Dechlorination of PCBs, CAHs, herbicides and pesticides neat and in soils at 25 degrees C using Na/NH3

The decomposition of aniline in supercritical water (SCW) was studied. Experiments were performed at various temperatures, pressures, residence times, dosage of oxidant H2O2 and initial aniline concentrations to investigate their effect on the destruction efficiency. Manganous sulfate and ferrous sulfate were screened out during the experiment to study the effect of the homogenous catalysts on destruction efficiency. The effect of pH was also studied. The experiments showed that the dosage of oxidant H2O2, experimental temperature, pressure, reaction residence time and even initial concentration of the aniline in wastewater have a significant affect on the TOC removal; manganous sulfate and ferrous sulfate improve the oxidation; TOC removal improves slightly with a decrease in the initial pH value. At a system temperature 450 degrees C, pressure 28 MPa, initial pH 4.0, residence time 46 s and K value 1.1, TOC removal can reach 100%.     

Desulfurization from thiophene by SO(4)(2-)/ZrO(2) catalytic oxidation at room temperature and atmospheric pressure

Thiophene, due to its poison, together with its combustion products which causes air pollution and highly toxic characteristic itself, attracted more and more attention to remove from gasoline and some high concentration systems. As the purpose of achieving the novel method of de-thiophene assisted by SO(4)(2-)/ZrO(2) (SZ), three reactions about thiophene in different atmosphere at room temperature and atmospheric pressure were investigated. SO(4)(2-)/ZrO(2) catalyst were synthesized and characterized by X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The products were detected by gas chromatography-mass spectrometry (GC-MS). XP spectra show that ozone-catalyst system (SZO) have two forms of sulfur element (S(6+) and S(2-)) on the catalyst surface, which distinguished from that of air-catalyst system (SZA) and blank-catalyst system (SZB) (S(6+)). And the results of GC-MS exhibited that some new compounds has been produced under this extremely mild condition. Especially, many kinds of sulfur compounds containing oxygen, that is easier to be extracted by oxidative desulfurization (ODS), have been detected in the SZA-1.5h and SZB-3h system. In addition, some long chain hydrocarbons have also been detected. While in SZO-0.5h system, only long chain hydrocarbons were found. The results show that total efficiency of desulfurization from thiophene with ozone near to 100% can be obtained with the SO(4)(2-)/ZrO(2) catalytic oxidation reaction.     

Removal of reactive red-120 and 4-(2-pyridylazo) resorcinol from aqueous samples by Fe3O4 magnetic nanoparticles using ionic liquid as modifier

The nanoparticles of Fe₃O₄ as well as the binary nanoparticles of ionic liquid and Fe₃O₄ (IL-Fe₃O₄) were synthesized for removal of reactive red 120 (RR-120) and 4-(2-pyridylazo) resorcinol (PAR) as model azo dyes from aqueous solutions. The mean size and the surface morphology of the nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. Adsorption of RR-120 and PAR was studied in a batch reactor at different experimental conditions such as nanoparticle dosage, dye concentration, pH of the solution, ionic strength, and contact time. Experimental results indicated that the IL-Fe₃O₄ nanoparticles had removed more than 98% of both dyes under the optimum operational conditions of a dosage of 60 mg, a pH of 2.5, and a contact time of 2 min when initial dyes concentrations of 10-200 mg L⁻¹ were used. The maximum adsorption capacity of IL-Fe₃O₄ was 166.67 and 49.26 mg g⁻¹ for RR-120 and PAR, respectively. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The Langmuir adsorption constants were 5.99 and 3.62 L mg⁻¹ for adsorptions of RR-120 and PAR, respectively. Both adsorption processes were endothermic and dyes could be desorbed from IL-Fe₃O₄ by using a mixed NaCl-acetone solution and adsorbent was reusable.     

