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Powdered milk and its derivatives are widely consumed worldwide, which require the development of reference materials for the evaluation of analytical methodologies that are developed for the analysis of these samples. In this work, the homogeneity and stability of a powdered milk laboratory reference material candidate were evaluated using chemometric tools as an alternative to analysis of variance (ANOVA). Elements Ca, Fe, K, Mg, P, Na and Zn were quantified by inductively coupled plasma optical emission spectrometry (ICP OES) after the acid digestion procedure using microwave-assisted radiation. The results obtained through not only ANOVA, but also PCA and HCA allow us to state that the material can be considered homogeneous and stable. However, the application of the chemometric tools (PCA and HCA) allowed the extraction of more information compared to ANOVA, besides confirming the homogeneity and stability of the powdered milk laboratory reference material candidate.

Nickel (Ni) is a frequently used metal in the production of many products, and Ni exposure occurs in humans through food, inhalation, and skin. Studies reported Ni as the most common allergen diagnosed in the serial patch test. The main purpose of our study was to determine the concentration of Ni and other elements in the urine samples of individuals with Ni-sensitivity and to determine the effect of lifestyle habits on these variables. This study was conducted with 388 participants; additionally, both Ni patch test and inorganic analysis (for 24 elements) method in urine with inductively coupled plasma-mass spectrometry (ICP-MS) were applied to all participants. Ninety-two (23.7%) of the participants were found to have nickel sensitivity with a mean urine concentration of 4.475 mu g/g creatinine (median=4.260; SD=2.527). The urine nickel concentration was significantly different between female and male participants (p =0.001). We found a significant correlation between Ni and other metals alongside various element pairs. The mean urine Ni concentration of the individuals with a positive Ni sensitivity test result was not different from that of the participants without Ni sensitivity (4.475 vs 4.256 mu g/g creatinine, respectively; p = 0.068). The high accuracy, recovery, and repeatability data obtained from the analyses indicate that this study is efficient and appropriate for the quantitative determination of nickel and other elements in urine samples. Ni-containing objects and Ni-rich foods should be of concern for individuals with hypersensitivity reactions to the element.

BACKGROUND: Rhaphidophora pinnata (L.f.) Schott is one of the Indonesian plants, has known as a medicinal plant. This plant is a vine; round stems have sticky roots and hanging roots. The leaves have been used as traditional anticancer in Singapore. Indonesian people have also used R. pinnata plants as a diuretic agent, anticancer and antibacterial. R. pinnata plants contain active substances from alkaloid compounds, flavonoids, saponins, tannins and triterpenoids/steroids. AIM: The purpose of this study was to determine the organic and inorganic content of Rhaphidophora pinnata (L.f.) Schott water extract in the form of fresh leaves, micro simplicia and nano simplicia. METHOD: The collected R. pinnata leaves are drained and grinded to make micro, and nano Simplicia powder of R. pinnata leaves. The size characterisation of R. pinnata leaves was analysing using Particles Size Analyzer. The water extract of R. pinnata leaves, micro simplicia, and nano simplicia R. pinnata leaves was made 10% (w / v) in water. Phytochemical screening of nano simplicia and nano simplicia water extract included an examination of alkaloid compounds, flavonoids, saponins, tannins, glycosides, and steroids/triterpenoids. Thin-layer chromatography analysis of water extract was analysed using TLC scanner. The element that contains in the water extract was analysed using atomic absorption spectrophotometry methods. RESULT: The results of phytochemical screening of nano simplicia powder and nano simplicia water extract showed the presence of flavonoids, alkaloids, saponins, tannins, and glycosides. Eluent, which shows good elution is n-butanol: acetic acid: water (6: 2: 2). This eluent is used to elute polar and semipolar compounds and is very good for separating flavonoids. R. pinnata water extract contains the minerals potassium, sodium, magnesium and calcium. CONCLUSION: R. pinnata water extract contains organic compounds in the form of flavonoids, alkaloids, saponins, tannins, and glycosides. The nano simplicia water extract showed more chemical content than other water extracts on the TLC plate by detection at a wavelength of 250 nm and 300 nm. The most element content in R. pinnata water extract is potassium, followed by magnesium, sodium, and calcium.

Purpose of this book on qualitative inorganic analysis, is to provide the students with the necessary guidelines for solving confidently an unknown inorganic sample, within the duration of a practical examination. It insists on acquiring the basic knowledge about the classical chemistry associated with detecting the cations and anions as well as the dissolution aspects in bringing them in solution. They enable a student to modify the detection procedures carefully according to the composition of the sample, without losing the logical aspects. Dry/preliminary tests for the cations and anions, treatment of the Na2CO3 extract as well as that of its residue, form the foundation of the present semi-micro analytical procedures.

Soil pollution and toxicity have been investigated in the Gardanne area (southern France) at a range of sites around a recognized pollution source, a bauxite processing plant (BPP), and a power plant (PP). Soil samples were submitted to inorganic and organic analyses and tested for toxicity in two invertebrate models. Inorganic analysis was based on determining elemental concentrations by ICP-MS, encompassing a total of 26 elements including 13 rare earth elements (REEs), of the soil samples and their leachates after 24 or 48 h in seawater. Organic analyses were performed by measuring the sums of 16 polycyclic aromatic hydrocarbons (PAHs) and of total hydrocarbons (C-10 to C-40). Bioassays were carried out on the early life stages of three sea urchin species (Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis), and on a nematode (Caenorhabditis elegans). Sea urchin bioassays were evaluated by the effects of soil samples (0.1–0.5% dry wt/vol) on developing embryos and on sperm, and scored as: a) % developmental defects, b) inhibition of sperm fertilization success and offspring damage, and c) frequencies of mitotic aberrations. C. elegans 24 h-mortality assay showed significant toxicity associated with soil samples. The effects of soil samples showed heightened toxicity at two groups of sites, close to the BPP main entrance and around the PP, which was consistent with the highest concentrations found for metals and PAHs, respectively. Total hydrocarbon concentrations displayed high concentrations both close to BPP main entrance and to the PP. Further studies of the health effects of such materials in Gardanne are warranted.

Nowadays it is well-established that microwave-assisted digestion of organic matrices can be efficiently performed in closed vessels using dilute nitric acid solutions. In this work microwave-assisted sample preparation procedures compatible with green chemistry recommendations were developed for grains and cereals used to raise swine. Digestion efficiency was evaluated by determining the residual carbon content, which was lower than 3.5%. Residual acidity was also evaluated and was lower than 0.65 mol L−1. Calcium, Co, Cu, Fe, K, Mg, Mn, Mo, Na, P, Sr, and Zn were determined using either ICP OES or ICP MS depending on respective concentrations. Certified reference materials were evaluated and most determined concentrations were between 80 and 120% compared to certified values. Finally, after analytical measurements an apparatus for recovering nitric acid by sub-boiling distillation was used. To the best of our knowledge, this is the first application of sub-boiling distillation for recovering nitric acid of digests. Then, the purified acid could be reused in further digestions. This is a promising alternative for increasing the green chemistry attributes of trace inorganic analysis. The combination of these strategies, i.e. dilute nitric acid digestion followed by recovery of the acid digests, represents steps towards green chemistry approaches: “reduce the use, recycle and reuse”, strictly following the major green chemistry recommendations. Fil: Savio, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina Fil: Fialho, Lucimar L.. Universidade Federal do São Carlos; Brasil Fil: Nóbrega, Joaquim A.. Universidade Federal do São Carlos; Brasil

The purpose of the study was to evaluate the surface substructure, inorganic and organic components present in partially demineralized tooth bone graft material in young and old, male and female subjects, which may vary due to formation of secondary dentin suggesting decrease in calcium content as we age. A total of 34 extracted teeth were collected, 15 belonging to young patients and, the remaining 15 belonging to old patients, and, divided into 4 subgroups and a 4 control group. All the samples were cleaned, washed, air dried and powdered and demineralized. However the control group having 4 samples each was not demineralized. The samples were subjected to Scanning electron microscope (SEM) and Energy dispersive X-ray spectroscopy (EDX) for surface substructure and inorganic component analysis, and Bradford Assay to assess the protein content. The SEM analysis revealed the presence of dentinal tubules, collagen and, dense crystals of hydroxyapatite in young subject samples, however in old subjects’ collagen fibers were not visible, and hydroxyapatite crystals randomly scattered in clusters. The EDS results showed statistical significance in the Calcium Phosphorus ratio between the groups. Bradford Assay, showed higher concentration of proteins in female subject samples irrespective of age. It can be concluded that inorganic analysis showed young subjects had more densely packed hydroxyapatite crystals and slightly higher Calcium Phosphorus ratio and, high protein concentration was seen in female subjects’ samples irrespective of age.

