Anionic Molecules Research Articles

Solvation Structure of Li+ in Concentrated Acetonitrile and N,N-Dimethylformamide Solutions Studied by Neutron Diffraction with 6Li/7Li Isotopic Substitution Methods.

Neutron diffraction measurements on 6Li/7Li isotopically substituted 10 and 33 mol % *LiTFSA (lithium bis(trifluoromethylsulfonyl)amide)-AN-d3 (acetonitrile-d3) and 10 and 33 mol % *LiTFSA-DMF-d7(N,N-dimethylformamide-d7) solutions have been carried out in order to obtain structural insights on the first solvation shell of Li+ in highly concentrated organic solutions. Structural parameters concerning the local structure around Li+ have been determined from the least squares fitting analysis of the first-order difference function derived from the difference between carefully normalized scattering cross sections observed for 6Li-enriched and natural abundance solutions. In 10 mol % LiTFSA-AN-d3 solution, 3.25 ± 0.04 AN molecules are coordinated to Li+ with a intermolecular Li+···N(AN) distance of 2.051 ± 0.007 Å. It has been revealed that 1.67 ± 0.07 AN molecules and 2.00 ± 0.01 TFSA- are involved in the first solvation shell of Li+ in the 33 mol % LiTFSA-AN solution. The nearest neighbor Li+···NAN and Li+···OTFSA- distances are obtained to be r(Li+···N) = 2.09 ± 0.01 Å and r(Li+···O) = 1.88 ± 0.01 Å, respectively. The first solvation shell of Li+ in the 10 mol % LiTFSA-DMF-d7 solutions contains 3.4 ± 0.1 DMF molecules with an intermolecular Li+···ODMF distance of 1.95 ± 0.02 Å. In highly concentrated 33 mol % LiTFSA-DMF-d7 solutions, there are 1.3 ± 0.2 DMF molecules and 3.2 ± 0.2 TFSA- in the first solvation shell of Li+ with intermolecular distances of r(Li+···ODMF) = 1.90 ± 0.02 Å and r(Li+···OTFSA-) = 2.01 ± 0.01 Å, respectively. The Li+···TFSA- contact ion pair stably exists in highly concentrated 33 mol % LiTFSA-AN and -DMF solutions.

Facile preparation of hierarchical porous 2MgO · B2O3 · 2H2O nanostructure with ultra-high adsorption performance for triphenylmethane dyes removal

The fan-like 2MgO · B2O3 · 2H2O porous nanostructures were prepared by a solvothermal approach. FT-IR, XRD, TG-DTA, SEM, and TEM were used to characterize the obtained sample, which was constructed by nanobelts with 20 nm in width, about 5 nm in thickness and 2 μm in length. Its specific surface area was measured as 118.94 m2/g. It exhibited ultra-high removal of triphenylmethane dyes for AF, MG and BF from aqueous solution, in which the maximum adsorption capacities are much higher than those of most reported adsorbents. The higher absorption for triphenylmethane dyes can be attributed to the positive surface charge, the main existing mesopores and macropores, and larger specific surface area of the prepared 2MgO · B2O3 · 2H2O sample, which make the absorbent and anionic dye molecules existing both the stronger electrostatic attraction and hydrogen bonds of N–H· · · O and O–H· · · N. The adsorption kinetics and isotherm were found to conform to pseudo-second-order model and Langmuir model. The competitive adsorption for BF and MG and the adsorption mechanism were also investigated. The as-prepared sample is of larger adsorption capacity and good reusability, which makes it valuable in potential wastewater treatment application.

Hopping in High Concentration Electrolytes - Long Time Bulk and Single-Particle Signatures, Free Energy Barriers, and Structural Insights.

