and Damköhler numbers, porous media flow field simulations, and absolute permeability. The results of both visual comparisons and quantitative analyses demonstrated a high degree of consistency between predicted and experimental results, and the trained multi-scale hierarchical regression residual neural network with prior knowledge (MSR-Net) demonstrates good accuracy and generalization ability. The results of this study demonstrate that model based on MSR-Net can be utilized to predict the dissolution properties of the pore space in the formation where the core was extracted, along with the related formation.

A Promising Plant-Based Eugenol-Loaded Nano Delivery System (EUG@CMC-PGMA-CS) for Enhanced Antibacterial and Insect Repellent Behavior.

Pathogens and pests pose significant threats to global crop productivity and plant immunity, necessitating urgent measures from researchers to prevent pathogen contamination and pest damage to crops. A natural plant-based antibacterial agent, eugenol (EUG), has demonstrated excellent antimicrobial and insect repellent capabilities, but the characteristics of volatilization and poor dissolution limit the practical application. The nanoization of pesticide formulations holds promise in the development of highly effective pesticides for antibacterial and insecticidal purposes. Herein, a eugenol-loaded nano delivery system (EUG@CMC-PGMA-CS) was synthesized using glycidyl methacrylate (GMA) as a functional monomer to connect carrier core structure carboxymethyl cellulose (CMC) with shell structure chitosan (CS), and EUG was encapsulated within the carrier. EUG@CMC-PGMA-CS demonstrated excellent leaf affinity, with minimum contact angles (CAs) of 37.83 and 70.52° on hydrophilic and hydrophobic vegetable leaf surfaces, respectively. Moreover, the maximum liquid holding capacity (LHC) of EUG@CMC-PGMA-CS on both hydrophilic and hydrophobic vegetable leaf surfaces demonstrates a noteworthy 55.24% enhancement compared to the LHC of pure EUG. The in vitro release curve of EUG@CMC-PGMA-CS exhibited an initial burst followed by stable sustained release. It is with satisfaction that the nano delivery system demonstrated exceptional antibacterial properties against S. aureus and satisfactory insecticidal efficacy against Spodoptera litura. The development of this eugenol-loaded nano delivery system holds significant potential for enhanced antibacterial and insect repellents in agriculture, paving the way for the application of volatile bioactive substances.

Experimental study of carbonate samples dissolution using X-ray microcomputer-based tomography

Background: The study of the interaction of hydrochloric acid with carbonate materialsis important in the oil and gas industry. Carbonate rocks are common rock types, and half of all petroleum reserves worldwide are found in carbonate deposits. Understanding the mechanisms and characteristics of dissolution of carbonate rocks is of great practical importance in the production of hydrocarbons and the injection of carbon dioxide into formations.
 Aim: The purpose of this article is to study the dissolution processes of carbonate samples in laboratory conditions using X-ray microcomputer-based tomography.
 Materials and methods: The study used 5 cylindrical carbonate samples, which were tested during the injection of hydrochloric acid solutions. Additional experimental and digital data from 8 samples are also used. The three-dimensional pore space of the samples was obtained using specialized software based on tomographic images.
 Results: The results obtained demonstrate the significance of the use of X-ray computed tomography for a deeper understanding of dissolution processes in geological and engineering studies. The study highlighted the complexity of the rock dissolution process, which depends on many factors. The created three-dimensional models of the samples allowed us to visualize wormholes, including branched and dominant wormholes. 3D imaging provided valuable information about changes in the pore structure of the samples before and after acid exposure.
 Conclusion: The results of this study highlight the importance of considering physical and structural properties when analyzing dissolution processes in carbonate samples. These data can have practical applications in the oil and gas industry, contributing to a more accurate understanding and optimization of the processes of interaction of acid solutions with carbonate samples.