Copper-exchanged chabazite (Cu/CHA) catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na + ions on Cu/SAPO-34 for ammonia selective catalytic reduction (NH 3 -SCR) are still unclear. In order to investigate the mechanism, five samples with various Na contents were synthesized and characterized. It was observed that the introduced Na + ion-exchanges with H + and Cu 2 + of Cu/SAPO-34. The exchange of H + is easier than that of isolated Cu 2 + . The exchanged Cu 2 + ions aggregate and form “CuAl 2 O 4 -like” species. The NH 3 -SCR activity of Cu/SAPO-34 decreases with increasing Na content, and the loss of isolated Cu 2 + and acid sites is responsible for the activity loss.

This study reports the parameters of electrolyte nonrandom two-liquid (eNRTL) model for aqueous Sr2+-Na+-Cl–-SO42– quaternary system. The molecule-electrolyte interaction parameters of eNRTL model and their temperature coefficients are identified for the H2O:(Sr2+-Cl–) pair via regression of available experimental data including vapor pressure, mean ionic activity coefficient, osmotic coefficient, liquid molar enthalpy, and liquid molar heat capacity. The electrolyte-electrolyte interaction parameters and their temperature coefficients are determined for the (Sr2+-Cl–):(Na+-Cl–) pair via regression of available solubility data of SrCl2 and SrSO4 in aqueous NaCl solution. Due to the low solubility of SrSO4 in water, the eNRTL interaction parameters corresponding to the Debye-Huckel theory are chosen for the H2O:(Sr2+-SO42–) pair and the interaction parameters for the (Sr2+-SO42–):(Na+-SO42–) and (Sr2+-Cl–):(Sr2+-SO42–) pairs are set to zero. The interaction parameters for the remaining molecule-electrolyte pairs, H2O:(Na+-Cl–) and H2O:(Na+-SO42–), and the electrolyte-electrolyte pair, (Na+-Cl–):(Na+-SO42–), are directly retrieved from the literature. The resulting eNRTL model satisfactorily calculates all thermodynamic and calorimetric properties for the quaternary system at 273.15–523.15 K and salt concentrations up to saturation.

The kinetics of ligation with OCS and CH 3 Cl were measured to assess the role of relativistic effects in these chemical reactions with the three d 10 s 1 transition metal cations Zn + , Cd + and Hg + as well as the three d 10 coinage cations Cu + , Ag + and Au + and the three d 9 cations Ni + , Pd + and Pt + . Measurements were performed at 295 K in helium bath gas at 0.35 Torr using an Inductively-Coupled Plasma/Selected-Ion Flow Tube (ICP/SIFT) tandem mass spectrometer. Rate coefficients are reported for OCS and CH 3 Cl ligation of Zn + , Cd + and Hg + and for OCS ligation with the adjacent d 10 coinage metal cations. A strong rate enhancement is observed for Hg + and Au + , similar to that we have reported recently for Pt + and Au + reacting with other ligands. We attribute this rate enhancement to the enhancement in the Hg + -OCS, Au + -OCS and Hg + -CH 3 Cl binding energies expected from relativistic effects. Comparisons are made with the measured rates of ligation of the adjacent main group d 10 s 2 atomic metal cations Ga + , In + and Tl + with OCS and CH 3 Cl and which don’t exhibit a relativistic effect. Further comparisons are made with the rates of ligation of Zn + , Cd + and Hg + with CH 4 , CH 3 F, and D 2 O that we reported previously and these also exhibit relativistic effects with Hg + . The relativistic effect is obfuscated by electron transfer to Hg + with NO, NO 2 , CS 2 , NH 3 , C 6 H 6 , C 6 F 6 and C 5 H 5 N as we measured previously. Ligation with O 2 , CO, CO 2 , N 2 O and SF 6 , is immeasurably slow, too slow to exhibit a relativistic effect with Hg + under our experimental conditions. Furthermore, the additional new measurements with OCS and CH 3 Cl provide examples of the occurrence of bimolecular channels in competition with ligation, such as S atom transfer with OCS and H 2 or HCl elimination with CH 3 Cl. Finally, we compare the maximum computed relativistic contraction of the 6s shell reported for Au with the occurrence of a maximum in the rate coefficient of ligation for the third-row transition metal cations Pt + , Au + and Hg + .

In the present research experimental data are obtained for the Jahn-Teller O′ phase formation, phase transformation “orthorhombic-rhombohedral structure” and the change of the conductance type in the systems of manganites La3+1–c+xSr2+c–xMn3+1–c–x–2γMn4+c+2γZn2+xO3+γ, La3+1–c–xSr2+c+xMn3+1–c–x–2γMn4+c+2γGe4+xO3+γ, La3+1–cSr2+cMn3+1–x–c–2γMn4+c+2γ(Zn2+0.5Ge4+0.5)xO3+γ, where Mn4+ ions concentration is independent of “x”. Ceramic samples were sintered in air at 1473 K. As-sintered samples had an excess of oxygen content. In order to provide stoichiometric oxygen content, the samples were annealed at 1223 K and partial pressure of oxygen PO2 = 10−1 Pа. Structural characteristics of the O′ phase were obtained. The position of the phase boundary “orthorhombic-rhombohedral structure” and the temperature of the conductance type change depending on the cation composition of manganites and oxygen content were determined. Possible approaches to the interpretation of experimental results were suggested.

In present study we demostrate the fabrication of nanoparticle (NPs) impregnated cellulose for the removal of metal ions from water. Co-precipitation method was employed to impregnate cotton fibers (cellulose) with silver and zinc oxide NPs. The NPs impregnated cellulose was characterised thorugh FTIR, XRD and SEM techniques. To study adsorption kinetics, NPs impregnated cotton was exposed to water containing Hg 2+ , Cr 3+ , Co 2+ , Pb 2+ , and Ni 2+ at 25 °C (pH 5.5) for 400 min, separately. The results reveal that adsorption follows Langmuir Isotherm with regression coefficient (R 2 ∼ 0.999). The adsorption of metal ions on zinc NPs impregnated cotton (ZnCt) and silver NPs impregnated cotton (AgCt) follows the pseudo second-order kinetics in which higher K 2 values indicate fast removal of Hg 2+ and Ni 2+ compared to Cr 3+ , Co 2+ and Pb 2+ . Though concentration of adsorbents has no apparent difference on adsorption capability; however, a significant difference is observed among q e values for metals ions. Among the tested metals ions, the Hg 2+ exhibited maximum adsorption capacity on both NPs impregnated cottons. The intermetallic competitive adsorption indicates that the adsorption capacity follows the sequence of Hg 2+ > Ni 2+ > Cr 3+ > Co 2+ > Pb 2+ , which roughly follow the same order of their hydration energies. The adsorption kinetics and competitive behavior of metals is further justified by Hotelling t 2 and t-statistics. This cellulose-metal oxide NPs composite material can be efficiently used for the removal of heavy metal ions from wastewater.

