Neutral Solution Research Articles

Atomically dispersed Fe–N4 sites activated 3D-on-2D derived porous carbon structure toward superior oxygen reduction reaction

The oxygen reduction reaction (ORR) is a crucial step in the energy transformation devices, which requires the fabrication of a cost-effective and energy-efficient Fe single-atom catalyst (SAC) to substitute platinum. However, achieving a controllable synthesis of Fe SAC is a formidable challenge. In this study, a Fe SAC with a novel 3D-on-2D architecture was fabricated by coating 3D metal-organic frameworks (MOFs) over the surface of 2D reduced graphene oxide (rGO). In-situ combining MOF and rGO in a composite structure by adjusting their weight proportion is a key to preparing an active 3D-on-2D structured catalyst with FeN4 active sites. Thanks to the favorable conductivity of the 2D rGO-derived carbon structure and the 3D MOF structure exposing an enhanced density of FeN4 sites, FeNC@rGO-2 demonstrates exceptional ORR activity. It performs more effectively than commercial Pt/C, exhibiting excellent half-wave potentials of 0.887, 0.705, and 0.741 V in alkaline, neutral, and acidic solutions respectively. Impressively, FeNC@rGO-2 exhibits excellent stability and methanol tolerance. When FeNC@rGO-2 is assembled as cathode catalyst in Zinc-air batteries (ZAB) and microbial fuel cells (MFC), FeNC@rGO-2-ZAB reveals outstanding power density (393 mW cm−2) and good charge/discharge cycling stability. Amazingly, FeNC@rGO-2-MFC also shows superior power density (2810 ± 19 mW m−2) and efficiency of electron recovery. This study reveals that FeNC@rGO-2 has extremely high application value in energy conversion devices oriented for alkaline and neutral electrolytes.

A Sustainable Complexation Leaching of Critical Metals from Spent Lithium-Ion Batteries by Glycine in a Neutral Solution

A Sustainable Complexation Leaching of Critical Metals from Spent Lithium-Ion Batteries by Glycine in a Neutral Solution

Red‐Shifting ESIPT Fluorescence by Site‐Specific Functionalization in 2‐(2’‐hydroxyphenyl)benzazole Derivatives

AbstractWe describe the synthesis, full photophysical study, and ab initio calculations of 2‐(2’‐hydroxyphenyl)benzazole (HBX) fluorophores substituted, at the meta position of the phenol group, by pyridine derivatives. HBX are commonly used as model dyes to study the stimuli‐induced modulation of the Excited State Intramolecular Proton Transfer (ESIPT) process. The meta‐substituted fluorophores reported herein, display a photophysical profile different from the previously reported ortho‐ and para‐substituted HBO pyridine isomers. Indeed, while all dyes undergo spontaneous deprotonation in neutral conditions, leading to highly emissive anionic species; upon protonation, ortho‐ and para‐pyridine substitution leads to resonance‐stabilized keto isomers, formed after ESIPT. Protonated meta derivatives, unable to stabilize their excited structure by such electronic delocalization process, display sizable intramolecular charge transfer (ICT) processes, translating into significantly redshifted emission. In addition, all dyes present a strong emission intensity, not only in neutral and acidic solutions, but also in the solid‐state. The nature of the emissive transitions was confirmed in each case by theoretical calculations combining Time‐Dependent Density Functional Theory (TD‐DFT) and second‐order Coupled Cluster (CC2) methods.

PH-Universal Electrocatalytic CO2 Reduction with Ampere-Level Current Density on Doping-Engineered Bismuth Sulfide.

