Hydroxide Hydrate Research Articles

Ovalbumin으로 유발된 아토피피부염 모델 마우스에 대한 복합한약추출물 경구투여의 효과

Objective: This study was to evaluate whether herbal mixture (HM-A : Houttuynia cordata Thunberg, Rubus coreanus, Rehmannia glutinosa, Prunus yedoensis, HM-B : Houttuynia cordata Thunberg, Rubus coreanus, Rehmannia glutinosa, Angelica gigas nakai) supresses the development of atopic dermatitis in Balb/c mice sensitized by ovalbumin. Methods: Mice were sensitized by intraperitoneal injection of ovalbumin plus aluminum hydroxide hydrate, followed by epicutaneous sensitization for 6 weeks. After induced atopic dermatitis, HM-A and HM-B were orally administrated for two weeks(once a two days) as a 50 mg/kg concentration. After all mice were sacrificed at the end of the experiment, skin and blood were harvested. Results: Oral administration group was reduced the infiltration of eosinophils, mast cells and total T cells on the skin areas as well as blood analysis. Also, cutaneous expression of IL-4,13,17 decreased. Blood IgE level was decreased. Conclusion: These drugs could be potential candidates for the atopic dermatitis.

Hydrothermal synthesis of CuV2O6 supported on mesoporous SiO2 as SO3 decomposition catalysts for solar thermochemical hydrogen production

Hydrothermal synthesis of CuV2O6 supported on 3-D ordered mesoporous SiO2 (CuV/SiO2) was studied to evaluate the catalytic activity for SO3 decomposition, which is a key step in solar thermochemical hydrogen production. A composite oxide hydrate, Cu3O(V2O7)·H2O, and an oxide hydroxide hydrate, Cu3(OH)2V2O7·(H2O)2, were formed at lower hydrothermal temperatures (≤200 °C). The oxide hydrate phase mainly yielded Cu2V2O7 after calcination at 600 °C in air. By contrast, the hydrothermal synthesis at 250 °C (CuV/SiO2@250) directly crystallized CuV2O6 from the oxide hydroxide hydrate, although its very large particle size (∼5 μm) is not suitable for the catalytic application. The SO3 decomposition activity measured at 600 °C was associated with the yield as well as the dispersion of CuV2O6, giving rise to the maximum for the hydrothermal synthesis at 200 °C. CuV/SiO2@250 achieved the highest catalytic activity at the reaction temperature of 650 °C, because the melting phase of CuV2O6 penetrated mesoporous SiO2 and thus improved the dispersion of the active phase.

Reaction products of diorganotin(IV) oxides, R2SnO, with nitric acid. Part 2 – R = n-butyl and t-butyl

The reaction of diorganotin(IV) oxides, R2SnO with R = n-butyl and t-butyl, with nitric acid in different stoichiometric ratios resulted in the formation of different products depending on the organic groups attached to the tin atom: the diorganotin(IV) dinitrate dihydrates, n-Bu2Sn(NO3)2·2H2O (2d) and t-Bu2Sn(NO3)2·2H2O (2e), the mixed diorganotin(IV) nitrate methoxide oxide n-Bu2Sn(NO3)(n-Bu2SnOMe)O (6), and the diorganotin(IV) nitrate hydroxide hydrate t-Bu2Sn(NO3)(OH)·H2O = [t-Bu2Sn(OH)(H2O)][NO3] (7). On examination of the solubility of the primary reaction products in different solvents, the three additional compounds t-Bu2Sn(NO3)(OH)·DMSO (8), t-Bu2Sn(NO3)(OH)·THF, and 2-t-Bu2Sn(NO3)(OH)·DMF = [t-Bu2Sn(OH)dmf]2[NO3]2·[t-Bu2Sn(NO3)OH]2 (9) could be isolated. All compounds have been structurally characterized by single crystal X-ray diffraction (primary results for 7) with special attention paid to dimensionality (2d and 2c = monomeric, hydrogen bonded molecules; 6 = dimeric molecules of ladder-type structure; 7 = dimeric cation; 8 = dimeric molecule with hydrogen bonded solvent molecules; 9 = both components dimeric), tin coordination (6, 7, 8, and 9 = trigonal bipyramidal; 2d and 2e = eightfold), and nitrate bonding modes (7 and 9 = isolated, hydrogen bonded; 6, 8, and 9 (component 2) = monodentate; 2d and 2e = symmetrical bidentate), the latter one being analyzed using both Sn–O and N–O distances.