A comprehensive study using sixteen different metal ions was conducted, in order to test the possibility of substituting one or more Cu 2+ ions in nanojars, [anion⊂{Cu(μ-OH)(μ-pz)} n ] 2− ( n = 27–32; anion = CO 3 2− or SO 4 2− ), with Zn 2+ , Ni 2+ , Co 2+ , Fe 2+ , Fe 3+ , Mn 2+ , Cr 3+ , VO 2+ , Cd 2+ , Ag + , Pd 2+ , Ce 4+ , Sn 2+ , Pb 2+ , Pr 3+ or Nd 3+ . An octanuclear nickel complex was isolated in the case of Ni 2+ , which inspired the synthesis of a series of (Bu 4 N) 2 [Ni 8 ( μ 4 -OH) 6 (μ-4-Rpz) 12 ] (R = H, Me, n Oct) complexes. Characterization was carried out in the solid state by X-ray crystallography and thermogravimetric analysis, and, for the first time for this type of complexes, in solution phase by variable-temperature 1 H NMR spectroscopy, UV–vis spectroscopy and electrospray-ionization mass spectrometry.

Fe-bipyridine complexes were encapsulated into cation-exchanged Y-type zeolites (M-Na-Y: M = K+, Cs+, Mg2+, Ca2+, NH4+, TMA+, and TBA+) and their catalytic activities for oxidation of benzene with hydrogen peroxide (H2O2) to phenol were investigated in three types of solvents (CH3CN, H2O, and CH3CN + H2O(1:1)). Regardless of the kind of solvent, the counter cation in [Fe(bpy)3]2+@M-Na-Y did not affect the selectivity to phenol. No significant difference in catalytic activity of [Fe(bpy)3]2+@M-Na-Y appeared in CH3CN + H2O (1:1), while a difference on catalytic activity appeared in each CH3CN and H2O solvent. It was suggested that the catalytic activity is related with the accessibility of benzene to [Fe(bpy)3]2+ site in [Fe(bpy)3]2+@M-Na-Y, controlled by the hydrated ionic radius of the counter cation introduced. The effect of ligand coordinated with Fe ion was investigated by comparing the catalytic activities for oxidation of cyclic hydrocarbons (benzene, cyclohexane, and cyclohexene) over [Fe(bpy)3]2+@Na-Y, [Fe(phen)3]2+@Na-Y, and [Fe(terpy)2]2+@Na-Y (phen = 1,10-phenanthroline and terpy = 2,2′;6′,2″-terpyridine). It was suggested that the expansion of π-electron over the ligands such as phen and terpy improves the uptake ability of substrates having π-electron such as benzene.

The major inorganic elements in cores of coal and associated non-coal materials, ranging up to 7.6 m in length, as well as in large, naturally-broken coal blocks, have been measured using a hand-held, field-portable energy-dispersive X-ray fluorescence (fp-XRF) analyser, to evaluate the potential of such technology in quality assessment of coal seams for exploration and mine geology programs. Calibration against a suite of independently-analysed coals was used to provide element-specific user factors, which were incorporated into the individual fp-XRF analyses to obtain data on the percentages of Si, Al, K, Ca, Fe, Ti and S, and in some cases Mg and P, at each measurement point. With the exception of (total) S, these values were then recalculated as percentages of the relevant oxides, and combined to provide an estimate of the expected ash yield from the materials concerned. Profiles were prepared illustrating the variation in the different components through seam sections in three different drill cores, based on measurement of points at a 10 mm spacing. Samples of selected core intervals were analysed by conventional techniques, and the ash yield, total sulphur and individual oxide percentages compared to those indicated for the same intervals by the fp-XRF data. Although difficulties were encountered due to precipitated salts and anomalous element concentrations on or near some core surfaces, the results have shown a general level of agreement for the different coal and non-coal materials involved. While the accuracy is not as high as that from conventional methods, the fp-XRF data allow the materials in cores and exposed coal faces to be categorised to an extent that is of value for many research and industry applications.

Mesoporous silica SBA-15 grafted with benzene-1,3,5-triamido-tetraphosphonic acid (SBA-15-BTATPA) was synthesized. After detailed characterization of the material using various analytical instrumentation, it was applied for the recovery of Nd 3+ as a function of the contact time, ion concentration, and pH, and the adsorption equilibria and kinetics were examined. Under the optimal conditions, adsorption equilibrium was reached within 60 min contact time, and the adsorption capacity of Nd 3+ at room temperature and pH 6 was 129.8 mg g −1 , which was higher than that by other rare earth element (REE) ions tested for comparison (Y 3+ , La 3+ , and Ce 3+ ). The adsorbent showed excellent distribution coefficient for Nd 3+ greater than 1.0 × 10 5 mL/g. The preferential order of adsorption in the ion mixture with equal ion concentrations was Y 3+ >Nd 3+ >Ce 3+ >La 3+ , which followed the sequence of their decreasing atomic size and increasing stability constant. The competing adsorption by transition metal ions, such as Cu 2+ , Ni 2+ , Co 2+ , and Zn 2+ , on the REEs recovery was negligible ( 2 > 0.99), whereas the adsorption kinetics could be described satisfactorily by a pseudo second order kinetic model. The material was reusable for up to 5 consecutive times with only a slight decrease in adsorption capacity.

Realizing the ubiquitous presence of rare-earth orthoborates in various applications involving their optical properties, the current investigation is directed towards the exploration of epoxide mediated rapid synthesis to make YBO3. Highly crystalline orthoborate with disordered vaterite structure resulted on calcining xerogel from the reaction of yttrium chloride, boric acid and propylene oxide at 900 °C as verified from diffraction, vibration spectroscopic and microscopic techniques. Following this approach, orthoborate containing 50 mol% of Y and Gd was obtained and characterized. Dissolution limit of Ce3+ in Y0.50Gd0.50BO3 has been determined. Cerium doping resulted in the reduction in the optical band gap of these samples and appended photocatalytic ability in terms of degradation of aqueous rhodamine-6G (Rh-6G) dye solution. The intensity of 4f → 5d transition of Ce3+ increased monotonously with increase in cerium content. The role of distortion on the blue emission from Ce3+ and photocatalytic properties of these samples were comprehended by characterizing Li+, Ca2+ and Al3+-doped samples (up to 10 mol%) for yttrium. The distortion of Y0.50−xMxGd0.45Ce0.05BO3 lattice decreased in the order, RCa2+ > RY3+ > RLi+ > RAl3+, with the emission intensity (5d → 4f transitions) from Ce3+ increasing in the reverse order. Optical band gap was found to decrease for the Li+, Ca2+ and Al3+ doped samples as compared to undoped one. These doped samples retained their catalytic ability as verified from their use in the photo degradation of rhodamine-B (Rh-B) dye. An insight in to possible mechanism operative in the present photo catalytic degradation experiments has been attempted by carrying out trapping experiments.

