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The synthesis, transformation, and application in catalysis of triphenyllead hydroperoxide, the first dioxygen lead complex, are described. Triphenyllead hydroperoxide is characterized by

X-ray diffraction of three new stable cocrystals of potassium salts of organic hydroperoxides with molecular hydroperoxides reveals strong charge-assisted ROO−⋯HOOR H-bonds.

In this study, we examine the possibility of detecting PTFE microparticles by ICP-qMS equipped with O2 dynamic reaction cell (DRC) and operated in single-particle mode.

Hydrogen peroxide assisted sol–gel coating of core-shell microcapsules of phase change materials (PCMs) is reported. A doubly coated paraffin core with an inner poly(melamine-formaldehyde) shell and an outer coating of peroxostannate, peroxoantimonate, their mixture or the respective metal oxides are reported. Triple coating of the paraffin core with a poly(melamine-formaldehyde) inner shell, tin oxide middle layer and graphene oxide outer coating is also achieved by hydrogen peroxide sol–gel processing. The latent heats of the microencapsulated PCMs ranged between 122 and 192 J g−1. The sol–gel process involves stabilization of the peroxostannate or peroxoantimonate sol in basic aqueous hydrogen peroxide and subsequent destabilization and deposition of the sol by addition of an antisolvent. Transformation to the metal oxide coating is conducted by chemical reduction with sodium sulfite or by mild heat treatment without leakage of the paraffin core.

Microencapsulation of a carbon nanotube (CNT)-loaded paraffin phase change material, PCM in a poly(melamine-formaldehyde) shell, and the respective CNT-PCM gypsum composites is explored. Although a very low level (0.001-0.1 wt %) of intramicrocapsule loading of CNT dopant does not change the thermal conductivity of the solid, it increases the measured effusivity and thermal buffering performance during phase transition. The observed effusivity of 0.05 wt % CNT-doped PCM reaches 4000 W s

We introduce a green synthesis approach for high-performance sodium-ion battery anodes that does not involve hydrothermal treatment or excessive energy use. Wet chemistry involving ammonium peroxostannate intermediate coating of reduced graphene oxide can be done at low temperature without excessive use of solvents. The process is practically waste-free and does not involve acid waste. Thermal treatment is required only for the solid material. The electrode exhibited very high stability and the charging capacity was reduced from 320 to 310 mA h g–1 after 2000 cycles at 3 A g–1. Moreover, the synthesis protocol demonstrated here is highly versatile with different, alternative pathways that provide many degrees of freedom in the process sheet design and in material composition.

Triphenyl silicon hydroperoxide and its isostructural germanium complex were characterized by single crystal X-ray analysis revealing H-bonding of two triphenylhydroperoxocomplexes, with each hydroperoxo ligand acting as a hydrogen donor and a hydrogen acceptor. Only two other structures with localized protons of hydroperoxo complexes' main group elements (boron and tin) are known (compared to 130 p-block element peroxo compounds) and both exhibit the same hydroperoxo double hydrogen bonding motif. The reaction of the hydroperoxo complexes with triphenylgermanium chloride to give the dinuclear peroxobridged germanium complex demonstrates the higher reactivity of the hydroperoxo moieties compared to the peroxo moiety. DFT calculations provide an estimate of the hydroperoxo double hydrogen bond energies: 62.8 and 63.6 kJ mol−1 for triphenyl silicon, 63.6 and 65 kJ mol−1 for the germanium complex.

Potassium-ion batteries are attracting considerable attention as a viable type of high voltage battery. Among available anode materials, composites containing Sb2S3are some of the most interesting high capacity candidates. A nanostructured Sb2S3-reduced graphene oxide composite anode material is evaluated in this study and compared with a structurally similar SnS2-reduced graphene oxide material reported previously by this team. The behaviour of the Sb2S3-based electrodes is assessed in both 1 M KPF6in ethylene carbonate-diethyl carbonate and 1 M KPF6in 1,2-dimethoxyethane electrolytes. Depotassiation capacities in excess of 650 mA h g−1are recorded for the composite electrodes, superior not only to SnS2-based electrodes but also to all previously reported Sb2S3-containing electrode materials for potassium-ion batteries. In order to establish insights into the reaction mechanism of the Sb2S3phase with potassium, post-cycling X-ray diffraction andin situtransmission electron microscopy are utilised. The recorded data suggest the presence of antimony alloys and potassium polysulphides as reaction products and intermediates; a possible conversion-alloying reaction mechanism is discussed. The results indicate that a capacity higher than previously believed is achievable in the Sb2S3active component of potassium-ion battery electrodes.