The practical application of the electrocatalytic CO2 reduction reaction (CO2RR) to form formic acid fuel is hindered by the limited activation of CO2 molecules and the lack of universal feasibility across different pH levels. Herein, we report a doping-engineered bismuth sulfide pre-catalyst (BiS-1) that S is partially retained after electrochemical reconstruction into metallic Bi for CO2RR to formate/formic acid with ultrahigh performance across a wide pH range. The best BiS-1 maintains a Faraday efficiency (FE) of ~95 % at 2000 mA cm-2 in a flow cell under neutral and alkaline solutions. Furthermore, the BiS-1 catalyst shows unprecedentedly high FE (~95 %) with current densities from 100 to 1300 mA cm-2 under acidic solutions. Notably, the current density can reach 700 mA cm-2 while maintaining a FE of above 90 % in a membrane electrode assembly electrolyzer and operate stably for 150 h at 200 mA cm-2. In situ spectra and density functional theory calculations reveals that the S doping modulates the electronic structure of Bi and effectively promotes the formation of the HCOO* intermediate for formate/formic acid generation. This work develops the efficient and stable electrocatalysts for sustainable formate/formic acid production.

PH‐Universal Electrocatalytic CO2 Reduction with Ampere‐Level Current Density on Doping‐Engineered Bismuth Sulfide

AbstractThe practical application of the electrocatalytic CO2 reduction reaction (CO2RR) to form formic acid fuel is hindered by the limited activation of CO2 molecules and the lack of universal feasibility across different pH levels. Herein, we report a doping‐engineered bismuth sulfide pre‐catalyst (BiS‐1) that S is partially retained after electrochemical reconstruction into metallic Bi for CO2RR to formate/formic acid with ultrahigh performance across a wide pH range. The best BiS‐1 maintains a Faraday efficiency (FE) of ~95 % at 2000 mA cm−2 in a flow cell under neutral and alkaline solutions. Furthermore, the BiS‐1 catalyst shows unprecedentedly high FE (~95 %) with current densities from 100 to 1300 mA cm−2 under acidic solutions. Notably, the current density can reach 700 mA cm−2 while maintaining a FE of above 90 % in a membrane electrode assembly electrolyzer and operate stably for 150 h at 200 mA cm−2. In situ spectra and density functional theory calculations reveals that the S doping modulates the electronic structure of Bi and effectively promotes the formation of the HCOO* intermediate for formate/formic acid generation. This work develops the efficient and stable electrocatalysts for sustainable formate/formic acid production.

Experimental, theoretical and computational studies of oxalyl dihydrazide as a novel corrosion inhibitor for mild steel in neutral saline solution

In this work, the corrosion inhibition performance and mechanism of oxalyl dihydrazide (ODH) for mild steel in neutral saline solution are in-depth studied using weight-loss and electrochemical tests, surface characterizations, theoretical calculation and computational simulations. Results indicate that ODH can act as a novel and superior mixed-type corrosion inhibitor for mild steel in neutral saline solution, its corrosion inhibition efficiency increases with the rising ODH concentration, and the optimum value reaches 88.7 % with adding 200 mg/L. Its corrosion inhibition ability becomes better with immersion time. A compact corrosion product film mainly consisting of Fe, O, N and Cl elements formed on metal surface after adding ODH. ODH molecules adsorb on metal surface in an orderly fashion to form a hydrophobic film, which is belonging to the physicochemical adsorption and obeys the Langmuir adsorption isotherm model. The corrosion inhibition process of ODH molecule on mild steel is the endothermic process, which enlarges the activation energy barrier of corrosion reactions. ODH molecule can expel the adsorbed water molecules on metal surface and form copolymers with increasing of ODH concentration, retarding the diffusion of water molecule thus protecting metal from corrosion. ODH is proved to be an effective organic corrosion inhibitor for protecting mild steel in neutral saline solution, and contributes toward research and application of easily accessible sources for organic corrosion inhibitors.

A potential-driven FeMnOx/CNTs film electrode for efficient extraction of WO42- via electrochemical coordination and inner-sphere complexation

A film electrode materials of iron-manganese oxide composite carbon nanotubes (FeMnOx/CNTs) with dual adsorption sites was obtained by a co-precipitation method, which exhibited excellent selectivity of WO42- in an electrochemically switched ion exchange (ESIX) system. The main components of FeMnOx are MnOx and Fe(OH)3. In FeMnOx/CNTs composite film, Fe(OH)3 with abundant hydroxyl functional groups on its surface improved the ion storage capacity, while MnOx served as the main selective separation material to selectively adsorb the WO42-. A scalable ESIX pilot system was also designed to examine the effect of different operating conditions on system performance. The W(Ⅵ) adsorption capacity was as high as 187.76 mg/g and the separation factor of W/Mo was 21.03. Combining experimental characterization and results, it was confirmed that the highly efficient selective extraction of WO42- in neutral solution should be derived from the dual-site (i.e., electrochemical coordination sites on MnOx and electrochemically induced inner-sphere complexation sites on Fe(OH)3) adsorption. Hence, it is believed that such a novel electroactive FeMnOx/CNTs film electrode with dual adsorption sites could be a promising candidate for industrialized tungsten-molybdenum separation by ESIX technology.

