Charged Sites Research Articles

Analysing electric vehicle charging power quality in large-scale charging sites - a data-driven approach

Analysing electric vehicle charging power quality in large-scale charging sites - a data-driven approach

Fabrication of hydrophilic porous carbon from polyvinylidene chloride-resin via synergetic activation of ZnO and tetrahydrofuran for aqueous supercapacitors

For high capacitance, aqueous supercapacitors use large-area porous carbon electrode based on the charging principle of ion adsorption. Nonpolar hydrophobic carbon prevents ion adsorption, limiting the exploitation of porous surfaces. A carbon synthesis method was developed from pyrolysis of a polyvinylidene chloride-resin precursor and excess ZnO to derive a highly porous structure with a high surface area. Ion adsorption is limited by the small, newly formed pores. Added tetrahydrofuran expands the reaction region between the precursor and etchant during pyrolysis by dissolving the precursor. Moreover, tetrahydrofuran activates oxygen in the precursor and ZnO during pyrolysis, forming hydrophilic phenol and carboxylic acid. The hydrophilicity and pore expansion induced during pyrolysis convert the extra surface area into active charging sites. Hydrophilic carbon with enlarged pores increases the specific capacitance by 5.7 times to 126 F g−1 (at 5 mV s−1) and the rate capability by 2.7 times to 62% (50 mV s−1 vs. 5 mV s−1) in neutral K2SO4 solution compared to carbon made from polyvinylidene chloride-resin. Notably, the synthesized functional groups yielded a high capacitance of 243 F g−1 based on the faradaic charging in the KOH electrolyte. Hydrophilic carbon originating from polyvinylidene chloride-resin can be a potential electrode with a high capacitance for aqueous supercapacitors.

Synthesis and characterization of tailor-made o-hydroxysubstituted anils through 1H NMR, ­13C NMR, SC-XRD and DFT studies for possible optoelectronic applications

The present work reports the synthesis of two simple tailor-made anils (o-hydroxybezylidene-orthochloroaniline & o-hydroxynaphthalidene-orthochloroaniline) and their characterization by 1H & 13C Nuclear magnetic resonance(NMR), single X-ray diffraction spectroscopy(SC-XRD) and DFT studies. DFT-B3LYP optimized the molecular structures with a 6-311G (d, p) basis set to accomplish the global minimum energy state. 1H NMR confirmed the occurrence of H-bonding between the phenolic hydrogen and azomethine nitrogen in both molecules, further supported by SC-XRD analysis and DFT studies. The structural parameters such as bond angle, bond length, and dihedral angle derived from the optimized structure of molecules with C1 symmetry were compared with the corresponding parameters extracted from the ORTEP diagrams for both anils. Appreciable harmony of the structural parameters was achieved between these two analyses, confirming the anils’ purity. Slight discrepancy observed between DFT and SC-XRD analyses was attributed to the difference in the state of the molecules. Geometric optimization indicated the molecules to be coplanar. The MEP surface and atomic charges on the atoms envisaged the electron population and charged sites of the anils. Conclusively, both the anils have a suitable structural hierarchy for superior electron transport from the phenyl rings over the entire molecular framework suitable for optoelectronics applications.

Unravelling the metal uptake process in mosses: Comparison of aquatic and terrestrial species as air pollution biomonitors

