Key Engineering Materials Vols. 336-338

Abstract: Alumina adsorbent was synthesized from waste aluminum sludge in this research. The nitrogen isothermal adsorption method (77K) is applied to measure the BET specific surface area and pore structure of activated alumina at different activation temperatures. The research results indicate that, thermal treatment has huge influences on the test sample’s specific surface area and pore structure. Its specific surface area and pore volume expand and then diminish, whereas the holding time rises, getting its peak of 348 m² /g and 0.55 (cm³ /g) respectively at the activation temperature of 600°C and holding time for 1 hour. The average pore diameter value increases along with the lengthening of activation temperature and holding time, reaching the maximum of 11nm at activation temperature of 750°C and holding time for 4 hours. After comprehensive analysis, the activation temperature of 600°C and holding time for 1 hour are determined as ideal conditions for activated alumina respectively.

Abstract: With the rapid development of the national economy, an effective way is urgently anticipated to unburden the pressure of low resources utilization, high energy consumption and serious environment pollution resulting from industry solid waste. In the present paper, a new process by applying atomization technique into disposing of melting slag is proposed for highly effective utilization of solid waste. It is characterized as simultaneous completion of super cooling and fine pulverized, and improvement on utilization efficiency of melted slag for increase of activity and saving of milling energy. This method is believed to be a new available approach to greatly promote the development of our recycling economy

Abstract: The phosphorus slag produced as the waste of yellow phosphorus manufacturing was studied for the production of calcium-aluminum-silicone system glass ceramic materials. The thermal behavior and crystallization processes of fine powders of parent glass with chemical composition (wt. %) 52-60 SiO2, 22-28 CaO, 2-10 Al2O3, 3-8Na2O+K2O, 1.7-2.1P2O5 and 1.6-2.0 F were carefully studied by DTA, XRD and SEM techniques. The desired sequence of events, i.e. nucleation, sintering and devitrification occurred by heat treating the glass powder. The results showed that the phosphorus slag can be as a main raw material directly in production of the glass ceramic.

Abstract: Sialite, made according to the theory of simulation to formation of rock, is a new aluminosilicate-based cementitious material. Production of sialite does not require calcination, which consists of a main body (90%-97%) and an auxiliary body. Main body is made up of solid wastes such as fly ash, gangue, blast furnace slag, steel slag, red mud, waste bricks, waste glass and any other types of slag produced as a by-product in burning processes. The auxiliary body is a diagentic substance made by natural minerals. Sialite products have been successfully put into practice, which have the characteristics of cleaning production and low consumption of natural resources. Therefore sialite technology would provide an efficient method for promoting the development of a sustainable economy.

Abstract: TiO2 coatings on ceramic substrate were prepared using TiOSO4 and silica sol. Coatings were then heat-treated respectively at 300°C, 400°C or 500°C for 30mins. Degradation of the solution of chlorinated methane by UV light and TiO2 coating were investigated. It can be concluded from the results that the coating with composition of 80wt%TiO2-20wt%SiO2 heated at 500°C display better degradation effect than the other coatings. As the initial concentration of chloromethane goes up, the degradation rate increases; while as the degree of substitution by chlorine goes up, the catalytic effects decreases.

Abstract: A new method for preparing microporous ceramics by the silicon carbide whiskers was studied in this paper. The physical and chemical properties and the microstructure of the microporous ceramics were tested, while some influencing factors for the product, such as the amount of sintering aids and sintering temperature, were discussed. The results suggest that the apparent porosity of the microporous ceramics is 55.7-59.8% and the flexural strength is 127-176MPa. The pore distribution of the microporous ceramics is uniformity and the diameter of the pore ranges between 0.5μm and 7μm. The porosity and pore size of the microporous ceramic can be controlled by adjusting the sintering temperature and the amount of sintering aids.

Abstract: The adsorption behavior of clay minerals in cadmium contaminated soils has been studied in order to remedy soils contaminated with this metal in this work. The results show that Langmuir model best describes the adsorption of Cd2+, and the maximum sorption values of 8.45 mg/g for bentonite, 5.69mg/g for sepiolite and 10.57mg/g for attapulgite are obtained at pH 5-6. In addition, the effect of clay minerals amendment on a highly cadmium contaminated soil has been studied by means of pot experiments. The results indicate that the metal concentrations in shoot and root of plant decreased with addition of clay minerals to soil (1%), and the highest decrease value of metal concentrations is obtained in the soils added by attapulgite amendment.

Abstract: Ag doped TiO2 whiskers were synthesized by calcining metatitanic acid with potassium car= bonate to form tetratitanate whisker precursor, following by proton-exchanged and immobilized with Ag+. The post treatment conditions for whiskers synthesis were investigated and the phase composition, morphology and photocatalytic performance were characterized. The results showed that the TiO2 whiskers had an aspect ratio more than 15 and the absorption edge of Ag doped titania whiskers were red shifted to 50 nm. The result of methylene blue degradation revealed that the photocatalytic performance of Ag doped TiO2 whisker has been greatly improved.

Abstract: In this paper, a novel and highly efficient hydroxyapatite (HA) carrier for cultivating hydrocarbon degradation bacteria (HDB) is introduced. The HA particles synthesized through a sol-gel method and different heat treatments were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET method. The microbial amount and activities of HDB cultivated on HA carriers were quantitatively investigated in order to assess their enriching capabilities. The results showed that HA synthesized at 550°C and the one without calcination could enrich HDB 3 and 2 magnitude orders more than the activated carbon, respectively. Mechanisms of bacterial enrichment on HA and activated carbon were also studied, and it is believed that the high bioactivity and the surface morphology of HA were responsible for the efficient reproduction of HDB. It is concluded that HA is a potential candidate to replace the conventionally used activated carbon as a novel carrier applied in the filed of bioremediation for oil contaminated soil.