2-Aminobenzimidazole hemiperoxosolvate 2(C7H7N3)·H2O2 was synthesized and studied by single crystal X-ray analysis and periodic (solid-state) DFT calculations. The obtained compound, after urea and melamine peroxosolvates, is the third example of an H2O2 crystalline adduct stabilized with the maximum possible number of hydrogen bonds formed by one hydrogen peroxide molecule – 2 H-bonds as proton donors and 4 as acceptors. Due to the small size of the hydrogen peroxide molecule, its hydrogen bonding energy contributes the maximal impact and determines the relative value of the hydrogen bonding energy of the peroxosolvate crystal and can be suggested as an energetic criterion of perhydrate stability. The total energy of the 6 hydrogen bonds formed by one hydrogen peroxide molecule in all three compounds (∼140–∼170 kJ mol−1) was calculated and compared to the corresponding values for crystalline hydrogen peroxide and L-serine peroxosolvate. The total energy of the 4 hydrogen bonds of hydrogen peroxide molecule in crystalline H2O2 and L-serine peroxosolvate (150 and 113 kJ mol−1, respectively) was evaluated by solid-state DFT calculations.

Despite the technological importance of urea perhydrate (percarbamide) and sodium percarbonate, and the growing technological attention to solid forms of peroxide, fewer than 45 peroxosolvates were known by 2000. However, recent advances in X-ray diffractometers more than tripled the number of structurally characterized peroxosolvates over the last 20 years, and even more so, allowed energetic interpretation and gleaning deeper insight into peroxosolvate stability. To date, 134 crystalline peroxosolvates have been structurally resolved providing sufficient insight to justify a first review article on the subject. In the first chapter of the review, a comprehensive analysis of the structural databases is carried out revealing the nature of the co-former in crystalline peroxosolvates. In the majority of cases, the coformers can be classified into three groups: (1) salts of inorganic and carboxylic acids; (2) amino acids, peptides, and related zwitterions; and (3) molecular compounds with a lone electron pair on nitrogen and/or oxygen atoms. The second chapter of the review is devoted to H-bonding in peroxosolvates. The database search and energy statistics revealed the importance of intermolecular hydrogen bonds (H-bonds) which play a structure-directing role in the considered crystals. H2O2 always forms two H-bonds as a proton donor, the energy of which is higher than the energy of analogous H-bonds existing in isostructural crystalline hydrates. This phenomenon is due to the higher acidity of H2O2 compared to water and the conformational mobility of H2O2. The dihedral angle H-O-O-H varies from 20 to 180° in crystalline peroxosolvates. As a result, infinite H-bonded 1D chain clusters are formed, consisting of H2O2 molecules, H2O2 and water molecules, and H2O2 and halogen anions. H2O2 can form up to four H-bonds as a proton acceptor. The third chapter of the review is devoted to energetic computations and in particular density functional theory with periodic boundary conditions. The approaches are considered in detail, allowing one to obtain the H-bond energies in crystals. DFT computations provide deeper insight into the stability of peroxosolvates and explain why percarbamide and sodium percarbonate are stable to H2O2/H2O isomorphic transformations. The review ends with a description of the main modern trends in the synthesis of crystalline peroxosolvates, in particular, the production of peroxosolvates of high-energy compounds and mixed pharmaceutical forms with antiseptic and analgesic effects.

Nanocrystalline zinc peroxide is passivated against further oxidation by the addition of minute, substoichiometric amounts of potassium permanganate, which also endows it with increased thermal sta...

Vanadium oxides (V3O7) have been used as electrode materials for supercapacitor applications because of its multiple oxidation states. V3O7 nanoparticles were coated on reduced graphene oxide (rGO) from a peroxovanadate-rGO composite by thermal microexplosive decomposition method. These V3O7 decorated rGO were made composite with the flexible multi redox conducting polymer (Polyaniline). The performance of the composite materials as electrode for supercapacitors was analyzed in a 3-electrode cell, obtaining a specific capacitance of about 579 F g−1 at 0.2 A g−1 specific current. Cycling stability is one of the main barriers noticed in V3O7, which limits the practical performance of supercapacitors. This is overcome by modifying V3O7 with rGO and polyaniline composites which produces good electrical contact resulting in higher capacitances and enhanced cycling stability when compared to pristine V3O7. A superior electrochemical performance and ultra-long cyclic stability of 94% over 2500 cycles was obtained through these developed electrodes.