Zeolite synthesis from paper sludge ash at low temperature (90 degrees C) with addition of diatomite

Paper sludge ash was partially converted into zeolites by reaction with 3M NaOH solution at 90 degrees C for 24 h. The paper sludge ash had a low abundance of Si and significant Ca content, due to the presence of calcite that was used as a paper filler. Diatomite was added to the NaOH solution to increase its Si content in order to synthesize zeolites with high cation exchange capacity. Diatomite residue was filtered from solution before addition of ash. The original ash without addition of diatomite yielded hydroxysodalite with a cation exchange capacity ca. 50 cmol/kg. Addition of Si to the solution yielded Na-P1 (zeolite-P) with a higher cation exchange capacity (ca. 130 cmol/kg). The observed concentrations of Si and Al in the solution during the reaction explain the crystallization of these two phases. The reaction products were tested for their capacity for PO(4)(3-) removal from solution as a function of Ca(2+) content, suggesting the formation of an insoluble Ca-phosphate salt. The product with Na-P1 exhibits the ability to remove NH(4)(+) as well as PO(4)(3-) from solution in concentrations sufficient for application in water purification. Both NH(4)(+) and PO(4)(3-) removal showed little variation with pH between 5 and 9. Alternative processing methods of zeolite synthesis, including the addition of ash to an unfiltered Si-NaOH solution and addition of a dry ash/diatomite mixture to NaOH solution, were tested. The third process yielded materials with lower cation exchange capacity due to formation of hydroxysodalite. The second process results in a product with relatively high cation exchange capacity, and reduces the number of processing steps necessary for zeolite synthesis.     

Measurements of the foreign-broadened continuum of water vapor in the 6.3 microm band at -30 degrees C

The foreign-broadened continuum of water vapor in the nu2 band (5-7.7 microm, 1300-2000 cm(-1)) is important for satellite-based retrievals of water vapor in the upper troposphere, where temperatures are below -25 degrees C. Continuum coefficients have previously been measured mostly at or above +23 degrees C. We present continuum coefficients in the nu(2) band retrieved from measurements made in Antarctica at temperatures near -30 degrees C: atmospheric transmission at South Pole Station and atmospheric emission at Dome C. The continuum coefficients derived from these measurements are generally in agreement with the widely used Mlawer, Tobin-Clough, Kneizys, Davies continuum. Differences are at most 30%, corresponding to a 6% relative error in retrieved upper-tropospheric humidity.     

KxSr(1-x)/2Zr2(PO4)3陶瓷的热膨胀异向性研究

应用湿化学法和低分子有机溶剂分散合成了复合磷酸锆锶钾KxSr(1-x)/2Zr2(PO4)3(x=0,0.25,0.5,0.75,1.0)(简写 KSZP)陶瓷粉体,制备了相应的陶瓷.研究了组成、添加剂种类、烧结条件对热膨胀异向性及热膨胀系数的影响,实现了用两种组成的互溶来消除热膨胀的异向性.当x=0.5时,热膨胀异向性最小且热膨胀系数α接近于零即获得了零膨胀的材料性能.     

超超临界锅炉材料TP310HCbN(HR3C)持久及析出行为

采用持久试样方法,结合Gleeble、硬度分析、SEM、EDS、TEM等分析手段,对TP310HCbN耐热钢热变形以及在650℃与700℃条件下持久及析出行为进行了分析。结果表明:两种持久温度条件下,硬度变化趋势差别不大;随着持久时间延长,TP310HCbN耐热钢晶内析出物由颗粒状转变为棒状,并存在大量与位错相互作用的蠕虫状NbCrN析出物;太钢生产的TP310HCbN耐热钢650℃/700℃-100000h外推持久强度均满足标准要求。     

Ultrasensitive detection of CrO4(2-) using a microcantilever sensor

Microcantilevers modified with a self-assembled monolayer respond sensitively to specific ion concentrations. Here, we report the detection of trace amounts of CrO4(2-) using microcantilevers modified with a self-assembled monolayer of triethyl-12-mercaptododecylammonium bromide. The self-assembled monolayer was prepared on a silicon microcantilever coated with a thin layer of gold on one side. The microcantilever undergoes bending due to sorption of CrO4(2-) ions on the monolayer-modified side. It was found that a concentration of 10(-9) M CrO4(2-) can be detected using this technology in a flow cell. Other anions, such as Cl-, Br-, CO3(2-) (or HCO3-), and SO4(2-), have minimal effect on the deflection of this cantilever. The mechanics of the bending and the chemistry of cantilever modification are discussed.     

