Advanced Materials Research Vols. 550-553

Abstract: This article has described the biosorption of heavy metal ions using agricultural wastes as a potential adsorbent. The modified methods, the characterization methods, the parameters influence, the adsorption kinetics, the adsorption isotherms, the adsorption thermodynamics and the regeneration of biosorbents have also been discussed. Moreover, the future development of biosorbents has been prospected.

Abstract: Nano-TiO₂ with photocatalytic activity were prepared by sol-gel progress. Nd³⁺ and Tb³⁺ were adoped to enhance the photocatalytic activity. TG, DTG ,UV etc were used to character Nano-TiO₂.From TG Nd restrains the growth of grain and the conversion of anatase to rutile.This improves the TiO₂ heat stability. photo-degradation of oily waste water on titanium dioxide under Xe lamp was investigated.The reaction also features the photocatalytic activity of Nano-TiO₂.The results indicate that Tb and Nd adoption have a positive effect on the photo-degradation.Lanthanon into titania could efficiently extend photoactivity and expand the visible light response range.

Abstract: Coal-gasification wastewater is an industrial toxic wastewater with high concentration of phenols. To provide process parameters for industrial practice, simulation and optimization were carried out on the phenol removal process for coal-gasification wastewater which included phenol extraction, solvent distillation and residual solvent stripping. Calculation results showed that the optimized process parameters were as the following. When solvent ratio was 1:6, after four-stage extraction by methyl isobutyl ketone, the concentration of phenols in the wastewater can be reduced to below 200mg/L from 5000mg/L. While in the solvent distillation column, to make the solvent recycling usable and cut down solvent consumption, the column stages was recommended as 15, reflux ratio R as 0.1360, and feed stage as 10. Moreover, to recover the residual solvent in the wastewater, the number of theoretical stages for the stripper was proposed as 5, and distillate rate as 2388kg/hr.

Abstract: The degradation of phenanthrene by potassium ferrate was researched by means of multiple fluorescence spectroscopic methods such as emission, time-scan, excitation emission matrix (EEM) and photometry, with which the characteristics of phenanthrene molecular changes were discussed within degradation, especially, the kinetics of the degradation was obtained efficietly. From the experimental data, both synchlorous and EEM spectra showed that concentration of phenanthrene was reduced 69.5% degraded by potassium ferrate within 17 s, 91% within 57 s, and the reaction’s processing was very slowly after 57 s. The degradation’s kinetic equation: ln(F0/Ft)=5365.64 - 294.93t, (R2=0.9677), was obtained simply through a convenient way that just combined time-scan fluorescence, emission photometry. according to the kinetic equation, the degradation of phenanthrene by potassium ferrate was in accord with the order of the first order reaction. Which could provide a very usefull conference for the research of degradation of the other pollutants such as POPs by potassium ferrate.

Abstract: The adsorption of Cr⁶⁺ ions by sulfuric acid -treated sunflower straw powder was investigated under batch mode. The influence of solution pH, adsorbent dosage, adsorbent particle size and temperature was studied. The results have shown that the absorbent was efficient, the removal ratio of Cr⁶⁺ up to 99.5% with an adsorbent dosage of 8 g•L^-1, a pH of 6.0, at 25°C and particle size in 80-100 mesh. The negative changes in free energy (△G) indicate that the adsorption is a spontaneous process, the positive values of the adsorption entropy △S indicate the increased randomness of the Cr⁶⁺ on straw active carbon surface than in solution.

Abstract: Using six kinds of concentration (ranged from 0.0 to 2.0mg.L-1) of flavone extract from C.cathayensis exocarp treats corn, soybean, wheat and mung bean seedlings, in order to study the photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2 on the seedling leaf. Results show that effects of flavone extract (0.1-0.5mg.L-1) increase content of the chlorophyll a, b and total chlorophyll, promote photosynthetic rate, stomatal conductance, transpiration rate, proper increase cell gap inside the CO2 concentration.0.1mg.L-1 treatment effect is the most obvious compare with the control, the total chlorophyll and photosynthetic rate increase by 20.9 % and 21% respectively; More than 0.5mg.L-1, the chlorophyll content, photosynthetic rate, stomatal conductance, transpiration rate decrease, the intercellular CO2 rapid increase. Research shows that, the appropriate concentration of flavone can increase the chlorophyll content in the leaf, promote stomatal opening, increase of intracellular CO2 supply, improve leaf photosynthesis efficiency.

Abstract: This study puts forward the Combined Biological Filter (CBF) as a new type of BAF for advanced treatment of industrial wastewater by changing its position of aeration, particularly for treating high nitrogen with low carbon wastewater. A chemical fertilizer plant is selected to put this set of CBF device after its wastewater treatment station. Methanol is used as external carbon resource for this CBF system. Operating parameters, such as the hydraulic loading rate and C/N ratio, are discussed to determine optimal ones: 0.64m³/ (m²•h) and 4:1. Path analysis is recorded to find different contribution of anoxic and aerobic zones of CBF reactor, and different working conditions are compared to find the best performance. CBF process could find further applications and improvement in engineering practices.

Abstract: his paper studies the feasibility of preparation high strength fired bricks from iron tailings with addition of clay and coal gangue. The results indicated that the optimum conditions were found to be that the hematite tailings content were 35%–50%; the firing temperature was 1000 °C. Under these conditions, the mechanical strength, the water absorption and the bulk density of the fired bricks were 21.17–26.14 MPa, 14.55–15.47% and 1.648–1.629g/cm³, respectively, these were well conformed to standards MU20 of Chinese Fired Common Bricks Standard (GB/T5101-2003).The phase composition and microstructure of the fired specimen were characterized by XRD and SEM. The results showed that the major crystalline phases present in fired brick were quartz, albite, amphibole, hematite and muscovite, and glass phase encapsulated and cement the crystalline phases forming strong entirety which promoted the strength of bricks.

Abstract: Vehicle emissions from mobile sources are major contributors to air pollution and varied with vehicle types, vehicle styles, traveled miles, temperature, oil types and the methods of operation and management. This study performs three emission factor models, Mobile-Taiwan 2, Mobile6.2 and EFDB to calculate emission factor of mobile sources from year 1986 to 2011. The emissions of primary air pollutants, MIRs and CO₂ emitted from mobile sources were calculated. The contribution ratios of varied vehicle types for different air pollutants would be compared and analyzed. Estimated emissions from mobile sources were 32.2, 177, 643, 197 and 401 kilotons/y for PM10, NO_x, CO, THC and MIR for 2000; 31.3, 115, 305, 114 and 227 kilotons/y for 2011. Emissions of traditional air pollutants presented a decreasing trend because of fourth-stage emission standards for mobiles sources and CO2 revealed an increasing trend. According to presented control technology for greenhouse gases on mobile sources, ratio of emission for year 2011 to 2000 would be 1.38-1.49.

Abstract: Fenton’s reagent was employed to treat four modeling compound of textile wastewater. The kinetic model of dye degradation during Fenton oxidation process was established. The results show that the relationship between and initial concentration of four dye is linear correlation. The calculated intrinsic rate constants of four dyes with ▪OH follow an order of k2(RB SRE)>k2(RR SBE)> k2(MB) >k2(RBB X-BR).