Construction of highly stable, monodisperse water-in-water Pickering emulsions with full particle coverage using a composite system of microfluidics and helical coiled tube

Water-in-water (W/W) Pickering emulsions, exhibit considerable potential in the food and pharmaceutical fields owing to their compartmentalization and high biocompatibility. However, constrained by the non-uniform distribution of shear forces during emulsification or the spatial obstruction in polydimethylsiloxane (PDMS) passive microfluidic platform, the existing methods cannot generate monodisperse W/W Pickering emulsions with high particle coverage rate, thereby limiting their applications. Herein, a novel microfluidic system is designed for the preparation of monodisperse and highly particle-covered W/W Pickering emulsions under mild conditions. pH-responsive Polyethylene glycol (PEG)/phosphate aqueous two-phase system (ATPS) is used for the emulsions' preparation. Notably, a coverage rate of 96 ± 3 % is obtained by adjusting the length of the helical coiled tube, as well as the size and contact angle of genipin cross-linked BSA (BSA-GP) particles. Moreover, these W/W Pickering emulsions, with surfaces almost completely covered, can maintain monodisperse (Ncoal = 1.18 ± 0.03) for one day. Furthermore, the results of ranitidine hydrochloride (RH) release demonstrated that the drug release rate of W/W Pickering emulsions in the simulated gastric fluid (SGF) was 10 times faster than that in the neutral solution. We believe that the highly particle-covered monodisperse W/W Pickering emulsions possess great potential applications in bioencapsulation for foods and drug delivery.

External electric field effects on asphaltene adsorption on Kaolinite-water interface: A molecular dynamics study

Applying electric fields to promote water/oil recovery efficiency is gaining increasing attention in downstream of heavy oil development. In this work, molecular dynamics simulations were performed to study the motion of N-(1-Hexylheptyl)-N′-(5-carboxylicpentyl) perylene-3,4,9,10-tetracarboxylic bisimide (C5Pe) between kaolinite (Kaol) surfaces mediated by external electric field in water under different pH. Aggregation of C5Pe was mainly mediated by pH and not affected by the electric field, while adsorption responded to both pH and the electric field. In neutral and alkaline solutions, C5Pe was deprotonated, and its distribution between two Kaol surfaces was mainly mediated by the Coulombic force exerted by the electric field. In acidic solutions, C5Pe carried zero charge, and yet its distribution was still affected by the electric field. The external electric fields mediated the wettability of the two Kaol surfaces in different extents, and C5Pe preferred to adsorb on the more hydrated surface. The mediation of the electric fields on the wettability of surfaces was achieved in two stages. In the first stage, when the electric field of a low strength was applied, diffusion of water enhanced. The hydration of both Kaol surfaces became increased as water molecules formed more hydrogen bonds with the surfaces. As the electric field strength became sufficiently high, diffusion showed no further enhancement, and the re-orientation of water dipoles started dominating the hydrogen bonding with the surfaces. Carrying opposite charges, the hydrogen bond donors and acceptors of water were differently regulated by the electric field, and therefore water molecules conformed in a certain manner under the electric field of high strength. As a result, the hydrogen bonding between water and the two Kaol surfaces (placed on two sides of the simulated box under the electric field) varied with their positions. Due to the structural hindrance of the hydroxyl groups on the surface, the surface could provide more hydrogen bonding donors formed more hydrogen bonds with water, and thus became more hydrophilic and had stronger attraction to C5Pe.