Facile synthesis of porous single crystalline ZnO nanoplates and their application in photocatalytic reduction of Cr(VI) in the presence of phenol

Porous single crystalline ZnO nanoplates were successfully synthesized through a facile and cost-effective hydrothermal process at low temperature condition, followed by annealing of the zinc carbonate hydroxide hydrate precursors. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) measurements. The porous single crystalline ZnO nanoplates are with 12nm thickness and pore ranging from 10nm to several tens of nanometers. The porous structure of the ZnO nanoplates caused large amount of surface defects which worked as photogenerated holes’ shallow trappers and largely restrained the recombination of photogenerated electrons and holes, resulting in a significantly high photocatalytic activity and durability toward the photoreduction of Cr(VI) under UV irradiation. Moreover, a synergistic effect, that is, increased photocatalytic reduction of Cr(VI) and degradation of phenol, can be observed. Furthermore, the synergistic photocatalytic mechanism has also been discussed. Those results present an enlightenment to employ porous single crystalline nanomaterials to remove Cr(VI) and organic pollutants simultaneously.

Corrosion of the Pozzolan Concrete in Sulfates

Sulfate attack and its effects are important from both scientific and industrial viewpoints. Itis perceived that cements containing pozzolan have better performance in sulfate solutions,since the pozzolanic reactions reduce the quantity of calcium hydroxide and increasecalcium silicate hydrate. This paper investigates the physical and mechanical properties ofconcretes made by blended cement containing Algerian natural pozzolan of volcanic origin, and Portland cement. in order to better determine the pozzolanic effect of the pozzolan addition in the concrete, the analysis of the experimental results of the effect of the partial replacement of the cement by the naturalpozzolana showed that it contributes positively to the improvement of its mechanical characteristics, its durability with respect to the permeability to the chlorine ions, the ultrasonic pulse velocity as well as the sulphate resistance. The present study confirms the pozzolanic reactivity of the natural pozzolans used.

First-Principles Studies of Paramagnetic Vivianite Fe3(PO4)2·8H2O Surfaces

Using density-functional theory, we have computed the structural and electronic properties of paramagnetic vivianite crystal Fe3(PO4)2·8H2O and its (010)-(1 × 1) and (100)-(1 × 1) surfaces. The properties of bulk vivianite are studied with a set of functionals: HSE06, PBE, AM05, PBEsol, and PBE with on-site Coulomb repulsions corrections (PBE+U). The appropriate U parameter is estimated by considering the HSE06 results, and it is used to study the vivianite surfaces. The computed surface energy predicts the (010) surface to be the most stable. The less stable (100) surface is observed to have important reconstructions with the spontaneous formation of a water molecule at the surface and two hydroxide hydrate anions per unit cell. Using thermodynamical considerations within DFT, we have calculated the phase diagram of the (010) surface in equilibrium with hydrogen gas. The results suggest that under ultralow hydrogen pressure, the (010) surface with two hydrogen vacancies is stable. The electronic structure calculations for the surfaces are complemented with the computed scanning tunneling microscopy (STM) images for constant-current mode. The topology is dominated by the surface Fe-3d states that protrude into the vacuum.

Comparative Performance of Three Magnesium Compounds on Thermal Degradation Behavior of Red Gum Wood.

The effect of basic magnesium carbonate (BMC), magnesium hydroxide (MH), and magnesium chloride hydrate (MCH) on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and X-ray diffraction (XRD) characterization. The results showed common fire retardation actions of the three compounds by releasing incombustible gas and/or water vapor to dilute combustible gas in the flaming zone, and by converting to MgO, which had a satisfactory protective wall effect on the wood. Individually, BMC absorbed heat from the wood at the pre-decomposition stage and, thus, slowed down wood pyrolysis process. It slightly increased the char yield by charring in both the charring stage and the char calcination stage. MH lost water at about 270°C, close to the temperature at which wood thermally degraded. MH rendered wood char quickly, and the compact char layer impeded further carbonization and burning of inner wood. MCH promoted charring with Mg2+ as a Lewis acid, and increased wood char yield. MCH also released Cl· free radical and HCl at 167°C, which easily coordinated with combustion reaction radical, and slowed down, even inhibited, the combustion chain reaction.

