Adsorption characteristics of thiobacillus ferrooxidans on surface of sulfide minerals

By using thiobacillus ferroxidans (T. f) from Qixiashan, Hubei Province, China, the adsorption characteristics of T. f on surface of sulfide mineral were studied. The influences of adsorption time, pH value, temperature, initial inoculated concentration of bacteria, concentration of sulfide mineral powder, and variety of minerals on the adsorption characteristics were firstly investigated by using the ninhydrin colorimetric method, and the changes of contact angles and Zeta potentials of mineral surface during the bacterial adsorption were then determined. The results show that when the leaching experiments are performed for a long time from several days to a month, the maximal quantity of adsorption of T f on the surface of pyrite is obtained under the following conditions: leaching for 20 d, pH value in range of 1–2 and temperature at 30 °C, respectively; when the bio-leaching experiments are performed for a shorter leaching time, the maximal quantity of adsorption is obtained under the conditions: bio-leaching for 2 h, at 2.4×10⁷ cell/mL of initial inoculated bacteria concentration, and at 10% of mineral powder concentration; and the adsorption quantities are different from one sulfide mineral to another, and the adsorption of T. f on the surface of sulfide minerals includes three phases: increasing phase, stationary phase and decreasing phase. Foundation item: Project(50321402) supported by the National Natural Science Foundation of China; project (2004CB619204) supported by the National Key Fundamental Research and Development Program of China     

Adsorption behavior of Pb^2＋ and Cd^2＋ ions on bauxite flotation tailings

The adsorption behavior of Pb^2＋ and Cd^2＋ ions on bauxite flotation tailings was investigated to demonstrate the adsorptivity of the bauxite flotation tailings. The adsorption percentage of Pb^2＋ and Cd^2＋ ions as a function of adsorbent dosage, solution pH value and shaking time were determined by batch experiments. The maximum adsorption percentage of 99.93% for Pb^2＋ ions and 99.75% for Cd^2＋ ions were obtained by using bauxite flotation tailings as adsorbent. The methods, such as zeta potentials, specific surface area measurements and the analysis of adsorption kinetics, were introduced to analyze the adsorption mechanisms of the Pb^2＋ ions on bauxite flotation tailings. The isoelectric point of bauxite flotation tailings shifts from 3.6 to 5.6 in the presence of Pb^2＋ ions. The specific surface area of bauxite flotation tailings changes from 12.57 to 20.63 m^2/g after the adsorption of Pb^2＋ ions. These results indicate that a specific adsorption of the cation species happens on the surface of bauxite flotation tailings. Adsorption data of Pb^2＋ ions on the surface of bauxite flotation tailings can be well described by Langmuir model, and the pseudo-second-order kinetic model provides the best correlation for the adsorption data of Pb^2＋ and Cd^2＋ ions on bauxite flotation tailings.     

Effect of rhamnolipids on cadmium adsorption by Penicillium simplicissimum

The effect of rhamnolipids (RL) on Cd²⁺ adsorption by Penicillium simplicissimum (P. simplicissimum) was studied. The maximum adsorption capacities of Cd²⁺ were obtained at pH 6.0 for the intact P. simplicissimum and at pH 5.0 for the RL-pretreated P. simplicissimum, respectively. The adsorption equilibrium was reached after about 4 h. The experimental adsorption isotherms were in good agreement with the Langmuir model. The maximum adsorption capacities (q _max) for the intact P. simplicissimum and for the RL-pretreated P. simplicissimum were 51.6 and 70.4 mg/g, respectively. The interactions between Cd²⁺ and functional groups on the cell wall surface of the P. simplicissimum were identified by SEM, EDAX and FTIR analysis. It is indicated that carboxyl, amino and hydroxyl groups play major roles in the Cd²⁺ adsorption. The results suggest that the RL-pretreated P. simplicissimum is a promising candidate for the removal of Cd ²⁺ from aqueous solutions.     

Determination of constituents of essential oil from Angelica sinensis by gas chromatography-mass spectrometry

Gas chromatography-mass spectrometry （GC-MS） coupled with chemometric resolution upon twodimensional data was employed to analyze the constituents of essential oils of Angelica sinensis. Constituents in essential oils of Angelica sinensis root were identified by GC-MS with the help of subwindow factor analysis （SFA） method resolving two-dimensional original data into mass spectra and chromatograms. 76 of 97 separated constituents in essential oil of Angelica sinensis root were identified and quantified, and they account for about 91.36% of the total content. The results show that ligustilide, butylene phthalide, 2-methoxy-4-vinylphenol, carvacrol, alloocimene, 2,6,6-trimethylbicyclo-[3,1,1] hept-2-ene are the main constituents in essential oil of Angelica sinensis root.     

Synthesis of N, N-diethyl dodecyl amine and its flotation properties on bauxite

N, N-diethyl dodecyl amine（DEN12） was synthesized from dodecyl amine, formic acid and acetic aldehyde. The collecting property of DENI2 on diaspore, kaolinite and illite was investigated by flotation test and infrared spectrum. The results show that in the presence of 2.0× 10^-4 mol/L DEN12, the recoveries of kaolinite and illite are all higher than 78% and the recovery of diaspore is 50% in the pH range of 5.5-6.0. The mass ratio of A1203 to SiO2 in concentrate obtained from separation artificial mixture is higher than 10, suggesting that DEN12 can be used as a collector to separate the aluminosilicates from diaspore in bauxite ores at the pulp pH below 8. The measurements of the infrared spectrum approve that the action between aluminosilicates and tertiary amine collector is strong electrostatic adsorption and that of diaspore is weak electrostatic adsorption.     