Study on tritium transport characteristics in fluoride-salt-cooled high-temperature advanced reactor

Fluoride-salt-cooled high-temperature reactors (FHRs) are a promising reactor class that combines prominent attributes from the Gen-Ⅳ reactors, raising attractive interests of the international community. However, tritium control has been a major challenge in FHRs because of the neutron reactions of lithium. It's necessary to study the transport characteristics of tritium in the fluoride-salt-cooled high-temperature advanced reactor (FuSTAR) and to provide theoretical support for appropriate tritium control measures and safe operation of the FHRs. In this paper, the inclusive transport characteristics of production, graphite adsorption, diffusion, dissolution, and permeation on tritium in the primary loop are analyzed. The mathematical and physical model of the tritium transport phenomenon is established, and an analysis model of tritium transport characteristics is also developed. Then, the tritium transport characteristics in the FuSTAR primary loop are analyzed. The results show that the tritium in the FuSTAR primary loop mainly exists in the form of Diatomic Tritium (T2), and it's found that Tritium Fluoride (TF) and T2 are adsorbed by graphite after being generated in the core, and this process reaches saturation in about 150 Effective Full Power Days (EFPDs). It also indicates that almost 48% of tritium penetrates the secondary loop through the heat exchanger, and only about 3.8% of tritium is adsorbed on the core graphite. TF makes the corrosion of the heat exchanger and downcomer more serious. Finally, the safety of tritium transport in FuSTAR is conservatively estimated, with a tritium emission dose of 0.1674 mSv/a. This study can provide a theoretical reference for the structural design, tritium recycling, and radiation protection of FHRs.

Differential Diagenesis and Pore Evolution Characteristics of Different Sedimentary Microfacies Reservoirs of Bioclastic Limestone: A Case Study of MB2-MC1 Section in X Oilfield in The Middle East

In order to clarify the differential diagenesis of different sedimentary microfacies of bioclastic limestone in Cretaceous M Formation in the Middle East and systematically analyze the characteristics of reservoir pore evolution, the data of regional geology, well logging, core, cast thin section, scanning electron microscope, three-dimensional CT and conventional porosity and permeability test are comprehensively used, taking MB2-MC1 section in X oilfield as an example, starting from the diagenesis and pore evolution of bioclastic-arene shoal, the characteristics of diagenesis of each sedimentary microfacies in different environments are analyzed, and the differential diagenesis, pore evolution process and its influence on physical properties are studied. It is showed that the reservoirs of MB2-MC1 section are mainly developed in the ramp shoal and platform margin shoal. The shoal facies can be further subdivided according to the type of bioclastic debris. The sedimentary microfacies determine the original fabric and bioclastic type of M Formation, and then control the diagenetic sequence and strength. Each sedimentary microfacies mainly experiences different degrees of mud crystallization and burrows in seawater environment, dissolution and cementation in atmospheric freshwater environment, compaction, pressure solution and dolomitization in burial environment. High energy microfacies have the characteristics of non-selective dissolution, mainly developing intergranular pores and intergranular dissolved pores. Medium energy microfacies have the characteristics of selective dissolution, mainly developing mould pores and intragranular pores. The medium-low energy microfacies have the characteristics of moderate cementation, moderate compaction and moderate-weak dolomitization, mainly developing intragranular pores and visceral foramen pores. The low energy microfacies have the characteristics of strong cementation, strong compaction and moderate dolomitization, mainly developing micropores, intercrystalline pores and visceral foramen pores, which are non-reservoirs.

Single-Particle Spectroelectrochemistry: Electrochemical Approaches for Tuning Chemical Interfaces and Plasmon Damping in Single Gold Nanorods.

The strong adsorption of thiol molecules on gold nanorods (AuNRs) results in localized surface plasmon resonance (LSPR) energy loss via chemical interface damping (CID). This study investigated the CID effect induced by thiophenol (TP) adsorption on single AuNRs and the in situ tuning of LSPR properties and chemical interfaces through electrochemical potential manipulation. The potential-dependent LSPR spectrum of bare AuNRs exhibited redshifts and line width broadening owing to the characteristics of capacitive charging, Au oxidation, and oxidation dissolution. However, TP passivation provided stability to the AuNRs from oxidation in an electrochemical environment. Electrochemical potentials induced electron donation and withdrawal, causing changes in the Fermi level of AuNRs at the Au-TP interface, thereby controlling the LSPR spectrum. Additionally, the desorption of TP molecules from the Au surface was electrochemically achieved at the anodic potentials further away from the capacitive charging region, which can be used to tune chemical interfaces and the CID process in single AuNRs.