The stable Cr isotope fractionation preserved in natural substances has been attributed predominantly to Cr(III)-Cr(VI) redox transformations. However, non-redox reaction pathways (e.g., ligand-promoted dissolution, ligand exchange, adsorption of Cr(III)) are liable to contribute to isotopic fractionation in natural systems given that soluble Cr(III)-ligands have been directly documented or modeled in several marine, continental, and hydrothermal environments. This study isolates the stable Cr isotope fractionation accompanying Cl-H2O ligand exchange during the transformation of three aqueous species in the Cr(III)-Cl-H2O system, [CrCl2(H2O)4]+aq (abr. CrCl2+ or S1), [CrCl(H2O)5]2+aq (abr. CrCl2+ or S2), and [Cr(H2O)6]3+aq (abr. Cr3+ or S3), at low pH (≤2). In dilute HCl (0.01 to 1 M), Cr3+ is the kinetically favoured species and transformation of CrCl2+ to CrCl2+ to Cr3+ via 2 steps of dechlorination/hydrolyzation begins immediately upon dissolution of a Cr(III)-Cl solid. Individual species are separated with cation exchange chromatography at different stages of transformation and inter- and intra-species (across an elution peak of one species) isotopic fractionation of up to 1 and 2 ‰ (δ53/52Cr), respectively, is documented. Comparison of peak elution characteristics with Cr-Cl-H-O isotopologue mass abundances suggests mass-dependent sorting of isotopologues alone cannot explain intra-species fractionation, supporting an earlier proposal that preferential adsorption of light Cr isotopes on the resin is driven by vibrational energy effects. The transformation of CrCl2+ to CrCl2+ is faster than CrCl2+ to Cr3+ and the rates of both transformations increase with higher solution pH. Preferential reaction of light Cr(III) isotopes into product species occurs during each transformation, consistent with closed-system, kinetic fractionation during Cl-H2O ligand exchange. Inter-species fractionation is assessed using time-series experiments beginning from the dissolution of two Cr(III)-Cl solids (dried NIST SRM979 standard and commercial CrCl3·6H2O salt) in 0.01 M HCl (pH ≈ 2). The e53/52Cr(CrCl2+/ CrCl2+) for the CrCl2+ to CrCl2+ reaction is -0.19 ‰ (SRM979) and -0.38 ‰ (salt) and the e53/52Cr(Cr3+/CrCl2+) for the CrCl2+ to Cr3+ reaction is consistent for both experiments at -0.49 ‰ (SRM979) and -0.51 ‰ (salt). Experiments where SRM979 is dissolved in 0.1 and 1 M HCl for a longer aging period provide preliminary evidence that the Cr3+/CrCl2+ Cr(III) isotopic fractionation scales with HCl concentration (transformation rate). Chromium(III) dissolved in 6 M HCl and aged 5 months still yields an inter-species Cr isotope distribution that is apparently inherited from kinetic effects (light Cr isotopes in Cr3+), attesting to the slow development of inter-species isotopic equilibrium, which instead predicts progressively heavier Cr isotopes from CrCl2+ to CrCl2+ to Cr3+. The kinetic Cr(III) isotopic fractionation documented herein is proposed to be relevant to understanding systems where aqueous Cr(III)-Cl species may be temporarily stable (e.g., metamorphic and hydrothermal systems or lateritic weathering). Further, the complexation of Cr(III) with other ligands (e.g., CO32-, organics), combined with additional kinetic effects of Cr(III) potentially occurring in soils or sediment, must be explored prior to establishing the significance of empirical stable Cr isotope signatures in marine and continental environments. Further understanding of non-redox effects may lead to stable Cr isotopes developing as a proxy for system pH or ligand chemistry.

The hydrazide (LH) using 6-(hydroxymethyl)picolinohydrazide and 2-hydroxynapthaldehyde was synthesized and characterized. This acts as a “TURN-ON” fluorescence sensor for Al3+, Zn2+ and Cd2+ ions by giving different emission maxima. The LH itself is weakly emissive having the maximum at 495 nm. Gradual addition of chloride salts of Al3+, Zn2+ and Cd2+ ions to LH, gave rise to emission peaks at 485, 570 and 540 nm, in MeOH-HEPES buffer solution (5 mM, pH = 7.3, 7:3, v/v). Addition of Al3+, Zn2+ and Cd2+ ions to a solution of LH generate new absorbance and fluorescence peaks due to binding of L− with Al3+ ion in 2:1 ratio; Zn2+ and Cd2+ ions in 1:1 ratios. Fluorescence reversibility was also studied by adding Al3+, Zn2+ and Cd2+ ions with Na2EDTA. Calculated detection limits of LH towards Al3+, Zn2+ and Cd2+ ions are 5.7 × 10−9, 1.09 × 10−6 and 1.64 × 10−6 M repectively. Based on experimental and theoretical results the formulae [Al(L)2]+, [Zn(L)Cl(H2O)2] and [Cd(L)Cl(H2O)2] were assigned and these complexes generated in situ are useful fluorophore to detect fluoride and dihydrogen phosphate ions, which act by quenching the fluorescence responses. The results of DFT/TDDFT calculations on LH, [Al(L)2]+, [Zn(L)Cl(H2O)2] and [Cd(L)Cl(H2O)2] were consistent with the experimental results.

A spiropyran-appended polysiloxane (SP-Si) was synthesized and characterized. The photochromic SP-Si has good thermal stability and exhibits high fatigue resistance to light. SP-Si acts as a dual colorimetric and spectroscopic probe for determining multi-scale pH over a wide range of 1∼14, and for detection of Ag+ and Fe3+ ions. Based on the transformation from colorless SP-Si solution without absorption at 440 nm to brown SP-Si/Ag+ showing extremely strong absorption at 440 nm by addition of Ag+ ions and subsequent transformation from brown to colorless SP-Si/Ag+/Hg2+ with very weak absorption at 440 nm after addition of 1 equivalent of Hg2+ ions, SP-Si/Ag+ system serves as a dual colorimetric and spectroscopic probe for highly selective and sensitive detection of Hg2+ ions. The detection is not interfered by common competitive metal ions such as Na+, K+, Li+, Ni2+, Fe2+, Zn2+, Co2+, Sr2+, Cu2+, Al3+, Ce3+ and Cr3+. Applicability of SP-Si for real water sample analysis has been proved.

The Mn4+,Zn2+:Li2TiO3red phosphors are synthesized through the high temperature solid state reaction method. The XRD, SEM, ICP, absorption spectra, excitation and emission spectra are described. The Zn2+ acts as the luminescence adjustment ion to enhance the red emission efficiency. The phosphors have the crystal structure consisting of [TiO6] and [LiO6] octahedral sites and the Zn-O-Zn bonds. Concentration dependence on Zn2+ in Mn4+,Zn2+: Li2TiO3 is presented. Results indicate the suitable concentration of Zn2+ can enhance the emission efficiency. In the region of 682–697 nm when excited by 475 nm, the external quantum efficiency are obtained to be 18%, correlative with the transition of 2Eg (2T1)→4A2g of Mn4+. The crystal field strength (Dq) and the Racah parameters (B and C) are estimated to evaluate the nephelauxetic effect of Mn4+. The white-LED performances and thermal stability are also presented.

The electrodeposition mechanism of pure phase Cu2ZnSnS4 (CZTS) thin film with subsequent annealing was investigated in detail. An electrolyte design principle of quaternary compounds was proposed. The complex ions of Cu(H2C6H5O7)+, Cu2(C6H5O7)+, Zn(C4H5O6)+, Sn(H2C6H5O7)+ and Sn2(C6H5O7)+, which influenced the reduction process and played important roles in co-deposition, were identified by UV spectra. Electrochemical studies indicated that trisodium citrate and tartaric acid could narrow the co-deposition potential range of the four elements to −0.8 V to −1.2 V (vs. SCE). The cause was the synergetic effect that trisodium citrate inhibited the reduction of Cu2+ and Sn2+ and tartaric acid promoted the reduction of Zn2+. The reduction of S2O32− was mainly attributed to the induction effect of the metallic ions, and the H+ dissociated from tartaric acid could also promote the cathode process of S2O32−. The reaction mechanism could be summarized as the following steps: (I) Cu(H2C6H5O7)+, Cu2(C6H5O7)+ → Cu, Sn(H2C6H5O7)+, Sn2(C6H5O7)+ → Sn, Zn(C4H5O6)+ → Zn; (II) the desorption of (H2C6H5O7)− and (C6H5O7)−, and the reduction of S2O32− induced by metallic ions and H+. The mechanism studies provided a path of electrolyte design for multicomponent compounds.

The removal of manganese, cobalt and nickel from industrial ammoniacal wastewaters has been studied using natural Cuban clinoptilolite modified to ammonium form. Favorable conditions to obtain the ammonium-clinoptilolite form (NH4-CLI) were determined from detailed kinetic studies of NH4+ ion-exchange in the clinoptilolite (CLI). Obtained NH4-CLI was characterized by IR spectroscopy and X-ray diffraction. NH4-CLI was used to remove Mn2+, Co2+ and Ni2+ from mixed aqueous solutions. The thermodynamic study on ion-exchange equilibrium between NH4+ in solution and these metallic cations from metal-clinoptilolite forms was performed. Increasing the temperature promotes the NH4+ exchange, which is controlled by the intracrystalline diffusion of ions inside the clinoptilolite. However, the activation energy of this process is not very high. This provides a wide temperature interval for the NH4-CLI efficient production. NH4-CLI removes Co2+ and Mn2+ by ion-exchange selectively at room temperature, being poorly selective to Ni2+, producing a well ions separation. Increasing the temperature greatly enhances the NH4-CLI capacity to remove these metal cations, which is substantially higher to Ni2+. The obtained values for the free energy variation and equilibrium constant lead to outline that the selectivity order of the metal-clinoptilolite forms by NH4+ at room temperature is Mn-CLI > Co-CLI > Ni-CLI. Divergences in the behavior to these exchange processes are associated with difference in the interaction of cations with their ligands in solution as well as into zeolite framework, and accessibility at ion-exchange sites inside clinoptilolite.