High, nearly 100%, yield synthesis of ammonium peroxogermanate (APG), (NH4)6[Ge6(μ-OO)6(μ-O)6(OH)6]·6H2O, is presented, and its crystal structure is determined by single crystal X-ray study. It comprises centrosymmetric hexanuclear peroxogermanate anions [Ge6(μ-OO)6(μ-O)6(OH)6]6- with six μ-oxo- and six μ-peroxo groups forming negatively charged layers. The space between these layers is filled by ammonium cations and water molecules, forming a highly stable structure due to hydrogen bonding. Highly soluble macroporous amorphous germanium oxide (HSGO) is then synthesized by mild treatment of APG. The compound forms highly oversaturated metastable germanium oxide solution with a solubility of 100 g/L, over 20 times higher than the solubility of amorphous germanium oxide. HSGO solution is a versatile reagent that can react with basic and acidic reagents to give a diverse range of salts including, e.g., germanium sulfide, germanium hydrophosphate, and potassium germanate. In the absence of acid or base, the aqueous HSGO solution yields hexagonal germanium oxide under ambient conditions.

Herein, peroxosolvates of the cyclic dipeptides disarcosine (C6H10N2O2·H2O2), dialanine (C6H10N2O2·2(H2O2)), diglycine (C4H6N2O2·2(H2O2) and C4H6N2O2·1.786(H2O2)·0.214(H2O)) were synthesized and studied by single crystal X-ray analysis and periodic DFT calculations. The hydrogen bonding networks of cyclic diglycine peroxosolvate and isomorphous hydrate were characterized using Bader analysis of periodic electron density and empirical correlations between enthalpy and metric and spectroscopic parameters of the H-bond. The obtained data for the peroxosolvate of cyclic dipeptides provided a molecular-level insight into the non-redox interaction of hydrogen peroxide with the peptide backbone in aqueous systems. In all structures, H2O2 acts as a proton donor in two hydrogen bonds. The carbonyl oxygen atom of the peptide (–CO–NH–) forms a relatively stronger hydrogen bond with the hydrogen peroxide molecule (32–34 kJ mol−1) as compared to that with water in the isomorphous hydrate of cyclic diglycine (26–28 kJ mol−1). The hydrogen atom of the peptide group (–CO–NH–) can form a moderate H-bond with hydrogen peroxide (25 kJ mol−1). The total hydrogen bonding energy of the peroxosolvate is higher than that of the corresponding hydrate (91 vs. 82 kJ mol−1). The stronger hydrogen bonding in peroxosolvates as compared to that in the hydrate and the fact that the intermolecular H-bonds C(O)NH⋯OCNH between cyclic dipeptides are not found in peroxosolvates, despite being prevalent in the structure of nonsolvated dipeptides, imply that hydrogen peroxide can interfere with the secondary structure of proteins via a mechanism that can lead to reversible inhibition or signaling in living systems.

A breakthrough "superoxide colloidal solution route" for low-temperature synthesis of barium and strontium stannate perovskites and their doped analogues was recently introduced. The synthesis starts from hydrogen peroxide-rich stannate solutions and yields a so-called "crystalline superoxide molecular cluster" that is converted by low temperature (300 °C) to the respective perovskites. In this paper, the so-called "crystalline superoxide molecular cluster" is identified as a superoxide-free, barium trihydroxo(hydroperoxo)peroxostannate, BaSn(OH)

Soil aquifer treatment (SAT) is a well-known method for treating water and polishing effluent for water reuse.