Dissolution and Deformation Characteristics of Limestones Containing Different Calcite and Dolomite Content Induced by CO2‐Water‐Rock Interaction

AbstractTo investigate the impacts of mineral composition on physical and mechanical properties of carbonate rocks, limestone specimens containing different contents in calcite and dolomite are selected to perform CO2‐water‐rock reaction experiments. The X‐ray Diffraction (XRD) and Nuclear Magnetic Resonance (NMR) are carried out to examine the change characteristics of mineral dissolution and pore structure after reaction. The core flooding experiments with Fiber Bragg gratings are implemented to examine the stress sensitivity of carbonate rocks. The results show that the limestones containing pure calcite are more susceptible to acid dissolution compared to limestone containing impure dolomite. The calcite content in pure limestone decreases as the reaction undergoes. The dissolution of dolomite leads to the formation of calcite in impure limestone. Calcite dissolution leads to the formation of macropore and flow channels in pure limestone, while the effects of impure dolomite in impure limestone results in mesopore formation. When confining pressure is lower than 12 MPa, pure limestones demonstrate higher strain sensitivity coefficients compared to impure limestone containing dolomite after reaction. When confining pressure exceeds 12 MPa, the strain sensitivity coefficients of both pure and impure limestones become almost equal.

Development and Drag Reduction Behaviors of a Water-in-Water Emulsion Polymer Drag Reducer

As a key component of slickwater fracturing fluids, drag reducers play a critical role. Water-in-water (W/W) emulsion polymer drag reducers with the characteristics of rapid dissolution and the ability to increase viscosity are attracting substantial attention. In this work, a W/W emulsion polymer drag reducer P(AM-DMC) was synthesized via dispersion polymerization. The material P(AM-DMC) was characterized using Fourier transform infrared spectrometry, hydrogen nuclear magnetic resonance spectrometry, and environmental scanning electron microscopy. The results showed that the aqueous P(AM-DMC) solution was a pseudoplastic fluid with appreciable viscosity enhancement and shear resistance. The dissolution time of 0.1 wt % P(AM-DMC) was only 29 s. The drag-reduction rate of P(AM-DMC) reached 71.75%. The drag reducer also exhibited good temperature and salt resistance. Finally, a drag-reduction mechanism was proposed. We hope that this study can broaden the application of W/W drag reducers in shale reservoir development.

Tuning formation process of void defects in microcolumn arrays via pulse reverse electrodeposition

The pulse reverse current electrodeposition process consists of two stages: the forward deposition and reverse dissolution. This study aims to understand the characteristics of forward deposition and reverse dissolution and to reveal their influences on the formation of void defects in electrodeposited microcolumn arrays. Both the simulation and experimental results show that pulse reverse current contributes to the void-free deposition of microcolumn arrays. During the deposition under forward pulse stage, the thickness of deposited layer in micro cavities via pulse reverse current is more uniform compared with direct current. Meanwhile, the dissolution behavior under reverse pulse stage is greatly determined by the reverse pulse current density. A low reverse pulse current density (1 A/dm2) leads to a slow dissolution at the mouth of micro cavities. In contrast, a high reverse pulse current density (4 A/dm2) contributes to a high electrolyte potential, as well as a rapid dissolution at the mouth of micro cavities, which helps to eliminate void defects. The experimental results exhibit that void-free microcolumn arrays with a high aspect ratio of 5:1 are obtained via pulse reverse current. This study provides a clear understanding on the formation process of void defects in microcolumn arrays via pulse reverse electrodeposition.

Amphibolite dissolution mechanism under chlorine-rich conditions during freeze-thaw cycles

The low-temperature weathering behavior of amphibolite is vital for revealing the cation source of groundwater and for understanding a wide range of geochemical evolution. This study aims to observe the macroscopic and microscopic characteristics of amphibolite dissolution under the freeze-thaw cycles (-25–25 °C) and chlorides (HCl, NaCl, KCl). The results show that Mg-hornblende was dissolved in chloride solutions of the same pH or concentration before albite. The change rule of the solution composition of freeze-thaw cycles is consistent with the results obtained from the dissolution experiment at room temperature. In addition, in an HCl solution of pH 1 and NaOH solutions of pH 11, 13, and 14, the dissolved amount of quartz in amphibolite can reach 11 wt %. KCl can powerfully dissolve quartz and efficiently dissolve Si in the silica-oxide tetrahedron (especially the T2 site) of Mg-hornblende. However, NaCl significantly dissolves cations in the Mg-hornblende octahedron. Analysis indicates that the leaching of Ca2+ and Mg2+ in proton-promoted dissolution strongly depended on the concentration of H+. At the same time, the release of Mg is closely related to Cl−. The results can help understand chemical element migration in the earth, especially providing a theoretical basis for groundwater cation in the Qaidam Basin.