Although ion-hopping is believed to be a significant mode of transport for small ions in liquid high concentration electrolytes (HCE), its bulk signatures over sufficiently long time intervals are yet to be shown. We computationally establish the long and short time imprints of hopping in HCEs using LiBF4-in-sulfolane mixtures as models. The high viscosity of this electrolyte leads to significant dynamic heterogeneity in Li-ion transport. Li-ions exhibit a preference to transit to previously occupied Li-ion-sites, bridged through anion or solvent molecules. Hopping in the liquid matrix was found to be an activated process, whose free energy barrier and transition state structure have been determined. Evidence for nanoscale compositional heterogeneity at high salt concentrations is also presented. The simulations shed light on the composition, stiffness, and lifetime of the solvation shell of Li ions. The understanding of HCEs gleaned from this study will spearhead the choice, engineering and applicability of this class of electrolytes.

Bojarite, Cu3(N3C2H2)3(OH)Cl2⋅6H2O, a new mineral species with a microporous metal–organic framework from the guano deposit at Pabellón de Pica, Iquique Province, Chile

AbstractThe new triazolate mineral bojarite (IMA2020-037), Cu3(N3C2H2)3(OH)Cl2⋅6H2O, is found in a guano deposit located at the Pabellón de Pica Mountain, Iquique Province, Tarapacá Region, Chile. Associated minerals are salammoniac, halite, nitratine and belloite. Bojarite occurs as blue fine-grained porous aggregates up to 1 mm × 3 mm × 5 mm combined typically in interrupted earthy crusts. The mineral is brittle. The Mohs hardness is 2.Dcalc= 2.057 g cm–3. The IR and Raman spectra show the presence of the 1,2,4-triazolate anion and H2O molecules. Bojarite is optically isotropic andn= 1.635(2) (λ = 589 nm). The chemical composition (electron-microprobe data for Na, Mg, Fe, Cu and Cl; H, C and N contents measured by gas chromatography on products of ignition at 1200°C; wt.%) is: Na 0.22, Mg 0.74, Fe 0.99, Cu 29.73, Cl 13.62, N 20.4, C 11.6, H 3.3, O (calculated by stoichiometry) 19.93, total 100.53.The empirical formula is (Cu2.68Mg0.17Fe0.10Na0.05)Σ3(N3C2H2)2.755[(OH)][Cl2.19(H2O)3.77(OH)0.04]Σ6⋅2.3H2O. The idealised formula is Cu3(N3C2H2)3(OH)Cl2⋅6H2O. The crystal structure of bojarite was refined based on powder X-ray diffraction data, using the Rietveld method. The final agreement factors are:Rp= 0.0225,Rwp= 0.0310 andRobs= 0.0417. The new mineral is cubic, space groupFd$\bar{3}$c;a= 24.8047(5) Å,V= 15,261.6(5) Å3andZ= 32. The strongest reflections of the powder X-ray diffraction pattern [d, Å (I,%)(hkl)] are: 8.83 (31)(220), 7.19 (100)(222), 6.23 (35)(400), 5.077 (28)(422), 4.194 (28)(531), 3.584 (23)(444), 2.865 (28)(660, 751) and 2.723 (22)(753, 842).

Reversibly Switchable Fluorescent Molecular Systems Based on Metallacarborane-Perylenediimide Conjugates.

Icosahedral metallacarboranes are θ-shaped anionic molecules in which two icosahedra share one vertex that is a metal center. The most remarkable of these compounds is the anionic cobalt-based metallacarborane [Co(C2 B9 H11 )2 ]- , whose oxidation-reduction processes occur via an outer sphere electron process. This, along with its low density negative charge, makes [Co(C2 B9 H11 )2 ]- very appealing to participate in electron-transfer processes. In this work, [Co(C2 B9 H11 )2 ]- is tethered to a perylenediimide dye to produce the first examples of switchable luminescent molecules and materials based on metallacarboranes. In particular, the electronic communication of [Co(C2 B9 H11 )2 ]- with the appended chromophore unit in these compounds can be regulated upon application of redox stimuli, which allows the reversible modulation of the emitted fluorescence. As such, they behave as electrochemically-controlled fluorescent molecular switches in solution, which surpass the performance of previous systems based on conjugates of perylendiimides with ferrocene. Remarkably, they can form gels by treatment with appropriate mixtures of organic solvents, which result from the self-assembly of the cobaltabisdicarbollide-perylendiimide conjugates into 1D nanostructures. The interplay between dye π-stacking and metallacarborane electronic and steric interactions ultimately governs the supramolecular arrangement in these materials, which for one of the compounds prepared allows preserving the luminescent behavior in the gel state.