Minute‐Scale High‐Temperature Synthesis of Polymeric Carbon Nitride Photoanodes

Polymeric carbon nitride (CN) has emerged as a promising photoanodic material in water‐splitting photoelectrochemical cells (PEC). However, the current deposition methods of CN layers on substrates usually include a long heating process at 500−550 °C, which might cause sublimation or decomposition of the CN monomers and destruction of the substrate, leading to a nonuniform CN film. Herein, a simple, fast, and scalable energy‐economic procedure to synthesize homogenous CN films is introduced. The predesigned CN monomers film is subjected for several minutes to higher temperatures than the standard calcination procedure. The short heating process allows the formation of a uniform CN layer, with excellent contact with the substrate and good activity as a photoanode in PEC. The optimal CN photoanode reaches photocurrent densities of ≈200 μA cm−2 at 1.23 versus reversible hydrogen electrode in neutral and acidic solutions and 120 μA cm−2 in a basic solution.

ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ СОСТОЯНИЯ КОЖИ ОБЛАСТИ РТА ЖИВОТНЫХ ПОСЛЕ ВОЗДЕЙСТВИЯ СТОМАТОЛОГИЧЕСКИХ ДИОДНЫХ ФОТОПОЛИМЕРИЗАТОРОВ

Aim of the study: studying the effect of light radiation from dental photopolymerizers on the soft tissues of the mouth area (regio oralis A01.2.01.018). Materials and methods. Experimental studies were carried out on 50 eight months male rats, randomly divided into 4 groups: 3 main (15 animals each), the fourth - control (5 animals). Under Zoletil anesthesia, the incisors of the lower jaw of experimental animals were exposed twice to light (wavelength 395 - 480 nm) from a dental photopolymerization device. Three photopolymerization modes were used: main group No. 1 – diode photopolymerizer with a luminous flux power of 1000 mW/cm2, main group No. 2 – diode photopolymerizer with a luminous flux power of 1400 mW/cm2; main group No. 3 – diode photopolymerizer with a luminous flux power of 3200 mW/cm2. Animals in the control group were not exposed to light radiation from dental photopolymerizers. After one, three and seven days, animals from groups No. 1 – 3, seven days – animals from the control group were subjected to ether anesthesia and removed from the experiment by decapitation. For pathomorphological studies, a fragment of skin from the mouth area was isolated. The material was fixed with a 15% aqueous neutral solution of formalin and embedded in paraffin. Histological sections were stained with hematoxylin and eosin, according to the van Gieson method, and Alcian blue; performed the CHIC reaction. The vascular bed and its elements were studied using the Gabu-Dybanu method. A standardized comparative microscopic study of skin tissue adjacent to the irradiation zone was carried out using the ZEISS Axio Imager A2 hardware and software complex at magnifications of 1:100 and 1:200. A descriptive method was used to evaluate the results obtained. Results. Microscopy of preparations of the skin of the lips of experimental animals allowed us to come to the conclusion that the primary reaction of tissues to the effects of light radiation from photopolymerizers is of the same type and does not depend on their technical characteristics. Hyperkeratosis and acanthosis of the epithelium, congestion of the microvasculature, the presence of edema and diffuse infiltration of the dermis were detected. Quantitative and qualitative changes in mast cells were observed - an increase in the degree of their degranulation and the number of process forms, which is a marker of tissue damage in response to irradiation. The described changes, which in general are pathomorphological signs of acute inflammation, were determined on the first and third days after irradiation. Further dynamics indicated a decrease in the described reactive changes by the third day when using the photopolymerization mode: wavelength 395 – 480 nm, power 1000 mW/cm2, exposure 10 sec. When using the photopolymerization mode: wavelength 395 - 480 nm, power 1400/3200 mW/cm2, exposure 3 seconds - by the seventh day of observation there was a positive dynamics in the relief of pathological processes, but signs of inflammation remained. Conclusion. Experimental data indicate the possible development of negative photochemical reactions in the skin of the lips after exposure to light from dental photopolymerizers during the treatment of patients with pathology of hard dental tissues. The results obtained can be used to substantiate the prevention of pathological processes in the tissues of the perioral area. Further in vitro, in vivo, and clinical studies are needed to determine the optimal irradiation intensity, irradiation time, and other aspects to ensure the safety and effectiveness of light curing agents.