Selection of a leaching system for the extraction of gold from the ore of the Byn’govskoye deposit

A theoretical substantiation of an environmentally friendly technology for extracting gold from mineral raw materials is presented. In terms of an alternative to conventional cyanide, the authors propose chlorine-bearing derivatives of organic isocyanuric acid (C3H3N3O3). In the studied process, this reagent combines the roles of a long-acting oxidant and complexing agent due to the resulting Cl– ion. For experimental purposes, the rotating disc technique was applied. Experimental results were evaluated by measuring the concentration of gold in solutions using the atomic adsorption method. The theoretical characteristics of gold dissolution using the proposed reagent were studied. In order to evaluate the applicability of the revealed regularities for practical purposes, comparative indicators for leaching gold from the ore of the Byn’govskoye deposit (Sverdlovsk Oblast) using the proposed reagent, cyanide and CYCAD cyanide substitute (China) were evaluated. The dependence of the gold disc dissolution rate on temperature, as well as leaching reagent and hydrochloric acid concentrations, were studied. In disc sample experiments, the exponential dependence of the dissolution rate on the concentration of the studied reagent was established. In this case, the maximum intensity of the process is achieved at a concentration higher than 50 g/dm3. The optimum acidity level comprises 0.3–0.4 g ion/dm3 of hydrochloric acid. Despite an increase in temperature being shown to accelerate the dissolution process, this appears to be technologically unjustified. Under optimal conditions, the gold disc dissolution rate reaches 0.5•10-3 g ion/(cm2•min), which is approximately one hundred times higher than during the dissolution by the cyanic solutions in conventional modes. Close gold extraction values were achieved in the solutions of cyanides and chlorine-bearing derivatives of isocyanuric acid during the leaching of gold from the ore under the comparable conditions. For CYCAD solutions, the same indicator is two times lower. The results of the performed studies demonstrate the high dissolution rate of gold using the proposed reagent along with the technological possibility of leaching gold from ores using this environmentally friendly reagent.

Potential Application of Paenibacillus sp. C1 to the Amelioration of Soda Saline-Alkaline Soil

In this study, a saline-alkaline-tolerant bacterial strain named Paenibacillus sp. C1 was screened and isolated, and its basic properties were characterized. Its phosphorus dissolution, organic acid production, and application on ameliorating soda saline-alkaline soil were studied, and the changes of microbial communities after adding strain C1 with or without rice straws, (NH4)2SO4 and Ca3(PO4)2 were investigated. The results demonstrated that when the nitrogen, carbon, and phosphorus sources were (NH4)2SO4, glucose, and Ca3(PO4)2, respectively, strain C1 was in the best phosphorus-dissolving condition. The strain had good characteristics of acid production and phosphorus dissolution under the condition of high salinity and alkalinity. It could secrete cellulases, decompose rice and corn straws, and produce polysaccharides effectively. Strain C1 [especially with rice straws, (NH4)2SO4 and Ca3(PO4)2] could increase the content of available phosphorus (AP), organophosphorus (OP), total organic carbon (TOC), and polysaccharide (PS) and the activity of alkaline phosphatase (ALP) in saline-alkaline soil. Furthermore, adding strain C1 [especially with rice straws, (NH4)2SO4 and Ca3(PO4)2] could alter the bacterial flora of soil to make it adapt to high salinity and alkalinity better. Our study can be an important step toward the application of Paenibacillus sp. C1 to the amelioration of soda saline-alkaline soil and the investigation of its deep mechanisms.

