Advanced Materials Research Vols. 197-198

Abstract: Response surface methodology (RSM) was adopted to study the key parameters such as activation temperature, activation time, and active agent amount in order to increase activated carbon iodine adsorption value from rice husk. A second order quadratic equation was established and the applicability of model and interaction involved factors on predicting the iodine adsorption value was verified. The results indicated that the effect on the iodine adsorption value was as follows: activation temperature, activation ratio, activation time. The optimal levels for achieving the highest iodine adsorption value were obtained, including activation temperature of 550°C, activation time of 48min and activation ratio of 1.25. The iodine adsorption value reached 1464.793mg/g under optimized conditions. Iodine adsorption value was conducted under the optimum condition and the results showed the average relative error 0.58%, it proved that the models fitted well, the experimental data and the model were feasible.

Abstract: Using La₂O₃ and Co(NO₃)₂•6H₂O as raw material, ultrafine perovskite-type oxides LaCoO₃ was prepared by Supercritical Fluid Drying Technology and Sol-Gel method. The prepared materials’ crystal structure and morphology were characterized by TG-DTA、XRD、FT-IR and TEM. The photocatalytic activity of ultrafine LaCoO₃ powders was evaluated by degradation of methyl orange (MO) solution under 15W UV light irradiation. The results show: At 250°C , the amorphous ultrafine La-Co particles with the size less than 10 nm can be obtained by Supercritical Fluid Drying Technology. At 850°C , the size of the particles increased to 15-35nm, the nanocrystalline LaCoO₃ had a perfect rhombohedral perovskite structure. At 900°C , the crystalline phases of the lanthanum-cobalt mixed oxides were LaCoO₃ and La₂O₃, and the amorphous component is Co₂O₃, the presence of lanthanum affects the crystallization of cobalt oxides. The LaCoO₃ has excellent photocatalytic activities and 100% MO solution was decolorized only after 4h.

Abstract: The TiO₂ /ACF composite photocatalyst was prepared by using the screen printed technology. X-ray diffraction (XRD) and scanning electron microscopy ( SEM) were used to characterize the obtained composite. The results of XRD show the TiO₂ /ACF composite photocatalyst is confirmed anatase as the only phase present and ACF has no effects on the phase structures of TiO₂. The results of SEM show that TiO₂ can form thin film on ACF surface. Benzene was chosen as the model of the volatile organic compounds (VOCs) to investigate the capability of TiO₂/ACF composite photocatalyst. The results show the TiO₂/ACF composite photocatalyst have higher activity for benzene removal than only TiO₂ photocatalyst.

Abstract: Silver-loaded maifanite prepared at different particle sizes (60 mesh~200 mesh) and light calcining temperatures (100°C~800°C) of maifanite, different AgNO₃ solution concentrations (0.025 mol•L^-1~0.300 mol•L^-1) and pH values (2~7) were researched, simultaneously antibacterial ability of silver-loaded maifanite was investigated. Results indicate that the appropriate conditions of preparing silver-loaded maifanite are that particle size is 200 mesh, light calcining temperature is 100°C, AgNO₃ concentration is 0.1 mol•L^-1 at pH=7, and then the silver-loading amount of maifanite gained at this conditions is 1.27wt%; antimicrobial ability of silver-loaded maifanite decreases with increase of light calcining temperature.

Abstract: In this study, Camphor leaves for the experimental materials, the activated composition was extracted by water, its consistency was 10%, and so the water extract was namely reagent A. The reagent B was obtained from added 5% MUF resins in reagent A, and the reagent C was obtained from added 10% MUF resins in reagent A. The Moso bamboo was treated respective by reagent A, reagent B, reagent C through vacuum/pressure process and the ability of resisted mould and mildew was tested. The results showed: The decay resistance of treated was stronger clearly than control, the weight lost rate was between 4% and 7%, it was up to the high anti-decay level. The decay resistance of treated by reagent B was strongest, so the appropriate MUF resins had function of fixation agent. The MOE and MOR of treated bamboo was almost equation to control. And the MOE and MOR of B and C was higher than control and A. It was feasible methods that the water extract of Camphor leaves was used to be a natural preservative. It was safe to human, animal, environment and the treated bamboo was an environmental friendly material.

