Advanced Materials Research Vols. 781-784

Abstract: The corrosion inhibition of N,N-diethylammonium O,O-di (3-methylphenyl) dithio-phosphate (NDOMD) for Q235 steel in HCl solution was studied by electrochemical measurements and weight loss measurements. And the effects of temperature, HCl concentration and immersion time were also studied. Polarization curves indicate the NDOMD is a mixed-type inhibitor which anodic plays a leading role. The studies of weight loss measurement show that the inhibition efficiency was up to 94.46% at the NDOMD concentration of 100 mg·L^-1 in 1.0 mol.L^-1 HCl solution at 30°C. The adsorption of NDOMD on Q235 steel surface obeys the Langmuir isotherm.

Abstract: The corrosion inhibition of S-benzyl-O,O'-dibenzyldithiophosphate (BBP) for carbon steel in hydrochloric acid solution was studied by electrochemical measurements and weight loss measurements. Polarization curves indicate BBP is a mixed-type inhibitor, and the effects of temperature, hydrochloric acid concentration and immersion time were also studied. The studies of weight loss measurement show that the inhibition efficiency was up to 97.39 % at the BBP concentration of 60 mg·L^-1 in 1.0 M hydrochloric acid solution at 30°C. The adsorption of BBP on carbon steel surface obeys the Langmuir isotherm.

Abstract: A new corrosion inhibior N,N-diethylammonium O,O-di (p-chlorophenyl) dithiophosphate (EDPDP) has been synthesized and its inhibition effect towards the corrosion of carbon steel in 1.0 molL^-1 HCl solution at 25 °C has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The obtained results show that EDPDP is a excellent inhibitor and the inhibition efficiencies exceed 90 %. The polarization measurements reveal that EDPDP is a mixed type inhibitor and the equivalent circuit model of the corrosion inhibition process is obtained by the analysis of EIS data.

Abstract: This work presents the synthesis and hydrodesulfurization performance of NiMo sulfide catalysts supported on γ-Al₂O₃ during the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The catalysts were synthesized by the co-impregnation method using an atomic ratio of Ni=Ni/(Ni+Mo)=0.5. The materials were characterized by N₂ physisorption, XRD and HRTEM. This catalyst exhibited the larger pore size and high specific surface area, as well as better morphological properties. The catalytic activity was evaluated using a high-pressure batch reactor at 280 °C and 3.0 MPa. The catalytic activity during HDS-DBT indicated that the NiMoS/γ-Al₂O₃ catalyst was better than that NiMoS/γ-Al₂O₃ catalyst. the NiMoS/γ-Al₂O₃ catalyst exhibits higher DDS selectivity (3.0) than NiMo/γ-Al₂O₃ catalyst (2.55).

Abstract: Manganese and cerium based catalysts with different Mn/Ce molar ratios prepared by impregnation method for ethyl acetate oxidation. The activity tests of the samples were performed in a fixed-bed reactor. The effect of gas hourly space velocity (GHSV) and ethyl acetate concentration on the catalytic activity of the catalyst were also investigated. The results showed that these catalysts had high activity for the catalytic oxidation of ethyl acetate, of which the catalyst Mn_0.9Ce_0.1O_x/TiO₂ exhibited the best activity, and the temperature required for 90% conversion of ethyl acetate was at 216 °C. The catalyst Mn_0.9Ce_0.1O_x/TiO₂ still maintained high activity in the range of GHSV (16,500 to 48,500 h^-1) and ethyl acetate concentration (4526 to 7092 mg/m³). In additional, experiments for measuring stability of Mn_0.9Ce_0.1O_x/TiO₂ were carried out, and experimental results showed that the good stability of Mn_0.9Ce_0.1O_x/TiO₂ was kept after it has run for 25 hours.

Abstract: The influence of the preparation conditions of the impregnation-vacuum filtration method was investigated systematically on the Ni dispersion and the activity of Ni-cordierite structured catalysts in hydrogenation of m-dinitrobenzene to m-phenylenediamine. H₂-TPD measurement showed that the Ni dispersion has close relationship with the impregnation solution concentration of nickel nitrate, the impregnation time, the vacuum degree, the vacuum filtration time and the calcination temperature. The hydrogenation activity test and nitrogen physisorption investigation showed that the catalytic performance of Ni-cordierite is dependent upon the Ni dispersion and the chemisorption mode of m-dinitrobenzene on Ni particles.

Abstract: An oxide diluted magnetic semiconductor, Co doped ZnO thin film was successfully fabricated by cathodic electrodeposition method. X-ray diffraction studies demonstrate that the ZnCoO thin film indicates that the wurtzite structure. X-ray photospectroscopy studies suggested Co ions have a chemical valence of 2+. Optical absorption spectrum further confirmed Co ions have been doped into ZnO crystal lattice successfully with substituting positions of Zn ions. In photoluminescence spectrum, the UV emission band shifted to low energy side because of the doping effect.

Abstract: Titanium Carbide (TiC) is a hard ceramic material with excellent tribological wear properties and high chemical stability at room temperature. To develop wear and corrosion resistant TiC coatings, electrodeposition of TiC coatings on the type 304 stainless steel (304SS) in molten NaCl-KCl-NaF-K₂TiF₆ at 900°C was investigated. Pulse plating technique in a form of periodically interrupted potential was applied using graphite (anode) as the source of carbon. It was found that a continuous TiC coating with a thickness less than 1 μm could be obtained on 304SS by periodically applying a potential of-2.8 V for 1h. Though this TiC coating delaminated, its inner layer exhibited excellent adhesion to the substrate. This method can be used to prepare compact TiC coatings.

Abstract: This work describes the preparation of multi-walled carbon nanotubes (MWCNT) and nickel oxide particles (NiO) composite modified electrode. The electrochemical catalytic performance of the new modified electrode toward sulfadiazine was studied by voltammetric method. The modified electrode exhibited good catalytic performance for the electrochemical oxidation of sulfadiazine at potential of 0.9 V, which was 0.2 V lower than that obtained by a normal glassy carbon electrode. The results of amperometric study suggested that the anodic current of the modified electrode linearly increased against the concentration of sulfadiazine in the range 1.0 - 7.9 μM.

Abstract: The pulsed discharge includes corona discharge and spark discharge. The voltage waveforms, photo, the decoloration rate of Crystal violet in corona discharge and spark discharge were investigated respectively. The results show that the spark discharge is more intense than the corona discharge. The decoloration rate of Crystal violet by spark discharge is 90%, which is higher than that corona discharge. From the UV-Visible and FTIR spectra, we can see that the molecular conjugated system and the benzene ring of CV were damaged by pulsed discharge.