Synthesis of Cationic PEM Emulsion and Application in Waste Water Treatment

Cationic polymer as a kind of flocculant is widely applied in purification treatment of waste water. Because it has positive charge group, it is able to connect strongly the suspended matters, short cellulose and other microparticles. The research on synthesis of cationic polymer and application in treatment of waste water is very universal abroad. But domestic research on those is not general. The technology of synthesis of PEM is simple, and the production cost is low. It is easy to apply in treatment of waste water.Synthesis of PEM Emulsion FlocculantSome distilled water, PVA(poly(vinyl alcohol)), EA(ethyl acrylate), and K2S2O8(potassium persulfate) were put into reaction vessel. Kept stirring up under nitrogen. When heated the solution to 40℃, dropped the water solution of MTA[(2-methacryloxylethyl)trimethyl ammonium].Maintained the temperature at 70℃, reacted about 7-8 hours. Then got the PEM emulsion. Changed the ratio of EA and MTA. Obtained a series of PEM emulsions.Stability and Convertibility of PEM EmulsionThe test results showed that when the EA/MTA was 85/15, the PEM emulsion was most stable.When the total monomer quantity was 35%, the convertibility of PEM emulsion was the highest,i.e.98.6%.The MTA Copolymerization Ratio and Morphology of PEM EmulsionWhen the monomers EA/MTA=85/15 and total monomer quantity was 35%, the MTA copolymerization ratio of PEM emulsion was 95.15%(the highest), and the PEM emulsion was some microspheres with 100-180nm of diameter.The Test Results of PEM Emulsion in Treatment of Waste Water The PEM emulsion flocculant was applied in treatment of waste water of paper mill, and measured the precipitation time(t) and transmittancy(T). The test results were showed in table 1. The optimum value of PEM which was able to make the waste water of paper mill into clear water was 0.008%.     

Non-protein amino acids in peptide design

An overview of the use of non-protein amino acids in the design of conformationally well-defined peptides, based on work from the author’s laboratory, is discussed. The crystal structures of several designed oligopeptides illustrate the useα-aminoisobutyric acid (Aib) in the construction of helices, D-amino acids in the design of helix termination segments and^DPro-Xxx segments for nucleating ofβ-hairpin structures.β- andγ-amino acid residues have been used to expand the range of designed polypeptide structures. Dedicated to Professor C N R Rao on his 70th birthday     

Nano-electrochemical detection of hydrogen or protons using palladium nanoparticles: distinguishing surface and bulk hydrogen.

The benefits of using nanoparticle-modified electrodes are exemplified through the electrochemical detection of protons and/or hydrogen. It is shown that a palladium-nanoparticle-modified boron-doped diamond allows voltammetric information relating to the relative roles played by the surface and the bulk metal to be obtained for the proton-hydrogen system at palladium surfaces which is not accessible using palladium macroelectrodes or microelectrodes.     

A new insight into the understanding of the collapsed form of poly(N-isopropylacrylamide) molecules

Possible collapsed forms of poly(N-isopropylacrylamide) molecules are reviewed on the basis of first principle calculations. Various configurations and associated conformations are detailed. The calculated optimized structures exhibit different possibilities of creating networks of intra-molecular bonds of the hydrogen type. We show that the most remarkable one is able to form a local, self-saturated and well ordered helix. We also indicate in which direction the synthesis of the molecule should be oriented to improve its global behavior in term of hydrophobic/hydrophilic behavior.     

The Systematics of Muonium Hyperfine Constants

The hyperfine constants for muonium in elemental and binary inorganic solids suggest formation of three different families of defect centre, with distinct electronic structures. The overall range of values, spanning nearly five orders of magnitude, and their correlation with host properties such as band gap and electron affinity, reveal a deep-to-shallow instability which has profound implications for the electrical properties of hydrogen impurity in electronic materials, both semiconducting and dielectric.     