Exploring highly efficient catalysts for the oxygen evolution reaction (OER) is essential for water electrolysis. Cost-effective transition-metal oxides with reasonable activity are raising attention. Recently, OER reactants' and products' differing spin configurations have been thought to cause slow reaction kinetics. Catalysts with magnetically polarized channels could selectively remove electrons with opposite magnetic moment and conserve overall spin during OER, enhancing triplet state oxygen molecule evolution. Herein, antiferromagnetic inverse spinel oxide LiCoVO

Formation of vanadium oxide nanofilm-coated graphene oxide (GO) is achieved by thermally induced explosive disintegration of a microcrystalline ammonium peroxovanadate-GO composite. GO sheets isolate the microcrystalline grains and capture and contain the microexplosion products, resulting in the deposition of the nanoscale products on the GO. Thermal treatment of the supported nanofilm yields a sequence of nanocrystalline phases of vanadium oxide (V3O7, VO2) as a function of temperature. This is the first demonstration of microexplosive disintegration of a crystalline peroxo compound to yield a nanocoating. The large number of recently reported peroxide-rich crystalline materials suggests that the process can be a useful general route for nanofilm formation. The V3O7@GO composite product was tested as a sodium ion battery anode and showed high charge capacity at high rate charge-discharge cycling (150 mAh g-1 at 3000 mA g-1 vs 300 mAh g-1 at 100 mA g-1) due to the nanomorphology of the vanadium oxide. NRF (Natl Research Foundation, S’pore)

High-charge-capacity sodium-ion battery anodes made of Sb2Te3@reduced graphene oxide are reported for the first time. Uniform nano-coating of graphene oxide is carried out from common sol of peroxotellurate and peroxoantimonate under room temperature processing. Reduction by hydrazine under glycerol reflux yields Sb2Te3@reduced graphene oxide. The electrodes exhibit exceptionally high volumetric charge capacity, above 2300mAhcm-3 at 100mAg-1 current density, showing very good rate capabilities and retaining 60% of this capacity even at 2000mAg-1. A comparison of sodiation and lithiation shows that lithiation exhibits better volumetric charge capacity, but surprisingly only marginally better relative rate capability retention at 2000mAg-1. Tellurium-based electrodes are attractive due to the high volumetric charge capacity of Te, its very high electric conductivity, and the low relative expansion upon lithiation/sodiation.

The Western Mountain Aquifer (Yarkon-Taninim) of Israel is one of the country's major water resources and partially flows through a karst system. During late winter 2013, maintenance actions were performed on a central sewage pipe that caused sewage to leak into the creek located in the study area. Carbamazepine (CBZ) was used as an indicator for the presence of sewage in the groundwater. The research goal was to develop a mathematical model for quantifying flow and contaminant transport processes in the karst/fractured-porous unsaturated zone and groundwater system. The model was used to simulate CBZ transport during and after an observed sewage leakage event. A quasi-3D dual permeability numerical model represents the 'vadose zone – aquifer' system, by a series of 1D vertical flow and transport equations solved in a variably-saturated zone and by 3D-saturated flow and transport equation in groundwater. The results of simulation showed that after the leakage stopped, significant amounts of CBZ were retained in the porous matrix of the unsaturated zone below the creek. Water redistribution and slow recharge during the dry summer season contributed to a continuous supply of CBZ to the groundwater in the vicinity of the creek and hundreds of meters downstream.

We demonstrate for the first-time liquid exfoliated few layers of 2D Black phosphorus (BP) nanosheets as a hole transporting material (HTM) for perovskite based solar cells. The photoelectron spectroscopy in air (PESA) measurements confirm the low laying valence band level of BP nanosheets (−5.2 eV) favourable for hole injection from CH3NH3PbI3 (MAPbI3). Our results show that ∼25% improvement in power conversion efficiency (PCE) of η = 16.4% for BP nanosheets + Spiro-OMeTAD as an HTM as compared to spiro-OMeTAD (η = 13.1%). When BP nanosheets are exclusively utilised as an HTM, a PCE of η = 7.88% is noted, an improvement over the 4% PCE values observed for HTM free devices. Photoluminescence (PL) quenching of MAPbI3 and impedance measurements further confirm the charge extraction ability of BP nanosheets. The structural and optical characterization of liquid exfoliated BP nanosheets is discussed in detail with the aid of transmission electron microscopy, Raman spectroscopy, absorption spectroscopy and photo-electron spectroscopy. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Accepted version

A composite based on sodium germanate and reduced graphene oxide was obtained for the first time by precipitating the initial peroxogermanate on a graphene oxide followed by heat treatment in vacuum. According to powder X-ray diffraction, sodium germanate crystallizes during the heat treatment in vacuum at 500°C. Scanning transmission electron microscopy examination showed that sodium peroxogermanate nanoparticles form a thin film on the surface of graphene oxide flakes. The electrochemical characteristics of composites obtained with different heat treatment conditions were studied as the anodes of lithium ion batteries.