稀土固体超强酸SO_4~(2-)/TiO_2-Ce~(4 )直接法催化合成聚乳酸及其机理的研究

对稀土固体超强酸SO_4~(2-)/TiO_2-Ce~(4 )催化剂直接法催化合成聚乳酸反应机理进行了研究,实验结果表明:SO_4~(2-)/TiO_2-Ce~(4 )直接法催化剂合成聚乳酸的聚合机理是酸性聚合,酸性越强所合成聚乳酸的分子量越高。     

Solid phase extraction method for selective determination of Pb(II) in water samples using 4-(4-methoxybenzylidenimine) thiophenole

A sensitive and selective extractive preconcentration procedure for the determination of traces of lead in water samples has been developed. An alumina-sodium dodecyl sulfate (SDS) coated modified with 4-(4-methoxybenzylidenimine) thiophenole (MBITP) was used for preconcentration and determination of Pb(II) by flame atomic absorption spectrometry. Lead was adsorbed quantitatively on modified column due to its complexation with MBITP and quantitatively eluted using 5 mL 1 mol L(-1) nitric acid in acetone. The effects of parameters such as pH, amount of solid phase, amount of MBITP, flow rate, type and concentration of eluting agent were examined. The effect of interfering ions on the determination of Pb(II) was also investigated. The response of proposed method is linear in the concentration range 0.05-1.2 microg mL(-1) of Pb(II). The limit of detections (3S.D.(b)/m, n=4) and relative standard deviations (n=11) are 1.6 ng mL(-1) and 0.9%, respectively. The presented procedure was successfully applied for determination of lead content in real samples such as river, spring, waste and drinking water.     

Synthesis of ultrasmooth nanostructured diamond films by microwave plasma chemical vapor deposition using a He/H(2)/CH(4)/N(2) gas mixture

Ultrasmooth nanostructured diamond (USND) films were synthesized on Ti-6Al-4V medical grade substrates by adding helium in H(2)/CH(4)/N(2) plasma and changing the N(2)/CH(4) gas flow from 0 to 0.6. We were able to deposit diamond films as smooth as 6 nm (root-mean-square), as measured by an atomic force microscopy (AFM) scan area of 2 μm(2). Grain size was 4-5 nm at 71% He in (H(2) + He) and N(2)/CH(4) gas flow ratio of 0.4 without deteriorating the hardness (~50-60 GPa). The characterization of the films was performed with AFM, scanning electron microscopy, x-ray diffraction (XRD), Raman spectroscopy, and nanoindentation techniques. XRD and Raman results showed the nanocrystalline nature of the diamond films. The plasma species during deposition were monitored by optical emission spectroscopy. With increasing N(2)/CH(4) feedgas ratio (CH(4) was fixed) in He/H(2)/CH(4)/N(2) plasma, a substantial increase of CN radical (normalized by Balmer H(α) line) was observed along with a drop in surface roughness up to a critical N(2)/CH(4) ratio of 0.4. The CN radical concentration in the plasma was thus correlated to the formation of ultrasmooth nanostructured diamond films.     

Kinetics and thermodynamics of adsorption of azinphosmethyl from aqueous solution onto pyrolyzed (at 600 degrees C) ocean peat moss (Sphagnum sp.)

The removal of azinphosmethyl from aqueous solution onto pyrolyzed ocean peat moss (Sphagnum sp.), as a residue, from the Rhode Island coast (USA), has been investigated at different temperatures and initial concentrations. The ocean peat moss had been pyrolyzed at 600 degrees C in nitrogen atmosphere before the adsorption process. The kinetic data obtained from batch studies have been analyzed using pseudo-first order kinetic model. The rate constants were evaluated at different temperatures. The thermodynamic parameters (DeltaG degrees , DeltaH degrees , DeltaS degrees ) for the adsorption process were calculated and the results suggest that the nature of adsorption is endothermic and the process is spontaneous and favorable. The activation energy for adsorption process was estimated, about 18.3 kJ mol(-1). According to this value the adsorption of azinphosmethyl onto pyrolyzed ocean peat moss is in the range of physical adsorption. The experimental data have been modeled using Langmuir, Freundlich and Temkin isotherms. It was found that Langmuir and Freundlich isotherms give the best correlation with the experimental data.     