Stability evolution of ultrafine Ag nanoparticles prepared by laser ablation in liquids

Understanding the stability evolution of the silver nanoparticles (Ag NPs) in colloid has great benefits for its controllable preparation, storage and application. Herein, uncapped Ag NPs with diameter of 1.66 ± 0.37 nm are obtained by laser ablation of Ag target in deionized water, corresponding surface plasma resonance (SPR) bands, ζ potential and particle size distribution are monitored to investigate uncapped Ag NPs’ stability evolution. Due to negatively charged surface, uncapped Ag NPs show an excellent dispersion stability in 70 days without any external disturbance. But its dispersion stability and structure stability are destroyed easily by an oscillation treatment, resulting in a tardy growth and the formation of one-dimensional Ag nanochain. In addition, the chemical stability of uncapped Ag NPs is dramatically varied by a displacement reaction with an inserted copper wire. As comparison, two typical cationic and anionic surfactant molecules, N-hexadecyl trimethyl ammonium chloride (CTAC) and sodium dodecyl benzene sulfonate (SDBS) are severally used to prepare surface capped Ag NPs. With same treatment of Ag colloid, both two kinds of capped Ag NPs display better dispersion stability and structure stability than uncapped Ag NPs. Moreover, CTAC capped Ag NPs keep a better chemical stability than SDBS capped Ag NPs.

A cationic cyclodextrin assisted aggregation of an anionic pyrene derivative and its stimuli responsive behavior

Stimuli-responsive supramolecular host assisted guest aggregation has attracted tremendous attention, of late, because of its various technological applications. However, a large majority of them involve anionic supramolecular hosts such as p-sulfonato calixarenes, sulfated cyclodextrin and so on, in combination with cationic guests. On the other hand, the phenomenon of host-assisted aggregation of anionic guests with cationic supramolecular hosts, which can significantly broaden the scope of this exciting field, has rarely been reported in the literature. In the present work, we report, host assisted aggregation of an anionic organic probe molecule, pyrene tetrasulfonate (PTS), in the presence of a cationic cyclodextrin derivative, amino-β-CD (AβCD), which has been studied, in detail, using various spectroscopic techniques including UV–Vis spectroscopy, fluorescence spectroscopy, time-resolved spectroscopy, and molecular docking calculations. The effect of ionic strength of the medium on the photophysical properties of PTS-AβCD complex indicates that electrostatic interaction is the predominant force in assisting the formation of PTS-AβCD complex. The monomer-aggregate equilibrium of PTS in the present system is also found to be extremely sensitive towards external stimuli like temperature, and pH of the medium. Finally, the PTS-AβCD assembly has been used for sensing an important charged bio-analyte, adenosine triphosphate (ATP), demonstrating the applicability of the present host-guest system.

Iron-based ionic liquid ([BMIM][FeCl4]) as a promoter of CO2 hydrate nucleation and growth

Hydrate technology is a promising alternative method for carbon dioxide (CO2) capture and storage from flue gas. In order to promote the hydrate growth rate and increase gas storage capacity, CO2 hydrate nucleation and growth induced by iron-based ionic liquid ([BMIM][FeCl4]) was studied with 400 rpm rotation speed at a temperature of 274.15 K and initial pressure of 5.0 MPa in this work. The induction time of CO2 hydrate formation was decreased by 52.8% and the storage capacity of CO2 hydrate was increased by 13.7% in 25.0 g/L [BMIM][FeCl4] solution. The local hydrogen bonds are strengthened by the combination interaction between the complex anion ([FeCl4]−) and water (H2O) molecules, which is favorable to the ordered arrangement and the proton exchange rate of H2O molecules during the hydrate nucleation. Besides, large mass transfer channels are formed by the large molar volume and regular tetrahedral structure of [FeCl4]− during the hydrate growth, which improves the diffusion rate of CO2 and H2O molecules in the solution to promote the hydrate growth. Distribution of lipophilic cation and hydrophilic anion with a large molecular volume of [BMIM][FeCl4] at the gas-liquid interface hinders the formation of cage structure of H2O molecules.