A novel coumarin-based receptor bearing a benzohydrazide (FCBH) was developed as a fluorescent chemosensor with high selectivity toward Cu2+. The sensor was successfully applied to the monitoring of Cu2+ in aqueous solution. After the addition of Cu2+ to FCBH, the color of the solution changed from greenish-yellow to red, and the absorption band at 457nm red-shifted to 517nm. The fluorescent green color of FCBH disappeared and the fluorescence emission was completely quenched in the presence of Cu2+. Upon the addition of Cu2+, deprotonation of FCBH occurred, and a 1:1 metal-ligand complex formed. DFT theoretical investigation was carried out to understand the behavior of the sensing probe toward Cu2+. Additionally, the quenched fluorescence of the FCBH-Cu2+ complex was restored upon the addition of CN- ions. The possible sensing mechanism of FCBH toward Cu2+ was derived from experimental and theoretical examinations.

Precipitation of hydrotalcite-like layered double hydroxides (HT-LDHs) from CO 3 2− -SO 4 2− -rich acidic and alkaline aqueous media through ionic substitution of Mg 2+ for Al 3+ + Fe 3+ and vice versa was investigated under ambient conditions. Diffractogram, spectroscopic, microprobe, microscopic, and synchrotron techniques were used to examine the mechanisms involved. The cations facilitated rapid precipitation of HT-LDH in alkaline conditions (pH ≥ 8.2) with SO 4 2− and CO 3 2− as the counter charge balancing interlayer anions, while initial formation of Fe 3+ - and Al 3+ -hydroxides in acidic conditions (pH ≥ 2.4) with subsequent transformation to MgAlFe-type HT-LDH (pH ≥ 8.2) occurred through substitution of Mg 2+ for Al 3+ and Fe 3+ . Substitution of Al 3+ and Fe 3+ in Mg 2+ -hydroxides did not yield HT-LDH, while the reverse, i.e., Mg 2+ substitution in Al 3+ and Fe 3+ -hydroxides, produced initial poorly ordered amorphous HT-LDH that gained better crystallinity and crystallite size upon neutralization. Linear combination fit analyses of XANES data suggest schwertmannite constituted the predominant Fe-phase until pH ∼3.7 followed by ferrihydrite and eventually HT-LDH after pH ≥ 10; basaluminite and epsomite constituted the predominant Al and Mg phases until pH ∼4.5, after which HT-LDH with minor Al(OH) 3 and HT-LDH with brucite, respectively, predominated. The study highlights that Mg 2+ substitution in Al- and Fe-precipitates is the governing mechanism for HT-LDH precipitation in oxic environments through neutralization of acidic cationic aqueous residues.

Stibnite solubility experiments and ambient temperature X-ray absorption spectroscopy (XAS) measurements of antimony in solution were undertaken to determine the aqueous speciation of Sb(III) in sulfide solutions having reduced sulfur concentrations from 0.001 to 0.1 mol kg− 1 S2 −total over the pH range of 3.5 to 12. At 30 °C, stibnite solubility curve was defined by a scheme of five species: Sb2S42 −, HSb2S4−, H2Sb2S52 −, H3SbS2O, and Sb(OH)3(aq). Equilibrium constants were determined for the following heterogeneous solubility reactions: Sb 2 S 3 s + HS − ⇋ Sb 2 S 4 2 − + H + S b 2 S 3 s + HS − ⇋ H S b 2 S 4 − S b 2 S 3 s + 2 HS − ⇋ H 2 S b 2 S 5 2 − 0.5 S b 2 S 3 s + 0.5 HS − + 1.5 H + + H 2 O l ⇋ H 3 S b S 2 O 0.5 S b 2 S 3 s + 3 H 2 O l ⇋ S b OH 3 aq + 1.5 HS − + 1.5 H + The Sb K-edge XAS measurements of antimony in alkaline (pH = 10.9 to 12) sulfide solutions gave average first shell coordination environments for strongly alkaline solutions that were consistent the speciation model derived from solubility experiments (i.e., Sb2S42 − and Sb(OH)3(aq)). XAS data enabled the elimination of a speciation model involving only Sb-S monomers at strongly alkaline pH. Antimony speciation in near neutral to strongly alkaline pH's is dominated by dimeric antimony sulfide complexes at sulfide concentrations > 0.001 mol kg− 1 S2 −total. Calculations of stibnite solubility and aqueous antimony speciation for conditions in anoxic marine basins indicate that sulfide species comprise a significant part of the total dissolved Sb(III) when mol kg− 1 S2 −total > ~ 0.00005 mol kg− 1 and that stibnite is close to saturation in some anoxic basins.

The designing of efficient, selective and stable adsorbents for heavy metals removal remained a challenging task, as most adsorbents did not exhibit consistent performance in diverse types of water. Unlike traditional adsorbents based on surface oxygen groups, thio-functionalized layered double hydroxide (LDH) as Mn-MoS 4 was designed by inserting MoS 4 2− anions into lamellar layers in LDH, and was applied as a highly stable, efficient and selective adsorbent for heavy metals removal. The record high distribution coefficient (K d ∼ 10 7 –10 8 mL/g), fast kinetics and enormous saturated uptake capacities (594, 564 & 357 mg/g) for Hg 2+ , Ag + and Pb 2+ placed Mn-MoS 4 as the most efficient adsorbent for the removal of such metals so far. Further, Mn-MoS 4 can completely tolerate the impact of huge concentration of background electrolytes (Ca 2+ , Mg 2+ , Na + , Cl − , NO 3 − & SO 4 2− ), and effectively control the concentrations of Hg 2+ , Ag + and Pb 2+ ions from tap water, lake water or industrial wastewater far below the limitation in drinking water. Similarly, Mn-MoS 4 is a potential filter due to its consistent performance over a broad pH range (from 2.0 to 11.0), changing ionic strength (up to 100 mM) or in the presence of organic matters. These remarkable features originate from the dominant chemical adsorption mechanism through inner-sphere coordination between thio groups as soft Lewis acid and Hg 2+ , Ag + and Pb 2+ as soft Lewis bases. More interestingly, LDH layers offer protective space for intercalated MoS 4 2− anions against oxidation, and facilitate Mn-MoS 4 with the advantage of easy storage and application over other adsorbents.

The present study concerns the preparation, characterization and testing of an inorganic ion exchanger Aluminum Silicate Modified Magnesia (ASMM). The ASMM composite was prepared using sol-gel technique and characterized by XRD, XRF, FTIR, TGA, DTA, SEM and surface area analysis. The capability of the prepared composite for the removal of (Cs+, Co2+ and Eu3+) from aqueous solution was evaluated. Sorption studies were carried out taking into account important parameters such as (pH, initial concentration, contact time and temperature). Kinetic and isotherm models were applied to the prepared composite, kinetic data is well fitted with pseudo-second order kinetic model, Dubinin-Radushkevich isotherm model indicates that sorption was controlled by chemisorption process. The removal efficiency found to be 80% for Cs+, 90% for Co2+ and 95% for Eu3+.