Characteristics of Anodic Dissolution for Al-Cu Alloys in EmImCl-AlCl3 Ionic Liquid

Recycled Al obtained by re-melting process used the primary Al can be produced with 3-5% of the energy required for the electrolysis. However, the Al recycled by this method contains various elements as impurities, resulting in lower quality. After this repeated recycling, the Al eventually becomes scrap that is difficult to recycle and is landfilled. As a purification process, we propose an electrorefining method using scrap Al as an anode. Copper (Cu) is one of the major additive elements in aluminum. The Cu should be removed as far as possible in the recycling of Al scrap, since this alloy corrode from Al-Cu compounds precipitated at the grain boundaries. As Cu is a more noble element than Al, when Cu dissolves from the anode into the electrolyte due to an increase in the anode potential, the Cu ions are rapidly reduced at the cathode and electrodeposited as metallic Cu. In order to remove copper from Al scrap by electrorefining, the anodic dissolution of copper in scrap Al must be avoided. In this study, the anodic dissolution behavior of Al-Cu alloys on the metallurgical structure was investigated using Al-Cu alloys with controlled copper concentration and size of intermetallic compounds.Al-1.0, 3.0 and 5.0 Cu casting alloy plates and cold-rolled plates were used as anode specimens. The preparation of the ionic liquid and all electrochemical measurements were carried out in Ar filled glove box. The ionic liquid electrolyte was prepared by mixing 1-ethyl-3-methyl imidazolium chloride (EmImCl) and AlCl3 in a molar ratio of 1 : 2. Electrochemical measurements were carried out in a three-electrode type cell using various Al-Cu alloys as working electrodes, Pt plates as counter electrode, and , Al wires as reference electrode. The electrolyte was heated at 323 K by hot plate stirrer, and each electrode was connected to a potentiostat for anodic polarization measurement and constant potential electrolysis. Anodic polarization curve was measured from the immersion potential to 1.5 V vs. Al/Al(III) with scanning rate of 1 mV s-1. Constant potential electrolysis was performed at potentials from 0.3 to 1.2 V, and amount of electric charge densities of 0.3, 3.0, and 30 C cm-2 were applied. The specimens after the constant potential electrolysis were rinsed by distilled water and dried, then observations of appearance, XRD measurement, and FE-SEM observation were carried out.In the anodic polarization measurements of various Al-Cu alloys, peaks of anodic current density were observed at around 0.3 V and 0.8 V in casting alloys and Al-5.0Cu alloy with Al2Cu on the surface. Constant potential electrolysis was then carried out at potentials of 0.3, 0.8 and 1.2 V with electric charge density of 30 C cm-2 in order to investigate the dissolution behavior of Al-Cu alloys depending on the electrolysis potential. Al-5.0Cu casting alloy and cold-rolled plate after constant potential electrolysis were analyzed by SEM-EDS. Al in the matrix phase was preferentially dissolved then Al2Cu was appeared on the surface at 0.3 V. Dissolution of Al2Cu and Al in the matrix phase was occurred at higher than 0.8 V. In summary, the potential dependence on the anodic dissolution behavior of the metallurgical structure of Al-Cu alloys in EmImCl-AlCl3 ionic liquid has been clarified. By controlling the anodic dissolution potential, the dissolution of Cu in Al2Cu into the electrolyte can be suppressed, which is expected to further improve the purity of the electrorefined aluminum. Acknowledgement Part of this work was supported by the New Energy and Industrial Technology Development Organization (NEDO). We would like to express our gratitude to all parties concerned.

Characteristics of Anodic Dissolution for Al-Cu Alloys in EmImCl-AlCl3 Ionic Liquid

To produce high-purity Al from Al–Cu alloys, the dissolution behaviors of various Al–Cu binary alloy anodes in EmImCl–AlCl3 ionic liquid have been investigated at 323 K. In the constant potential electrolysis of the Al–5.0Cu casting alloy and cold-rolled plate at 0.3 V, Al atoms in the matrix phase were preferentially dissolved followed by the formation of Al2Cu surface species. The dissolution of both Al2Cu and Al in the alloy matrix occurred during electrolysis at 0.8 and 1.2 V. Moreover, a Cu-rich layer derived from Al2Cu was formed on the cold-rolled plate surface at a potential of 0.8 V and high electric charge densities. From the results, potential dependence of the anodic dissolution of the Al−Cu alloys in the ionic liquid was clarified.

