Knowledge extraction of sonophotocatalytic treatment for acid blue 113 dye removal by artificial neural networks.

Removing decolorizing acid blue 113 (AB113) dye from textile wastewater is challenging due to its high stability and resistance to removal. In this study, we used an artificial neural network (ANN) model to estimate the effect of five different variables on AB113 dye removal in the sonophotocatalytic process. The five variables considered were reaction time (5-25 min), pH (3-11), ZnO dosage (0.2-1.0 g/L), ultrasonic power (100-300 W/L), and persulphate dosage (0.2-3 mmol/L). The most effective model had a 5-7-1 architecture, with an average deviation of 0.44 and R2 of 0.99. A sensitivity analysis was used to analyze the impact of different process variables on removal efficiency and to identify the most effective variable settings for maximum dye removal. Then, an imaginary sonophotocatalytic system was created to measure the quantitative impact of other process parameters on AB113 dye removal. The optimum process parameters for maximum AB 113 removal were identified as 6.2 pH, 25 min reaction time, 300 W/L ultrasonic power, 1.0 g/L ZnO dosage, and 2.54 mmol/L persulfate dosage. The model created was able to identify trends in dye removal and can contribute to future experiments.

Prediction of batch sorption of barium and strontium from saline water.

Celestite and barite formation results in contamination of barium and strontium ions hinder oilfield water purification. Conversion of bio-waste sorbent products deals with a viable, sustainable and clean remediation approach for removing contaminants. Biochar sorbent produced from rice straw was used to remove barium and strontium ions of saline water from petroleum industries. The removal efficiency depends on biochar amount, pH, contact time, temperature, and Ba/Sr concentration ratio. The interactions and effects of these parameters with removal efficiency are multifaceted and nonlinear. We used an artificial neural network (ANN) model to explore the correlation between process variables and sorption responses. The ANN model is more accurate than that of existing kinetic and isotherm equations in assessing barium and strontium removal with adj. R2 values of 0.994 and 0.991, respectively. We developed a standalone user interface to estimate the barium and strontium removal as a function of sorption process parameters. Sensitivity analysis and quantitative estimation were carried out to study individual process variables' impact on removal efficiency.

Synthesis and Electrochemical Properties of Amorphous Carbon Coated Sn Anode Material for Lithium Ion Batteries and Sodium Ion Batteries.

Sn is one of the promising anode material for lithium-ion and sodium-ion batteries because of Sn has many advantages such as a high theoretical capacity of 994 mAh/g, inexpensive, abundant and nontoxic. However, Sn-based anodes have a critical problem from pulverization of the particles due to large volume change (>300% in lithium-ion battery and 420% in the sodium-ion battery) during alloying/dealloying reaction. To overcome this problem, we fabricate Sn/C particle of core/shell structure. Sn powder was produced by pulsed wire explosion in liquid media, and amorphous carbon coating process was prepared by hydrothermal synthesis. The charge capacity of Sn electrode and amorphous carbon coated Sn electrode was 413 mAh/g and 452 mAh/g after 40 cycles in lithium half-cell test. The charge capacity of Sn electrode and amorphous carbon coated Sn electrode was 240 mAh/g and 487 mAh/g after 40 cycles in sodium half-cell test. Amorphous carbon coating contributed to the improvement of capacity in lithium and sodium battery systems. And the effect of amorphous carbon coating in sodium battery system was superior to that in lithium battery system.

Microstructural Evolution and Electrochemical Properties of HRDSR AZ61-X (X = Ca, Ti) Alloys.

The microstructure and corrosion properties of as-cast AZ61 (Mg-6%Al-1%Zn) and AZ61 alloys doped with titanium and calcium and subjected to high ratio differential speed rolling were investigated. Addition of the alloying elements to the AZ61 alloy resulted in remarkable modification of the morphology and the amount of continuous ß (Mg17Al12)-phase. Addition of Ti to the as-cast AZ61 alloy causes a decrease in the volume fraction (or discontinuity of the ß-phase), leading to strong anodic dissolution. In contrast, addition of Ca to the as-cast AZ61 alloy is rather effective for preventing pitting corrosion. This is attributed to the formation of a semi-continuous network ß-structure. The (Mg, Al)4Ca phases dispersed between the ß (Mg17Al12)-phases led to continuity in the AZ61 alloy with Ca. The AZ61 and AZ61-X(Ca, Ti) alloys subjected to severe plastic deformation via high-ratio differential speed rolling possessed a nano-composite-like microstructure in which the α-Mg matrix with an ultra-fine grain was surrounded by a large number of fine ß particles. These particles were either dynamically precipitated or broken at the grain boundaries, as well as in the grain interiors, by the high ratio differential speed rolling process. The corrosion resistance of the AZ61 and AZ61-X (X = Ca, Ti) alloys subjected to high ratio differential speed rolling was largely improved by the microstructural modification. The high ratio differential speed rolling process greatly influenced the texture of the Mg alloys, which significantly affected their corrosion behavior.

