European Journal of Chemistry
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Vanadyl(acetylacetonate)2 mediated hydrolytic splitting of 1,3,5-triazine in a solution of toluene at 130 °C: The crystal structure of its axial formamide adduct
Get PDFA toluene reaction of vanadyl bis(acetylacetonate) with 1,3,5-triazine produces a symmetrical three-fold hydrolytic cleavage of the triazine, and these three formamide moieties are found in the crystal structure. One of the resulting formamides attaches itself to the sixth (axial) position of the vanadyl complex, producing materials in which the remaining two formamides are trapped in the resulting lattice. Those crystals belong in space group Pca21, Z = 4 and the final R-factor = 0.030 for 3213 data collected at 100 K
Effect of calcination temperature on the structure and morphology of zinc oxide nanoparticles synthesized by base-catalyzed aqueous sol-gel process
Get PDFThis study reports the base-catalyzed aqueous sol-gel synthesis of zinc oxide nanoparticles. The solution was primarily comprised of zinc nitrate hexahydrate as a metal precursor, isopropyl alcohol and water as solvents, and glycerin as a stabilizing agent. The effect of calcination temperature on the structure and morphology of the prepared nanoparticles was investigated by varying the calcination temperature from 500 to 900 °C. The X-ray diffraction analysis, infrared spectroscopy, thermogravimetric analysis, and field emission scanning electron microscopy were employed to determine the crystal structure, surface functional groups, thermal stability, and surface morphology of the nanoparticles. The particle size was found to be directly proportional to the calcination temperature
Electronic band structure of Bi5O7NO3 and its methyl orange removal mechanism
Get PDFA detailed study of the electronic band structures and partial density of states of Bi5O7NO3 with different exchange correlation functionals was performed using the generalized gradient approximation. Bi5O7NO3 has two direct energy gap transitions of 2.84 and 3.66 eV at the experimental lattice parameters, revealing a semiconductor characteristic of a crystal. Molecular Mechanics; however, tends to underestimate the band-gap energies with indirect characters. This deviation is due to the slight decrease in the cell edges and the significant increase in the β angle during the optimization process. The mechanism of removal of methyl orange and its derivatives by the Bi5O7NO3 unit cell, which has the same experimental UV-Vis band gap, was later investigated through a DMol3 module. To do that, frontier molecular orbitals, global reactivity parameters, and electrostatic potential surface maps were evaluated. The high values of the electrophilicity indexes hint that the dyes are more reactive and can work as good electrophile species. A molecular packing of dye molecules and the ionic natural of Bi5O7NO3 generate a synergistic effect between π-π stacking, anion-π stacking, cation-π stacking and electrostatic interactions, which are thought to be the driven forces during dye removal
Evaluation of the effects of significant factors and interactions on the enrichment of arsenic and chromium by pipette tip solid phase extraction using novel P-ZrO2CeO2ZnO nanoparticles/alginate beads
Get PDFThe study seeks to determine the most significant factors affecting arsenic and chromium enrichment using novel P-ZrO2CeO2ZnO nanoparticles/alginate beads in order to minimize the total number of runs needed to successfully run the experiment. The effects of interactions between factors were also evaluated so that the optimum conditions which are not affected by the other factors are chosen for the experiments. The most significant factors on arsenic and chromium enrichment were screened for by using a half-factorial design, followed by the optimization of significant factors using the full-factorial design, and the interaction between factors was determined using ANOVA and interaction plots. The most significant factors for chromium recovery were sample volume, eluent flow rate, and sorbent dosage. For both chromium and arsenic recovery, interactions occurred between sample volume, dosage, and pH. The optimum conditions chosen for the experiment that gave favourable results for both metal ions were sample volume 5 mL, dosage 40 mg, pH = 7 and eluent flow rate 1 mL/min. This study showed that a preliminary screening step for the most significant factors for arsenic and chromium enrichment helps to reduce the number of total runs, and for the same experiment interactions between factors were present; hence, it is necessary to take this into account during the experimental design
Modification of coconut shell charcoal for metal removal from aqueous solutions
Get PDFTreatment of the contaminated aqueous solutions to improve their quality is indispensible for their reuse resulting in an emergent challenge to develop facile, nontoxic and less energy consuming techniques to purify water. Present study is therefore aimed at the synthesis of an adsorbent using agricultural waste i.e. coconut shell. The charcoal obtained from coconut shell was modified by acid activation and manganese doping following a simple chemical route. The products were characterized by scanning electron microscopy, energy dispersive X-ray analysis and infrared spectroscopy. Preliminary studies were carried out to compare the adsorption potential of acid modified coconut shell charcoal (AMCSC) and manganese doped coconut shell charcoal (MDCSC) for the removal of chromium (VI) and iron (III) from aqueous solutions. Various physicochemical parameters such as adsorbent dosage, initial metal ions concentration and pH were studied. MDCSC was found to be a better adsorbent for metals as compared to AMCSC and removed chromium more efficiently than iron from synthetic solutions i.e. 56.10% at optimum conditions i.e. 0.6 g/L adsorbent dosage, 10 mg/L initial metal ions concentration and pH = 3. The effect of adsorbents on color and conductivity of the aqueous solutions was also noted; slight variation in color of all the aqueous solutions with a maximum of 91.67% removal was observed
Crystal and molecular structure of Michler’s ketone as a pure phase
Get PDFThe pure phase crystals of Michler’s ketone, [4-(CH3)2NC6H4]2CO, are reported herein as monoclinic in the space group P21/c with Z’ = 2 by single-crystal X-ray diffraction. The data collection of the title compound proved quite difficult, which could explain why the structure has not been reported previously. The crystallographically independent molecules in the asymmetric unit differ by dihedral angles of 24.60/30.34° and 25.25/27.20° between the essentially planar 4-dimethylaminophenyl (DMAP) rings and the central C2C=O plane of the ketone and dihedral angles of 52.14 and 47.41°, respectively, between the DMAP planes. A DMAP ring of each molecule overlaps in the lattice with a methyl ring that overlays the ring centroid of the opposite number (CMe-Cg distances of 3.452 and 3.505 Å), describing sets of trifurcated CAr-acceptor hydrogen bond interactions (HBIs). The trifurcated HBIs possess H∙∙∙CAr distances of 2.90, 2.75, and 2.86 Å; CMe∙∙∙Car distances of 3.554(5), 3.798(5) and 3.881(5) Å; and ÐCMe-H∙∙∙CAr of 115.0, 121.3 and 167.7°, respectively. Stabilization of the asymmetric unit in the title compound is further achieved by supramolecular synthons such as CMe-H∙∙∙CAr (2.831 Å), CAr-H∙∙∙O (2.561 Å) and CAr-H∙∙∙H-CAr (2.290 Å) and coulombic CMe-Ocontact (3.209 Å). The structures of the two independent molecules in the asymmetric unit of the title compound were compared with the same molecule as found in the following co-crystals, adducts or salts: a halogen-bonded adduct with 1,4-diiodotetrafluorobenzene; a hydrogen-bonded adduct with a fluorinated phenol; a coordination complex between the ketone and a trimeric mercury acceptor; and two salts from protonation or methylation at one of the amino nitrogen atoms