介孔SO_4~(2-)/TiO_2固体超强酸的制备与表征

以工业硫酸钛液为原料,分步水解制得吸附硫酸根的介孔偏钛酸,焙烧得到介孔SO42-/TiO2固体超强酸。用Hammett指示剂法、XRD、BET和FI-IR等多种手段对催化剂进行了表征;以乙酸乙酯的合成为模型反应,考察了催化活性。结果表明所制备的SO42-/TiO2催化剂是介孔结构;随着焙烧温度的升高和SO42-含量的增加,其比表面积和酸强度都先增大后减小,最高酸强度H0=-14.52,最大比表面积为192m2/g;酸强度及硫含量与催化活性都有着密切联系,在500℃下焙烧,硫含量为2.7%时,催化活性最高。     

Modified SO(4)(2-)/Fe(2)O(3) solid superacid catalysts for electrochemical reaction of toluene with methanol

A series of sulfate, different metal promoted SO(4)(2-)/Fe(2)O(3) catalysts were prepared and investigated by means of Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). All catalysts exhibit good catalytic activity for the electrochemical reaction of toluene with methanol assisted with a pair of porous graphite plane electrodes and chemical conversion higher than 80% was observed. In particular, molybdate promoted catalysts exhibited excellent catalytic activity.     

Synthesis and characterization of poly(3-hexylthiophene)/poly(3-(trimethoxysilyl)propyl methacrylate) rod-coil block copolymers by using atom transfer radical polymerization

In this study, polythiophene based rod-coil block copolymers (P3HT)47-b-(PMSMA)34 are synthesized by atom transfer radical polymerization (ATRP). The effects of altering the mix of solvent and processing temperature on the morphologies and photophysical properties of the block copolymers in both solution and solid state are investigated. The chemical structure of the prepared block copolymers is confirmed by NMR and FTIR analysis. TEM results show that different morphologies of aggregates can be obtained by varying the toluene/methanol ratios. Such aggregation leads to a significant red shift on the optical absorption and photoluminescence spectra of the P3HT-b-PMSMA in mixed solvents. The results of AFM, UV-Vis, and PL show that the morphologies and photophysical properties of P3HT-b-PMSMA films are also significantly affected by the curing temperature. Blue shifts on the optical absorption and photoluminescence spectra are observed upon increasing the curing temperature.     

Detection of CrO4(2-) using a hydrogel swelling microcantilever sensor

Hydrogels containing various mounts of tetraalkylammonium salts were used to modify microcantilevers for measurements of the concentration of CrO4(2-) in aqueous solutions. These microcantilevers undergo bending deflection upon exposure to solutions containing various CrO4(2-) concentrations as a result of swelling or shrinking of the hydrogels. The microcantilever deflection as a function of the concentration of CrO4(2-) ions is nearly linear in most concentration ranges. It was found that a concentration of 10(-11) M CrO4(2-) can be detected using this technology in a fluid cell. Other ions, such as Br-, HPO4(2-), and NO3-, have minimal effect on the deflection of this cantilever. The anions SO4(2-) and CO3(2-) could interfere with the CrO4(2-) detection, but only at high concentrations (> 10(-5) M). Such hydrogel-coated microcantilevers could potentially be used to prepare microcantilever-based chemical and biological sensors when molecular recognition agents are immobilized in the hydrogel.     

Simple and effective synthesis of methoxy-dimethylbenzene from electrochemical oxidation of p-xylene in methanol solvent catalyzed by SO(4)(2-)/ZrO(2)-M(x)O(y)

A series of composite solid superacid catalysts SO(4)(2-)/ZrO(2)-M(x)O(y) (M=Ti, Ni, Si) were prepared and investigated by means of Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). All catalysts exhibit good catalytic activity in the electrochemical reaction of p-xylene with methanol assisted with a pair of porous graphite plane electrodes and the selectivity of main products higher than 90% were observed. In particular, SO(4)(2-)/ZrO(2)-SiO(2) catalyst exhibited excellent catalytic activity. According to the experimental results, a possible free radical reaction mechanism confirmed by XPS and ultraviolet-visible (UV-vis) spectra was proposed. It may be concluded that a simple and feasible electrochemical catalytic oxidation reaction at room temperature and standard atmosphere may be possible.