Applied Mechanics and Materials Vols. 522-524

Abstract: Visible-light responsive SrBi₄O₇ photocatalyst was prepared by a traditional copreparation method. The photocatalyst was characterized by XRD and UV-Vis diffuse reflectance spectra. The as-prepared photocatalysts were used for the photocatalytic degradation of malachite green (MG) under visible light irradiation. Preparation conditions of catalysts, concentration of malachite green, photocatalyst dosage, irradiation time and photocatalytic reaction kinetics have been investigated. Under the optimized reaction conditions, decolourization ratio and COD removal rates of MG were 99.62% and 95.6%, respectively. The results indicate that SrBi₄O₇ has good photocatalytic activities for the decomposition of MG. And it has the potential higher visible light photocatalytic activity with a band gap of 2.44 eV.

Abstract: To establish a simple method to separate and purify the magnesium lignosulfonate from the red liquor, the properties of the alkali precipitation of magnesium lignosulfonate in the red liquor were investigated. The results show that the magnesium lignosulfonate could be precipitated by alkali from red liquor. The maximum amount of precipitation occurs when pH value was 13. The precipitation of the red liquor of acid magnesium sulfite is caused by magnesium. It was different from sodium lignosulfonate of the red liquor of acid sodium sulfite. The repeated alkaline precipitation after acid soluble method could be isolated and purified lignosulfonate magnesium effectively at some extent.

Abstract: The decolorization of methyl orange wastewater by DC stream discharge with MgO-CuO-Al₂O₃ catalyst was investigated. The removal efficiency was studied for different experimental parameters. Results showed that the removal efficiency by discharge with catalyst was better than discharge only. The removal efficiency was 98% under the condition of applied voltage 18kV, current 9mA, volume of catalyst 20cm³, initial concentration 40mg/L with treatment for 10min. The intensity of methyl orange absorption peak (465nm) gradually weakened and disappeared by discharge with catalyst, the conjugated system composed of azo group and benzene in the molecular structure was destroyed, methyl orange molecules were degraded effectively.

Abstract: A research study has been undertaken to develop the fundamentals of a method for the direct dissolution of metal platinum. At room temperature and pressures, the reaction between sodium cyanide and platinum group metals (PGMs) does not occur because of poor kinetics. However, at elevated temperatures, PGMs can be dissolved by sodium cyanide like the reaction of gold. In this work, the dissolution of Platinum was measured in pressure clear cyanide solution. The data at different cyanide concentrations, temperature and oxygen pressure are obtained. With increasing cyanide concentration and oxygen pressure, the dissolution first increased to a maximum value and then decreased. With increasing temperature the dissolution is increased.

Abstract: The effect of extraction temperature,extraction time,alcohol concentration, ratio of material to liquid (g/ml)on extraction yield of natural yellow pigment from waste almond shell were studied. The optimum conditions were determined by L9 (34) the orthogonal test . The optimum extraction conditions are the extraction temperature at 75°C;the extraction time for 2h; the extraction agent concentration of 20%ethanol ; the material-liquid ration (g/ml) 1:15.The extraction yield of natural yellow pigment from almond shell is 6.25%,The order of effects are extraction temperature>extraction time>ratio of material to liquid(g/ml)>alcohol concentration.This research provides the theoretical basis for the industrial production of the extraction of natural almond shell pigment and provides a new way for the re-use of the abandoned almond shell.

Abstract: To establish the physical filtration equation of Biological Aerated Filter (BAF), the porosity calculating model (Eq. 5) and SS concentration calculating model (Eq. 16) were constructed respectively by the way of infinitesimal element analysis. And then the BAF physical filtration equation had been derived by using the relationship among headloss, porosity and SS. The BAF physical filtration equation was shown as Eq. 19.Then the Kozeny-Carman coefficient in Eq. 19, kc, was confirmed to be 0.040 by experimental adjusting and domesticating. In the condition of kc=0.040, the predicted values of Eq. 19 fitted the experimental values of BAF reactor well, which illustrated that the BAF filtration equation constructed in this study was scientific and the parameters value adopted in this equation was reasonable.

Abstract: The experiments of TOC and UV₂₅₄ removal of humic acid (HA) solution by ultrasound (US) irradiation with the presence of H₂O₂ and Fe₃O₄ nanoparticles (NP) were carried out. The comparison of enhancement effect of humic acid sonolysis by H₂O₂ and NP was investigated. It was found that removal efficiency of TOC and UV₂₅₄ increased significantly in the order of US< US/NP< US/H₂O₂< NP/H₂O₂< US/NP/H₂O₂. During US/NP/H₂O₂ combining process, the contribution of H₂O₂ should be presenting most OH radicals for humic acid degradation, Fe₃O₄ nanoparticles would supply adsorption surface for humic acid to have more chance to be oxidized, and ultrasonic would work as main energy for OH radicals generation and offer sonochemical environment.

Abstract: Microorganisms in aquatic ecosystems play an important role in the processes like water purification, nutrition regeneration and biochemical circulation. Some microorganisms are also related to human diseases. To analyze the main microorganisms in the water systems in northern Hangzhou, water was sampled from three different rivers for isolation and identification of microorganisms. The highest diversity and quantity of bacterium was found in the rivers in Banshan industrial district, with an average 127 clones in each plate. For the Beijing-Hangzhou Grand Canal and Longshan reservoir, the number was 20 and 7, respectively. Similar trends were also observed for actinomycetes and molds. CCA analysis showed that the microorganism abundance was mostly related to the NO₃-N, TP and TN values of water. Totally, 7 bacterium strains were identified, including Bacillus cereus, Escherichia coli., Klebsiella pneumoniae, and so on, which belong to 7 different genera. In an antibiotics sensitivity analysis, all of the 7 bacteria showed sensitivity to tetracycline.

Abstract: Characteristics of sexual reproduction of two L. chinensis ecotypes under saline-alkali soil and sandy soil habitats on Songnen plain were studied, such as number of florets, number of grains, seed-setting percentage and the weight of thousand grains. The results showed that number of florets, number of grains, seed-setting percentage and the weight of thousand grains of two L. chinensis ecotypes fluctuated at some range. Variation coefficients of number of florets, number of grains and seed-setting percentage were 34.63%, 79.37% and 87.2% higher, but variation coefficient of the weight of thousand grains was lower. Number of grains and seed-setting percentage of two L. chinensis ecotypes under saline-alkali soil habitat were lower than those under sandy soil habitat. Significance test showed that number of florets and seed-setting percentage of two L. chinensis ecotypes, number of grains of grey-green ecotypes L. chinensis and the weight of thousand grains of yellow-green ecotype L. chinensis between saline-alkali soil habitat and sandy soil habitat were significant or very significant. Number of florets and the weight of thousand grains between two L. chinensis ecotypes under the same habitat were significant or very significant. In results, adaptation of sexual reproduction of two L. chinensis ecotype populations on habitat was stronger. The two ecotypes adopt the same adaptable reproduction strategy. Condition change arose plasticity feedback of characteristics of sexual reproduction. And individual difference in population under the same habitat was results by microhabitat difference.

Abstract: Applications of PBTCA modified nanoscale zero valent iron (P-Fe⁰) prepared by borohydride reduction for removal of Cu²⁺ ions from aqueous solution are investigated under a variety of experimental conditions. According to X-ray photoelectron spectroscopy (XPS) results, Cu²⁺ ions were removed primarily via a redox mechanism that resulted in the formation of Cu⁰ and Cu₂O. The contact of P-Fe⁰ with aqueous media caused extensive formation of iron oxide.