Abstract: The palladium-based combustion catalysts on cordierite honeycomb ceramics (CHC) substrate without interlayer film (Pd/CHC) were prepared by electroless plating method. By means of scanning electron microscopy (SEM) and BET specific surface area, it was found that the palladium phases on the prepared catalyst after calcination treatment at 500°C were well dispersed on substrate with small and uniform particles. The X-ray diffraction, energy dispersion X-rays (EDX) analysis, adherence test and temperature programmed reduction (H₂-TPR) analysis further indicated that the palladium phase had good adherence strength on the surface of CHC substrate and the moderate ratio of metallic Pd and PdO phase was only obtained on the catalyst calcined at 500°C . Moreover, the results of activity tests for toluene combustion showed that the 0.24%Pd/CHC catalyst had good low temperature catalytic activity and temperature-resistance property. The total combustion temperature (T₉₀) for toluene over catalyst calcined at 300, 500 and 900°C was at 239, 225 and 233°C respectively. And the toluene conversion could keep up above 97% during the stability test of Pd/CHC catalyst at 230°C for 105 h, indicating the good catalytic stability of the prepared catalyst.

Abstract: Several pollution assessment indexes were applied in the pollution evaluation of Luanhe-Beidaihe Estuary. The results of evaluation by single diversity index of phytoplankton (DIP), diversity index of zooplankton (DIZ), and diversity index of macrobenthos (DIM) showed that the environment of seven sections were all not severe polluted. Otherwise, the results of evaluation by eutrophication index (E. I.) showed that six sections (section A, B, C, D, E, and F) were in the level of eutrophication, only section G was in the level of mesotrophy. Pollution assessment by E. I. was more appropriate than biodiversity index, according to the fact of ‘red tide’occurrence in August 2009. It was suggested that the comprehensive pollution index, considering both of the response of pullution and the cause of pollution simultaneously, should be developed to reduce the the discrepancy resulted from the pollution assessment by singular index.

Abstract: Palladium-copper bimetallic catalysts supported over different supporters were prepared by chemical reduction method, and their catalytic performance was investigated with the hydrogenation of nitrate ions in drinking water under mild conditions. The results show that Pd-Cu/ZSM-5 bimetallic catalyst has the highest catalytic activity among all used catalysts. In addition, nitrate conversion influenced by metal content, metal molar ratio (Pd:Cu) and the addition of CO₂ are also discussed. It is well established that the addition of CO₂ has changed the reduction path of the intermediate nitrite, but is no influence on the steps of nitrate-to-nitrite reduction. In the end, the mechanism of catalytic nitrate reduction was discussed on the basis the literature results.

Abstract: Bittern-resisting cement (BR) has more excellent performance to resist physical attack and chemical corrosion in high-concentration brine environment than ordinary Portland cement or sulfate- resisting Portland cement. The durability and chemical stability of bittern-resisting cement are studied under drying-wetting cycles in brine, the microstructure and chemical component of hydration products also are determined by SEM/EDXA. The corrosion resistance coefficient K_f of BR mortar prisms in high-concentration brine for 6 months is over 96%, and the mass loss of mortar prisms after 30 drying-wetting cycles in brine is only 4.3%. SEM/EDXA analysis shows that the microstructure and chemical composition of BR hydration products exposed to high-concentration brine environment is more densely and stable than those of ordinary Portland cement.

Abstract: A supported amorphous Ni-B/TiO₂-Al₂O₃ catalyst was synthesized by a silver-catalyzed electroless plating method. To control the deposition of Ni-B particles on support, the distribution and load of silver clusters were designed by combining the photocatalysis of TiO₂ and the sol-gel technique. The as-prepared catalyst exhibits superior catalytic activity in the hydrogenation of sulfolene.