Advanced Materials Research Vol. 549

Abstract: The removal of ammonia-nitrogen (NH4+–N) in water by activated attapulgite was investigated. The study focuses on the effect of different activated attapulgite. The influence factors include microwave power, heating time and pH value in solution. The results show that heating 4 minutes, microwave power of 89 watts, and pH value of 9 are the best conditions to remove NH4+-N in the wastewater and the removal efficiency can above 80%. The attapulgite activated by microwave and alkali can remove NH4+-N in breeding waste effectively and the removal efficiency can reach 84.15%.

Abstract: Activated carbons to be used as electrode in electrochemical double-layer capacitors were fabricated using amphiphilic carbonaceous material (ACM) as precursor. To study the significance of functional groups and microcrystalline of the precursor in preparing AC, we applied pre-carbonization upon the ACM under different conditions to control these two parameters in this paper. FTIR and XPS spectra showed functional groups on the precursors decreased as the increase of pre-carbonization temperature. After carbonization at 800 °C, the growth of graphitic microcrystallites was noticeable. Porous structure parameters of final ACs inferred that the functional groups on the precursors have a more significant effect than microcrystalline size on formation of mesopores during activation process not only for its role as active sites but also the homogeneous activation profited from the solubility of samples in alkaline solutions. The sample AC0 with almost half mesopores showed the best electrochemical behavior with a specific gravimetric capacitance of 255 F/g at current density of 1000mA/g and kept rectangular shape cyclic voltammetry curve even at scan rate high as 400 mV/s.

Abstract: In this paper, the bentonite supported silicotungstic acid with Kiggen structure was prepared by the adsorption of silicotungstic acid on the pretreated bentonite. The bentonite supported silicotungstic acid was characterized with IR、XPS and TG/DTA. The effect of acidification and loading time on the loading amount of silicotungstic acid was investigated. The results indicates that bentonite supported silicotungstic prepared with high temperature activation is stable.

Abstract: A new mechanism has been proposed for synthesizing barium ferrite by sol-gel method. The mechanism takes account of the structure of barium hexaferrite and the least structure change principle. It is useful in optimizing the synthetic conditions.

Abstract: Different solid base catalysts used for the polymerization of glycerol were prepared by impregnation. Catalyst type and the preparation conditions were optimized on the base of polymerization degree. Results showed: the best catalyst was KF/Al₂O₃, and optimal condition for catalyst preparation was as follows: loading of 40% KF, calcinations temperature 600°C. The polymerization degree of 5.92 was obtained under the following reaction condition: the amount of catalyst 11.62,reaction temperature 250°C, reaction time 4 h.

Abstract: Calcium carbonate (CaCO₃) is abundant in nature, and is also an important material applied in industry as pigment, filler material, etc. It is a challenge to control the desired CaCO₃ properties for industry applications. In this study, three typical morphologies of CaCO₃, calcite, aragonite and vaterite were prepared. The crystallization temperature and addition of acrylic-acrylate-sulfosalt copolymer play a significant effect on the polymorph change of CaCO₃ sediment. Higher temperature promoted the formation of aragonite, while more additives tended to form the vaterite. The x-ray diffraction and scanning electron microscope analysis confirmed the formation of CaCO₃ with various polymorphs.

Abstract: A spinel-type metal compound [LiMn_0.5Ti_0.75O₃], was prepared by a solid state reaction crystallization method. The Li⁺ extraction/insertion with this material were investigated by X-ray and Kd measurement. The results showed that the Li+ extraction/insertion be progressed mainly by an ion-exchange mechanism. The acid treated samples had an ion exchange capacity of 4.2mmol/g for Li⁺.

Abstract: It is well known that the exploitation of brine resources of salt lakes is based on the relevant phase equilibrium and phase diagrams. In this paper, the progresses on the stable and metastable equilibria, thermodynamic properties and predictive solubilities of the brine system containing lithium and borate ions at present were summarized. The problems existed and the new trends in the future were also carried out.

Abstract: The solid complex of antimony trichloride with thiourea was synthesized by solid-solid reaction or liquid state reaction of antimony trichloride and thiourea. The formula of solid complex is all SbCl₃[CS(NH₂)₂]₃. The crystal structure of the complex belongs to monoclinic system and the lattice parameters are: a = 1.2426 nm, b = 1.6396 nm, c = 1.9254 nm and β = 96.24° for solid-solid reaction, and a = 1.2343 nm, b = 1.6585 nm, c = 1.9252 nm and β = 96.46° for liquid state reaction, respectively. The infrared spectra reveal that antimony ion in the complex is coordinated only by the sulfur atom of CS(NH₂)₂. The possible pyrolysis reactions in the thermal decomposition process of the complex, the experimental and calculated percentage mass loss were also given.

Abstract: Dextran catches increasing attentions as a drug carrier because of its biocompatibility, biodegradability and ease of modification. In this study, we synthesized the derivated dextran by grafting with 1-(3-aminopropyl) imidazole. The dextran-based nanoparticles with sizes of 1H NMR, SEM, AFM and Zetasizer.