Effects of Na-salt solutions on the biomass pyrolysis and CO2-assisted gasification behavior

This study aims to explore the effects of different Na-salt solutions on the behavior of biomass pyrolysis and gasification. The same molar number of Na was introduced via the impregnation method. The distinction was that pine wood impregnated with neutral NaCl and Na2SO4 solutions was the Na in physical adsorption form, whereas the alkaline Na2CO3, CH3COONa, and NaOH solutions resulted in both carboxylate form and physical adsorption form. Thermogravimetric analysis results showed that impregnating alkaline Na solution was more potent than the neutral Na solution in reducing the thermal stability of pine wood structures. Results of pyrolysis and CO2-assisted gasification indicated that samples impregnated with the alkaline Na solutions obtained lower CO and higher CO2 evolution than that from the neutral Na solution during pyrolysis. The Na in carboxylate form was more difficult to volatilize, and formed more Na-containing active catalytic structures, resulting in biochar that provided higher reactivity in gasification. However, different Na solutions on the biochar's gasification reactivity showed the order of NaCl-loaded sample < CH3COONa-loaded sample ∼ NaOH-loaded sample < Na2SO4-loaded sample < Na2CO3-loaded sample. This can be attributed to the combined effects of Na-containing active catalytic structures, along with the active surface salt complex formed by molten Na species and biochar. As for the overall energy efficiency of pine wood impregnated with different Na solutions, gasification of Na2CO3-loaded sample provided the highest maximum overall energy efficiency (49.2 %). The results presented here provide useful insights for practical application of using syngas for electricity generation.

Microstructures and Rheological Properties of Short-Side-Chain Perfluorosulfonic Acid in Water/2-Propanol.

The viscosity and viscoelasticity of polyelectrolyte solutions with a single electrostatic interaction have been carefully studied experimentally and theoretically. Despite some theoretical models describe experimental results well, the influence of multiple interactions (electrostatic and hydrophobic) on rheological scaling is not yet fully resolved. Herein, we systematically study the microstructures and rheological properties of short-side-chain perfluorosulfonic acid (S-PFSA), the most promising candidate of a proton exchange membrane composed of a hydrophobic backbone with hydrophilic side-chains, in water/2-propanol. Small-angle X-ray scattering confirms that semiflexible S-PFSA colloidal particles with a length of ~38 nm and a diameter of 1-1.3 nm are formed, and the concentration dependence of the correlation length (ξ) obeys the power law ξ~c-0.5 consistent with the prediction of Dobrynin et al. By combining macrorheology with diffusing wave spectroscopy microrheology, the semidilute unentangled, semidilute entangled, and concentrated regimes corresponding to the scaling relationships ηsp~c0.5, ηsp~c1.5, and ηsp~c4.1 are determined. The linear viscoelasticity indicates that the entanglement concentration (ce) obtained from the dependence of ηsp on the polymer concentration is underestimated owing to hydrophobic interaction. The true entanglement concentration (cte) is obtained by extrapolating the plateau modulus (Ge) to the terminal modulus (Gt). Furthermore, Ge and the plateau width, τr/τe (τr and τe denote reptation time and Rouse time), scale as Ge~c2.4 and τr/τe~c4.2, suggesting that S-PFSA dispersions behave like neutral polymer solutions in the concentrated regime. This work provides mechanistic insight into the rheological behavior of an S-PFSA dispersion, enabling quantitative control over the flow properties in the process of solution coating.