着生刚毛藻处理富营养化湖泊水

分别研究了室内和露天条件下在鹅卵石上着生的刚毛藻Cladophora oligoclona对富营养化湖水中氮(N)和磷(P)的净化效果及其对水华藻类生长的抑制能力,同时对处理后湖水的藻类生长潜力进行了测试.结果显示,刚毛藻在原始浓度总氮(TN)10.512 mg/L和总磷(TP)0.856 mg/L的富营养化湖水中能维持正常的生长代谢,并能有效去除水体中的N、P养分.在室内12 d培养期间,刚毛藻对TN、氨氮(NH4-N)、TP和无机磷(PO4-P)的平均去除率分别达53.13%,44.40%,35.71%和30.53%.在室外6 d培养期间,刚毛藻对TN、NH4-N、TP和PO4-P的日均减少量分别为1.643 5±0.413 9,1.350 3±0.352 4,0.113 7±0.041 1,0.074 2±0.033 0 mg/L,总去除率分别高达93.81%,94.62%,79.67%和77.66%.刚毛藻对水华微囊藻生长的抑制率达99.63%,处理后湖水的藻类生长潜力较原湖水下降了40.17%.据此认为,刚毛藻在净化污染水体、修复受损湖泊及防治水体富营养化等方面具有潜在的应用前景.     

Paper-like Microfibrous Nickel Catalyst for Hydrogen Production via NH3 Decomposition in Fuel Cell Applications

Recently, miniature H2 generator to power fuel cells for portable/micro electronic devices and passenger propulsion has been the focus of intense research activities1-3. One of the strategies is to find simple CO-free H2 production with novel microreactor…     

Effect of plasma treatment on interface property of BCN/GaN structure

Interface properties of BCN/GaN metal-insulator-semiconductor (MIS) structures are investigated by X-ray photoelectron spectroscopy (XPS) and capacitance versus voltage (C-V) characteristics measurements. The BCN/GaN samples are fabricated by in situ process consisting of plasma treatment and deposition of BCN film in the plasma-assisted chemical vapor deposition (PACVD) apparatus. XPS measurement shows that the oxide formation at the BCN/GaN interface is suppressed by nitrogen (N₂) and hydrogen (H₂) plasma treatment. The interface state density is estimated from C-V characteristics measured at 1 MHz using Terman method. The minimum interface state density appears from 0.2 to 0.7 eV below the conduction band edge of GaN. The minimum value of the interface state density is estimated to be 3.0 × 10¹⁰ eV⁻¹ cm⁻² for the BCN/GaN structure with mixed N₂ and H₂ plasma treatment for 25 min. Even after annealing at 430 °C for 10 min, the interface state density as low as 6.0 × 10¹⁰ eV⁻¹ cm⁻² is maintained.     

Microstructure of laser melted Al18B4O33w/2024Al composite

The microstructure of a laser treated Al₁₈B₄O₃₃w/2024Al composite has been investigated using transmission electron microscope (TEM), low-angle (glancing angle) X-ray diffraction (XRD) techniques. Various surface microstructures were observed in the laser treated composite. The Al₁₈B₄O₃₃ whisker on the surface of the composite was decomposed during laser surface melting, various decomposition products were studied in the laser treated composite. Eutectic phases and the precipitation in the matrix of the composite with laser-treated were observed. The main phases detected in the molten zone were aluminum and decomposition products Al₂O₃. The effect of laser treatment on the hardness of the composite was also examined. A surface hardness of 400 Hv was noted.     

Effect of Hydrolysis Conditions on the Direct Formation of Nanoparticles of Ceria–Zirconia Solid Solutions from Acidic Aqueous Solutions

The effect of the cation concentration, hydrolysis temperature, and composition in the CeO₂–ZrO₂ system on the direct precipitation of ceria–zirconia solid solutions and the structure of the precipitates from acidic aqueous solutions of (NH₄)₂Ce(NO₃)₆ and ZrOCl₂ by hydrolysis under hydrothermal conditions were investigated. Nanometer-sized (8–10 nm) ceria–zirconia solid solution particles in a composition range of 0 to 60 mol% ZrO₂ were directly precipitated from the solutions with total metal cation concentration less than 0.2 mol/dm³ by simultaneous thermal hydrolysis at 150–240°C. The crystalline phase of the precipitates gradually changed from cubic and/or tetragonal to monoclinic with increasing the cation concentration of the solution from 0.2 to 0.8 mol/dm³ at the starting composition of 50 mol% ZrO₂ under hydrolysis condition of 150°C for 48 h, which was attributed to decrease in the supply of hydrolyzed Ce component caused by decrease in the hydrolysis ratio of (NH₄)₂Ce(NO₃)₆. Ceria–zirconia solid solutions containing large amount of ZrO₂ maintained high specific surface area and small-sized crystallite after heat-treatment at 900–1000°C for 1 h.