Molecular modelling as a downstream effort in the discovery of novel anionic sulphate surfactants

Sulphate anionic surfactant is a type of surfactant that is widely used as a cleaning agent. The discovery and development of anionic sulphate surfactant molecule is necessary because it has a huge impact, both in science and economics. Molecular modelling to produce new anionic sulphate surfactant molecules has been carried out. The mathematical equation of the Quantitative Structure-Property Relationship (QSPR) based on Ab Initio has been obtained. Molecules that were candidates for structural modelling and modification were those that have the smallest critical micelle concentration (CMC). The smallest experimental data was C16H33SO4Na with a CMC value = 0.000579 M. The result of this study was CnH3sSO4Na molecules with a theoretical CMC value of 0.000515 M.

Portably parallel construction of a configuration-interaction wave function from a matrix-product state using the Charm++ framework.

The construction of configuration-interaction (CI) expansions from a matrix product state (MPS) involves numerous matrix operations and the skillful sampling of important configurations in a large Hilbert space. In this work, we present an efficient procedure for constructing CI expansions from MPS employing the parallel object-oriented Charm++ programming framework, upon which automatic load-balancing and object migrating facilities can be employed. This procedure was employed in the MPS-to-CI utility (Moritz et al., J. Chem. Phys. 2007, 126, 224109), the sampling-reconstructed complete active-space algorithm (SR-CAS, Boguslawski et al., J. Chem. Phys. 2011, 134, 224101), and the entanglement-driven genetic algorithm (EDGA, Luo et al., J. Chem. Theory Comput. 2017, 13, 4699). It enhances productivity and allows the sampling programs to evolve to their population-expansion versions, for example, EDGA with population expansion (PE-EDGA). Further, examples of 1,2-dioxetanone and firefly dioxetanone anion (FDO- ) molecules demonstrated the following: (a) parallel efficiencies can be persistently improved by simply by increasing the proportions of the asynchronous executions and (b) a sampled CAS-type CI wave function of a bi-radical-state FDO- molecule utilizing the full valence (30e,26o) active space can be constructed within a few hours with using thousands of cores.

Structural Characterization of Glycerophosphorylated and Succinylated Cyclic β-(1→2)-d-Glucan Produced by Sinorhizobium mliloti 1021.

Rhizobia produces different types of surface polysaccharides. Among them, cyclic β-(1→2)-d-glucan is located in the periplasmic space of rhizobia and plays an important role in the adaptation of bacteria to osmotic adaptation. Cyclic β-(1→2)-d-glucan (CG), synthesized from Sinorhiozbbium meliloti 1021, has a neutral and anionic form. In the present study, we characterized the exact chemical structures of anionic CG after purification using size exclusion s (Bio-Gel P-6 and P-2) chromatography, and DEAE-Sephadex anion exchange chromatography. The exact structure of each isolated anionic CG was characterized using various analytical methods such as nuclear magnetic resonance (NMR), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and matrix associated laser desorption ionization-time of Flight (MALDI-TOF) mass spectrometry. The precise chemical structures of novel anionic CG molecules were elucidated by various NMR spectroscopic analyses, including 1H, 13C, 31P, and 2D HSQC NMR spectroscopy. As a result, we discovered that anionic CG molecules have either glycerophosphoryl or succinyl residues at C6 positions of a neutral CG. In addition, the results of MALDI-TOF mass spectrometric analysis confirmed that there are two types of patterns for anionic CG peaks, where one type of peak was the succinylated CG (SCG) and the other was glycerophospholated CG (GCG). In addition, it was revealed that each anionic CG has one to four substituents of the succinyl group of SCG and glycerophosphoryl group of GCG, respectively. Anionic CG could have potential as a cyclic polysaccharide for drug delivery systems and a chiral separator based on the complexation with basic target molecules.