High‐charge‐capacity sodium‐ and lithium‐ion battery anodes based on tin telluride are reported for the first time. Graphene oxide/cubic β‐SnTe electrodes exhibit exceptionally high reversible volumetric charge capacities above 3000 and 1300 mAh cm−3 at 100 mA g−1 charging rate for lithium and sodium ion batteries, respectively, and they show very good rate capabilities retaining 68 and 60 % of the respective capacities even at 2000 mA g−1 charging rate. The reversible charge capacity for lithiation is approximately equal to the theoretical value of the active material. The superior electrode performance is attributed to the high conductivity of tellurium, the mechanical buffering of volume changes by the large row‐V host elements, the elasticity of the reduced graphene oxide support, and the very low specific equivalent volumes involved in sodiation and lithiation of SnTe. NRF (Natl Research Foundation, S’pore)

Peroxosolvates of 2-aminonicotinic acid (I) and lidocaine N-oxide (II) including the largest insular hydrogen peroxide clusters were isolated and their crystal structures were determined by single-crystal X-ray diffraction. An unprecedented dodecameric hydrogen peroxide insular cluster was found in I. An unusual cross-like pentameric cluster was observed in the structure of II. The topology of the (H2 O2 )12 assembly was never observed for small-molecule clusters. In I and II new double and triple cross-orientational disorders of H2 O2 were found. Cluster II is the first example of a peroxosolvate crystal structure containing H2 O2 molecules with a homoleptic hydrogen peroxide environment. In II, a hydrogen bond between an H2 O2 molecule and a peptide group -CONH⋅⋅⋅O2 H2 was observed for the first time.

Quantification of dissolved organic carbon (DOC) in pore water is vital for understanding the transport of solutes and the fate of contaminants. However, the extraction of pore water from saturated soils, and even more so, from unsaturated soils without an artificial increase in the DOC content is challenging. To this end, we have established a methodology for pore water extraction from unsaturated and saturated soils based on the displacement of the pore water from cores withdrawn from the ground by direct-push drilling machines. The displacement extraction is performed by introducing distilled water at the top of a liner filled with soil core and collecting the displaced eluent from the bottom. This positive displacement extraction (PDE) method was compared to pore water extraction by centrifugation for the analysis of DOC. Method validation was carried out with various DOC levels using different flow rates and three different soil types: sandy, sandy-clayey and clayey. The limit of detection for the suggested method was 15%) under flow rates lower than 1 mL min− 1. Extraction by centrifugation gave biased, unacceptable results throughout the studied DOC range (0–25 mg L− 1). Detailed parametric dependence by mobile – immobile modeling showed that for most soils and saturation levels collection of the first 10% of the pore water initially present in the core will introduce a bias of less 8% in DOC. For clayey soils with an exceedingly high immobile water fraction, a pedotransfer parameter estimation or comprehensive column tests should be carried out in order to estimate accurately the collectible water fraction and assure accurate prediction of the DOC level. Field studies that were carried out in a Soil Aquifer Treatment system provided 30 m deep DOC profiles with

Nitroguanidine, a widely used nitramine explosive, is an environmental contaminant that is refractory, persistent, highly mobile in soils and aquifers, and yet under-researched. Nitroguanidine determination in water and soil poses an analytical challenge due its high hydrophilicity, low volatility, charge neutrality over a wide pH range, and low proton affinity which results in low electrospray interface (ESI)-MS sensitivity. A sensitive method for the determination of nitroguanidine in aqueous and soil matrices was developed. The method is based on reduction by zinc in acidic solution, hydrophobization by derivatization, preconcentration on C18 cartridge, and LC-MS quantification. The demonstrated limit of detection (LOD) reaches 5 ng/L and 22 ng/g in water and soil, respectively. Analysis of a contaminated site demonstrates that it is possible to map a contamination plume that extends over 1 km from the source of the contamination.