Electrochemical Behavior of Sn/Cu6Sn5/C Composite Prepared by Using Pulsed Wire Explosion in Liquid Medium for Lithium-Ion Batteries.

Tin-based materials, due to their high theoretical capacity of 994 mAh g-1 are potential candidates which can substitute the commercialized graphite anodes (372 mAh g-1). However, practical usage of pure tin in Li-ion cells has been hampered by the tremendous volume expansion of more than 260% during the lithium insertion/extraction process, resulting in particle pulverization and electrical disconnection from the current collector. In order to overcome this shortcoming, Sn/Cu6Sn5/C composites in this work were prepared by using pulsed wire explosion in a liquid medium and subsequently in situ polymerization. For comparison, Sn/C composite without tin-copper chemical compounds are also fabricated under a similar process. The Sn/Cu6Sn5/C and Sn/C composites were used as anodes for lithium-ion batteries. The Sn/Cu6Sn5/C composite anode showed good cyclability (scalability) and was maintained up to a capacity of 430 mAh g-1 after 100 cycles at 1 C-rate. The rate capability of the Sn/Cu6Sn5/C composite anode also showed higher performance (280 mAh g-1) than that (200 mAh g-1) of Sn/C composite at the 5 C-rate.

Carbon-Coated Ordered Mesoporous SnO2 Composite Based Anode Material for High Performance Lithium-Ion Batteries.

Recently, tin oxide (SnO2) has received significant attention for use as an anode material for next generation lithium-ion batteries (LIBs) owing to its high theoretical capacity (782 mAh g-1), which is more than twice of that of the commercialized graphite (372 mAh g-1). Several additional advantages, such as low cost, environmental friendliness, easy fabrication and natural abundance improve its promise. Although the theoretical capacity of SnO2 is high, volume expansion during cycling causes issue with cycling stability. In this study, an ordered mesoporous SnO2 was synthesized using a hard template (SBA-15), such that its mesoporous structure can buffer SnO2 particles from cracks caused by volume expansion. It can also allow effective electrolyte infiltration to ensure better reactivity of the active material with Li+ ions. The capacity of synthesized mesoporous SnO2 improved to 218.4 mAh g-1 compared regular SnO2 nanoparticles (69.6 mAh g-1) after 50 cycles at a rate of 0.1 C. Furthermore, carbon-coated mesoporous SnO2 enhanced capacity retention upon cycling (844.6 mAh g-1 after 50 cycles at 0.1 C) by insulating and preventing the cracking of the active material during lithiation and delithiation.

Electrochemical Properties of Micron-Sized SnO Anode Using a Glyme-Based Electrolyte for Sodium-Ion Battery.

Tin monoxide (SnO) anodes are promising candidates for use in sodium-ion batteries because of their high theoretical capacities and stable cycle performance. In previous reports, electrodes with excellent performance have been prepared by using nano-sized SnO particles. However, the synthesis of nano-sized SnO particles is complex, time-consuming, and expensive. In this paper, an anode of micron-sized SnO is prepared by using commercial micron-sized SnO particles. The electrode exhibits a reversible capacity of 450 mAh g-1 in the 1st cycle at a current rate of 100 mA g-1. We used a tetraethylene glycol dimethyl ether (TEGDME)-based electrolyte, which is well known for its superior electrochemical performance in sodium-ion batteries. The mechanism of operation of the anode containing micron-sized SnO particles has been confirmed by a detailed study using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). During initial discharge, the SnO changed to Sn and sodium oxide, and the surface of the electrode became covered with a film. The electrode composed of micron-sized SnO is a potential candidate for use in sodium-ion batteries.

High performance enzyme fuel cells using a genetically expressed FAD-dependent glucose dehydrogenase α-subunit of Burkholderia cepacia immobilized in a carbon nanotube electrode for low glucose conditions.