Inhibition of metal corrosion in neutral aqueous solutions by succinic acid salts

The adsorption, protective and passivating effect of sodium succinate and a blend of sodium alkenylsuccinates SKAP-25 on the oxidized surface of copper, copper-nickel alloy MNZh5-1 and low-carbon steel St3 in a neutral chloride solution were studied. The free adsorption energy (–ΔG0a,max) values for all studied metals suggest chemisorption interaction of these organic anion with oxidized metals surfaces: (–ΔG0a,max) for St3 60.2 kJ/mol, for copper 77.4 kJ/mol and for copper alloy 89.3 kJ/mol. Sodium succinate is able to stabilize the passive state of the MNZh5-1 alloy in a neutral chloride buffer solution. On copper, copper alloy and St3, protection against local depassivation is observed up to a certain concentration, above which the protective properties of sodium succinate decrease. Polarization measurements on the air-oxidized surface of low-carbon steel St3 showed that sodium succinate and SKAP-25, as well as their compositions with 2-mercaptobenzothiazole (2-MBT), are able to reduce anodic dissolution currents and increase the local depassivation potential. Corrosion tests of St3 in a 0.01 M NaCl solution proved the advantage of using the composition of SKAP-25 with 2-MBT (7.1:1) in comparison with the individual compound: the degree of protection of St3 at Cinh=7 mmol/L is 99%, and sodium succinate+SKAP-25 (1:1) at Cinh=7 mmol/L is Z=93%.

Immersion Behavior Study of Hydroxyapatite Scaffolds Derived from Bovine Sources In Acidic, Basic, and Neutral Solutions

This research investigates the effects of particle size and compaction pressure on the dissolution behavior of hydroxyapatite scaffolds synthesized from bovine bone in acidic neutral and basic solutions. Hydroxyapatite was extracted through a process involving cutting, cleaning, boiling, soaking in NaOH, sun drying, grinding into powder and calcination at 800°C. The powder was then sieved into two size fractions (75 and 150 microns) and compacted at pressures of 200, 250, and 300 MPa. The mass and dimensions of the scaffolds were measured to calculate porosity, followed by immersion in the respective solutions for 24 hours to determine dissolution rates. Results indicated that smaller particle sizes and higher compaction pressures resulted in reduced porosity and enhanced structural integrity. The dissolution rates varied significantly with pH levels, exhibiting the highest rates in acidic conditions up to 215.83 mg/cm2 and the lowest in basic solutions up to 11.32 mg/cm2. Additionally, scaffolds with smaller particles and higher compaction pressures demonstrated lower dissolution rates across all pH levels due to lower porosity. In conclusion, both particle size and compaction pressure are critical factors influencing the dissolution behavior of hydroxyapatite scaffolds. These findings have significant implications for the design and optimization of hydroxyapatite-based materials for biomedical applications, where controlled dissolution rates are crucial for performance and longevity.

Cross-linking of mesoporous bioactive glass nanoparticle incorporated gelatin hydrogels by tannic acid with enhanced mechanical performance and stability

Gelatin-based hydrogels are used in diverse biomedical applications, such as wound dressings, tissue regeneration, and cell culture models. However, gelatin requires additional cross-linking to form a stable hydrogel. Tannic acid (TA), a polyphenolic compound, can undergo the Michael addition reaction and Schiff's base reaction with primary amine groups in neutral aqueous solutions. In this work, TA was selected as a cross-linker of gelatin to fabricate hydrogels reacting with primary amine groups in the gelatin molecular chain. Primary amine-modified mesoporous bioactive glass nanoparticles (AMBGNs) were added to further enhance the cross-linking of the system. The swelling ratios and weight losses showed that the most stable hydrogels retain approximately 53 % of their mass after 28 days of immersion in PBS solution. Young's modulus increased significantly with the increase in the content of TA and AMBGNs. The addition of TA and AMBGNs also resulted in a substantial reduction of gelation time. The prepared hydrogels possessed adequate stability and mechanical properties and showed potential for customized application in a variety of clinical service settings, such as wound healing, bone regeneration, and soft tissue regeneration.

PH-response of protein-polysaccharide multilayers adsorbed on a flat gold surface: A surface plasmon resonance study.