Hydrodynamic characteristics of the microbubble dissolution in liquid using the swirl flow type of microbubble generator

The present experimental study aimed to investigate the performance and characteristics of the dissolved oxygen in water aeration under the variations of the gap between the air nozzle and the outlet of new developed swirl flow type of the microbubble generator (MBG). The present experimental investigation, the flow rates of both of air (QG) and the water (QL) were determined in the range of (0.1–0.8) l/min and (20–50) l/min, respectively. The shadow photographic technique was used to extract the results of a high-speed camera of microbubbles images to find the bubbles size and their distribution. The dynamic physical absorption model was used to measure the coefficient of the oxygen volumetric mass transfer (KLa). The results show that the microbubbles size (diameter average davg and peak PDF curve) produced by the swirl MBG type was smaller and more uniform than that of produced by orifice MBG type. Next, the characteristics of the microbubbles were investigated by the combinations of QG, QL and the gap between the air nozzle and the outlet of the microbubble generator. Here, it is noticed that the higher the gas flow rate, the higher the average diameter of the bubble. The higher the liquid flow rate, the lower the average diameter of the bubble. Furthermore, the QL increases with KLa. Finally, the empirical correlations to predict the KLa, davg and the log-normal distribution of the bubble diameter were proposed.

Photoreductive Dissolution of Iron (Hydr)oxides and Its Geochemical Significance

Iron (hydr)oxides are the most abundant metal oxides, which are widespread on Earth’s surface in the major form of micro/nanoparticles. Dissolution of iron (hydr)oxides significantly controls their compositions on Earth’s surface and is a critical step for the global Fe cycling. Photoreductive dissolution of iron (hydr)oxides is recognized as one of the most important process for generating Fe2+ in surface water and is also a common pathway for transforming solar energy into chemical energy. This review article dissects the main characteristics of photoreductive dissolution of iron (hydr)oxides and discusses its geochemical and environmental significance. We categorize the mechanisms for photoreduction of iron (hydr)oxides into three types: reduction by intrinsic photogenerated electrons, reduction by ligand to metal electron transfer (LMCT), and reduction by direct injection of exogenous photoelectrons. The efficiency of photoreductive dissolution is constrained by both the structure of iron (hydr)oxides (e.g., crystal structure and particle size) and environmental conditions (e.g., light, pH, and concurrent chemicals). Therefore, different iron (hydr)oxides may exhibit quite distinctive photoreductive dissolution characteristics because of their unique crystal structures and physicochemical properties. Iron (hydr)oxides with low crystallinity (e.g., ferrihydrite, lepidocrocite) are subject to direct photoreductive dissolution, while those with high crystallinity (e.g., goethite, hematite) generally need ligands to proceed with photoreductive dissolution. The photoreductive dissolution of iron (hydr)oxides is involved in many important geochemical and environmental processes, such as the Fe availability to primary producers, the generation of reactive oxygen species, the transportation and fate of contaminants, and the phase transformation of iron (hydr)oxides. Given the ubiquitous occurrence of photoreductive dissolution of iron (hydr)oxides, this review will advance our understanding of the role of this process in Earth’s surface environments.

Electrospun Polymer-Free Nanofibers Incorporating Hydroxypropyl-β-cyclodextrin/Difenoconazole via Supramolecular Assembly for Antifungal Activity.

In this study, flexible and self-standing hydroxypropyl-β-cyclodextrin/difenoconazole inclusion complex (HPβCD/DZ-IC) nanofibers were prepared by polymer-free electrospinning, which exhibited potential to be a new fast-dissolving pesticide formulation. Scanning electron microscopy and optical microscopy were applied to evaluate the morphology of nanofibers, which showed that the resulting HPβCD/DZ-IC nanofibers were bead-free and uniform. In addition, the proton nuclear magnetic resonance (1H NMR) spectrum suggested a stoichiometric ratio of 1:0.9 (HPβCD/DZ). Other characterization methods, such as UV-vis absorption, fluorescence spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), were applied in this study. On the one hand, UV-vis absorption, fluorescence spectroscopy, FT-IR, XRD, and TGA provided useful information for the successful formation of an inclusion complex; on the other hand, the results of TGA indicated the thermal stability of DZ was enhanced after the formation of inclusion complexes. Besides, the phase solubility test could explain the increased water solubility of the nanofibers of inclusion complexes formed by DZ and HPβCD. The results of molecular docking studies demonstrated the most favorable binding interactions when HPβCD combined with DZ. The dissolution test and the antifungal performance test exhibited the characteristics of fast dissolution and the excellent antifungal performance of HPβCD/DZ-IC nanofibers, respectively.