The formation of different Mg-Al LDHs (Mg/Al=2:1) under hydrothermal conditions and their application for Zn2+ ions removal

The formation of different Mg-Al LDHs (Mg/Al = 2:1) under hydrothermal conditions (200?C; 4-24 h) was investigated in the 4MgCO3?Mg(OH)2?5H2O - ?-Al2O3/Al(OH)3 - H2O and Mg5(CO3)4(OH)2?4H2O - ?-Al2O3 - H2O systems. It was determined that chemical nature of the initial Mg containing components changes the formation mechanism of the synthesis products during isothermal curing. Magnesium aluminum hydroxide hydrate is crystallized by using 4MgCO3?Mg(OH)2?5H2O as starting material while hydroxide hydrate in the Mg5(CO3)4(OH)2?4H2O presence. The sequence of the compounds formation is presented. It should be noted that different modifications of Al containing components have only a slight influence on the meixnerite-type LDH hydrothermal synthesis. It was determined that after 45 min of sorption all Zn2+ ions are incorporated into the crystal structure of hydrotalcite. It should be underlined that crystallinity of the latter compound do not change during ion exchange experiments. Thus, the latter compound can be used as adsorbent for Zn2+ ion removal. Synthesized samples were characterized by powder X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), simultaneous thermal analysis (STA) and scanning electron microscopy (SEM).

A coordination chemistry approach for shape controlled synthesis of indium oxide nanostructures and their photoelectrochemical properties

False color scanning electron microscopic images of indium hydroxide cubes, maize corns and indium sulfate hydroxide hydrate crystals.

Thermodynamics of hydronium and hydroxide surface solvation

The concentration of hydronium and hydroxide at the water–air interface has been debated for a long time. Recent evidence from a range of experiments and theoretical calculations strongly suggests the water surface to be somewhat acidic. Using novel polarizable models we have performed potential of mean force calculations of a hydronium ion, a hydroxide ion and a water molecule in a water droplet and a water slab and we were able to rationalize that hydronium, but not hydroxide, is slightly enriched at the surface for two reasons. First, because the hydrogen bond acceptance capacity of hydronium is weaker than water and it is more favorable to have the hydronium oxygen on the surface. Second, hydroxide ions are expelled from the surface of the droplets, due to the entropy being lower when a hydroxide ion is hydrated on the surface. As a result, the water dissociation constant pKw increases slightly near the surface. The results are corroborated by calculations of surface tension of NaOH solutions that are in reasonable agreement with the experiment. The structural and thermodynamic interpretation of hydronium and hydroxide hydration provided by these calculations opens the route to a better understanding of atmospheric and surface chemistry.

Characterization of Early Pozzolanic Reaction of Calcium Hydroxide and Calcium Silicate Hydrate for Nanosilica Modified Cement Paste

This study intends to investigate the early pozzolanic reaction of Nanosilica (nS) modified cement paste (NMCP) by the characterization technique of Calcium Hydroxide (CH) and Calcium Silicate Hydrate (C-S-H ) using Fourier Transform Infrared Spectroscopy (FT-IR). NMCP samples were prepared with water-binder ratio of 0.50. nS of 5-15nm particle size were used as 1%, 3% ,5% ,7% and 10% replacement of cement by weight. All samples were cured in the concrete laboratory at daily room temperature (T) and relative humidity (RH) in the range of 18-28oC and 65-90%, respectively. Powdered samples were prepared and tested at day 1,7,21 and 28. It was found that characterization technique used were able to give satisfactory qualitative indication of pozzolanic reactivity of NMCP by the presence and absence of C-S-H and C-H that can indicate which replacement has higher pozzolanicity. NMCP exhibited a higher pozzolanic reactivity compare to conventional cement paste by which cement performance was enhanced.

Corrosion behavior of arc sprayed Al–Zn–Si–RE coatings on mild steel in 3.5 wt% NaCl solution

Al–Zn–Si–RE coating was deposited on mild steel by arc spraying Al–Zn based alloy wire with a high Al content. The corrosion behavior of Al–Zn–Si–RE coating was investigated by corrosion morphologies and electrochemical measurements. The results indicated that Al–Zn–Si–RE coating exhibited homogeneous distributions of elements and a dense homogeneous lamellar microstructure with good scale adhesion. The phases of the coatings are Zn-rich phase, Al-rich phase, Al0.403Zn0.597 and Al9Si phase. Corrosion products had been deposited in the defects, which caused self-sealing behavior and hindered further corrosion. Corrosion products formed on Al–Zn–Si–RE coating surface consisted mainly of simonkolleite [Zn5(OH)8Cl2·H2O], zinc aluminum hydrotalcites [Zn0.71Al0.29(OH)2(CO3)0.145·xH2O, Zn0.70Al0.30(OH)2(CO3)0.15·xH2O, Zn6Al2(OH)16CO3·4H2O] and aluminum chloride hydroxide hydrate [Al5Cl3(OH)12·4H2O]. Corrosion products had been deposited in the defects, which caused self-sealing behavior and hindered further corrosion. Furthermore, sacrificial anodic protection played a dominant role during the corrosion process. There were different corrosion stages of the coating in sodium chloride solution, such as pitting-dissolution-redeposition, active dissolution, cathodic protection and physical barriers caused by corrosion products. Finally, schematic model of the protective mechanisms of Al–Zn–Si–RE coating during immersion in sodium chloride solution was given.

