Search results for "Zinc"
showing 10 items of 1081 documents
Chitosan Functionalized with Carboxyl Groups as a Recyclable Biomaterial for the Adsorption of Cu (II) and Zn (II) Ions in Aqueous Media
2022
The modification of chitosan represents a challenging task in obtaining biopolymeric materials with enhanced removal capacity for heavy metals. In the present work, the adsorption characteristics of chitosan modified with carboxyl groups (CTS-CAA) towards copper (II) and zinc (II) ions have been tested. The efficacy of the synthesis of CTS-CAA has been evaluated by studying various properties of the modified chitosan. Specifically, the functionalized chitosan has been characterized by using several techniques, including thermal analyses (differential scanning calorimetry and thermogravimetry), spectroscopies (FT-IR, XRD), elemental analysis, and scanning electron microscopy. The kinetics an…
Inorganic Phosphate and Arsenate within New Tetranuclear Copper and Zinc Complexes: Syntheses, Crystal Structures, Magnetic, Electrochemical, and The…
2017
Three, PO43–/HPO42– and AsO43–-incorporated, new tetranuclear complexes of copper(II) and zinc(II) ions have been synthesized and fully characterized. In methanol–water, reactions of H3cpdp (H3cpdp = N,N′-Bis[2-carboxybenzomethyl]-N,N′-Bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol) with copper(II) chloride in the presence of either NaOH/Na2HPO4·2H2O or KOH/Na2HAsO4·7H2O lead to the isolation of the tetranuclear complexes Na3[Cu4(cpdp)2(μ4-PO4)](OH)2·14H2O (1) and K2[Cu4(cpdp)2(μ4-AsO4)](OH)·162/3H2O (2), respectively. Similarly, the reaction of H3cpdp with zinc(II) chloride in the presence of NaOH/Na2HPO4·2H2O yields a tetranuclear complex, Na(H3O)2[Zn4(cpdp)2(μ4-HPO4)]Cl3·121/2H2O (3). All c…
Synthesis, structure and properties of new heterometallic octanuclear Li2Na2Cu4 and decanuclear Li2Zn8 complexes
2019
Abstract A carboxylate containing polydentate ligand in combination with exogeneous succinate (suc) has been used to stabilize heterometallic octanuclear [Li2Na2Cu4(cpdp)2(suc)2(CH3OH)2(H2O)4]Cl2·6H2O (1) and decanuclear Na(H3O)2[Li2Zn8(cpdp)4(suc)2(H2O)4]Cl2Br3·6MeOH·19H2O (2) complexes. The reaction of ligand H3cpdp (H3cpdp = N,N'-bis[2-carboxybenzomethyl]-N,N'-bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol) with stoichiometric amounts of CuCl2/sodium succinate, and ZnCl2/sodium succinate, allowed isolation of complexes 1 and 2, respectively. Analyses of single crystal X-ray structures indicate that complex 1 is capped by two [Cu2(cpdp)]+ molecular building units and two succinate linkers, w…
Nanocrystalline ZnCO3—A novel sorbent for low-temperature removal of H2S
2013
Abstract The reactivity of a nanocrystalline ZnCO 3 toward H 2 S (0.2 vol% in N 2 /H 2 mixture) at 140–180 °C was characterized by thermal gravimetric analysis and by breakthrough curves measurements. We have found that under used conditions transformation of ZnCO 3 into ZnS is complete and the rate determining step of the sulfidation is the surface reaction. Such behavior is in strike contrast with that of ZnO whose sulfidation is severely limited by diffusion. The higher reactivity of ZnCO 3 in comparison with ZnO is attributed to the different microstructure of ZnS layer formed in these materials after a partial sulfidation. As in ZnO–ZnS transformation the molar volume increases (from 1…
Precursor Polymers for the Carbon Coating of Au@ZnO Multipods for Application as Active Material in Lithium-Ion Batteries
2014
