The research on the high quality TiO2, MoO3-doped WO3 electrochromic film

The high quality TiO2, MoO3-doped WO3 electrochromic film was prepared by the sol–gel method for the first time. The sol, which has hydrogen peroxide (H2O2) and oxalic acid (H2C2O4), was very stable at room temperature and quite suitable for the deposition of films. The WO3 electrochromic film prepared from this doped sol had excellent performance, such as short response time, no cracks, good adhesion to the substrate, high coloring efficiency and longevity of service.     

Experimental study and thermodynamic modeling of the MgO–NiO–SiO2 system

The MgO–NiO–SiO₂ system has been studied by a combination of thermodynamic modeling and experimental measurements of phase equilibria. A complete literature review, critical evaluation and thermodynamic modeling of phase diagrams and thermodynamic properties of all oxide phases in the MgO–NiO–SiO₂ system at 1 atm total pressure are presented. To resolve the contradictions in the literature data, a new experimental investigation has been carried out over the temperature range from (1400 to 1650) °C using an equilibration and quenching technique followed by electron probe X-ray microanalysis (EPMA). Tie-lines between olivine and monoxide, olivine and proto-pyroxene, liquid and olivine and liquid and cristobalite have been measured. The whole set of experimental data, including the new experimental results and previously published data, has been taken into consideration in thermodynamic modeling of oxide phases in the MgO–NiO–SiO₂ system. The Modified Quasichemical Model has been used for the liquid phase. A simple random mixing model with a polynomial expansion of the excess Gibbs energy has been used for the monoxide solid solution. The models for olivine and proto-pyroxene were developed within the framework of the Compound Energy Formalism. The optimized model parameters reproduce all available thermodynamic and phase diagram data within experimental error limits.     

Influence of modifiers and glass-forming ions on the crystallization of glasses of the NaCaPO4–SiO2 system

Silicate?Cphosphate glasses of the XYPO₄?CSiO₂ and XYPO₄?CSiO₂?CAlPO₄ (where X?=?Na⁺ and/or K⁺ and Y?=?Ca²⁺ and/or Mg²⁺) systems have been the subject of the presented investigations. Bioactive glasses from these systems are the base for obtaining glass-crystalline biomaterials through a direct crystallization. However, growth of crystalline phases very adversely affects the bioactivity of the glasses. Uncontrolled growth of crystalline phases can be reduced by means of a glass phase separation phenomenon in the silicate?Cphosphate glasses because boundaries of inclusion-matrix phase may be a barrier limiting the growth of crystalline phases. Microscopic and EDX investigations which have been carried out have shown that glass phase separation occurs in glasses belonging to XYPO₄?CSiO₂ and XYPO₄?CSiO₂?CAlPO₄ systems. Introduction of aluminum ions into the glass structure leads to a rapid homogenization of its texture. Based on DSC examinations it has been found out that crystallization of the glasses of XYPO₄?CSiO₂ systems is a multistep process. The presence of several (the number depends on the type of modifiers and glass-forming ions) clearly separated exothermic peaks in DSC curves of investigated glasses makes it possible to crystallize only the inclusions with the matrix remaining amorphous or vice versa. It has been shown that, crystallization of glasses of XYPO₄?CSiO₂?CAlPO₄ system is single-stage process, which is the consequence of the homogenizing effect of aluminum ions on their texture.     

Synthesis of the novel CuAl2O4–Al2O3–SiO2 nanocomposites for the removal of pollutant dye and antibacterial applications

Research on Chemical Intermediates - CuAl2O4–Al2O3–SiO2 nanocomposites with different amounts of CuAl2O4 (40, 50, 60 and 70 wt. %) were synthesized by the sol–gel method and...     

Assessment of adsorption properties of inorganic–organic hybrid cyclomatrix type polyphosphazene microspheres for the removal of Pb(II) ions from aqueous solutions

Abstract

Inorganic–organic hybrid cyclomatrix type polyphosphazene microspheres (poly[cyclotriphosphazene-co-(4,4′-diaminodiphenylmethane)]) (HDMS) and poly[cyclotetraphosphazene-co-4,4′-diaminodiphenylmethane)] (ODMS) were prepared to investigate their possible use as alternative adsorbents for the comparative study on Pb(II) ions removal from aqueous solutions. The structures of the microspheres were elucidated by Fourier Transform Infrared (FTIR) spectroscopy and Dynamic Light Scattering (DLS) measurements, and the surface morphologies were also observed by Scanning Electron Microscopy (SEM). The adsorption of Pb(II) ions onto HDMS and ODMS from aqueous solutions was examined by means of pH, temperature, contact time and concentration. Furthermore, adsorption kinetics and isotherm models were applied and the experimental data fitted well with Langmuir isotherm and pseudo-second-order kinetic models. The maximum adsorption capacities of HDMS and ODMS for Pb(II) ions were obtained as 157.8 and 308.0?mg g^?1 at 20?°C and pH 5.5, respectively.     

