Application of dielectric barrier discharge(DBD) plasma packed with glass and ceramic pellets for SO_2 removal at ambient temperature: optimization and modeling using response surface methodology

Air pollution is a major health problem in developing countries and has adverse effects on human health and the environment. Non-thermal plasma is an effective air pollution treatment technology. In this research, the performance of a dielectric barrier discharge(DBD) plasma reactor packed with glass and ceramic pellets was evaluated in the removal of SO_2 as a major air pollutant from air in ambient temperature. The response surface methodology was used to evaluate the effect of three key parameters(concentration of gas, gas flow rate, and voltage) as well as their simultaneous effects and interactions on the SO2 removal process. Reduced cubic models were derived to predict the SO_2 removal efficiency(RE) and energy yield(EY). Analysis of variance results showed that the packed-bed reactors(PBRs) studied were more energy efficient and had a high SO2 RE which was at least four times more than that of the non-packed reactor. Moreover, the results showed that the performance of ceramic pellets was better than that of glass pellets in PBRs. This may be due to the porous surface of ceramic pellets which allows the formation of microdischarges in the fine cavities of a porous surface when placed in a plasma discharge zone. The maximum SO_2 RE and EY were obtained at 94% and 0.81 g kWh^(-1),respectively under the optimal conditions of a concentration of gas of 750 ppm, a gas flow rate of 2lmin^(-1), and a voltage of 18 kV, which were achieved by the DBD plasma packed with ceramic pellets. Finally, the results of the model's predictions and the experiments showed good agreement.

Antibacterial Properties of TiO_2 Ceramic Pellets Prepared Using Nano TiO_2 Powder

Titanium dioxide （TiO2） porous ceramic pellets with three dimension nano-structure were prepared using nano TiO2 powder. The TiO2 porous ceramic pellets were composed of TiO2 nanoparticles with 14-16 nm in diameter and had porosity of 74.85%. The mean pore size of the TiO2 porous ceramic pellets was 20.73 nm and the main pore size ranged from 3 to 16 nm. The mass loss of the TiO2 ceramic pellets was less than 5% after 20 d immersion in water. The antibacterial properties of the TiO2 pellets were studied. The sterilization rate of Colibacillus （hospital polluted water with bacterium） can reach 99% after 3 h photocatalytic process and these TiO2 pellets are easy to be re-activated and cyclically be used. The shaping mechanism and photocatalysis sterilization mechanism of the TiO2 pellets were discussed.

Cathodic Using of ZrB2-αSiC and TiB2-αSiC for PEM Electrolysis and Water Electrolysis at Low Temperature

39 mol% SiC of ceramic pellets ZrB2-αSiC and TiB2-αSiC were synthesized by the reactive hot pressure RHP process at 1850°C under 40 Mpa in vacuum. The XR diffraction displays the absence of other reagents apart from ZrB2, SiC and TiB2 confirming the purity of the pellets. The cathodic exploitation of both of them through electrochemical study shows that TiB2-αSiC is the most active for Hydrogen Evolution Reaction (HER) and Hydrogen Oxidation Reaction (HOR) in 0.5 M of H2SO4 solution at room temperature. Moreover, the kinetic exploitation shows that for both pellets the system is controlled by mass transport when they are used as HER. However, in the case of HOR, the system is controlled by the electron transfer.

Study on analysis of crystal structure in CeO_2 doped with Er_2O_3 or Gd_2O_3

To simulate the effects of burnable poison doping in nuclear fuel UO2,Er2O3(or Gd2O3)-doped CeO2 pellets were prepared. Changes in lattice constant and atomic disordering for CeO2 due to the Er2O3 and Gd2O3 doping were measured by means of XRD and XAFS. By the Er2O3 doping,the lattice constant decreased,and a disordering of lattice structure was induced in the samples. The doping with Er2O3 also induced the disordering of atomic arrangement around Er atoms,which was observed through the change in XAFS spectra. In contrast,the effect of Gd2O3 doping was smaller than that of Er2O3 doping. The result was discussed in terms of ionic size of dopants in CeO2 crystal.