A peroxogermanate thin film was deposited in high yield at room temperature on graphene oxide (GO) from peroxogermanate sols. The deposition of the peroxo-precursor onto GO and the transformations to amorphous GeO2, crystalline tetragonal GeO2, and then to cubic elemental germanium were followed by electron microscopy, XRD, and XPS. All of these transformations are influenced by the GO support. The initial deposition is explained in view of the sol composition and the presence of GO, and the different thermal transformations are explained by reactions with the graphene support acting as a reducing agent. As a test case, the evaluation of the different materials as lithium ion battery anodes was carried out revealing that the best performance is obtained by amorphous germanium oxide@GO with >1000 mAh g–1 at 250 mA g–1 (between 0 and 2.5 V vs Li/Li+ cathode), despite the fact that the material contained only 51 wt % germanium. This is the first demonstration of the peroxide route to produce peroxogermanate ...

Sodium peroxostannate nanoparticles with graded composition were produced from aqueous hydrogen peroxide–sodium hydroxostannate solution. The uniform particles were converted to composition graded sodium stannate by mild thermal treatment for peroxide decomposition and yielded yolk–shell tin dioxide particles by dilute acid treatment. The mechanism of formation of the graded sodium concentration is explained in view of the solubility of peroxostannate in H2O2–H2O solution and based on 119Sn NMR, XRD, dynamic light scattering (DLS) and electron microscopy studies. Initial studies illuminating sensitive hydrogen sensing by yolk–shell tin oxide particles are presented.

An anode material incorporating a sulfide is reported. SnS2 nanoparticles anchored onto reduced graphene oxide are produced via a chemical route and demonstrate an impressive capacity of 350 mA h g−1, exceeding the capacity of graphite. These results open the door for a new class of high capacity anode materials (based on sulfide chemistry) for potassium-ion batteries.

The oxidation of ammonium in the vadose zone of soil aquifer systems is discussed and examined by detailed analysis of the depth profiles of dissolved oxygen, nitrate and ammonium concentrations in the vadose zone of a soil-aquifer treatment (SAT) system of a municipal wastewater treatment system of the Tel Aviv metropolitan area. Nitrification kinetics and ammonium adsorption capacity studies show that neither the nitrification rate nor the ammonium adsorption capacity controls the capacity of the Shafdan SAT system for ammonium removal. Evaluation of the ammonium adsorption capacity of the soil reveals that under ideal conditions, a depth of less than 50 cm is sufficient to adsorb all the ammonium supplied in a flooding cycle. In-field studies show that all the ammonium is concentrated within the first 80 cm of the vadose zone. A depth profile of the Potential Nitrification (P.N), a measure of the local amount and activity of nitrifiers, is presented for the first time in the vadose zone of a SAT system showing that there are sufficient nitrifiers to oxidize all the ammonia that is supplied in a flooding cycle within less than 2 h, under optimal microbiological conditions based on the existing nitrifiers and their spatial distribution. The biodegradation rate in the field corresponds to first order ammonium conversion with a kinetic coefficient of 8.0 ± 0.2 d−1. Accordingly, the average measured rate was 8.6 ± 5.8 mg NH4+–N per kg per d for in-field tests, which can be compared to the average P.N, with a value of 34.5 ± 16.8 mg NH4+–N per kg per d. The results suggest that a SAT design, taking into account full ammonium removal capacity, is feasible and can rely on the evaluation of the ammonium adsorption capacity in the SAT soil, the ammonium input and the P.N of the equilibrated target soil under conditions simulating the operation of the infiltrating basins.

The Cambridge Structural Database has been used to investigate the detailed environment of H2O2 molecules and hydrogen-bond patterns within “true” peroxosolvates in which the H2O2 molecules do not interact directly with the metal atoms. A study of 65 crystal structures and over 260 hydrogen bonds reveals that H2O2 always forms two H-bonds as proton donors and up to four H-bonds as a proton acceptor, but the latter can be absent altogether. The necessary features of peroxosolvate coformers are clarified. (1) Coformers should not participate in redox reactions with H2O2 and should not catalyze its decomposition. (2) Coformers should be Bronsted bases or exhibit amphoteric properties. The efficiency of the proposed criteria for peroxosolvate formation is illustrated by the synthesis and characterization of several new crystals. Conditions preventing the H2O2/H2O isomorphous substitution are essential for peroxosolvate stability: (1) Every H2O2 in the peroxosolvate has to participate in five or six hydrogen b...