ATP Kinetically Modulates Pathogenic Tau Fibrillations

Advanced understanding of Alzheimer's disease (AD) and several tauopathies over the past decades indicates the pathological importance of tau aggregation in these diseases. Herein, we demonstrated that adenosine triphosphate (ATP), a highly charged anionic molecule found abundantly in the cytosol of cells, catalyzes fibrillation of tau as well as human islet amyloid polypeptide, a representative of basic intrinsically disordered proteins. Our results showed that ATP attracts multiple lysine residues of the four-repeat domain of tau (K18) via supramolecular complexation, thereby forming dimers that are converted to nuclei and accelerate fibril elongation. However, ATP was not directly incorporated into the K18 fibrils, suggesting that ATP plays the role of a catalyst, rather than a reactant, during K18 fibrillation. We also characterized the correlation between ATP dyshomeostasis and tau aggregation in the cellular environment. Our multiple biophysical approaches, including native mass spectrometry (MS), small-angle X-ray scattering (SAXS), and molecular dynamics (MD) simulation, provided insights into the molecular-level influence of ATP on the structural changes and fibrillation of tau.

Synthesis and crystal structure of tri-ethyl-ammonium hexa-bromido-uranate(IV) di-chloro-methane monosolvate.

Tri-ethyl-ammonium hexa-bromido-uranate(IV) di-chloro-methane monosolvate, [(C2H5)3NH]2[UBr6]·CH2Cl2, was obtained in the form of dark-brown crystals from the reaction of uranium penta-bromide with NEt3 and ethyl-ene glycol in di-chloro-methane at low temperature. During the progress of the reaction, the reduction of uranium(V) to uranium(IV) was observed, whose associated oxidation product could not be identified. The uranium atom of the [UBr6]2- anion is coordinated by six bromido ligands in the shape of an octa-hedron. Between cations, anion and solvent mol-ecules of crystallization, numerous C-H⋯Hal hydrogen-bond-like inter-actions are present, leading to a three-dimensional network structure.

Xanthan gum as a carrier for bacterial cell entrapment: Developing a novel immobilised biocatalyst.

Xanthan gum (XAN) is a widely used polysaccharide in various industries. Because of its unique properties, in this study, an attempt was made to adopt the procedure of xanthan gum cross-linking for the entrapment of bacterial cells that are able to biodegrade naproxen. The developed procedure proved to be completely neutral for Bacillus thuringiensis B1(2015b) cells, which demonstrated a survival rate of 99%. A negative impact of entrapment was noted for strain Planococcus sp. S5, which showed a survival rate in the 93-51% range. To achieve good mechanical properties of the composites, they were additionally hardened using polydopamine (PDA). XAN/PDA composites revealed a high stability in a wide range of pH, and their sorption capacity included both cationic and anionic molecules. Analysis of the survival rate during storage at 4°C in 0.9% NaCl showed that, after 35days, 98-99% of B1(2015b) and 47% of S5 cells entrapped in XAN/PDA remained alive. This study also presents the results of naproxen biodegradation conducted using XAN/PDA/B1(2015b) in a trickling filter with autochthonous microflora. Hence, owing to the significant acceleration of drug biodegradation (1mg/L in 14days) and the chemical oxygen demand removal, the entrapped B1(2015b) cells in XAN/PDA composites showed a promising potential in bioremediation studies and industrial applications.

MDA-MB-231 Breast Cancer Cells Resistant to Pleurocidin-Family Lytic Peptides Are Chemosensitive and Exhibit Reduced Tumor-Forming Capacity.

