Volume 2 Issue 3
Authors: Ismael Acosta-Rodríguez; Damaris L. Arévalo-Rangel; Juan F. Cárdenas-González; Víctor Manuel Martínez-Juárez
Abstract: The authors studied the Chromium (VI) removal capacity in aqueous solution by fungal biomass of Penicillium sp., using the diphenylcarbazide method to evaluate the metal concentration. The biosorption of the metal (50 mg/L) occurs within 150 minutes, at pH of 1.0, and 28 °C. According to temperature, the highest removal was observed at 50 °C, and 60 °C, in 40 minutes, when the metal (50 mg/L) is completely adsorbed. At the analysed concentrations of Cr(VI), fungal biomass showed excellent removal capacity, besides it removes efficiently the metal in situ (63.24%, and 43% removal, seven days of incubation, 5 g of biomass, in earth and water contaminated); so it can be used to eliminate it from industrial wastewater.
Keywords: Chromium (VI); Biosorption; Fungal Biomass
Authors: Zina Al-Shadidi
Abstract: Generation energy has been an important subject for humans since the beginning of civilization, and the renewable energy is the most important type of energy because of its wonderful properties where it’s the cheapest energy sources and the disappearance of pollution. The new idea here is very simple, and it’s the combination of two renewable sources of energy, (takes from the sea). Among different types of sea energy the author chooses the wave energy, and the sea thermal energy conversion (i.e. the way to differentiate temperature difference into electricity). Studying and analyzing the new system properties for the new system have been done using Matlab.
Keywords: Theoretical Study; Electrical Power Station; Wave Energy; Matlab
Authors: Motoki Shimada; Hisashi Tamaki; Eiji Higuchi; Hiroshi Inoue
Abstract: Hydrogen absorption-desorption properties at various temperatures for three MgH2-based composites, MgH2-Ni, MgH2-Ni-Si and MgH2-Ni-Ni2Si, were evaluated, and the most plausible reaction model and the rate-determining process for hydrogen absorption and desorption were determined for each composite. For each composite all hydrogen absorption curves at over 150 °C best fitted the three-dimensional diffusion-controlled contracting volume (CV-diffusion) model whose rate-determining step was hydrogen diffusion through the hydrogenated phase. Activation energy for hydrogen absorption was decreased in the order of MgH2-Ni-Si > MgH2-Ni-Ni2Si > MgH2-Ni. The hydrogen desorption rates of these composites also were significantly improved compared to the ball-milled MgH2. The three-dimensional CV model whose rate-determining step was the movement of the metal/hydride interface at a constant velocity was most closely fit for the hydrogen desorption curves at over 250 °C for three composites were most fitted. Activation energy for hydrogen desorption was decreased in the order of MgH2-Ni > MgH2-Ni-Si > MgH2-Ni-Ni2Si. Thus, the ball-milling of MgH2 with Ni and Ni2Si also greatly improved hydrogen absorption-desorption properties compared to ball-milled MgH2.
Keywords: Hydrogen Storage Material; Mechanochemical Method; Magnesium Hydride; Ni2Si; Hydrogen Absorption-Desorption