Using peroxostannate as a precursor, a composite material based on tin dioxide and carbon black was obtained, in which tin dioxide forms a coating on the surface of carbon black nanoparticles. The synthesized material was characterized by electron microscopy and X-ray powder diffraction analysis, and also the electrochemical characteristics of this material as an anode material for lithium-ion batteries were studied. The material demonstrates good stability and rate performance, which is indicative of the efficiency of the peroxide method for producing promising inexpensive anode materials based on tin dioxide and carbon black.

Antibiotic resistance genes (ARGs) have been considered as emerging contaminants of concern nowadays. There are no special technologies designed to directly remove ARGs in wastewater treatment plants (WWTPs). In order to reduce the risk of ARGs, it is vital to understand the efficiency of advanced treatment technologies in removing antibiotic resistance genes in WWTPs. This review highlights the application and efficiency of tertiary treatment technologies on the elimination of ARGs, s, based on an understanding of their occurrence and fate in WWTPs. These technologies include chemical-based processes such as chlorination, ozonation, ultraviolet, and advanced oxidation technology, as well as physical separation processes, biological processes such as constructed wetland and membrane bioreactor, and soil aquifer treatment. The merits, limitations and ameliorative measures of these processes are discussed, with the view to optimizing future treatment strategies and identifying new research directions. Keywords: Wastewater treatment plants, Antibiotic resistance genes, Chemical-based approaches, Physical separation process, Biological processes, Soil aquifer treatment

Multiple sources contribute to the presence of antibiotic residues in water environments, and the environmental risks caused by antibiotics were paid more and more attention. This work aims to establish a relationship between optical properties of dissolved organic matter (DOM) and sources and risks of antibiotics. Occurrence of antibiotics and DOM in a city-river-reservoir freshwater system containing distinct antibiotic sources was investigated during three seasons using LC-MS and fluorescence excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC), respectively. The results showed that antibiotics and DOM in the water had trends of increasing levels from the upstream to the midstream in the system. Five classes of antibiotics had statistically significant correlations with the humic-like component (C3) in the water (Pearson, p

Understanding the relationship between lithium anode and electrolyte is important to develop a more compatible lithium/electrolyte system for stable and safe cycling of lithium-metal based batteries. However, to date, there has not been any work to quantify the effects of electrolyte on the performance of electrode due to the complexity. Herein, we quantify the relationship between an electrolyte additive, LiNO3, and the stability of lithium anode. It is found that, with increasing the amount of LiNO3, the cyclability of lithium anode rises linearly and the risk of dendrite-induced short circuits can be reduced. Low Coulombic efficiency (CE) and short circuits tend to occur in tandem. LiNO3 is found to be continuously consumed upon electrochemical cycling, which leads to a low CE and a high risk of short circuits. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Published version

A tin dioxide–sodium stannate composite has been obtained by the thermal treatment of sodium peroxostannate nanoparticles at 500°C in air. X-ray powder diffraction study has revealed that the composite includes crystalline phases of cassiterite SnO2, sodium stannate Na2Sn2O5, and sodium hexahydroxostannate Na2Sn(OH)6. Scanning electron microscopy has shown that material morphology does not change considerably as compared with the initial tin peroxo compound. Electrochemical characteristics have been compared for the anodes of lithium-ion batteries based on tin dioxide–sodium stannate composite and anodes based on a material manufactured by the thermal treatment of graphene oxide–tin dioxide–sodium stannate composite at 500°C in air.

Rationale Brominated organic compounds (BOCs) are common persistent toxic pollutants. Compound-specific stable bromine isotope ratio analysis is one of the potential approaches for investigating BOC transformations in the environment. In the present study, we demonstrate that precise bromine isotope analysis of BOCs can be successfully performed by gas chromatography/quadrupole mass spectrometry (GC/qMS) systems that are widely available in analytical laboratories. Methods Optimization and validation of the GC/qMS method were performed by analysis of bromoform, 3-bromophenol and 4-bromotoluene. In addition, comparison of the results obtained by GC/qMS and GC/multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) for 1,2-dibromoethane and 3-bromophenol samples with different bromine isotope composition was carried out to evaluate the analytical performance of the developed method. Results Precisions in the range 0.2–0.3‰ were attained for sample amounts in the range of tens to thousands pmol. Good correlation between the results obtained by GC/qMS and GC/MC-ICPMS for laboratory standard materials (1,2-dibromoethane and 3-bromophenol) (regression coefficient R2 > 0.98) was achieved. Conclusions The GC/qMS method for bromine isotope analysis shows a good performance and can be applied routinely for studying transformations of BOCs. Due to the observed dependence of the measured isotope ratios on the amount of the analyte and the calculation scheme applied, normalization of the results versus appropriate standards is required for source attribution applications. Copyright © 2016 John Wiley & Sons, Ltd.