Transplanted mosses have been widely shown to be excellent tools for biomonitoring air pollution; however, it is not clear how the functional groups present on their surfaces affect the uptake of metal cations. In the present study, we examined differences in trace metal accumulation in two terrestrial and one aquatic moss species, and investigated whether the differences depended on their physico-chemical characteristics. In the laboratory, we determined C, N and H contents in their tissues and obtained the ATR-FTIR spectra (to identify the presence of functional groups). We also conducted surface acid-base titrations and metal adsorption assays with Cd, Cu and Pb. In the field, we exposed transplants of each species near different air-polluting industries, and determined the mosses enrichment of Al, Cd, Co, Cr, Cu, Fe, Ni, Pb and V. Laboratory results demonstrated higher metal uptake capacity in the terrestrial mosses Sphagnum palustre and Pseudoscleropodium purum, compared to that in the aquatic moss Fontinalis antipyretica, which can be attributed to a greater abundance of acidic functional groups (i.e. negatively charged binding sites) on the surface of the terrestrial mosses. The affinity of moss for certain elements depends on the abundance and nature of surface functional groups. Accordingly, the metal concentrations generally reached higher levels in S. palustre transplants compared to the other species, except for the uptake of Hg, which was higher in F. antipyretica. However, the findings also suggest an interaction between the type of environment (terrestrial or aquatic) and the moss characteristics that may influence the abovementioned trend. Thus, irrespective of the physico-chemical characteristics, metal uptake varied depending on the environment of origin of the mosses “i.e. atmospheric or aquatic”. In other words, the findings suggest that species that accumulate more metals in terrestrial environments will accumulate lower amounts of metals in aquatic environments and vice versa.

Modulation of Functional Phosphorylation Sites by Basic Residues in the Unique Domain of c-Src.

In contrast to the well-studied canonical regulatory mechanisms, the way by which the recently discovered Src N-terminal regulatory element (SNRE) modulates Src activity is not yet well understood. Phosphorylation of serine and threonine residues modulates the charge distribution along the disordered region of the SNRE and may affect a fuzzy complex with the SH3 domain that is believed to act as an information transduction element. The pre-existing positively charged sites can interact with the newly introduced phosphate groups by modulating their acidity, introducing local conformational restrictions, or by coupling various phosphosites into a functional unit. In this paper, we use pH-dependent NMR measurements combined with single point mutations to identify the interactions of basic residues with physiologically important phosphorylated residues and to characterize the effect of these interactions in neighbor residues, thus providing insight into the electrostatic network in the isolated disordered regions and in the entire SNRE. From a methodological point of view, the linear relationships observed between the mutation-induced pKa changes of the phosphate groups of phosphoserine and phosphothreonine and the pH-induced chemical shifts of the NH groups of these residues provide a very convenient alternative to identify interacting phosphate groups without the need to introduce point mutations on specific basic residues.

Engineering iron carbide catalyst with aerophilic and electron-rich surface for improved electrochemical CO2 reduction

Highly efficient electrocatalyst for carbon dioxide reduction (CO2RR) is desirable for converting CO2 into carbon-based chemicals and reducing anthropogenic carbon emission. Regulating catalyst surface to improve the affinity for CO2 and the capability of CO2 activation is the key to high-efficiency CO2RR. In this work, we develop an iron carbide catalyst encapsulated in nitrogenated carbon (SeN-Fe3C) with an aerophilic and electron-rich surface by inducing preferential formation of pyridinic-N species and engineering more negatively charged Fe sites. The SeN-Fe3C exhibits an excellent CO selectivity with a CO Faradaic efficiency (FE) of 92 % at −0.5 V (vs. RHE) and remarkably enhanced CO partial current density as compared to the N-Fe3C catalyst. Our results demonstrate that Se doping reduces the Fe3C particle size and improves the dispersion of Fe3C on nitrogenated carbon. More importantly, the preferential formation of pyridinic-N species induced by Se doping endows the SeN-Fe3C with an aerophilic surface and improves the affinity of the SeN-Fe3C for CO2. Density functional theory (DFT) calculations reveal that the electron-rich surface, which is caused by pyridinic N species and much more negatively charged Fe sites, leads to a high degree of polarization and activation of CO2 molecule, thus conferring a remarkably improved CO2RR activity on the SeN-Fe3C catalyst.

Co-adsorption characteristics of antibiotics with different functional groups and cadmium combined contamination on activated carbon

