Oxidized coal as a sorbent for softening water

Sorption tests carried out oxidized nitric acid active carbon in H+- and Na+- form in relation to cations Mg2+ and Ca2+ and mixture thereof. Values obtained statistical volumetric capacity samples and mass loss them during processing nitric acid, that is oxidation state. Discovered correlation between these data and relevant sorption volume samples. Demonstrated a possible water softening oxidized coal subject to specific solution acidity.

Molecular Rotor based on an Oxidized Resorcinarene

Molecular single stator-double rotor activity of an oxidized resorcinarene (fuchsonarene) macrocycle containing unsaturated hemiquinonoid groups at its meso positions was investigated. Fuchsonarenes containing two hemiquinonoid substituents at diagonally-opposed meso-positions with two electron rich phenol groups at the remaining meso-positions between the hemiquinonoid groups. All meso-substituents are in proximity at one side of the resorcinarene macrocycle (so-called rccc-type isomer) with rotational activity of the phenol meso-substituents. Rotation rates of the phenol moieties can be controlled by varying temperature, solvent polarity and acidity of the medium of study with rotation being thermally activated in neutral and acidic media and tunable in the range from 2 s-1 to 20,000 s-1. Experimental and computational data indicate that rotation of the mobile phenol meso-substituents is remotely affected by interactions with acidic solvents at the carbonyl C=O groups of macrocyclic acetyloxy groups, which occurs with the emergence of a lower energy electronic absorption band whose intensity is correlated with both the acidity of the medium and the rotation rate of the phenol substituents. Time-dependent DFT calculations suggest that the low energy band is due to a molecular conformational adjustment affecting electronic conjugation caused by strong interaction of macrocyclic acetyloxy carbonyl groups with the acid medium. The work presents a molecular mechanical model for estimating solution acidity and also gives insight into a possible method for modulating rotor activity in molecular machines.

Preparation and characterization of NiO/HY catalyst

NiO/HY catalyst was prepared by impregnation method with the nickel acetate as the precursor and the HY as the carrier. The influences of impregnation solution acidity, the nickel species and the calcination process on the catalyst structure were studied by the nitrogen physical adsorption and XRD. The hydrogenation reaction of dicyclopentadiene (DCPD) was selected to evaluate the catalytic performance of the prepared catalyst. Experiments showed that the structure of the catalyst is critical to its performance, and NiO/HY catalyst has a good application prospect.

Synthesis of Mn(II)-containing paratungstate B from aqueous solutions acidified by acetic acid

The method of pH-potentiometric titration and mathematical simulation were used to study the equilibrium processes in aqueous solutions of the WO42––CH3COOH–H2O system in the acidity range Z=(CH3COOH)/(Na2WO4)=0.8–1.7 at СW=0.01 mol L–1 and T=2980.1 K, a constant ionic strength being maintained by sodium nitrate as a background electrolyte ((NaNO3)=0.10 mol L–1). We developed the models of polyoxotungstate anions formation and the equilibrium transformation processes, which adequately describe experimental pH vs. Z dependences. It was found that acetic acid using to create the solution acidity that is necessary for the formation of isopoly tungstate anion contributes only to the formation of protonated paratungstate B anions Нх[W12O40(ОН)2](10–х)– (where x=0–4). We calculated the logarithms of the concentration equilibrium constants of the polyanion formation and plotted the distribution diagrams. Double sodium-manganese(II) paratungstate B Na8(H2O)28Mn(H2O)2[H2W12O42]4H2O was synthesized at Z=1.00 to confirm the results of the mathematical modeling. The chemical composition of the prepared salt was established by chemical elemental analysis, thermal analysis, FTIR spectroscopy, and single crystal X-ray analysis. The stepwise process of salt dehydration was studied by means of differential thermal analysis.

