Enhanced solubilization of phenanthrene and pyrene from bentonite in micellar solution of Brij 30 and Triton X-100 has been studied. Experiments in batch bentonite/aqueous system were conducted to investigate the effectiveness of solubilization of phenanthrene and pyrene. The results obtained in this study are as follows: The solubilization of pyrene from bentonite in surfactant solutions was very low because of low water solubility and strong sorption onto bentonite of pyrene. Meanwhile, the solubilization of phenanthrene increased at bulk surfactant concentrations greater than the surfactant critical micelle concentration and was in order of Triton X-100>Brij 30. The solubilization of phenanthrene was also analyzed based on the partitioning of phenanthrene between bentonite, nonionic surfactant micelle and aqueous solution surrounding the micelles.
Two component metal oxide nanoparticles such as lithium cobalt oxides (LiCoO2), indium tin oxides (ITO) were synthesized from aqueous aerosol precursors by the flame spray pyrolysis. A high enough flame temperature was used for the complete thermal decomposition of the aerosol precursor. Molar concentration of the aqueous precursor solution, and the flow rate of combustion gas such as hydrogen are varied to control particle size, size distribution and crystal structure. Crystalline LiCoO2 and ITO nanoparticles with the average particle diameter ranging from 11 to 35 nm and from 11 to 20 nm were synthesized, respectively.
CaCO3 was synthesized under various basic conditions through carbonation reaction. CO2 gas was blown into calcium hydroxide solution and the reaction pH was controlled constantly with NH4OH and KOH aqueous solution at specific levels which are 12.5, 11.5, 10.5, 9.5 and 8.5. Each sample prepared was analyzed with X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and BET surface area. And concentration of Ca2+ ion of filtered solution was measured with inductively coupled plasma-atomic emission spectrometer (ICP-AES). It was found that the pH affect on the crystallization when the NH4OH was used as pH control additives. In the case of the NH4OH addition, the particle size grew larger with decreasing of pH and increasing of reaction time. Ammonia induced the calcium carbonate dissolution, so that the small nuclei were dissolved and re-precipitated on the surface of larger nuclei. Because of the effect of ammonia, calcite particle prepared grew gradually as the reduction of pH. On the contrary, there are not influences of pH for precipitation of calcium carbonate when the KOH solution was added. It was suggested that the additives to control pH affect on the precipitation of calcium carbonate rather than reaction pH.
Activated carbon was successfully produced from beer lees which are the main waste material from a beer-production process, when KOH and CO2 were used as oxidizing agents in activation process. KOH activation produces well-developed porous structure. CO2 activation deserves attention in ecological and economical aspects. Adsorptions of 1,2-dichloroethane and 1,2-dichloropropane onto the obtained activated carbon in aqueous solutions were studied. Adsorptions are found to be affected by the solubility of adsorbate and the porous properties of adsorbent such as specific surface area and total pore volume. KOH-activated carbon shows distinguished performance for adsorption of 1,2-dichloropropane. Applicability of the obtained activated carbon was examined with McCabe-Thiele analysis which calculates the specific amount needed for removal of the above organic contaminants in aqueous solutions to meet a given standard.
Computer simulation for the preparation of C/SiC composites from methyl-trichlorosilane and hydrogen by F-CVI (Forced-flow Chemical Vapor Infiltration) reactor was studied. The mathematical modeling for the actual processes was carried out. With one overturning, the process time could be continued for 50 min longer than that without overturning. Additionally, the total amount of deposition increased 1.4 times with several times of overturning. Additionally, effects of many operation parameters were observed for the process with four overturnings. Effects of the flow rate, the initial porosity, and the inlet concentration were observed.
In the present work, the energy recovery and the mechanical recycling, i.e. two recycling options for plastic wastes from the discarded mobile phone have been assessed and compared in the context of the life cycle assessment methodology (LCA). The environmental impact of each option was assessed by first calculating the following impact indicators: depletion of abiotic resources (ADP), and global warming potential (GWP). Then, the indicators were aggregated and compared to select the option with the smaller environmental impact. The main finding of this study was that mechanical recycling of plastics is more attractive treatment option in environmental terms than incineration for energy recovery.