Due to the diversity of functional groups of antibiotics, antibiotics are easy to complex with metals, thereby changing their migration and transformation behavior. The adsorption/complexation mechanism of three antibiotics co-adsorbed with Cd(Ⅱ) and systematic comparison were studied using Raman, FTIR, XPS and Materials Studio (norfloxacin (NOR), sulfamethazine (SMT) and tetracycline (TC)). We concluded that two NORs complexed with Cd(Ⅱ) through oxygen atoms from carboxylic acid and carbonyl in ketone group to form a six-membered ring chelate. The Cd(II)(NOR±)2+ showed a stronger adsorption coefficient than other forms of NOR, Cd(II)(NOR±)2+, NOR and Cd(Ⅱ) would compete the same permanent charge sites, thus exhibiting an inhibitory effect on NOR adsorption. Contrarily, one SMT molecule complexed with Cd(Ⅱ) through the N atom on pyrimidine ring and the -NH attached to the pyrimidine ring, forming an AC-Cd(Ⅱ)-SMT ternary complex on activated carbon (AC), and Cd(Ⅱ) acted as bridge. The bridging effect of Cd(Ⅱ) and multi-layer adsorption of SMT provided more adsorption sites for SMT, thus promoting the SMT adsorption. There was no complexation between TC and Cd(Ⅱ), and the addition of Cd(Ⅱ) had no significant effect on TC adsorption. The adsorption capacity of AC-Cd(Ⅱ)-SMT complex (107.4 mg·g−1) was stronger than NOR-Cd(Ⅱ) complex (40.2 mg·g−1), and the adsorption capacity of antibiotics was SMT>TC>NOR in all systems. The correlation analysis and molecular orbital calculation further supported the strong effect of complexation between Cd(Ⅱ) and antibiotics with different function groups on the adsorption, and the environmental behavior of system was jointly determined by complex structure and adsorption mechanism.

Optimal site selection of electric vehicle charging stations exploiting multi-criteria decision analysis: The case of Greek municipalities

The opportunities created in the Greek electric vehicle (EV) market have allowed potential investors to participate in the development of the EV charging infrastructure of the country. Yet, the decision process of relevant stakeholders for strategic investments is challenging, involving the identification of the most promising charging sites from a set of multiple alternative locations of various features that may significantly affect their business competitive advantage. This paper attempts to facilitate decision making in such settings using a comprehensive, yet thorough multi-criteria decision analysis framework. The proposed approach is validated considering ten Greek municipalities of different characteristics. The results show- case the overall strengths of the proposed approach and its utility in the strategic planning process of potential investors.

Charge site manipulation to enhance top-down fragmentation efficiency.

In recent years, top-down mass spectrometry has become a widely used approach to study proteoforms; however, improving sequence coverage remains an important goal. Here, two different proteins, α-synuclein and bovine carbonic anhydrase, were subjected to top-down collision-induced dissociation (CID) after electrospray ionisation. Two high-boiling solvents, DMSO and propylene carbonate, were added to the protein solution in low concentration (2%) and the effects on the top-down fragmentation patterns of the proteins were systematically investigated. Each sample was measured in triplicate, which revealed highly reproducible differences in the top-down CID fragmentation patterns in the presence of a solution additive, even if the same precursor charge state was isolated in the quadrupole of the instrument. Further investigation supports the solution condition-dependent selective formation of different protonation site isomers as the underlying cause of these differences. Higher sequence coverage was often observed in the presence of additives, and the benefits of this approach became even more evident when datasets from different solution conditions were combined, as increases up to 35% in cleavage coverage were obtained. Overall, this approach therefore represents a promising opportunity to increase top-down fragmentation efficiency.

Dual-Functional Super-Assembled Mesoporous Carbon-Titania/AAO Hetero-Channels for Bidirectionally Photo-Regulated Ion Transport.

Photo-regulated nanofluidic devices have attracted great attention in recent years due to their adjustable ion transport in real time. However, most of the photo-responsive nanofluidic devices can only adjust the ionic current unidirectionally, and cannot simultaneously increase or decrease the current signal intelligently by one device. Herein, a mesoporous carbon-titania/ anodized aluminum hetero-channels (MCT/AAO) is constructed by super-assembly strategy, which exhibits dual-function of cation selectivity and photo response. The polymer and TiO2 nanocrystals jointly build the MCT framework. Polymer framework with abundant negatively charged sites endows MCT/AAO with excellent cation selectivity, and TiO2 nanocrystals are responsible for the photo-regulated ion transport. High photo current densities of 1.8mAm-2 (increase) and 1.2mAm-2 (decrease) are realized by MCT/AAO benefiting from the ordered hetero-channels. Significantly, MCT/AAO can also achieve the bidirectionally adjustable osmotic energy by alternating the configurations of concentration gradient. Theoretical and experimental results reveal that the superior photo-generated potential is responsible for the bidirectionally adjustable ion transport. Consequently, MCT/AAO performs the function of harvesting ionic energy from the equilibrium electrolyte solution, which greatly expands its practical application field. This work provides a new strategy in constructing dual-functional hetero-channels toward bidirectionally photo-regulated ionic transport and energy harvesting.