Carbonation of Portland Cement Studied by Diffuse Reflection Fourier Transform Infrared Spectroscopy

Carbonation is a natural ageing process for cement. This study focuses on how the carbonation rate varies with selected hydration times and atmospheric conditions during the early stages of reacting dried cement paste. Diffuse reflection Fourier transform infrared spectroscopy is shown to be a suitable technique to monitor the formation of carbonates in cement. Combined with a previously developed freeze drying technique, carbonation can be studied at specific hydration stages. In ambient air both calcium hydroxide and calcium silicate hydrate (C–S–H) in cement are carbonated. Increased hydration time enhances the carbon dioxide uptake, which indicates that the calcium in the hydration products reacts more easily than the calcium in the clinker phase. In a humid CO2 atmosphere, the carbonation process is so pronounced that it decomposes C–S–H into calcium carbonate and silica. In a moist N2 atmosphere no carbonation occurs, but the sulfate chemistry of the cement seems to be affected due to the formation of ettringite.

Magnesium hydroxide – expanded graphite composite pellets for a packed bed reactor chemical heat pump

The chemical heat pump is a promising technology for the recovery of waste heat from industrial processes or cogeneration systems. It can be used for storing the surplus heat during low demand periods and release it for shaving the peaks of heat demand, with a benefit for the overall system efficiency. In this work, a packed bed reactor chemical heat pump based on the dehydration and hydration of magnesium hydroxide has been investigated. Due to its high thermal conductivity, expanded graphite was mixed with magnesium hydroxide to enhance heat transfer. The composite material, named EM, was developed and tested experimentally in order to understand the effects of expanded graphite on the chemical reactions occurring in the packed bed reactor.

Experimental etch-and-rinse adhesives doped with bioactive calcium silicate-based micro-fillers to generate therapeutic resin–dentin interfaces

ObjectivesThis study aimed at evaluating the therapeutic bioactive effects on the bond strength of three experimental bonding agents containing modified Portland cement-based micro-fillers applied to acid-etched dentin and submitted to aging in simulated body fluid solution (SBS). Confocal laser (CLSM) and scanning electron microscopy (SEM) were also performed. MethodsA type-I ordinary Portland cement was tailored using different compounds such as sodium–calcium–aluminum–magnesium silicate hydroxide (HOPC), aluminum–magnesium–carbonate hydroxide hydrates (HCPMM) and titanium oxide (HPCTO) to create three bioactive micro-fillers. A resin blend mainly constituted by Bis-GMA, PMDM and HEMA was used as control (RES-Ctr) or mixed with each micro-filler to create three experimental bonding agents: (i) Res-HOPC, (ii) Res-HCPMM and (iii) Res-HPCTO. The bonding agents were applied onto 37% H3PO4-etched dentin and light-cured for 30s. After build-ups, they were prepared for micro-tensile bond strength (μTBS) and tested after 24h or 6 months of SBS storage. SEM analysis was performed after de-bonding, while CLSM was used to evaluate the ultra-morphology/nanoleakage and the mineral deposition at the resin–dentin interface. ResultsHigh μTBS values were achieved in all groups after 24h. Only Res-HOPC and Res-HCPMM showed stable μTBS after SBS storage (6 months). All the resin–dentin interfaces created using the bonding agents containing the bioactive micro-fillers tested in this study showed an evident reduction of nanoleakage and mineral deposition after SBS storage. ConclusionResin bonding systems containing specifically tailored Portland cement micro-fillers may promote a therapeutic mineral deposition within the hybrid layer and increase the durability of the resin–dentin bond.

A combined QXRD/TG method to quantify the phase composition of hydrated Portland cements

A new method is reported for quantifying the mineral phases in hydrated cement pastes that is based on a combination of quantitative X-ray diffractometry (QXRD) and thermogravimetry (TG). It differs from previous methods in that it gives a precise measure of the amorphous phase content without relying on an assumed stoichiometric relationship between the principal hydration products, calcium hydroxide (CH) and calcium silicate hydrate (C–S–H). The method was successfully applied to gray and white ordinary Portland cements (GOPC and WOPC, respectively) that were cured for up to 56days. Phase distributions determined by QXRD/TG closely matched those from gray-level analysis of backscattered scanning electron microscope (BSEM) images, whereas elemental compositions obtained for the amorphous phase by QXRD/TG agreed well with those measured by quantitative energy dispersive X-ray spectroscopy (EDS).