Direct-acting anticancer (DAA) peptides are cytolytic peptides that show promise as novel anticancer agents. DAA peptides bind to anionic molecules that are abundant on cancer cells relative to normal healthy cells, which results in preferential killing of cancer cells. Due to the mechanism by which DAA peptides kill cancer cells, it was thought that resistance would be difficult to achieve. Here, we describe the generation and characterization of two MDA-MB-231 breast cancer cell-line variants with reduced susceptibility to pleurocidin-family and mastoparan DAA peptides. Peptide resistance correlated with deficiencies in peptide binding to cell-surface structures, suggesting that resistance was due to altered composition of the cell membrane. Peptide-resistant MDA-MB-231 cells were phenotypically distinct yet remained susceptible to chemotherapy. Surprisingly, neither of the peptide-resistant breast cancer cell lines was able to establish tumors in immune-deficient mice. Histological analysis and RNA sequencing suggested that tumorigenicity was impacted by alternations in angiogenesis and extracellular matrix composition in the peptide-resistant MDA-MB-231 variants. Collectively, these data further support the therapeutic potential of DAA peptides as adjunctive treatments for cancer.

Ion-induced free energy landscapes of Aβ33–42 peptide dimer in wet ionic liquids

The transitions between α-helix and β-sheet conformation of Aβ33–42 peptide dimer in water and an aqueous solution of three ionic liquids (ILs) at two concentrations are investigated using umbrella sampling-based classical molecular dynamics simulations. The ionic liquids chosen for this study are Ethylammonium Mesylate (EAM), Ethylammonium Nitrate (EAN), and Triethylammonium Mesylate (TEAM). The average psi angle of the peptide backbone was used as the reaction coordinate to explore the free energy pathway of the transition. The secondary structure element values were calculated for peptide dimer along the reaction coordinate to probe the conformational changes during the transition between α-helix and β-sheet conformations. We observe the α-helix conformation as the global minimum at low concentration of EAM and EAN ILs and β-sheet conformation as the global minimum at low concentration of TEAM as well as the high concentration of EAM, EAN, and TEAM ILs. The average numbers of intramolecular and intermolecular hydrogen bonds were calculated for the conformations corresponding to the free-energy minima; these numbers are in correlation with the secondary structure element values. The atom-atom radial distribution functions of cation, anion, and water around amide hydrogen and oxygen atoms of the peptide backbone were calculated to understand the peptide-IL interactions. The solvent-accessible surface area of the peptide was calculated to understand the exposure to the solvent during the transition. Finally, to understand the stability of conformations on the free-energy landscape, we calculated van der Waals and Coulomb interaction energies between peptide-cation, peptide anion, and peptide-water molecules. We find that the TEA cation in TEAM contributes more towards the vdWs and less towards Coulomb interactions with the peptide as compared to EA cation in EAM and EAN ILs, which results in destabilization of α-helix conformation in TEAM ILs.

X‐Ray Total Scattering of Electrolytes in Liquid‐Based Fluoride Shuttle Battery: Electrolyte Composition Dependence of the Low‐Q Peak

X‐ray total scattering is applied to a series of molecular liquids including the CsF salt, which is expected to be a promising electrolyte in fluoride shuttle batteries. These electrolytes are composed of solvent molecules and addition agents (AAs), together with CsF. Tetraglyme (G4) or γ‐butyrolactone (GBL) is used as a solvent molecule, and lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), triphenylboroxine (TPhBX), or lithium bis(oxaloto)borate (LiBOB) as an AA. It is found that an additional peak appears on the low‐Q side of the main peak by the addition of LiFSI, LiTFSI, or TPhBX to the solvent, which indicates that correlation between cation and anion molecules is induced by these AAs. Furthermore, the position and the intensity of this peak are changed by the addition of the CsF salt, suggesting the modification of the correlation in the presence of the Cs+ and F− ions.

Effect of PAMAM Dendrimers on Interactions and Transport of LiTFSI and NaTFSI in Propylene Carbonate-Based Electrolytes.