Polysaccharide-protein multilayers (PPMLs) consisting of bovine serum albumin (BSA) and chondroitin sulfate (CS) are assembled in acidic solution (pH 4.2) via layer-by-layer deposition method. The formation of PPMLs on gold surface and their responsiveness to pH change from 4.2 to 7 is investigated by Surface Plasmon Resonance Spectroscopy. The buildup of the multilayer at pH 4.2 exhibits non-linear growth while the formation of the first layers is strongly affected by the physicochemical properties of the gold surface. Neutral solution (pH 7) affects the interactions between the biopolymers and results in a partially disassemble (disintegration) of the multilayer film. On one hand, the single pair of layers, BSA-CS and the double pair of layers, (BSA-CS)2, assemblies are stable in neutral pH, a result that will be of interest for biomedical applications. On the other hand, multilayer films consisting of more than four layers that is (BSA-CS)2<n<5, disintegrated down to the 4-layered structure by changing pH to neutral, a fact that renders the (BSA-CS)n assembly useful in the field of drug and protein delivery. The residual mass after the disintegration of the assembly never falls below the mass of four layers. The disintegrated multilayer film can be reconstructed and disassembled repeatedly, simply by cycling the pH value.

Variation in chemical property of asphalt immersed in varying aqueous solutions and its leachate property

The pavement asphalt properties are susceptible to deterioration under environmental factors, and the deterioration product will affect its surrounding aqueous environment. For this reason, the idealized asphalt-aggregate mixture was treated with coupled temperature, ultraviolet and aqueous solutions based on self-made multifactorial coupled simulation device. Subsequently, the deterioration of asphalt chemical properties was analyzed by fourier transform infrared spectroscopy and saturate-aromatic-resin-asphaltene tests. Meanwhile, the effect of environmental factors on leachate properties was explored based on organic matter contents and chemical elements. Based on that, the grey correlation method was adopted to correlate asphalt chemical properties and leachate properties. The results clearly showed that environmental factors increased the sulfoxide and carbonyl group content of asphalt and transformed the chemical components within it into polar substances. The asphalt chemical properties were gradually improved when coupling ultraviolet with sodium carbonate, sodium chloride and distilled water sequentially. Compared to neutral solution, alkaline solution exacerbated the effect of asphalt precipitates on leachate properties. The environmental factors increased the organic matter contents and chemical elements of leachate with time. The interaction mechanism between asphalt and aqueous environment involved the deterioration of asphalt properties caused by the presence of water, as well as the release of precipitates from aged asphalt into surrounding aqueous environment.

Adsorptive removal of arsenic from drinking water using KOH-modified sewage sludge-derived biochar

This paper reveals a green chemistry approach to remove arsenic (As+3) from water using potassium hydroxide (KOH) modified sewage sludge-derived biochar (SSDB-KOH). Characterisation of the morphology, particle size and composition of the SSDB-KOH pre- and post-adsorption confirmed porous and heterogenous surface favouring adsorption. At ambient temperature (20 °C), the SSDB-KOH dose of 20 g/l achieved 98 % arsenite removal at nearly neutral solution pH (8). This compared favourably with pristine SSDB, where the performance was limited to 41.6 % removal. The enhanced arsenite adsorption of SSDB-KOH was informed by several mechanisms, including ionic interactions, pore filling and metal-pi interactions. The experimental data fits closely with the Langmuir isotherm and pseudo-second-order kinetic models, revealing monolayer adsorption and the chemical interaction between adsorbents and the adsorbate. The spontaneous and endothermic nature of the process was confirmed by the negative value of ΔG and the positive value of ΔH, respectively. The performance of the biochar was evaluated for four-cycle regeneration. Finally, a cost analysis was performed to demonstrate the economic feasibility of using SSDB-KOH to remove arsenic from water.

Holographic supersymmetric Rényi entropies from hyperbolic black holes with scalar hair

We study holographic supersymmetric Rényi entropies from a family of hyperbolic black holes in an Einstein-Maxwell-dilaton (EMD) system under the BPS condition. We calculate the thermodynamic quantities of these hyperbolic black holes. We find a remarkably simple formula of the supersymmetric Rényi entropy that unifies (interpolates) 11 cases embeddable to 10 or 11 dimensional supergravity. It reproduces many known results in the literature, and gives new results with distinctive features. We show that the supersymmetric version of the modular entropy and the capacity of entanglement cannot be mapped to thermal quantities, due to the dependence of the temperature and the chemical potential by the BPS condition. We also calculate the entanglement spectrum. We derive the potential of the EMD system from a V = 0 solution and obtain two neutral solutions with scalar hair as a byproduct.