Microwave-assisted hydrothermal synthesis of spinel nickel cobaltite and application for supercapacitors

A novel method has been developed in this study for preparation of the spinel nickel cobaltite (NiCo2O4) nanoparticles. The workflow comprises a microwave-assisted hydrothermal process using nickel nitrate hexahydrate and cobalt nitrate hexahydrate as precursor and urea as hydrolysis-controlling agent, followed by calcination. First, the needle-like nickel carbonate hydroxide hydrate and cobalt basic carbonate are obtained by microwave-assisted hydrothermal process under 800W microwave irradiated for 5min. Then, the needle-like nickel carbonate hydroxide hydrate and cobalt basic carbonate composites are calcined at 400°C for 2h to fabricate NiCo2O4 nanoparticles. The NiCo2O4 nanoparticles show a high-specific capacitance of 332.8F/g under a mass loading of 2mg/cm within −0.5 and 0.5V at a scan rate of 100mV/s in a 0.5M H2SO4 solution. The NiCo2O4 is analyzed and characterized by X-ray power diffraction (XRD), transmission electron microscopy (TEM), infrared spectroscopy (IR), and cycle voltammograms (CV).

Highly regular and ultra-thin porous ZnO nanosheets: An indirect electrodeposition method using acetate-containing precursor and their application in quantum dots-sensitized solar cells

Ultra-thin porous ZnO nanosheets with high regularity were obtained by electrodeposition followed by annealing. The nanosheets were first electrodeposited by controlling the concentration of potassium acetate (KAc) in nitrate electrolyte. The effects of KAc concentration on the electrochemical behavior, the composition and morphology of samples were further discussed. It was indicated that the as-deposited nanosheets were a mixture of ZnO and zinc acetate hydroxide hydrate (ZAHH). After annealing at 450°C for 30min, ZnO/ZAHH nanosheets with smooth surfaces were converted to pure ZnO nanosheets with porous structure, which were oblong in shape, ultra-thin (about 20nm in thickness) and constructed with well-distributed single-layer ZnO nanoparticles with the size of 30–60nm. As preliminary application in quantum dots-sensitized solar cells (QDSCs), porous ZnO nanosheets were co-sensitized with CdS and CdSe QDs and the QDSCs based on porous ZnO nanosheets deposited for 15min achieved a high efficiency of 2.67%.

Designed constitution of NiO/Ni nanostructured electrode for high performance lithium ion battery

Porous NiO/Ni foam electrode is fabricated by a simple two-step method. Firstly, nickel hydroxide hydrate nanoflakes are deposited on Ni foam via a chemical liquid deposition (CLD) method. Then NiO/Ni architecture is obtained by subsequent graft growth in air atmosphere at 350°C. Galvanostatic battery testing shows that NiO electrode exhibits fine capacity retention and good rate performance. It exhibits high initial discharge and charge capacity of 1.94 and 1.36mAhcm−2, maintaining of 1.41 and 1.38mAhcm−2 after 140 cycles under a discharge/charge rate of 0.4C. It delivers high discharge capacity retention of 70% (comparing with that of 0.2C) even at a high rate of 2.5C. After that, the discharge capacity can gradually resume along with the decrease of discharge/charge rate, showing capacity retention of 105% when lowering the discharge/charge rate to 0.2C. The fine electrochemical performance of NiO/Ni is due to the maintenance of porous architecture and the prevention of active nano-sized NiO from aggregation in cycling, which is relevant to both the interweaved structure of NiO nanoflakes and the graft growth between NiO and Ni.

Porous ZnO Sheets Transformed from Zinc Sulfate Hydroxide Hydrate and Their Photoluminescence Performance

Highly crystalline, porous ZnO sheets were prepared from chemically-deposited zinc sulfate hydroxide hydrate (ZSH) sheets by sintering at 1000 °C. The formation mechanism of ZSH in Zn 2+ - hexamethyltetramine (HMT) precursor system, the transformation process of ZSH to ZnO, and the crystalline, microstructural and optical properties of the ZnO sheets were investigated. The porous ZnO sheets possessed a well-defined hexagonal shape with controllable size (10-50 μm) and thickness (200-500 nm), high crystallinity, and strong ultraviolet photoluminescence without detectable defect- related visible emission. Submicron-sized pores (100-500 nm) and polygonal or irregular ZnO particles resulting from the limited mass transport during high temperature sintering were observed in the ZnO sheets. Analysis of the formation mechanism indicated that the high affinity of SO 2-