Fabrication of N-doping activated carbons from fish waste and sawdust for Acid Yellow 36 dye removal from an aquatic environment

Acid Yellow 36 (AY36) dye is a synthetic azo dye that is excessively used in various industries, causing hazardous environmental effects. The main target of this study is the preparation of self-N-doped porous activated carbon (NDAC) and the investigation in eliminating the AY36 dye from the water solution. The NDAC was prepared by mixing fish waste (60% protein content) which was considered a self-nitrogen dopant. A combination of Fish waste, sawdust, zinc chloride and urea with a mass ratio (5:5:5:1) was submitted to hydrothermal process at 180 °C for 5 h followed by pyrolysis for 1 h under N2 stream at 600, 700, and 800 °C. Fabricated NDAC was qualified as an adsorbent for recovering AY36 dye from water using batch trials. The fabricated NDAC samples were characterized by FTIR, TGA, DTA, BET, BJH, MP, t-plot, SEM, EDX, and XRD methods. The results showed the successful formation of NDAC with nitrogen mass percentage content (4.21, 8.13 and 9.85%). The NDAC prepared at 800 °C had the largest nitrogen content (9.85%) and was labeled as NDAC800. This later had 727.34 m2/g, 167.11 cm3/g, and 1.97 nm for specific surface area, the monolayer volume and the mean pores diameter respectively. By being the more efficient adsorbent, NDAC800 was chosen to test AY36 dye removal. Therefore, it is selected to investigate the removal of AY36 dye from aqueous solution by varying important parameters such as solution pH, initial dye concentration, adsorbent dosage and contact time. The removal of AY36 dye by NDAC800 was pH-dependent, with the optimum pH value 1.5 giving 85.86% removal efficiency and 232.56 mg/g maximum adsorption capacity (Qm). The kinetic data exhibited the best fit model with the pseudo-second-order (PSOM), while the equilibrium data fit well with the Langmuir (LIM) and Temkin (TIM). The mechanism of AY36 dye adsorption may be ascribed to the electrostatic contact between the dye and the available charged sites on NDAC800 surface. The prepared NDAC800 may be considered as an efficient, available, and eco-friendly adsorbent for AY36 dye adsorption from simulated water.

Enhancing methyl orange adsorption capacity via functionalizing ZIF-8 with amphiphilic cetylpyridinium bromide

BackgroundThe precise design or functionalization of metal organic frameworks (MOFs) based on the properties of organic dyes is a promising direction in environment remediation. MethodsHerein, using methyl orange (MO) as the target dye, cetylpyridinium bromide (CPB) functionalized ZIF-8 (CPB@ZIF-8) was fabricated by the post-synthetic modification strategy. Significant findingsThe surface area and the pore volume of CPB@ZIF-8 are greatly reduced compared with pure ZIF-8. However, the introduction of amphiphilic CPB molecules into ZIF-8 can significantly enhance the adsorption performance of MO. This enhanced MO adsorption capacity can be attributed to the incorporation of more positively charged sites, hydrophobic sites and aromatic rings in the CPB-modified ZIF-8 frameworks, which provides the electrostatic attractions, the hydrophobic and π-π interactions that mainly govern the adsorption of MO on CPB@ZIF-8. The pseudo-second-order kinetic model and the Langmuir isotherm model can well represent the adsorption process of MO. The maximum adsorption capacity (195.54 mg/g) has been obtained at 30 °C, outperforming pristine ZIF-8 and various reported absorbents. The prepared CPB@ZIF-8 composite is a superior example of the tunable adsorption affinity of MOFs for anionic dyes.

Directional Ionic Bonds.