Preparation of novel chelating sponge as an adsorbent for the removal of Cu~（2＋） from water

The novel chelating sponge modifed with hydroxamic acid groups was prepared by a grafting polymerization followed by a nucleophilic substitution reaction.Elementary analysis,SEM,FT-IR spectroscopy and XPS were used to characterize the spongy adsorbent（PVA-MA-HH）.Adsorption isotherm study indicated that PVA-MA-HH had high equilibrium adsorption capacity for Cu2＋.     

Simultaneous removal of ethanol, acetaldehyde and nitrogen oxides over V-Pd/γ-Al_2O_3-TiO_2 catalyst

V-Pd/γ-Al2O3-TiO2 catalysts with different vanadium contents were prepared by a combined sol-gel and impregnation method. X-ray diffraction (XRD), N2 adsorption-desorption (BET), X-ray photoelectron spectroscopy (XPS) and catalytic removal of ethanol, acetaldehyde and nitrogen oxides at low temperature (<300 ?C) were used to assess the properties of the catalysts. The results showed that the sample with 1wt% vanadium exhibited an excellent catalytic performance for simultaneous removal of ethanol, acetaldehyde and nitrogen oxides. The conversions of ethanol, acetaldehyde and nitrogen oxides at 250 ?C were 100%, 74.4% and 98.7%, respectively. V-Pd/γ-Al2O3-TiO2 catalyst with 1 wt% vanadium showed the largest surface area and higher dispersion of vanadium oxide on the catalyst surface, and possessed a larger mole fraction of V4+ species and unique PdO species on the surface, which can be attributed to the strong synergistic effect among palladium, vanadium and the carriers. The higher activity of V-Pd/γ-Al2O3-TiO2 catalyst is related to the V4+ and Pd2+ species on the surface, which might be favorable for the formation of active sites.     

Ammonium salt of the cross-linked maleic acid–allylpropionate–styrene terpolymer as effective sorbent for removal of Cu2+ ions from water solutions (sorption of the copper ions)

The capability of the ammonium salt of the cross-linked maleic acid–allylpropionate–styrene terpolymer for the adsorption of Cu²⁺ from aqueous solutions was examined. Effect of the various experimental parameters on removal degree of the copper ions was investigated. Equilibrium data were fitted to the Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherm models. Kinetics studies suggested that the adsorption allowed pseudo-second-order reaction. The negative values of ΔG° and the positive value of ΔH° indicate that the sorption process is spontaneous and endothermic in nature. The positive value of ΔS° shows the increasing randomness during adsorption process. Considering the FTIR and UV–vis spectra of the sorbent after sorption, it is concluded that Cu²⁺ enters a complex with carboxylate and ester groups of the sorbent.     

Evaluating the photovoltaic properties of two conjugated polymers synthesized by Suzuki polycondensation and direct C–H activation

Two conjugated polymers HXS-1 and PDFCDTBT were prepared by direct C–H activation and Suzuki polycondensation and their chemical structures were characterized by 1H NMR spectroscopy.The molecular weight of conjugated polymer synthesized by direct C–H activation is lower than the corresponding polymers prepared by Suzuki polycondensation.Conjugated polymers synthesized by direct C–H activation have considerable solubility in common organic solvents and form amorphous film.The photovoltaic property of conjugated polymers synthesized by direct C–H activation is inferior to the corresponding polymers synthesized by Suzuki polycondensation.     

High Activity and Selectivity of Cu／SiO2 Catalyst for the Direct Synthesis of Indole

Copper supported over silica exhibited very high activity and selectivity for the direct synthesis of indole at atmospheric pressure. Under the reaction temperature of 325℃,the yield of indole could obtain 88%.     

Rhodamine 6G-based Chemosensor for the Visual Detection of Cu2＋ and Fluorescent Detection of Hg2＋ in Water

A novel water soluble chemosensor 1 based on rhodamine 6G spirolactam scaffold has been synthesized and characterized.Upon addition of a wide range of the environmentally and biologically relevant metal ions,chemosensor 1 shows a colorimetric selective Cu2＋ recognition from colorless to pink confirmed by UV-Vis absorption spectral changes,while it also exhibits a fluorometric selective Hg2＋ recognition by fluorescence spectrometry.An absorption enhancement factor over 17-fold with 1-Cu2＋ complex and a fluorescent enhancement factor over 45-fold with 1-Hg2＋ complex were observed.Their recognition mechanisms were assumed to be a 1：1 stoichiometry for 1-Cu2＋ complex and a 1：2 stoichiometry for 1-Hg2＋ complex,respectively,which were proposed to be different ligation leading to the ring-opening of rhodarnine 6G spirolactam.Furthermore,the detection limits for CU2＋ or Hg2＋ were 3.3 × 10-8 or 1.7x 10-7 mol/L,respectively.     

