Papers by Author: Wu Li

Abstract: Potassium zinc hexacyanoferrate (KZnFc) was synthesized, and the adsorption amount at equilibrium and adsorption rate of uptake of cesium (I) on KZnFc from several aqueous solutions was investigated comprehensively by varying the initial cesium concentration and temperature. The rate of uptake of cesium was analyzed using pseudo-first-order and pseudo-second-order kinetic models. This study will be helpful for understanding the adsorption mechanisms of cesium ion, and KZnFc could be used as potential adsorbent for adsorbing Cs (I) from oil field water of Nanyishan.

Abstract: Low-temperature heat capacities of butyl 4-hydroxybenzoate have been measured by a high precision automated adiabatic calorimeter over the temperature range from 79 to 399 K. The melting temperature, the molar enthalpy and entropy of the phase transition were determined to be (342.227 ± 0.054) K, (26.122 ± 0.192) kJmol^-1 and (76.33 ± 0.55) JK^-1mol^-1.The thermodynamic functions (H_T -H_298.15K) and (S_T- S_298.15K) were calculated in the range from 80 to 400 K with the interval of 5 K. The constant-volume energy and standard molar enthalpy of combustion have been determined, _cU (C₁₁H₁₄O₃,s) =-(5760.30 ± 2.70) kJmol^-1 and _cH_m⁰ (C₁₁H₁₄O₃, s) =-(5765.26 ± 2.70) kJmol^-1, by means of a precision oxygen-bomb combustion calorimeter at T = 298.15 K. The standard molar enthalpy of formation has been derived, _fH_m⁰ (C₁₁H₁₄O₃, s) =-( 564.16 ± 4.41) kJmol^-1, from the standard molar enthalpy of combustion in combination with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.

Abstract: To improve the strength and toughness performance of PVC, the resin reinforced with magnesium borate whiskers (MBO_W ) were prepared by mixing whiskers into liquid PVC at room temperature. The effects of borate coupling agent (SBW-III) and contents of MBOw (0~30wt%) on tensile of PVC and composites were studied. The compatibility, hydrophilicity and morphology of MBOw/PVC composites were characterized by Fourier transform infrared spectroscopy ( FTIR), surface contact angle measurement and scanning electron microscopy (SEM) respectively. The results show that both the chemical bonding and physically adsorbed layers exist between MBOw and SBW-III. The surface of modified MBOw is hydrophobic which improves the binding force between PVC and treated MBOw, and the dispersibility of MBOw in PVC significantly. The tensile and the elastic modulus of the SBW-III-treated MBO_w /PVC composites increase in comparison to that of the composites filled with untreated MBOw.

Abstract: The simulation of natural evaporation process of Longmucuo brine in winter was conducted in laboratory, and the original brine was preliminarily concentrated in field. The crystallization sequence of salts, enrichment rule of boron and lithium were obtained. The crystallization sequence of salts of this brine is similar to that of Da Qaidam brine in winter. The boron is enriched in concentrated brine at the same concentration factor with the brine. The concentration factor of lithium is the same as that of the brine at the early evaporating process before the brine is concentrated to 4 times, and it is much lower than that of the brine because of the crystallization of lithium in the late process.

Abstract: An experimental SGSP was constructed in Tibet and its thermal performance in winter was investigated in this paper. The LCZ temperature observed was no less than 20 oC in winter subfreezing time. The impact of ice layer upon SGSP was analysed briefly as well, it was found that the ice layer showed different impacts on the performance of SGSP depended on its thickness and transparency condition. Several promising measures for the improvement of SGSP operating in winter were also proposed.

Abstract: Zinc borate Zn2B6O11•7H2O was prepared at room temperature using Na2B4O7•10H2O, ZnSO4•7H2O and H3BO3 as raw materials. The synthesized product was characterized by XRD, SEM, TG-DSC and FT-IR. SEM results showed that the synthesized zinc borate had uniform morphology with a length up to a few microns. The experiment result indicates that additional H3BO3 in starting materials was beneficial to the uniform morphology of Zn2B6O11•7H2O.

Abstract: KH550 modified ZnO/TiO2 was prepared. The surface of nano-TiO2 was coated with ZnO derived from Na2Zn(OH)4 via a heterogeneous nucleation process, and coupling agent KH550 was used to treat the surface of ZnO/TiO2. Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and Optical contact angle measuring instrument were used to characterize the effect of surface modification. The results showed that the surface of nano-TiO2 was coated by ZnO nanoparticles; After modified by the KH550, the modified ZnO/TiO2 showed better dispersion in water-toluene solution; and the surface of modified ZnO/TiO2 became more hydrophobic-lipophilic than that of modified uncoated nano-TiO2.

Abstract: Well dispersive and single crystal calcium titanate (CaTiO₃) whisker with a length of 50-100μm was synthesized by sintering the mixture of calcium chloride and titanium dioxide with improvement of adding the mineralization agent of Pb(Ac)₂.3H₂O. The as-prepared samples were characterized by XRD, SEM. The optimum synthesis condition and the effect of the mineralization agent were discussed respectively. In the end, the possible reaction process was given and a LS growth mechanism was proposed.

Abstract: Ba2B5O9Cl whiskers with uniform morphology were synthesized by a simple flux method, using BaCl2•2H2O, H3BO3 as the starting materials, and KCl as the flux. The products were characterized by X-ray diffraction (XRD) and scanning electron microcopy (SEM), and the optimum conditions for preparing high quality Ba2B5O9Cl whiskers were studied. Results show that a sintering temperature around 700 °C, an Ba/B mole ratio of 1:3 and a raw materials to flux mass ratio of 1:2 lead to uniform orthorhombic Ba2B5O9Cl whiskers with a diameter of 0.4-1.0 µm and a length of 10-25 µm.

Abstract: Calcium carbonate (CaCO₃) whiskers were firstly treated by sodium stearate, and then blended with polypropylene (PP) to prepare the composites by a closely intermeshing co-rotating twin-screw extruder at 200°C. The performance of the composites, such as thermal behavior, microstructure and mechanical properties, were analyzed with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical testing. The results showed that CaCO₃ whisker influenced the crystalline behavior of PP phase in the blends because of its intervening. Moreover, thermo-decomposing temperature, tensile and bending strengths of the blends all increased with increasing whisker content. CaCO₃ whiskers had good reinforcing and toughening effects on PP.