Covalent and ionic bonds represent two fundamental forms of bonding between atoms. In contrast to bonds with significant covalent character, ionic bonds are of limited use for the spatial structuring of matter because of the lack of directionality of the electric field around simple ions. We describe a predictable directional orientation of ionic bonds that contain concave nonpolar shields around the charged sites. Such directional ionic bonds offer an alternative to hydrogen bonds and other directional noncovalent interactions for the structuring of organic molecules and materials.

Preparation and Characterization of Silver Nanoparticles by Pulsed Laser Ablation and Investigation of their Effect on Bacteria

Synthesis of silver nanoparticles (AgNP) by pulsed liquid laser ablation (PLAL) produces AgNPs that are better suited for biological applications compared to those prepared by standard wet-chemical methods. These were mainly achieved by water ablation with pulse widths in the nanosecond range. In the case of surface NP activation, we previously detected a strong surface-enhanced Raman scattering (SERS) signal from such AgNPs. To do this, we dilute Colloid slightly with LiCl. These surface alterations may have an effect on the NPs' capability to combat bacteria. every time, AgNPs with a median diameter of under ten nm were created., that has been incontestible in alternative studies to be the optimum size for germicidal activity.. Furthermore, minimum restrictive concentration (MIC) values for LiCl-modified AgNPs fell inside a slender vary of 1.1-3.8 g/mL, creating them the foremost efficient. This result's believed to be explained by the metal surface's enhanced surface reactivity, which is brought on by the existence of charged active sites.

Tetraphenylethylene fluorophore based AIE-fluorescent probe for detection of ATP in mitochondria

A tetraphenylethylene fluorophore based on D-π-A structure was employed to design and synthesize the TPE-Py-FP probe for selective detection of ATP. TPE-Py-FP had the advantages of large Stokes shift, great hydrophilicity and good selectivity. Especially, the pyridine portion and quaternary ammonium structure of TPE-Py-FP had positively charged sites, which could be used as recognition groups to interact with the negatively charged triphosphate structure of ATP. Then the fluorescence emission of TPE-Py-FP at 580 nm showed a “turn-on” response after adding ATP. Moreover, this probe could rapidly respond to ATP over a wide linear range of 10–120 μM and the limit of detection (LOD) was 2.76 μM. The zeta potential and dynamic light scattering experiments revealed that the detection mechanism was mainly the electrostatic adsorption interaction between the dual positively charged sites of TPE-Py-FP and the negatively charged triphosphate structure of ATP. Additionally, TPE-Py-FP could localize in mitochondria specifically with a Pearson's coefficient of 0.81, and show great utility in monitoring the fluctuation of mitochondrial ATP level.

Radial growth of polymeric Fe/S rods for improving removal of Cu/Zn from real electroplating wastewater

A mass production of one-dimensional polymeric Fe/S rod with 200 nm diameter and 300 nm length was developed under atmosphere conditions with FeCl3 and Na2S/NaOH. When such Na was partly/fully replaced by K, the polymeric Fe/S rod grow radially alongside the lattice planes of 020 and 221 from 300 nm to 1 µm and/or 5–10 µm, respectively, to form a long rod. In the long rod, such Na/K occupied the charged sites of Fe/S structure and can be replaced by each other in an alkaline solution with the retention of log-rod shape. The long rods showed superior efficiencies of Zn/Cu removal (nearly 100 %) from real electroplating wastewater, compared with short rods and other reagents, e.g., diethyldithiocarbamate and polymeric ferric sulfate. The processing method allows not only the development of a clean production to recycle the K and that used alkaline supernatant for preparing long rods without any secondary waste, but also posed the application prospect of long rods in wastewater treatment.

Computational characteristics of the structure-activity relationship of inhibitors targeting Pks13-TE domain

Multiple studies have established the Pks13-TE domain as a promising target for anti-tuberculosis drug development. However, recent findings have revealed that the lead compound currently in the pipeline for Pks13-TE has significant cardiotoxicity issues. Given the pressing need for new chemical structures for Pks13-TE inhibitors, this study aims to provide a detailed understanding of the Pks13-TE domain binding site through the application of computational chemical biology techniques. Our results highlight the size and shape of the Pks13-TE domain binding pocket, key residues including Asp1644, Asn1640, Phe1670, and Tyr1674 within the pocket, and inhibitor pharmacophore characteristics such as aromatic ring sites, positively charged sites, and hydrogen bond donors. To our knowledge, these simulation results are novel and contribute to the discovery of next-generation Pks13-TE inhibitors without similar prior studies.