FAD-dependent glucose dehydrogenase (FAD-GDH) of Burkholderia cepacia was successfully expressed in Escherichia coli and subsequently purified in order to use it as an anode catalyst for enzyme fuel cells. The purified enzyme has a low Km value (high affinity) towards glucose, which is 463.8 µM, up to 2-fold exponential range lower compared to glucose oxidase. The heterogeneous electron transfer coefficient (Ks) of FAD-GDH-menadione on a glassy carbon electrode was 10.73 s(-1), which is 3-fold higher than that of GOX-menadione, 3.68 s(-1). FAD-GDH was able to maintain its native glucose affinity during immobilization in the carbon nanotube and operation of enzyme fuel cells. FAD-GDH-menadione showed 3-fold higher power density, 799.4 ± 51.44 µW cm(-2), than the GOX-menadione system, 308.03 ± 17.93 µW cm(-2), under low glucose concentration, 5 mM, which is the concentration in normal physiological fluid.

Electrical and mechanical properties as a processing condition in polyvinylchloride multi walled carbon nanotube composites.

We investigated the electrical conductivity (sigma) and mechanical property of polyvinylchloride/carbon nanotube composites as a function of the CNT content and processing time during a solid-state process of high speed vibration mixing (HSVM) and high energy ball milling (HEBM). Both processes were suggested to avoid high temperatures, solvents, chemical modification of carbon nanotubes. In this study, the percolation threshold (phi(c)) for electrical conduction is about 1 wt% CNT with a sigma value of 0.21 S/m, and the electrical conductivity is higher value than that reported by other researchers from melt mixing process or obtained from the other solid-state processes. We found that the dispersion of CNTs and morphology change from CNT breaking are closely related to sigma. Especially, a large morphology change in the CNTs was occurred at the specific processing time, and a significant decrease in the electrical conductivity of polyvinylchloride/carbon nanotube composite occurred in this condition. A meaningful increase of electrical properties and mechanical property is observed in the sample with about 1-2 wt% CNT contents sintered at 200 degrees C after the milling for 20 min by HEBM process. Our study indicates the proper process condition required to improve sigma of PVC/CNT composites.

Effect of precursor supply on structural and morphological characteristics of fe nanomaterials synthesized via chemical vapor condensation method.

Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying, have been used to synthesize nanoparticles. Among them, chemical vapor condensation (CVC) has the benefit of its applicability to almost all materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, Fe nanoparticles and nanowires were synthesized by chemical vapor condensation method using iron pentacarbonyl (Fe(CO)5) as the precursor. The effect of processing parameters on the microstructure, size and morphology of Fe nanoparticles and nanowires were studied. In particular, we investigated close correlation of size and morphology of Fe nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. The atomic quantity was calculated by Boyle's ideal gas law. The Fe nanoparticles and nanowires with various diameter and morphology have successfully been synthesized by the chemical vapor condensation method.

Influence of Mechanical Fatigue at Different States of Charge on Pouch-Type Li-Ion Batteries.

Since flexible devices are being used in various states of charge (SoCs), it is important to investigate SoCs that are durable against external mechanical deformations. In this study, the effects of a mechanical fatigue test under various initial SoCs of batteries were investigated. More specifically, ultrathin pouch-type Li-ion polymer batteries with different initial SoCs were subjected to repeated torsional stress and then galvanostatically cycled 200 times. The cycle performance of the cells after the mechanical test was compared to investigate the effect of the initial SoCs. Electrochemical impedance spectroscopy was employed to analyze the interfacial resistance changes of the anode and cathode in the cycled cells. When the initial SoC was at 70% before mechanical deformation, both electrodes well maintained their initial state during the mechanical fatigue test and the cell capacity was well retained during the cycling test. This indicates that the cells could well endure mechanical fatigue stress when both electrodes had moderate lithiation states. With initial SoCs at 0% and 100%, the batteries subjected to the mechanical test exhibited relatively drastic capacity fading. This indicates that the cells are vulnerable to mechanical fatigue stress when both electrodes have high lithiation states. Furthermore, it is noted that the stress accumulated inside the batteries caused by mechanical fatigue can act as an accelerated degradation factor during cycling.

Synthesis of gallium oxide nanomaterials on source material supply and their growth behavior.