絮凝污泥作为低碳氮比生活污水补充碳源的脱氮试验研究

为解决低碳氮比生活污水生物脱氮过程中碳源不足的问题,本试验利用絮凝污泥水解酸化液作为外加碳源,通过生物絮凝吸附-前置反硝化曝气生物滤池(BAF)组合工艺,研究水解酸化液对低碳氮比生活污水生物脱氮性能的影响。试验结果表明:未投加水解酸化液的条件下,出水COD、NH_+~4-N和TN平均值为17.57 mg/L、1.27 mg/L和10.21 mg/L,系统去除率分别达到77.91%、95.48%、64.52%左右;在碳源投配比1:60时,进入前置BAF系统的COD/TN为3.71,NH_+~4-N和TN的去除率分别达到96.12%和79.80%。研究表明,以絮凝污泥水解酸化液作为低碳氮比生活污水补充碳源,可显著提高前置BAF生物脱氮性能,且实现絮凝污泥的资源化与减量化。     

Comparative analysis of volatile constituents between herbal pair flos lonicerae-caulis lonicerae and its single herbs

Gas chromatography-mass spectrometry (GC-MS) and the chemometric resolution method (alternative moving window factor analysis, AMWFA) were used for comparative analysis of volatile constituents in herbal pair (HP) flos lonicerae-caulis lonicerae (FL-CL) and its single herbs. The temperature-programmed retention index (PTRI) was also employed for the identification of compounds. In total, 44, 39, and 50 volatile chemical components in volatile oil of FL, CL and HP FL-CL were separately determined qualitatively and quantitatively, accounting for 87.22%, 94.54% and 90.08% total contents of volatile oil of FL, CL and HP FL-CL, respectively. The results show that there are 32 common volatile constituents between HP FL-CL and single herb FL, 33 common volatile constituents between HP FL-CL and single herb CL, and 10 new constituents in the volatile oil of HP FL-CL.     

Influence of different medium aging on advanced composite T300/5405

The aging properties of advanced composite T300/5405 which soaked in 15# hydraulic oil, 4010 lubricating oil, RP-3 kerosene and AHC-1 cleaner were studied. The absorption and mechanical properties of the composites were measured, and the scanning electron microscopy （SEIVO, dynamic mechanical analysis （DMA） and the infrared analysis （IR） were used to investigate the properties＇ changes of the composite. The aging mechanism of composite T300/5405 was also discussed. The experimental results show that the absorption of the composite in AHC-1 was the biggest, and the other three mediums had little effect on the composites. The mechanical properties declined in the aging. The composites have undergone chemical change in the test; Tg rose or declined atter the aging, and the AHC-1 cleaner and 4010 lubricating oil had the greatest influence on the Tg.     

The Effect of Surface Etching and Dation on the Permeability Spectrum of Nanoerystalline Fe85-xCoxNb7B8 Ribbon

Etching and oxidation were adopted to improve the frequency dependence of permeability of nanocrystalline Fe85-xCoxNb7B8 ribbons. The effect of etching and oxidation on the permeability spectrum of nanocrystalline Fe85-CoxNb7B8 ribbons was investigated. The relaxation frequency shifted to higher frequency end after etching and oxidation while the amplitude of μ1 was reduced at the same time. As a whole, μf0 rises and reflects the increasing of resistivity after etching and oxidation.     

龙牙草石油醚提取物中的挥发成分研究

为探讨龙牙草在石油醚中的溶解成分,利用索氏提取器获取了龙牙草石油醚提取物,并利用气相色谱-质谱(GC - MS)联用技术对其进行了分析.研究显示:龙牙草石油醚提取物的收率为3.20%; 在龙牙草石油醚提取物的35个强色谱峰中共鉴定出27个成分,占石油醚提取物总含量的45.28%.27个成分中相对百分含量较高的成分依次为三环[3,5,7]癸烷 -1- 羧酸辛酯(6.42%)、胆酸乙酯(3.87%)、棕榈酸(3.67%)、(E)- 3,7,11,15- 四甲基十六醇 -2- 烯 -1- 醇(3.37%)、α- 姜黄烯(2.93%)、绵马素(2.15%)等.该结果可为龙牙草的药理研究和开发利用提供参考.     

X-Z倒立摆的一种饱和非线性稳定控制方法的研究

针对立方体机器人的平衡控制问题,建立其以角为支点平衡的动力学模型.以所设计的物理样机为具体研究对象,在分析其运动学原理的基础上,定义了表达系统运动属性所需的最少变量,基于拉格朗日方法,对系统的能量函数和广义力进行计算,建立了立方体机器人以其角为支点平衡的动力学模型.通过数值仿真,对所建立模型的正确性进行了理论分析,并将模型与虚拟样机的零输入响应进行对比,响应曲线基本一致,验证了模型的准确性.将基于所建立动力学模型设计的平衡控制器应用于虚拟样机的控制,实验表明,该控制器可有效实现立方体机器人的平衡控制,进一步完成了对模型有效性的验证.建立的动力学模型为后期继续研究立方体机器人平衡控制问题提供了基础.