A novel electrochemical sensor was developed for the sensitive and selective detection of Cu2 +, Pb2 + and Cd2 +, which was based on NH2-MIL-88(Fe)-rGO composite modified glass carbon electrode (NH2-MIL-88(Fe)-rGO/GCE). The NH2-MIL-88(Fe)-rGO composite was facilely prepared by a one-step method and characterized by SEM, XRD, Raman spectrum and electrochemical methods. The stepwise GCE modified process was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of Cu2 +, Pb2 + and Cd2 + ions on the NH2-MIL-88(Fe)-rGO/GCE were explored by differential pulse anodic stripping voltammetry (DPASV). It was found that NH2-MIL-88(Fe)-rGO was capable of adsorbing Cu2 +, Pb2 + and Cd2 + ions from aqueous solutions and the NH2-MIL-88(Fe)-rGO/GCE could enhance the electrochemical responses of Cu2 +, Pb2 + and Cd2 + effectively. Important operational parameters such as electrolyte pH and deposition time were investigated and optimized for the determination of trace Cu2 +, Pb2 + and Cd2 + ions. Under the optimum conditions, the proposed electrochemical sensor had a linear range of 0.005––0.3 μM for Cd2 +, 0.01–0.3 μM for Pb2 + and 0.005–0.05 μM for Cu2 +, respectively. The limits of detection (LODs) are 4.9 nM for Cd2 +, 10 nM for Pb2 + and 3.6 nM for Cu2 +, respectively. The proposed method has been successfully applied to determine three metal ions in water samples. The developed sensor promises simple preparation, fast operation, good sensitivity and excellent reusability, showing great potential for monitoring of water quality.

An off-on-off emissive and colorimetric probe L , based on a Pseudo-Crown cysteine dye was designed for Copper (II). Compound L was studied in solution and in gas-phase (MALDI-MS) over alkaline, alkaline, earth-alkaline and transition metal ions (Li + , Na + , K + , Ca 2 + , Mg 2 + , Zn 2 + , Cu 2 + , Co 2 + , Ni 2 + , Pb 2 + , and Hg 2 + ) in organic media. The recognition of Cu 2 + by L lead to red/dark red colored complexes, one emissive L 2 Cu and another L Cu, less emissive. In regards to fluorescent quantum yield in both cases an increase respective to L was visualized (2 fold for L Cu and 7 fold for L 2 Cu). The paramagnetic nature of both complexes was proved by the synthesis of both complex species, as well as, through 1 H NMR and FTIR. Compound L demonstrate to be able to detect and quantify the minimal amounts of 1.3 μM/3.3 μM of Cu 2 + .

Hydrocalumite (CaAl-LDH) was prepared by the co-precipitation method with different Ca2+/Al3+ molar ratios. Hydrocalumite at the molar ratio of 4:1 Ca2+/Al3+ (4HC) showed to be efficient in the removal of Cu2+, Ni2+ or Zn2+ from the aqueous solution. The products formed between 4HC and the Cu2+, Ni2+ or Zn2+ cations were characterized by atomic absorption, SEM, XRD and IR. The effect of several factors such as pH, dose, contact time and metal concentration were evaluated. The maximum removal capacity was 7.0 mmol g−1 for Cu2+ and Ni2+, and 6.3 mmol g−1 for Zn2+. X-ray diffraction analyses showed that the products formed were CuAl, NiAl and ZnAl LDHs. The 4HC also was applied for removal of metal cations and the oxyanions Cr(VI) or phosphate from the same solution. In solutions containing 400 mg L−1 of Cu2+, Ni2+ or Zn2+ and 200 mg L−1 of Cr(VI) or phosphate (expressed as phosphorus), and in the presence of 1 g L−1 of 4HC, 100% of the metals and 60, 57 and 52% of Cr (VI) or 93, 80 and 92% of phosphate were removed, respectively. The results showed that 4HC has great potential to be used in the treatment of effluents containing metal cations and oxyanions.

The prepared titanium type lithium ion sieve H x TiO 3 are characterized and tested as adsorbents for selective adsorption of lithium from high Mg-containing brine. The maximum adsorption capacities of Li + , Na + , K + , Ca 2 + and Mg 2 + ions onto H x TiO 3 reached 36.34, 1.93, 1.99, 2.58 and 3.53 mg/g, respectively, under the initial pH 8.8 at 25 °C for 24 h. Adsorption isotherms and kinetic analysis indicated that the adsorption of Li + ions and other cations onto H x TiO 3 followed Langmuir isotherm model and pseudo-second order kinetic equation. A diffusion model simulation showed that the Li + ions had the highest external diffusion coefficients (7.7 × 10 − 2 cm s − 1 ) while the other cations had small effect on the adsorption rate of Li + . The Biot number was > 100 signified that these ions adsorption onto H x TiO 3 were controlled by the internal diffusion. The separation factors ( α ) of Li + over other cations were much > 1. In particular, the α value of Li + over Mg 2 + reached 4783, indicating the high selectivity for Li + . In addition, the Li + ion adsorption capacity kept constant during the six adsorption-desorption cycles and molar ratio of Mg to Li of eluents was as low as 0.08, indicating that the H x TiO 3 ion sieve could effectively extract Li + from the enriched brine.

ZnO nanoparticles were employed as efficient adsorbent for the removal of Cr 3 + , Co 2 + , and Ni 2 + ions from aqueous solution. The metal uptake percentage of Cr 3 + was higher than Co 2 + and the Co 2 + was greater than Ni 2 + . The obtained ZnO-Cr 3 + , ZnO-Co 2 + , and ZnO-Ni 2 + nanoparticles have been characterized by FT-IR, XRD, EDX, SEM, and TEM techniques. The impregnated metal ions are homogeneously dispersed on the surface of ZnO without altering its morphology. These materials (ZnO-Cr 3 + , ZnO-Co 2 + , and ZnO-Ni 2 + ) were tested as adsorbents for the removal of Acid blue 92 (AB92) from aqueous solution. It was found that ZnO-Cr 3 + was the more efficient adsorbent for the dye. Under several reaction conditions, the removal efficiency increased with the increase in the adsorbent dose and the initial concentration of the dye. The adsorption process was retarded with increasing the pH and addition of NaCl and a triple mixture of salts (NaCl, Na 2 SO 4 , CH 3 COONa). The activation and thermodynamic parameters characteristics of the dye removal were determined. The value of activation energy obtained (25.71 kJ mol − 1 ) indicated physisorption process. The dye uptake followed pseudo-second order kinetics and obeyed the Langmuir adsorption isotherm. ZnO-Cr 3 + proved efficient catalyst compared with ZnO-Co 2 + , ZnO-Ni 2 + and pure ZnO for the catalytic oxidative dissipation of AB92 with H 2 O 2 or irradiation with UV light.

2-(3-Ethylthioureido)benzoic acid was prepared and characterized by electronic spectrum, elemental analysis, Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectrum and mass spectrum. The produced ligand was applied for the preconcentrative of Fe3+, Co2+, Cu2+ and Zn2+ in aqueous samples by cloud point extraction methodology. Triton X-114 was used as extractant. Experimental parameters that may affect the extraction process were examined and optimized; such as pH, ligand and triton concentrations, type of diluting solvent, extraction temperature and ionic strength. The calibration curves were linear upto 500 μg L−1 for Fe3+, Cu2+ and Zn2+ and upto 200 μg L−1 for Co2+. The achieved detection limits were 1.5, 0.23, 0.71 and 0.35 μg L−1 for Fe3+, Co2+, Cu2+ and Zn2+ respectively. The accuracy was established by analysis of certified reference materials (Seronorm whole blood L2 and ZCS ZC85006 Tomato). The proposed procedure was used for preconcentration of these metal ions in water, biological and food samples prior to their determination by flame atomic absorption spectrometry.

The tie-line and solubility data, i.e. formic acid (FA) + n-butanol + water + NaCl, were resolved at T = 298.15 K and under ambient pressure. The Othmer–Tobias equation was applied in this study. T...