We report the assembly of an asymmetric membrane consisting of octadecyltrimethoxysilane (ODTMS) Langmuir film covalently attached to a sol-gel based sublayer, supported by a mesoporous membrane. The ODTMS Langmuir film was compressed at the interface of a subphase containing tetramethoxysilane (TMOS), formamide and polyethylenimine. Exposure of the Langmuir film to NH3 vapours increased the pH at the interface (pHinterface) and catalysed the condensation of TMOS. The assembly of the layers was of a self-healing nature, due to the π-pressure set-up of the Langmuir film and the faster diffusion of the NH3 through the defects. The resulting asymmetric film was transferred onto polysulfone ultrafiltration membranes to form a thin film composite (TFC) structure composed of a Langmuir organic skin, the sol-gel blend sublayer and the support. The asymmetry of the film was confirmed by various methods and a gradual transition from mesoporous support to dense ceramic-polymeric film was seen. A preliminary study demonstrated that the modification of the polysulfone membrane improved its selectivity from ultra to nanofiltration range. The obtained fluxes were significantly higher as compared to commercial membranes of similar selectivity. This generic approach is applicable for assembling large-area selective TFC membranes with ultrathin skin layers and high fluxes of effluents.

Exploring highly efficient catalysts for the oxygen evolution reaction (OER) is essential for water electrolysis. Cost-effective transition-metal oxides with reasonable activity are raising attention. Recently, OER reactants' and products' differing spin configurations have been thought to cause slow reaction kinetics. Catalysts with magnetically polarized channels could selectively remove electrons with opposite magnetic moment and conserve overall spin during OER, enhancing triplet state oxygen molecule evolution. Herein, antiferromagnetic inverse spinel oxide LiCoVO4 is found to contain d7 Co2+ ions that can be stabilized under active octahedral sites, possessing high spin states S = 3/2 (t2g5 eg2 ). With high spin configuration, each Co2+ ion has an ideal magnetic moment of 3 µB , allowing the edge-shared Co2+ octahedra in spinel to be magnetically polarized. Density functional theory simulation results show that the layered antiferromagnetic LiCoVO4 studied contains magnetically polarized channels. The average magnetic moment (µave ) per transition-metal atom in the spin conduction channel is around 2.66 µB . Such channels are able to enhance the selective removal of spin-oriented electrons from the reactants during the OER, which facilitates the accumulation of appropriate magnetic moments for triplet oxygen molecule evolution. In addition, the LiCoVO4 reported has been identified as an oxide catalyst with excellent OER activity.

This paper presents the analysis of caffeine and carbamazepine transport in the subsurface during and after sewage discharge in the Sorek creek over outcrops of the Western Mountain Aquifer (Yarkon-Taninim) in Israel. Both caffeine and carbamazepine were used as indicators for sewage contamination in the subsurface. While carbamazepine is considered conservative, caffeine is subject to sorption and degradation. The objective of the study was to quantify differences in their transport under conditions in the carbonate aquifer. A quasi-3D dual permeability numerical model was used to simulate water flow and transport of both pollutants in a vadose zone – aquifer system. The results of this study show that each of these two pollutants can be considered as effective tracers for characterization and assessment of aquifer contamination. Carbamazepine was found to be more suitable to assess the contamination boundaries, while caffeine can be used as a contaminant tracer only briefly after contamination occurred. In instances when there are low concentrations of carbamazepine which appear as background contamination in an aquifer, caffeine might serve as a better marker for detect new contamination events given its temporal nature. The estimated caffeine degradation rate and the distribution coefficient of linear sorption isotherm were 0.091 d−1 and 0.1 L/kg, respectively, which imply a high attenuation capacity. The results of the simulation indicate that around 95 % of carbamazepine mass was retained in the porous matrix of the unsaturated zone by the end of the year, while all of the caffeine was completely degraded a few months after the sewage was discharged.