Adsorption of Zirconium Ions by X-Type Zeolite

Dependence of zirconium adsorption value on agitation time, solution acidity, equilibrium concentrations of zirconium cations, and zeolite NaX particle size was investigated. The two most common adsorption theories Langmuir and Freundlich, were used to analyzing equilibrium adsorption data. Nonlinear approximation shows that the Freundlich adsorption theory provides higher R2 and lower χ2 for zirconium adsorption by NaX than the Langmuir adsorption theory. Experimental maximum adsorption values of NaX toward zirconium and strontium cations are 75 mg·g-1 and 156 mg·g-1, respectively. The desorption studies of zirconium ions from the surface of NaX by 1% oxalic acid and 10% HNO3 were performed. Degradation of the adsorbent in nitric acid was studied in a batch mode. The recovered suspended particles filter cake was investigated by X-ray fluorescence analysis. Alumina oxide (Al2O3) fraction decreases, and MgO is completely washed out from the adsorbent matrix in concentrated HNO3.

Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems: synthesis and crystal structures of Rb2[(UO2)(Cr2O7)(NO3)2] and two new polymorphs of Rb2Cr3O10

Three new rubidium polychromates, Rb2[(UO2)(Cr2O7)(NO3)2] (1), γ-Rb2Cr3O10 (2) and δ-Rb2Cr3O10 (3) were prepared by combination of hydrothermal treatment at 220 °C and evaporation of aqueous solutions under ambient conditions. Compound 1 is monoclinic, P 2 1 / c $P{2}_{1}/c$ , a = 13.6542(19), b = 19.698(3), c = 11.6984(17) Å, β = 114.326(2)°, V = 2867.0(7) Å3, R 1 = 0.040; 2 is hexagonal, P 6 3 / m $P{6}_{3}/m$ , a = 11.991(2), c = 12.828(3) Å, γ = 120°, V = 1597.3(5) Å3, R 1 = 0.031; 3 is monoclinic, P 2 1 / n $P{2}_{1}/n$ , a = 7.446(3), b = 18.194(6), c = 7.848(3) Å, β = 99.953(9)°, V = 1047.3(7) Å3, R 1 = 0.037. In the crystal structure of 1, UO8 bipyramids and NO3 groups share edges to form [(UO2)(NO3)2] species which share common corners with dichromate Cr2O7 groups producing novel type of uranyl dichromate chains [(UO2)(Cr2O7)(NO3)2]2−. In the structures of new Rb2Cr3O10 polymorphs, CrO4 tetrahedra share vertices to form Cr3O10 2− species. The trichromate groups are aligned along the 63 screw axis forming channels running in the ab plane in the structure of 2. The Rb cations reside between the channels and in their centers completing the structure. The trichromate anions are linked by the Rb+ cations into a 3D framework in the structure of 3. Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems is discussed.

EXTRACTION OF CHLORIDE AND THIOCYATE ACIDOCOMPLEXES OF METALS IN SALTING-OUT AGENT – MONOALKYLPOLYETHYLENE GLYCOL – WATER SYSTEMS

Distribution of iron (III), thallium (III, gallium, titanium (IV) chloride complexes in sodium chloride – synthanol DS-10 – water and ammonium sulfate – synthanol DS-10 – water systems, as well as iron (III), cobalt , nickel, cadmium and copper (II) thiocyanate complexes in the ammonium sulfate – synthanol DS-10 – water system investigated. It was found that the main influence on extraction is exerted by solution acidity and nature of the salting-out agent. The conditions for quantitative extraction of thallium (III) and gallium in the form of chloride complexes, as well as the conditions for maximum extraction of iron (III), zinc and cobalt thiocyanate complexes are established.

Experimental Evidence for a General Model of Modulated MOF Nanoparticle Growth

<p>Nanoparticles of metal-organic frameworks (nanoMOFs) boast superior properties compared to their bulk analogs, yet little is known about how common synthetic parameters dictate particle sizes. Here, we provide experimental evidence for the “seesaw” model of nanoMOF growth. Solution acidity, ligand excess, and reactant concentrations are decoupled and shown to form the key independent determinants of nanoMOF sizes, thereby validating the proposal that nanoMOFs arise from coupled equilibria involving ligand deprotonation and metal-ligand complexation. By achieving the first demonstration of a seesaw relationship between nanoMOF sizes and ligand excess, these results provide further proof of the model, as they required deliberate manipulation of relationships outlined by the model. Exploring the relative impacts of these parameters reveals that ligand excess has the greatest ability to decrease sizes, although low acidity and high concentrations can exhibit similar effects. As a complement to existing models of polymer formation and crystal growth, the seesaw model therefore offers a powerful tool for reliable control over nanoMOF sizes.</p>