The reversibility of cesium adsorption in contaminated soil is largely dependent on its interaction with micaceous minerals, which may be greatly influenced by various cations. Herein, we systematically investigated the effects of NH4+, K+, Mg2+, and Ca2+ on the adsorption/desorption of Cs+ into different binding sites of vermiculitized biotite (VB). Original VB was initially saturated by NH4+, K+, or Mg2+; we then evaluated the adsorption of Cs+ on three treated VBs, and the desorption by extraction with NH4+, K+, Mg2+, or Ca2+ was further evaluated. Our structural analysis and Cs+ extractability determinations showed that NH4+ and K+ both collapsed the interlayers of VB, resulting in the dominant adsorption of Cs+ to external surface sites on which Cs+ was readily extracted by NH4+, K+, Mg2+, or Ca2+ irrespective of their species, whereas Mg2+ maintained the VB with expanded interlayers, leading to the overwhelming adsorption of Cs+ in collapsed interlayer sites on which the Cs+ desorption was difficult...

In this work, a detailed study of the redox properties of solid solution RhxCe1–xO2−δ in correlation with its catalytic activity in CO oxidation reaction was carried out. The ex situ X-ray photoelectron spectroscopy technique was applied to follow the charging states of the elements on the surface during the redox treatments at a temperature range of 25–450 °C. The results were compared with the data of temperature-programmed reduction by CO. The dissolution of rhodium in the ceria bulk considerably increased the mobility of CeO2 lattice oxygen, with redox transitions Ce4+ ↔ Ce3+ and Rh3+ ↔ Rhnδ+ observed already at low temperatures (below 150 °C). The reduced rhodium clusters (Rhnδ+) formed during the reduction treatment significantly improved the catalytic activity of the RhxCe1–xO2−δ solid solution. The small size of the rhodium clusters (Rhnδ+) and high defectiveness of the fluorite phase provided the reversibility of Rhnδ+/CeO2 ↔ RhxCe1–xO2−δ transitions upon redox treatment, resulting in the high re...

Ruthenium complexes containing the pentapyridyl ligand 6,6′′-(methoxy(pyridin-2-yl)methylene)di-2,2′-bipyridine (L-OMe) of general formula trans-[RuII(X)(L-OMe-κ-N5)]n+ (X=Cl, n=1, trans-1+; X=H2O, n=2, trans-22+) have been isolated and characterized in solution (by NMR and UV/Vis spectroscopy) and in the solid state by XRD. Both complexes undergo a series of substitution reactions at oxidation state RuII and RuIII when dissolved in aqueous triflic acid–trifluoroethanol solutions as monitored by UV/Vis spectroscopy, and the corresponding rate constants were determined. In particular, aqueous solutions of the RuIII-Cl complex trans-[RuIII(Cl)(L-OMe-κ-N5)]2+ (trans-12+) generates a family of Ru aquo complexes, namely trans-[RuIII(H2O)(L-OMe-κ-N5)]3+ (trans-23+), [RuIII(H2O)2(L-OMe-κ-N4)]3+ (trans-33+), and [RuIII(Cl)(H2O)(L-OMe-κ-N4)]2+ (trans-42+). Although complex trans-42+ is a powerful water oxidation catalyst, complex trans-23+ has only a moderate activity and trans-33+ shows no activity. A parallel study with related complexes containing the methyl-substituted ligand 6,6′′-(1-pyridin-2-yl)ethane-1,1-diyl)di-2,2′-bipyridine (L-Me) was carried out. The behavior of all of these catalysts has been rationalized based on substitution kinetics, oxygen evolution kinetics, electrochemical properties, and density functional theory calculations. The best catalyst, trans-42+, reaches turnover frequencies of 0.71 s−1 using CeIV as a sacrificial oxidant, with oxidative efficiencies above 95 %.

Synthesis and characterization of potassium zinc hexacyanoferrate (KZnFC) as nano ion exchanger material are performed. Sorption characterization investigations on the removal of some radionuclides (134Cs, 60Co), heavy metal (Pb2+) and lanthanides (Ce3+ and Gd3+) from aqueous and nitric acid solutions using mesoporous KZnFC ion exchange have been done. Selective removal of 134Cs rather than 60Co and Ce3+ (lanthanides) is achieved in aqueous solution and nitric acid solution, respectively. The maximum sorption capacity of 134Cs, 60Co, Pb2+, Ce3+ and Gd3+ is 170, 10.5, 3.88, 0.72 and 0.55 mg/g, respectively, onto nano-material of KZnFC.

In order to understand water chemistry after impoundment of the Three Gorges Reservoir (TGR), the authors assessed the hydrogeochemical parameters (water temperature, pH, conductivity, dissolved O2), major element composition, and the carbon stable isotopic value of dissolved inorganic carbon (δ13CDIC) in summer and winter at various depths in the water column at TGR in 2009. In reservoir water, the DO values are lower in winter than in summer, but the pH values and conductivity values are higher. Ca2+ and Na+ are the dominant cations and HCO3− and SO42− are the dominant anions. In surface waters, the δ13CDIC values are more negative in summer than they are in winter, whereas the dissolved inorganic carbon (DIC) concentrations are relatively lower. In the water column, the DIC and δ13CDIC values do not change significantly with water depth or seasons. The DIC content shows a dilution effect in summer and is not modified by phytoplanktonic activity or photosynthesis. Even after the dam obstructed flow, the chemical profile of water in TGR is similar to that of the natural rivers before impoundment. Therefore, in this study, the water at TGR still had riverine characteristics and was still a heterotrophic system.

The study of ion chemistry involving the NO2+ is currently the focus of considerable fundamental interest and is relevant in diverse fields ranging from mechanistic organic chemistry to atmospheric chemistry. A very intense source of NO2+ was generated by injecting the products from the dielectric barrier discharge of a nitrogen and oxygen mixture upstream into the drift tube of a proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) apparatus with H3 O+ as the reagent ion. The NO2+ intensity is controllable and related to the dielectric barrier discharge operation conditions and ratio of oxygen to nitrogen. The purity of NO2+ can reach more than 99% after optimization. Using NO2+ as the chemical reagent ion, the gas-phase reactions of NO2+ with 11 aromatic compounds were studied by PTR-TOF-MS. The reaction rate coefficients for these reactions were measured, and the product ions and their formation mechanisms were analyzed. All the samples reacted with NO2+ rapidly with reaction rate coefficients being close to the corresponding capture ones. In addition to electron transfer producing [M]+ , oxygen ion transfer forming [MO]+ , and 3-body association forming [M·NO2 ]+ , a new product ion [M-C]+ was also formed owing to the loss of C═O from [MO]+ .This work not only developed a new chemical reagent ion NO2+ based on PTR-MS but also provided significant interesting fundamental data on reactions involving aromatic compounds, which will probably broaden the applications of PTR-MS to measure these compounds in the atmosphere in real time.

Separation of rare earth ions (RE3+) from aqueous solution is a tricky problem due to their physico-chemical similarities of properties. In this study, we investigate the influence of the functiona ...

Macrocyclic benzo-thio crown ethers and benzo-oxo crown ethers were prepared using an esterification–ring closing method. These compounds were synthesised using 2,2′-dithiodibenzoyl chloride, and various glycols and dithiols, in the presence of pyridine base under a nitrogen atmosphere in chloroform. All reactions were performed under reflux condition with conventional heating and microwave (MW) irradiation. The synthesised macrocycles were characterised by FT-IR, 1 H NMR, 13 C NMR, LC-MS, and elemental analysis methods. Extraction studies have been performed on these original macrocycles using liquid-liquid ion-pair extraction with Li + , Na + , K + , Ni 2+ , Ca 2+ , Mg 2+ , Zn 2+ , Fe 2+ ,Fe 3+ , Co 3+ , Pb 2+ , Cr 3+ , Ag + , and Cd 2+ .The K D , ext.%, ΔG and log K Ext values were also calculated. While ( U1-U7 ) ligands exhibits selectivity for Zn 2+ , Ag + , Ca 2+ , Pb 2+ , Fe 3+ , Cr 3+ , Co 2+ , Mg 2+ , Cd 2+ , and Ni 2+ metal salts, they showed no selectivity for Li + , K + and Na + metal salts. Furthermore, Fe 3+ is the most selective cation for all ligands for competitive extraction. We also observed that microwave heating can have certain benefits over conventional ovens: reaction rate acceleration, milder reaction conditions, higher chemical yield, and lower energy usage. These ligands could be used as metal sensors, enzyme inhibitors, antimicrobial/antifungal agents, and in biological applications.

