Macrokinetic determination of isopropanol removal using a downward flow biofilter

Biofiltration is a process for eliminating contaminants in air using microorganisms immobilized on a surface of solid support media. This technique has been used successfully to control a number of air contaminants such as odors, Volatile Organic Compounds (VOCs), and Hazardous Air Pollutants (HAPs) due to its economic attraction.Microorganisms obtained from local activated sludge (Huay-Kwang wastewater treatment plant (Bangkok, Thailand)) were selectively enriched and inoculated to the biofilter. The downward flow biofilterwas chosen, due to the ease of water compensation at the dry zone, to operate continuously for more than 3 months under various concentrations of isopropanol alcohol (IPA) input at a constant filtered air flow rate of 3 L/min. The maximum IPA elimination capacity of 276 g/m3-h was achieved at the IPA inlet of 342 g/m3-h with acetone production rate of 56 g/m3-h as the intermediate. It was also found that the acetone vapour was partly degraded by the acetone-utilizing microorganisms before leaving the bed. In order to understand the transport phenomena of biofiltration, it is necessary to consider the kinetic behavior of the bioreaction. Therefore, this paper introduces Wani’s method of macrokinetic determination based on the simple Monod kinetic (Wani, Lau and Branion, 1999). In this study, the maximum reaction rate per unit volume (Rm) and the Monod constant (KM) were found to be 0.12 g/m3 -s and 2.72 g/m3 respectively

xNi/Ni0.05Ce0.20Zr0.75O2 Solid Solution over a CO2 Methanation Reaction

A Ni-modified ceria-zirconia support with Ni impregnation at different Ni-loading catalysts for a CO2 methanation reaction was systematically studied. The corresponding structures of each catalyst were characterized by Brunauer-Emmett-Teller surface area analysis, X-ray powder diffraction, X-ray fluorescence, H-2 temperature-programmed reduction, CO2 temperature-programmed desorption, Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric/differential thermal analysis. The results showed that Ni-modified Ce-Zr oxide improved the basic properties as well as the oxygen vacancies. A gradual increase in Ni loading from 15 to 45 wt % was found to increase medium-strong basic sites, and surface Ce3+ and Ni-0 species along with oxygen vacancies favor high activity. The CO2 methanation activity was related to the amount of Ni loadings where the 45Ni/Ni005CZO catalyst was reported to be the most active catalyst. This is due to the high amount of Ni surface suitable for H-2 activation and high medium basic sites to accommodate CO2 activation, leading to high catalytic activity

Preparation, Characterization and Thermo-Chromic Properties of EVA/VO2 Laminate Films for Smart Window Applications and Energy Efficiency in Building

Thermochromic films based on vanadium dioxide (VO2)/ethylene vinyl acetate copolymer (EVA) composite were developed. The monoclinic VO2 particles was firstly prepared via hydrothermal and calcination processes. The effects of hydrothermal time and tungsten doping agent on crystal structure and morphology of the calcined metal oxides were reported. After that, 1 wt % of the prepared VO2 powder was mixed with EVA compound, using two different mixing processes. It was found that mechanical properties of the EVA/VO2 films prepared by the melt process were superior to those of which prepared by the solution process. On the other hand, percentage visible light transmittance of the solution casted EVA/VO2 film was greater than that of the melt processed composite film. This was related to the different gel content of EVA rubber and state of dispersion and distribution of VO2 within the polymer matrix phase. Thermochromic behaviors and heat reflectance of the EVA/VO2 film were also verified. In overall, this study demonstrated that it was possible to develop a thermochromic film using the polymer composite approach. In this regard, the mixing condition was found to be one of the most important factors affecting morphology and thermo-mechanical properties of the films

Preparation of platinum-free tubular dye-sensitized solar cells by electrophoretic deposition

Tubular dye-sensitized solar cells (DSSCs) were developed by replacing expensive materials with lower cost materials as follows: (1) replacing conductive glass electrodes with titanium (Ti) wires and (2) replacing platinum (Pt) catalyst with the mixture of multi-walled carbon nanotubes, MWCNTs and Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), PEDOT-PSS. Platinized counter electrodes were used as the standard counter electrodes for comparison. The effects of the chemical treatment of titanium wire substrate and electrophoretic deposition condition on the efficiency of DSSCs were also investigated. The chemical treatment of titanium wires was carried out by soaking the wires in HF-HNO3 solutions at three different concentrations of 0.8, 1.6 and 2.4 M and three different soaking durations of 5, 10 and 15 min. The optimum condition was found at HF-HNO3 concentration of 0.8 M and soaking duration of 10 min. Film coating on working electrodes was performed using electrophoretic technique at three different voltages of 5, 8 and 10 V and four different coating durations of 1, 3, 5 and 7 min. Then, the optimum condition at deposition voltage of 5 V and deposition duration of 5 min was applied for film deposition on counter electrodes. The efficiency of DSSC with CNTs/TiO2 counter electrode was 0.03%. The addition of PEDOT-PSS improved the efficiency of DSSC to 0.08%