Effect of Pb2＋ on the Kinetic and Spectral Characterization of Ribulose-1,5-bisphosphate Carboxylase/Oxygenase

本文利用各种光谱手段在体外研究了各种浓度的Pb2+对菠菜Rubisco活性影响的机制。 结果表明,Rubisco活性随着Pb2+处理浓度的增加而逐渐下降,低浓度Pb2+下Rubisco的动力学常数和最大反应速率分别为1.74 µM 和 0.42 µmol CO2/mg protein∙min,高浓度Pb2+下Rubisco的动力学常数和最大反应速率分别为11.82 µM and 0.28 µmol CO2/mg protein∙min。光谱学分析证实Pb2+可直接结合到Rubisco上, 其结合位点数为1.1个,结合常数分别为8.63×104 和 2.18×105 L/mol。ICP-MS和圆二色谱分析证实Pb2+取代了酶活性中心的Mg2+ 并改变了酶的构象。     

Mechanism of simultaneous removal of Ca2+, Ni2+, Pb2+ and Al3+ ions from aqueous solutions using Purolite® S930 ion exchange resin

The sorption mechanism of Ca²⁺, Ni²⁺, Pb²⁺, and Al³⁺on ion exchange resin S930 has been studied as a function of pH in both mono-component and quaternary systems at ion ratio 1:1:1:1. The equilibrium of ion exchange process in mono-component systems has been followed as an adsorption process and it was tested for Langmuir and Freundlich isotherm equations. The selectivity coefficient of the resin for these cations varied in different manners depending on the pH range. The structural characteristics of pores in the initial resin and the resin after contact with synthetic solutions at pH 3.03 and 3.95 have been investigated by using SEM and EDAX techniques.     

Sol–gel synthesis of Mn2O3/Al2O3/SiO2 hybrid nanocomposite and application for removal of organic dye

Journal of Sol-Gel Science and Technology - Nanocomposite of Mn2O3/Al2O3/SiO2 was prepared through an in situ sol–gel process, in which Mn2O3 nanocrystals were dispersed in the silica-alumina...     

Cu/SiO2：A recyclable catalyst for the synthesis of octahydroquinazolinone

A simple and one-pot method for the synthesis of octahydroquinazolinone is reported.Cu/SiO₂ in refluxing ethanol catalyzes this three-component condensation reaction to afford the corresponding quinazolinones in good yields.     

Effects of Pb2+ ions concentration on the structure and PL intensity of Pb-doped ZnAl2O4 nanocrystals synthesized using sol–gel process

Undoped and Pb²⁺-doped ultrafine cubic zinc aluminate (ZnAl₂O₄) hosts were successfully prepared at a relatively low temperature (~80 °C) using the sol–gel method. The concentration of Pb²⁺ was varied from 0 to 5 mol%. The TGA showed that the minimum annealing temperature required to obtain single phase ZnAl₂O₄ must be above 400 °C. The XRD data revealed that all the annealed samples were single phase crystalline structures and the estimated crystallites size were in the range of 21–30 nm in diameter. The FTIR results suggest that heat-treating can destroy some of the bonds. The surface morphology of the phosphors was influenced by the Pb²⁺ mol%. Undoped and Pb²⁺-doped ZnAl₂O₄ nanoparticles exhibit the violet emission at slightly different positions. The slight peak shifts suggests the possibilities that the luminescence centre can either be due to the defects level in the host or Pb²⁺ ions. The emission peaks at 390 and 399 nm are ascribed to the typical UV transitions ³P_0,1 → ¹S₀ in Pb²⁺ ion. At the higher Pb²⁺ mol%, the luminescence quenching behaviour occurs, which suggests that doping with Pb²⁺ ions is accompanied by the introduction of new defect sites that enhance non-radiative recombination of the excited electrons.     

Influence of Pretreatment on the Interaction of Oxygen with Silver and the Catalytic Activity of Ag／SiO2 Catalysts for CO Selective Oxidation in H2

The interactions of oxygen with pre~reduced silver catalysts as well as their catalytic propertiesfor CO selective oxidation in H2 after oxygen pre-treatment are studied in this paper. It is found that the pretreatment exerts a strong influence on the activity and selectivity of the silver catalyst. A drop in activity and selectivity is observed after treating a pre-reduced catalyst with oxygen at low temperatures,whereas a converse result is obtained after an oxidizing treatment at high temperatures (T≥350℃). O2-TPD results show that surface oxygen species adsorbs on silver surface after the oxygen treatment at low temperatures. However, penetration of oxygen into the silver is enhanced by a high temperature treatment, meanwhile the surface oxygen species disappear. No other silver species except metallic silver are observed on all the catalysts by XRD, and the size of silver particle is not changed after the treatment with oxygen at low temperatures. The surface oxygen species formed by oxygen treatment can also be removed by hydrogen reduction. The strongly-adsorbed surface oxygen species prohibit the adsorption and diffusion of oxygen species in reaction gas on the surface of silver catalyst, causing the decrease in CO oxidation activity, in other words, it is important to obtain a clean silver surface for increasing the catalyst activity in CO removal from H2-rich feed gas. The differences in activity and selectivity due to the oxygen pretreatment at different temperatures axe discussed in terms of the changes in the surface/subsurface oxygen species of the silver particles.