Advanced Materials Research Vols. 233-235

Abstract: For comparing the adsorption of Synthetic Organic Chemicals (SOC) competing with background pollutants between a bifunctional resin and a commercial granular activated carbon (GAC), tannic acid (TA) was preloaded to the two adsorbents at quantities of 60 and 120 μmol/g. As a result, decreases of micropores volume in the resin were 75.5 and 98.9%, while those in the GAC were only 19.0 and 30.0%, respectively. Preloading attenuated surface heterogeneities and phenol’s capacities of two adsorbents distinctly. But maximumly, 1.0 mole TA’s preloading on GAC could decline 9.23 mole phenol’s adsorption. Under the same condition, the resin’s capacity of phenol was only descended at 2.68 times, when 98.9% micropores have been blocked. In kinetic tests, blockages in the resin were misapprehended to be much lighter than those in the GAC by the Homogeneous Surface Diffusion Model (HSDM). One steady operation engineering at micropore volume 37.8% decline was introduced. The conflicts were explained by quite a number of resin’s functional groups in the macroporous and mesoporous region could attract enough phenol molecular rapidly, even if almost all micropores were blocked.

Abstract: A plan of preparing ice particles continuously has been put forward, and the analyses and calculations are done in terms of theory. An injection ice jet system has been established. Through ice jet removing paint experiments by the use of the ice jet system established, the examination of the ice parameters which influence the surface cleaning performances such as ice diameter , ice temperature and ice flow rate is conducted. When the pressure, standoff and traverse speed are fixed, orthogonal cleaning paint experiment is conducted and three parameters of ice particles are investigated. The results of variance analysis and direct analysis of experimental data show that flow and temperature are more important factors affecting the surface cleaning performance of ice jet and the effect of diameter is rather little.

Abstract: In order to further study the mechanism of hydrolysis reactions to sugars using cornstalk on plasma, preliminary study of reactive process are carried out. Model compounds of cornstalk components are chosen and hydrolyzed on plasma. Activation energy of elementary reactions, which are single-molecule reactions, free radical reactions and bimolecular reactions, are calculated by bond energy percentage rules. Elementary reactions and preliminary reaction mechanism model, which cornstalk hydrolyzes to sugars on plasma are identified.

Abstract: This paper describes the characteristics and mechanism of fly ash deposited in Shell coal gasification process. The chemical composition, particle size distribution, surface topography and elemental composition of fly ash samples derived from coal A and coal B are studied by X-ray fluorescence spectrometer, JX-2000 microscopic image analyzer and computer controlled scanning electron microscopy (SEM/EDX) respectively. The results show that the differences in ash deposition characteristics result from the differences in surface properties and element composition of fly ash particles generated from different coal feed. The fly ash formation and deposition mechanism are discussed based on physicochemical changes in gasification, particle size distribution and surface composition enriched in Ca, Fe in fly ash particles. The results can serve as reference data for a variety of deposition studies.

Abstract: According to the difference of chemical deposition behavior of arsenic and iron ion in the different pH value solution, valuable element Fe was first recovered by the selective deposition from bio-oxidation wastewater and then it was used to prepare nano-iron oxide red pigment powders. The effect of purifying conditions, calcinations temperature and calcinations time on the product color, the average partical size had been investigated. The crystal structure, particle-size and properties of the nanoparticles were characterized by means of XRD, TEM. The optimal process conditions of the preparation of iron oxide red were: calcinations temperature was 900°C, calcinations time was 120min. Under these conditions, the color of production was bright red. The particles were fully developed, and the average diameter of nanometer particle was about 70.8nm. In the visible light region of 380 to 780nm, the particle possessed good transparency, achieving the standard of GB1863 – 89.

Abstract: A novel process was proposed for the activation pretreatment of Cr-containing limonitic laterite ores by NaOH roasting. The dechromization kinetics of the laterite ores and the effect of particle size, NaOH-ore ratio, and roasting temperature on Cr extraction were studied in detail. Experimental results indicate that decreasing the particle size and increasing the NaOH-ore ratio and roasting temperature increase the Cr extraction rate. Approximately 96% Cr in the laterite ores could be extracted under the optimal alkali-roasting conditions. The results also indicate that the Avrami model is suitable for the dechromization process and that the apparent activation energy is calculated 11.12 kJ·mol^-1. The 99.5% Cr₂O₃ was obtained from Na₂CrO₄ leached in the alkali solution by liquid-phase reduction and then calcining at high temperature.

Abstract: In order to reduce fluorine pollution, partial fluoride could be replaced by B₂O₃ in mould flux. The effects of B₂O₃ on properties of low fluoride content mould flux for thin slab continuous casting were studied. The properties included melting temperature, viscous characteristics, fluidity, surface tension and Al₂O₃ inclusion adsorption. The results showed that with the increase of B₂O₃ content, melting temperature, viscosity, viscous activation energy and surface tension of mould flux decreased obviously, fluidity increased, and Al₂O₃ inclusion adsorption of mould flux changed little. The B₂O₃ could play effective role when its content was less than 6%. The results would play a guiding role in designing of low fluoride content mould flux for thin slab continuous casting.

Abstract: Nitrate is one of the major nitrogen forms absorbed by plants. Dual-wavelength Ultraviolet Spectrophotometry (DUS) is a simple, rapid and environmental method to measure soil nitrate. In this study, DUS as well as Phenol Disulfonic Acid Procedure (PDAP) were adopted to analyze nitrate in five types of soils in China. It was showed that the concentrations of soil nitrate determined by DUS were higher than those by PDAP. Meanwhile, these two series of measurements were significantly correlated. Therefore, the DUS is worthy in rapid detection of soil nitrate.

Abstract: The present work sought to make a contribution to the study on application of Mg(OH)₂ in peroxide bleaching of the wheat straw soda-AQ pulp. The results showed that: (1) for an unbleached pulp, when 24-73% of the NaOH was replaced with Mg(OH)₂, a higher brightness and viscosity were achieved comparing to the NaOH as the sole alkaline source. The brightness and viscosity of the bleached pulp at 48% of Mg(OH)₂ replacement were respectively 6.4%ISO and 107 mL.g^-1 higher than those of the NaOH as the sole alkaline source. (2) for a chelated oxygen-delignified pulp, the brightness of bleached pulp at 24% Mg(OH)₂ replacement was considerable to that of the NaOH as the sole alkaline source, and at 48% Mg(OH)₂ replacement 2.8% ISO lower than that of the NaOH as the sole alkaline source. While the viscosity increased consistently with the increase of Mg(OH)₂, and the COD load of bleaching filtrates at 24-48% Mg(OH)₂ replacement was lower 22-31% than that of the NaOH as the sole alkaline source. Therefore, partial substitution of Mg(OH)₂ for NaOH had positive effects on peroxide bleaching of wheat straw soda-AQ pulp.

Abstract: The dyeing properties of lac dyes for wool, silk and nylon fibers were investigated, and compared in terms of dependence of dye uptake on pH, dyeing rates, and building-up performance as well as color hue and color fastness of dyed fabrics. For all the three fibers, the uptake of lac dyes was greatly influenced by pH, indicating that the electrostatic interaction between lac dyes and fibers predominantly contributes to lac adsorption. The maximum adsorption wavelength of dyed fabrics shifted to a higher value with increasing application pH, indicating the existence of bathochromic effect. Lac dyes showed the quickest initial uptake rate for silk, the slowest rate for wool. The capacity of lac uptake by three fibers was in the following order: wool > silk > nylon, this being in accord with the quantity of amino groups in these fibers. Dyed wool exhibited the best color fastness.