Zincon (ZI) is one of the most common chromophoric chelating probes for the determination of Zn 2 + and Cu 2 + ions. It is also known to bind other metal ions. However, literature data on its binding properties and molar absorption coefficients are rather poor, varying among publications or determined only in certain conditions. There are no systematic studies on Zn 2 + and Cu 2 + affinities towards ZI performed under various conditions. However, this widely commercially available and inexpensive agent is frequently the first choice probe for the measurement of metal binding and release as well as determination of affinity constants of other ligands/macromolecules of interest. Here, we establish the spectral properties and the stability of ZI and its complexes with Zn 2 + , Cu 2 + , Cd 2 + , Hg 2 + , Co 2 + , Ni 2 + and Pb 2 + at multiple pH values from 6 to 9.9. The obtained results show that in water solution the MZI complex is predominant, but in the case of Co 2 + and Ni 2 + , M(ZI) 2 complexes are also formed. The molar absorption coefficient at 618 nm for ZnZI and 599 nm for CuZI complexes at pH 7.4 in buffered ( I = 0.1 M) water solutions are 24,200 and 26,100 M − 1 cm − 1 , respectively. Dissociation constants of those complexes are 2.09 × 10 − 6 and 4.68 × 10 − 17 M. We also characterized the metal-assisted Zincon decomposition. Our results provide new and reassessed optical and stability data that are applicable to a wide range of chemical and bioinorganic applications including metal ion detection, and quantification and affinity studies of ligands of interest. Synopsis Accurate values of molar absorption coefficients of Zincon complex with Zn 2 + , Cd 2 + , Hg 2 + , Co 2 + , Ni 2 + , Cu 2 + , and Pb 2 + for rapid metal ion quantification are provided. Zincon stability constants with Zn 2 + and Cu 2 + in a wide pH range were determined.

The effect of Na + /K + ion exchange on the distribution of the modifier ions and on their interaction with the oxygen atoms in the network is investigated in ternary Na,Mg- and Na,Ca- silicate glasses using 17 O triple-quantum magic-angle-spinning nuclear magnetic resonance spectroscopy. The results indicate that the K + ions preferentially exchange with the Na + ions present in {Na,Ca}-NBO and {Na,Mg}-NBO environments, while the Na-NBO environment is not significantly affected. Remelting of the ion-exchanged glasses leads to a homogenization of the modifier ion distribution around the NBO sites. The dynamical site preference for the Na + /K + ion exchange has far-reaching implications in our understanding of the alkali ion transport and more specifically of the mixed-alkali effect in silicate glasses.

Electrochemical selective ion separation via capacitive deionization, for example, separation of lithium resource from brine, using lithium ion batteries is proposed and demonstrated to have the potential for separating specific ions selectively from a solution containing diverse ions. This separation method is of great industrial concern because of applicability in various fields such as deionization, water softening, purification, heavy metal removal, and resource recovery. Nevertheless, besides the selectivity of materials for lithium ion batteries toward Li + , there is very little investigation on the selectivity of the materials for sodium ion batteries toward Na + . Here, the electrochemical selectivity of sodium manganese oxide (Na 0.44 MnO 2 ), one of the most widely used material in sodium ion batteries, for Na + and other cations (K + , Mg 2+ , and Ca 2+ ) is investigated. Selective Na + separation using the system consisting of Na 0.44 MnO 2 and a Ag/AgCl electrode is successfully demonstrated from a solution containing diverse cations (Na + , K + , Mg 2+ , and Ca 2+ ) via a two-step process that involves a capturing step (charging process) and a releasing step (discharging process). The results showed that Na 0.44−x MnO 2 has over 13 times higher selectivity for Na + than for K + and 6–8 times higher selectivity for Na + than for Mg 2+ and Ca 2+ in the electrolyte containing equal concentrations of the respective ions. Additionally, as a practical demonstration, Na + was successfully separated from an industrial raw material used for pure KOH production (estimated ratio of Na + :K + = 1:200).

A selective and multifunctional chemosensor 1 for Fe2+, Co2+ and Cu2+ was designed and synthesized. 1 could simultaneously detect Fe2+, Co2+ and Cu2+ by changing its color from colorless to pink (Fe2+) and to yellow (Co2+ and Cu2+), respectively, in a near-perfect aqueous solution. The binding modes of 1 to Fe2+, Co2+ and Cu2+ were determined to be a 1:1, 2:1, and 1:1, respectively, through Job plot and ESI-mass spectrometry analysis. The detection limits (0.43 μM, 0.11 μM and 0.28 μM) of 1 for Fe2+, Co2+ and Cu2+ were much lower than the US Environmental Protection Agency (EPA) guidelines (5.36 μM for Fe2+ and 1.7 μM for Co2+) and the WHO guideline (31.5 μM for Cu2+) for the drinking water. Moreover, the chemosensor 1 could be used to quantify Fe2+, Co2+ and Cu2+ in water samples, and applied to test kits for detecting Fe2+, Co2+ and Cu2+. The sensing mechanisms of Co2+ and Cu2+ by 1 were supported by theoretical calculations.

The control of the corrosion phenomenon occurring at the metal interface requires the development of new non-toxic anticorrosion additives. For this purpose, zirconium orthophosphate compounds (Zr(HPO 4 ) 2 ,H 2 O noted α-ZrP) were synthesized by both hydrothermal and refluxing methods The Ca 2+ -cationic exchange in the layered structure is kinetically favoured by low crystallinity of α-ZrP synthesized by refluxing process, and leads to the formation of CaZr(PO 4 ) 2 ,4H 2 O, noted Ca 2+ -ZrP. The H + /Ca 2+ exchange mechanism is mainly triggered by acid-base considerations, and especially the pKa of α-ZrP/Ca 2+ -ZrP acid-base couple (evaluated to 2.5). Both compounds are acidic compounds by internal exchangeable H+ for α-ZrP and surface protons for Ca 2+ -ZrP, and can be used as potential inhibitors of zinc corrosion. Electrochemical measurements show that Ca 2+ -ZrP compounds dispersed in the NaCl electrolyte buffer the pH value over a long time and therefore allow controlling the corrosion rate of zinc.

Selective catalytic reduction of NOx with NH3 (NH3-SCR) was investigated over a series of Fe-containing samples prepared by the coprecipitation method. The doping effect of introducing representative cations (M = Ti4+, Ce3+/4+, Al3+) with apparent different acidity and redox properties was systematically studied. The results indicated that suitable acidity and redox property as well as the balance between them were extremely important for the NH3-SCR reaction. Ti4+-doped catalysts showed the most prominent effect, obtaining 4-fold increase in NOx conversion compared to Fe2O3 at 100 °C, due to their strong acidity and slight reducibility. Samples with Ce3+/4+ doping, which could be facilely reduced but lacked sufficient acidity, showed lower catalytic activity than Al3+-doped samples with relatively stronger acidity. Thus, the activity followed Fe9Ti1Ox > Fe9Al1Ox > Fe9Ce1Ox. In addition, the Fe9Ti1Ox catalyst exhibited an ∼80% NOx conversion and remained stable in the presence of SO2 and H2O at 250 °C for...

Divalent calcium ion conducting solid electrolyte with three-dimensional NASICON-type structure, (CaxHf1−x)4/(4−2x)Nb(PO4)3, was successfully developed by introducing Ca2+ cations into HfNb(PO4)3 as mother solid. The existence of three kinds of high valence cation, Hf4+, Nb5+, and P5+, in the structure successfully realized the effective reduction of electrostatic interaction functioned to Ca2+ in the structure. The (Ca0.05Hf0.95)4/3.9Nb(PO4)3 solid showed considerably higher Ca2+ cation conductivity and lower activation energy than those of previously reported NASICON-type Ca0.5Zr2(PO4)3 solid.