Jinglong Chu

Removal of Ca(II) and Mg(II) from potassium chromate solution on Amberlite IRC 748 synthetic resin by ion exchange

Experimental measurements have been made on the batch ion exchange of Ca(II) and Mg(II) from potassium chromate solution using cation exchanger of Amberlite IRC 748 as K+ form. The ion exchange behavior of two alkaline-earth metals on the resin, depending on contact time, pH, temperature and resin dosage was studied. The adsorption isotherms were described by means of the Langmuir and Freundlich isotherms. For Ca(II) ion, the Langmuir model represented the adsorption process better than the Freundlich model. The maximum ion exchange capacity was found to be 47.21 mg g(-1) for Ca(II) and 27.70 mg g(-1) for Mg(II). The kinetic data were tested using Lagergren-first-order and pseudo-second-order kinetic models. Kinetic data correlated well with the pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. Various thermodynamic parameters such as Gibbs free energy (DeltaG degrees ), enthalpy (DeltaH degrees ) and entropy (DeltaS degrees ) were also calculated. These parameters showed that the ion exchange of Ca(II) and Mg(II) from potassium chromate solution was feasible, spontaneous and endothermic process in nature. The activation energy of ion-exchange (E(a)) was determined as 12.34 kJ mol(-1) for Ca(II) and 9.865 kJ mol(-1) for Mg(II) according to the Arrhenius equation.

Synthesis of high quality MCM-48 with binary cationic-nonionic surfactants.

Highly ordered MCM-48 was synthesized in the hydrothermal system of a mixture of cationic cetyltrimethylammonium bromide (CTAB) and nonionic poly(ethylene glycol) monooctylphenyl ether (Tx-100) using water glass as the silicon source. The effect of various factors, such as the amount of surfactant, CTAB/Tx-100, Si source, crystallization temperature, and crystallization time, on the synthesis were discussed in detail. The local effective surfactant packing parameter theory and the charge balance theory were used to explain the reason that various factors can affect the product structure reasonably. Especially, the role of Tx-100 was expounded. The optimum synthesis conditions for MCM-48 were obtained.

One-step synthesis of Ti-MSU and its catalytic performance on phenol hydroxylation

In this study, high-quality Ti-MSU was synthesized by a convenient one-step hydrothermal synthesis procedure. This is the first detailed study on the role of addition time of a Ti source. We found that the addition time of the Ti source can effectively influence the structure and morphology of the product by adjusting the balance of hydrolysis-polymerization and nucleation-aggregation in different self-assembly steps. The optimum synthesized Ti-SMU sample showed a good catalytic performance on the phenol hydroxylation.

Preparation and Characterization of Titanium Tetrachloride-Based Ionic Liquids

A series of TiCl(4)-based ionic liquids (ILs) was synthesized by mixing TiCl(4) with quaternary ammonium, pyridinium, and imidazolium chlorogenated salt, respectively. The structure and composition of the ILs were studied with Fourier transform ion cyclotron resonance mass spectrometry. IR, and Raman spectra. The primary anions of the TiCl(4)-based ILs were TiCl(9)(-) and TiCl(6)(2-), whose amounts were different by variation of the molar ratio of TiCl(4) to organic halogenated salt. The physical properties such as the phase transition behavior, surface tension, density, viscosity, and conductivity of these ILs were also investigated. Temperature-dependent viscocity and conductivity of the ILs followed the Vogel-Tammann-Fulcher equation, and the best-fit parameters had been estimated, together with the lienar fitting parameters for the density. The conductivity and viscosity of the TiCl(4)-based ILs were controlled by the ion mobility and the availability of voids with suitable dimensions. Hole theory could well explain the physicochemical properties of the TiCl(4)-based ILs. (c) 2008 The Electrochemical Society. [DOI: 10.1149/1.3046160] All rights reserved.

Removal of zirconium from hydrous titanium dioxide

A method was proposed for removing zirconium (Zr) from hydrous titanium dioxide (HTD) by the NaF solution. The effects of main parameters, i.e. pH values, NaF dosage, temperature and retention time, on the removal of zirconium were studied. The optimal conditions were found as the following: pH value, <5.5; molar ratio of NaF to TiO2, 0.6; retention time, 80 min; and temperature, 80°C. The removal rate of Zr under the optimized conditions was above 87.7%. The adsorption energy of the preferential absorption of hydrofluoric acid for Zr(OH)2SO4(OH2) on the (001) crystal surface of HTD was determined by theoretical calculation. The possible mechanism of the removal process was also discussed.

Synthesis of submicron spherical Fe–MCM-48 with actual gyroid like structure

Highly ordered submicron spherical Fe-MCM-48 was successfully synthesized by a mixed surfactant method using cheap water glass as silica source. The gyroid like structure of MCM-48 was captured by a TEM image for the first time, and it was corresponded well to the previous simulated gyroid model. A tentative mechanism of homogenization cooperative process involving the Helmholtz double electrical layer was purposed. After the loading of metal Ag, the resulting Ag/Fe-MCM-48 catalyst showed good catalytic performance in the catalytic combustion of benzene.