The synthesis of statistical and block copolymers based on polyacrylonitrile, as a source for carbonaceous materials, and thiol-containing repeating units as inorganic nanoparticle anchoring groups is reported. These polymers are used to coat Au@ZnO multipod heteroparticles with polymer brushes. IR spectroscopy and transmission electron microscopy prove the successful binding of the polymer onto the inorganic nanostructures. Thermogravimetric analysis is applied to compare the binding ability of the block and statistical copolymers. Subsequently, the polymer coating is transformed into a carbonaceous (partially graphitic) coating by pyrolysis. The obtained carbon coating is characterized by…
Synthesis, Characterization and Sorption Capacity Examination for a Novel Hydrogel Composite Based on Gellan Gum and Graphene Oxide (GG/GO)
2020
A novel hydrogel composite based on gellan gum and graphene oxide (GG/GO) was synthesized, characterized and tested for sorption capacity in this work. The microstructural, thermogravimetric and spectroscopic analysis confirmed the formation of the GG/GO composite. Comparative batch sorption experiments revealed a sorption capacity of the GG/GO composite for Zn (II) ions of approximately 2.3 higher than that of pure GG. The GG/GO composite exhibits a maximum sorption capacity of 272.57 mg/g at a pH of Zn (II) initial solution of 6. Generally, the sorption capacity of the sorbents is approximately 1.5 higher in slightly acidic conditions (pH 6) comparative with that for strong acidic conditi…
Synthesis and characterization of α-hopeite, Zn3(PO4)2·4H2O
1999
Orthorhombic α-Zn3(PO4)2·4H2O, α-hopeite, was synthesized from an aqueous solution of zinc acetate and orthophosphoric acid. The synthesis from these starting materials yielded best results with respect to purity and crystallinity. Structural characteristics of the compound were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and thermogravimetric/differential thermal analysis (TG/DTA). Supplemental data came from surface area, particle size distribution, and density measurements. The obtained compound proved to be highly crystalline and stoichiometric. Dehydration of α-hopeite is accompanied by at least two endothermic effect…
Dicaesium silver zinc thiocyanate, Cs2[AgZn(SCN)5]
2001
The title compound, dicaesium(I)-μ-thiocyanato-κ2N:S-zinc(II)-tetra-μ-thiocyanato-κ2S:N-argentate(I), crystallizes in the orthorhombic space group Pmn21 and contains units of composition AgZn(SCN)3 lying on a mirror plane and bonded together through Cs+ ions and thiocyanate groups. The crystal studied contained equal numbers of inversion twins.
Batch experiments for the determination of the Ti(IV,III) couple in 1 moldm-3 HCl, 2 moldm-3 NaCl medium at 25°C
2009
The determination of the Ti(IV, III) redox couple formal potential in 1 M HCl 2 M NaCl medium at 25°C through batch experiments involving the preparation of Ti(IV) and Ti(III) mixtures via the reaction of Ti(IV) with Zinc amalgam, has been carried out with emf measurements in order to verify the correctness of the previous value that the authors obtained by a coulometric-potentiometric investigation in the same conditions. The results from the two independent methods are in good agreement: 9 ± 1 mV the first and 9 ± 2 the average batch result.
Cytotoxicity and bioactivity of various pulpotomy materials on stem cells from human exfoliated primary teeth.
2017
Aims To investigate the cytotoxicity and bioactivity of several pulpotomy materials: Biodentine (Septodont, Saint-Maur-des-Fosses, France) MTA (Angelus, Londrina, PR, Brazil), Theracal LC (Bisco Inc., Schamburg, IL, USA) and IRM (Dentsply DeTrey GmbH, Konstanz, Germany), after contact with stem cells isolated from human exfoliated primary teeth (SHEDs). Methodology SHEDs were cultured in the presence of the eluates of various pulpotomy materials for 24, 48 and 72 h. Cell viability was determined by mitochondrial dehydrogenase enzymatic (MTT) assay. Apoptosis and changes in cell phenotype were evaluated by flow cytometry. Also, an in vitro scratch wound-healing assay was used to determine th…