High purity and single crystalline beta-Ga2O3 nanomaterials with various morphologies were obtained through the simple thermal evaporation of metal gallium powder on a gold-coated silicon substrate in argon. In this report, the growth behavior of the beta-Ga2O3 nanomaterials as a function of synthesis time and source material supply was delicately surveyed via FESEM and HRTEM. The synthesis time and source material supply affected morphology, growth rate and growth mechanism of the grown nanomaterials. It was confirmed that the growth mechanism of the beta-Ga2O3 nanomaterials was varied in the order of VLS, combination of VLS and VS, and VS, by increasing the synthesis time without regard to the supply of the source material. When the source materials supply was increased, many beta-Ga2O3 nanomaterials with various morphologies, such as sheet, triangle, and belt-like were appeared. It was confirmed that the oxidation reaction of gallium and oxygen for the formation of gallium oxide nanomaterials carried out the precipitation of gallium at the same time due to the supersaturation of the gallium atoms in gold catalyst. The growth and formation mechanism of the beta-Ga2O3 nanomaterials are discussed herein.

Electrochemical characteristics with the addition of carbon nanotubes and the manufacturing process for sulfur cathode in the Li/S cell.

Carbon nanotubes (CNTs) were purified using acid solution, and CNT-sulfur composite powder was prepared via precipitation, using the purified CNTs. In addition, the effect of the purified CNTs (PUCNTs) on the electrochemical performance of the Li/S cell was investigated. After the purification, almost all the impurities in the as-synthesized CNTs (ASCNTs) were removed, and the dispersibility of the CNTs was improved. On the other hand, the concentration of the structural defects and of the disordered structures in the PUCNTs was increased due to the surface oxidation of the tubes during acid treatment. In the case of the PUCNT-S composite powder, the outer wall of the tubes was well covered with sulfur, as opposed to the tubes in the ASCNT-S composite powder. The Li/S cell containing ASCNT-S composite cathode showed a large voltage decrease and a 680 mAh/g capacity during the first discharge process. The Li/S cell with PUCNT-S composite cathode, however, showed a higher discharge capacity and better cycle performance than the cell with ASCNT-S composite cathode. The electrochemical performance of the Li/S cell was improved for the PUCNT-S composite cathode using the CNTs purified by acid treatment.

Ultrahigh-rate nickel monosulfide anodes for sodium/potassium-ion storage.

Transition-metal sulfides have been extensively studied as anode materials for use in sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to their multi-electron reactions, high rate performance, and abundant available resources. However, the practical capacities of metal sulfides remain low due to conductivity issues, volume expansion, and the use of traditional carbonate electrolytes. To overcome these drawbacks, ether electrolytes can be combined with nanoparticle-based metal sulfide anodes. Herein, a nanoparticle-based nickel monosulfide (NiS) anode with high rate performance in the ether electrolytes of SIBs/PIBs was prepared by heating a mixture of nickel nanoparticles with sulfur. In SIBs, the NiS anode capacity was 286 mA h g-1 at a high current density of 100 A g-1, and excellent cycling performance was observed at 25 A g-1 with a capacity of 468 mA h g-1 after 1000 cycles. Moreover, a full-cell containing a Na3V2(PO4) cathode demonstrated a rate performance of 65 mA h g-1 at a high current density of 100 A g-1. In PIBs, the NiS electrode capacity was 642 and 37 mA h g-1 at 0.5 and 100 A g-1, respectively. Hence, the synthesised NiS nanoparticles possessed excellent storage capability, regardless of the alkali-ion type, suggesting their potential use as robust NiS anodes for advanced battery systems.

Binder-free and high-loading sulfurized polyacrylonitrile cathode for lithium/sulfur batteries.

Sulfurized polyacrylonitrile (SPAN) is a promising active material for Li/S batteries owing to its high sulfur utilization and long-term cyclability. However, because SPAN electrodes are synthesized using powder, they require large amounts of electrolyte, conducting agents, and binder, which reduces the practical energy density. Herein, to improve the practical energy density, we fabricated bulk-type SPAN disk cathodes from pressed sulfur and polyacrylonitrile powders using a simple heating process. The SPAN disks could be used directly as cathode materials because their π-π structures provide molecular-level electrical connectivity. In addition, the electrodes had interconnected pores, which improved the mobility of Li+ ions by allowing homogeneous adsorption of the electrolyte. The specific capacity of the optimal electrode was very high (517 mA h gelectrode -1). Furthermore, considering the weights of the anode, separator, cathode, and electrolyte, the Li/S cell exhibited a high practical energy density of 250 W h kg-1. The areal capacity was also high (8.5 mA h cm-2) owing to the high SPAN loading of 16.37 mg cm-2. After the introduction of 10 wt% multi-walled carbon nanotubes as a conducting agent, the SPAN disk electrode exhibited excellent cyclability while maintaining a high energy density. This strategy offers a potential candidate for Li/S batteries with high practical energy densities.

