Advanced Materials Research Vols. 634-638

Abstract: Spherical sponge iron (SSI) with high activity and intension could be could be utilized to remove nitrate from wastewater. Influence of reaction temperature on nitrate removal by SSI from wastewater was investigated. Because of erosion battery reaction of SSI in solution, pH in solution increased quickly once SSI was added in and then maintain above 10 despite of nitrate original concentration. The reaction temperature has certain influence under higher nitrate original concentration, while little influence under lower nitrate concentration. It was concluded that nitrate removal by SSI appeared to be the first-order reaction because most of the reaction order was 1. The apparent reaction rate constant of nitrate removal was change slightly with the reaction temperature. It was suggested that the limited key of nitrate reduction by SSI was the diffusion of reactant because the activity energy, which was 11.37 and 7.24kJ/mol, was lower than 30kJ/mol.

Abstract: A self-made coagulant was applied in the treatment of some membrane concentrated reject of the “young” landfill leachate. The optimum operation diameters were determined by orthogonal and single factor experiments. Under the optimum conditions, the values of COD and ammonia nitrogen of water sample after treatment were 88 mg/L and 10.8 mg/L, respectively, which reached the standard in Pollution Control Standard of Domestic Refuse Landfill GB 16889-2008. Therefore, coagulation method can be applied in the treatment of membrane concentrated “young” landfill leachate to achieve standard discharge.

Abstract: Surface modification of microporous polypropylene membrane was performed by grafting polymerization of acrylamide.The morphological and microstructure changes of the membrane surface were confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and atomic force microscopy. The results indicate that the pore size of the grafted membrane was reduced.

Abstract: The content of SiO2 was more than 60% in the residue of pyrolusite detached manganese by reduction roasted and acid leached, and it was a better siliceous raw material because of less other impurities. Through leaching silicon process in the residue of pyrolusite with alkali at atmospheric pressure, leaching kinetics of silica in the sodium hydroxide solution was researched. The effects of the leaching temperature and the concentration of sodium hydroxide solution on the leaching behavior of silica from acid-leached pyrolusite slag were examinted. It was found that the extracting rate of silica is significantly influenced by the temperature, and the concentration of NaOH solution. The experimental datas were well interpreted with a shrinking core model under chemical control. On the basis of the Arrhenius expression the apparent activation energy of 77.69 kJ/mol and a reaction order of 0.34 for the extraction of silica was evaluated.

Abstract: SrZr4(PO4)6 (SZP) materials were synthesized by precipitate method and dispersed by small molecular solvent. The properties of adsorption materials SZP to Fe3+ have been examined. The equilibrium adsorption indicated that the adsorption equilibrium time of SZP to Fe3+ was 16h at room temperature, and the equilibrium adsorption capacity was 0.318~0.924mg Fe3+/gSZP. The adsorption capacity of 60°C is less than 20°C’s. In addition, the optimum dosage of the SZP adsorbent was 3g , and the corresponding adsorption ratio is 50% .

Abstract: The adsorption of fluoride by chitosan magnetic microspheres of loading lanthanum metal (CTS-La) was investigated in this study. The chitosan magnetic materials were prepared by organically-linking technique. The effects of pH, the reaction time, the initial concentration, dosage and temperature on the removal rate were studied to determine to the optimum operating parameters. The experimental results show that CTS-La is a black particle shape material with magnetism. The magnetic microspheres have high adsorption ability for fluoride, and the maximum removal of F- was 98.4% under the operating parameters of the initial fluoride concentration 10mg/L, pH=2-3,the reaction time 60minutes, dosage 0.1g, temperature 318K. . The equilibrium sorption data are fitted reasonably well in Langmuir and Freundlich isotherm model, and the correlation coefficients (R2) were Langmuir’s correlation and 0.9997 respectively.

Abstract: The initial activity, selectivity, and especially catalytic stability of mesoporous MCM-41 supported phosphotungstic acid (HPW) prepared by ultrasonic-assisted impregnation (UAI) method and the HY zeolite were contrastively investigated for alkenylation of p-xylene with phenylacetylene in a fixed-bed continuous flow reactor. N2 adsorption-desorption, FT-IR, X-ray diffraction (XRD) and NH3 temperature-programmed (NH3-TPD) desorption characterization techniques were employed to explore the relationship of catalyst nature and catalytic performance in alkenylation. Results illustrate that the as-prepared HPW/MCM-41 catalyst exhibits notably superior catalytic activity, selectivity and stability to microporous HY zeolite, ascribed to its well-ordered mesoporous architecture, appropriate acidic sites and high dispersity of HPW phase.

Abstract: The experimental studies for purification of 1,8-cineole by vacuum batch distillation as well as the application of additives in 1,8-cineole purification were carried out. There were two steps during the purification. In the first step, experimental results showed that the optimal operation conditions for purification of 1,8-cineole were the temperature of the reboiler at about 320.15 K under a certain vacuum degree. In the second step, the optimal operation temperature of the reboiler was 331.15 K. The optimal reflux ratio was generated finally. Vacuum degree was controlled between 1.1 kPa and 1.3 kPa.

Abstract: Elemental Chlorine Free (ECF) bleaching sequence of O₁/O₂D₀E_OPD₁D₂ was adopted to bleach the pro-hydrolyzed Larix kraft pulp, where O₁/O₂ was two-stage oxygen delignification without interstage treatment, D was chlorine dioxide bleaching, EOP was pressurized alkaline extraction strengthened by hydrogen peroxide. Keeping bleaching temperature and time unchanged, sodium hydroxide charge(NaOH) in O₁ stage, chlorine dioxide(ClO₂) charge in D₀ stage and D₂ stage were studied, pulp properties such as brightness, kappa number, alpha-cellulose, pentosan and polymerization degree were measured and compared to establish optimal bleaching conditions. Results show that the optimal charge of NaOH in O₁ stage is 2.5%, ClO₂ in D₀ and D₂ stage are 2.5%, 0.6%, and the pulp gained at the optimal bleaching conditions has the properties of 93.9% of alpha-cellulose, 2.60% of pentosan, 375.5 ml/g of viscosity and 86.6%ISO of brightness.

Abstract: Using unconcentrated TiOSO₄ solution from sulfate process as titanium source, anatase TiO₂ white pigment was prepared by self-generating seed thermal hydrolysis route via short sulfate process. The effects of concentration of TiOSO₄ solution and Fe/TiO₂ ratio on the structure and pigment properties of the TiO₂ white pigments were investigated. The samples were characterized by XRD, particle size distribution and pigment properties test. The concentration of TiOSO₄ solution and Fe/TiO₂ ratio had great effects on the super-saturation of TiO²⁺, crystal formation, nucleation, crystallization and aggregation process, eventually determined the crystal structure, particle size distribution and its pigment properties. The optimized concentration of TiOSO₄ solution was of 195 g/L, and the Fe/TiO₂ ratio was at 0.30.The as-prepared anatase white pigment was appropriate particle size, narrow particle size distribution and good pigment properties.