Poly(amidoamine) (PAMAM)-based electrolytes are prepared by dissolving the PAMAM half-generations G1.5 or G2.5 in propylene carbonate (PC), either with lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) or sodium bis(trifluoromethylsulfonyl)imide (NaTFSI) salts. The solutions, designed for ion battery applications, are studied in terms of ions transport properties. Raman Spectroscopy reveals information about the interactions between cations and PAMAM dendrimers as well as full dissociation of the salts in all solutions. Pulsed-field gradient Nuclear Magnetic Resonance (PFG NMR), measured as a function of both temperature and PAMAM concentration, are obtained for the cation, anion, solvent, and dendrimer molecules using lithium (7Li), sodium (23Na), fluorine (19F), and hydrogen (1H) NMR, respectively. It was found that lithium diffusion is slow compared to the larger TFSI anion and decreases with PAMAM concentration due to interactions between cation and dendrimer. Comparison of conductivities calculated from diffusion coefficients using the Nernst–Einstein equation, with conductivity measurements obtained from Impedance Spectroscopy (IS), shows slightly higher IS conductivities, caused among others by PAMAM conductivity.

Influence of W6+ cations on the photocatalytic activity of Zn2+Al3+W6+ layered double hydroxides in the degradation of diclofenac

The photocatalytic activity of ZnAl and ZnAlW-x layered double hydroxides (where x = 1.5, 3.0 and 5.0 mol% of W6+ cations) prepared by the coprecipitation method was studied in the photo-degradation of diclofenac (DCF) in aqueous medium using UV light irradiation. The incorporation of W6+ cations within the ZnAl LDH brucite-type layer structure promotes the elimination of CO23– anions and H2O molecules from since the interlayer space as well as the decrease in the band gap energy and the retarding in the recombination rate of electron-hole pairs, giving rise to the improvement in the photocatalytic activity in the degradation of DCF in aqueous medium. Such improvement in the photocatalytic activity could be favored by the increase in the positive charge of the ZnAl LDH sheets due to the incorporation of W6+ cations, arising an increase in the attractive potential for the uptake of anionic diclofenac molecules within the inter-lamellar spacing to compensate the excess of positive charge. ZnAl LDH photoconverts 29.0% of DCF after 90 min of photoreaction. However, the photoconversion percentage of DCF increases with the molar concentration of W6+ to reach 68.0% in 40 min and 82.0% in 90 min of photoreaction respectively using either ZnAlW-1.5 or ZnAlW-3 LDHs. The kinetics studies confirmed that ZnAlW-1.5 and ZnAlW-3 LDHs are the photocatalysts with the highest activity for the elimination of DCF in aqueous medium. Total organic carbon analysis also confirmed the highest efficacy of ZnAlW-1.5 and ZnAlW-3 LDHs to mineralize diclofenac molecules in aqueous medium.

Highly efficient removal of cationic, anionic and neutral dyes by hierarchically porous structured three-dimensional magnetic sulfur/nitrogen co-doped reduced graphene oxide nanohybrid

The versatile three-dimensional magnetic sulfur/nitrogen co-doped reduced graphene oxide nanomaterials (3D-MSNGs) have been constructed and generated via interfacial coordination assembly of three-dimensional sulfur/nitrogen dual-doped reduced graphene oxide (3D-SNG) with concurrent modification by formed magnetic Fe3O4. Using ferric ions as iron source, the as-obtained nanohybrid 3D-MSNG-1 possesses abundant hierarchical porous structure on graphene network, large BET surface area and favorable magnetic properties, which is proved excellent adsorption capacity and easy magnetic separation. When 3D-MSNG-1 was utilized to absorb the dyes of methylene blue (MB), congo red (CR) and neutral red (NR) considered as cationic, anionic and neutral model dye molecules, respectively, the adsorption equilibrium for MB, CR and NR were rapidly achieved in 15 min. The adsorption isotherm fits Langmuir adsorption model well with the maximum uptake capacity for MB, CR and NR high to 171.53 mg/g, 909.09 mg/g and 877.19 mg/g, respectively. Meanwhile, an efficacious treatment of ternary dyes mixed solution and a good recyclability manifests that 3D-MSNG-1 is supposed to be a superior adsorbent in the areas of water treatment.