Fabrication of Nickel Sulfide/Nitrogen-Doped Reduced Graphene Oxide Nanocomposite as Anode Material for Lithium-Ion Batteries and Its Electrochemical Performance.

In this study, NiS/graphene nanocomposites were synthesized by simple heat treatment method of three graphene materials (graphene oxide (GO), reduced graphene oxide (rGO) and nitrogen-doped graphene oxide (N-rGO)) and NiS precursor. The morphology and crystal structure of NiS/graphene nanocomposites were characterized using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Electrochemical properties were also investigated. NiS/graphene nanocomposites homogeneously wrapped by graphene materials have been successfully manufactured. Among the three nanocomposites, NiS/N-rGO nanocomposite exhibited the highest initial and retention capacity in discharge, respectively, of 1240 mAh/g and 467 mAh/g up to 100 cycles at 0.5 C.

Hydrothermal Synthesis and Electrochemical Behavior of the SnO2/rGO as Anode Materials for Lithium-Ion Batteries.

In this work, the hydrothermal method was employed to produce SnO2/rGO as anode material. Nanostructured SnO2 was prepared to enhance reversibility and to deal with the undesirable volume changes during cycling. The SnO2/rGO hybrid exhibits long cycle life in lithium-ion storage capacity and rate capability with an initial discharge capacity of 1327 mAh/g at 0.1 C rate. These results demonstrate that a fabricated SnO2/rGO matrix will be a possible way to obtain high rate performance.

Controlling the Voltage Window for Improved Cycling Performance of SnO2 as Anode Material for Lithium-Ion Batteries.

Transition metal oxide materials with high theoretical capacities have been studied as substitutes for commercial graphite in lithiumion batteries. Among these, SnO2 is a promising alloying reaction-based anode material. However, the problem of rapid capacity fading in SnO2 due to volume variation during the alloying/dealloying processes must be solved. The lithiation of SnO2 results in the formation of a Li2O matrix. Herein, the volume variation of SnO2 was suppressed by controlling the voltage window to 1 V to prevent the delithiation reaction between Li2O and Sn. Using this strategy the unreacted Li2O matrix was enriched with metallic Sn particles, thereby providing a pathway for lithium ions. The specific capacity decay in the voltage window of 0.05-3 V was 1.8% per cycle. However, the specific capacity decay was improved to 0.04% per cycle after the voltage window was restricted (in the range of 0.05-1 V). This strategy resulted in a specific capacity of 374.7 mAh g-1 at 0.1 C after 40 cycles for the SnO2 anode.

High power Na3V2(PO4)3 symmetric full cell for sodium-ion batteries.

Sodium-ion batteries (SIBs) are a viable substitute for lithium-ion batteries due to the low cost and wide availability of sodium. However, practical applications require the development of fast charging sodium-ion-based full-cells with high power densities. Na3V2(PO4)3 (NVP) is a bipolar material with excellent characteristics as both a cathode and an anode material in SIBs. Designing symmetric cells with NVP results in a single voltage plateau with significant specific capacity which is ideal for a full cell. Here we demonstrate for the first time a tremendous improvement in the performance of NVP symmetric full cells by introducing an ether-based electrolyte which favors fast reaction kinetics. In a symmetric full cell configuration, 75.5% of the initial capacity was retained even after 4000 cycles at 2 A g-1, revealing ultra-long cyclability. Excellent rate performances were obtained at current densities as high as 1000C, based on the cathode mass, revealing ultrafast Na+ transfer. The power density obtained for this NVP symmetric cell (48 250 W kg-1) is the best among those of all the sodium-ion-based full cells reported to date.

Effect of Ordered Carbon Structures on Electrochemical Properties of Carbon/Sulfur Composites in Lithium-Sulfur Batteries.

In this paper, the relationship between the pore spatial structures, pore sizes, and pore types of highly ordered mesoporous CMK-based carbons (CMK-1, CMK-3, and CMK-5) and their electrochemical performance in Li-S batteries is investigated. CMK-1 has a complex spatial structure and small pores. The structure is good for limiting polysulfide in the pores, but not for rapid transfer of Li+ ions in the cell. CMK-3 and CMK-5 have similar spatial structures and pore sizes, but different pore types. Compared to the single pore structure of CMK-3, the bimodal pore structure of CMK-5 not only improves the electrolyte accessibility, but also increases the number of reaction sites, resulting in better electrochemical performance. Studying the correlation between the physical structure of carbon-based materials and their electrochemical performance in Li-S batteries will provide new insights for optimizing porous electrode materials.