A High‐Valent Ru−PCP Pincer Catalyst for the Hydrogenation of Organic Carbonates

AbstractIn this communication, we report on the successful application of a high‐valent RuIV bifunctional catalyst (1) for mild hydrogenation of cyclic and acyclic carbonates. Our experimental and theoretical studies suggest that the hydrogenation mechanism is operated by an unusual formally zwitterionic RuIV complex. According to our hypothesis, the positively charged high‐valent metal center is responsible for stronger hydrogen coordination. On the other hand, the proximate negatively charged ligand site facilitates heterolytic H2 bond activation, which leads to efficient catalysis.

Metal Oxide Particles as Atmospheric Nuclei: Exploring the Role of Metal Speciation in Heterogeneous Efflorescence and Ice Nucleation

Mineral dust can indirectly impact climate by nucleation of atmospheric solids, for example, by heterogeneously nucleating ice in mixed-phase clouds or by impacting the phase of aerosols and clouds through contact nucleation. The effectiveness toward nucleation of individual components of mineral dust requires further study. Here, the nucleation behavior of metal oxide nanoparticle components of atmospheric mineral dust is investigated. A long-working-distance optical trap is used to study contact and immersion nucleation of ammonium sulfate by transition-metal oxides, and an environmental chamber is used to probe depositional ice nucleation on metal oxide particles. Previous theory dictates that ice nucleation and heterogeneous nucleation of atmospheric salts can be impacted by several factors including morphology, lattice match, and surface area. Here, we observe a correlation between the cationic oxidation states of the metal oxide heterogeneous nuclei and their effectiveness in causing nucleation in both contact efflorescence mode and depositional freezing mode. In contrast to the activity of contact efflorescence, the same metal oxide particles did not cause a significant increase in efflorescence relative humidity when immersed in the droplet. These experiments suggest that metal speciation, possibly as a result of cationic charge sites, may play a role in the effectiveness of nucleation that is initiated at particle surfaces.

Diserinol Isophthalamide: A Novel Reagent for Complexation with Biomolecular Anions in Electrospray Ionization Mass Spectrometry

Transferring biomolecules from solution to vacuum facilitates a detailed analysis of molecular structure and dynamics by isolating molecules of interest from a complex environment. However, inherent in the ion desolvation process is the loss of solvent hydrogen bonding partners, which are critical for the stability of a condensed-phase structure. Thus, transfer of ions to vacuum can favor structural rearrangement, especially near solvent-accessible charge sites, which tend to adopt intramolecular hydrogen bonding motifs in the absence of solvent. Complexation of monoalkylammonium moieties (e.g., lysine side chains) with crown ethers such as 18-crown-6 can disfavor structural rearrangement of protonated sites, but no equivalent ligand has been investigated for deprotonated groups. Herein we describe diserinol isophthalamide (DIP), a novel reagent for the gas-phase complexation of anionic moieties within biomolecules. Complexation is observed to the C-terminus or side chains of the small model peptides GD, GE, GG, DF-OMe, VYV, YGGFL, and EYMPME in electrospray ionization mass spectrometry (ESI-MS) studies. In addition, complexation is observed with the phosphate and carboxylate moieities of phosphoserine and phosphotyrosine. DIP performs favorably in comparison to an existing anion recognition reagent, 1,1'-(1,2-phenylene)bis(3-phenylurea), that exhibits moderate carboxylate binding in organic solvent. This improved performance in ESI-MS experiments is attributed to reduced steric constraints to complexation with carboxylate groups of larger molecules. Overall, diserinol isophthalamide is an effective complexation reagent that can be applied in future work to study retention of solution-phase structure, investigate intrinsic molecular properties, and examine solvation effects.