A method for preparation of silica particles from rice husk ash (RHA) is developed for use as fillers in an enhancement of gas permeability of polylactic acid (PLA) resin. Silica particles are produced in a one-step process by employing PLA-grafted-chitosan copolymer (PCT) as a polymeric surfactant. Particles with an average size of ca. 30 micron, which are smaller than those obtained from a conventional method, are obtained. The major advantage of this technique is its ease of operation, in which mechanical grinding is not required. The resulting particles are then used in preparation of PLA/silica composites by varying the silica contents from 0-2.0 wt %. The PCT copolymer is present as a coating layer on the particles surface, which promotes compatibility with the PLA matrix. Gas permeability (water vapor, carbon dioxide, and oxygen) and mechanical properties of the composite films are examined. Enhancements in gas permeability and selectivity are achieved, with slight drops in mechanical properties. The materials have high potential for use as degradable packaging films with tunable gas permeability.
The catalysts, 5 wt% Na2WO4-2 wt% Mn on mullites sintered at 1200°C, 1300°C, 1400°C, and 1500 °C, were prepared by incipient wetness impregnation method for the oxidative coupling of methane (OCM) reaction in a fixed-bed quartz tube reactor. These catalysts were characterized by XRD, XPS and BET method. The XRD pattern of Na2WO4-Mn/mullite indicated that the main crystal phase of metal oxide was MnWO4. From the XPS spectra, the results revealed the information on Na, W and Mn species distributed on the catalyst surface. For catalytic activity testing, Na2WO4-Mn/mullite sintered at 1300 °C showed the highest C2selectivity of 11.4% and Na2WO4-Mn/mullite sintered at 1400 °C showed the highest CH4conversion of 56.6%.
Abstract-In order to increase the efficiency in municipal solid waste management (MSWM), waste-to-energy (WtE) technologies are provided as a solution towards the successful policy in Thailand. WtE is perceived as a means to dispose MSW, produce energy, recover materials, and free up scarce land that would otherwise have been used for landfill. Thailand considers WtE to be a renewable technology, incineration, refuse derived fuel (RDF), anaerobic digestion, pyrolysis and gasification, and landfill gas recovery. These lists are a number of technologies for energy recovery from urban and industrial wastes that "not only reduce the quantity but also improve the quality of waste to meet the required pollution control standards, besides generating a substantial quantity of energy". While the WtE technologies would be suggested that the cost of WtE is somewhat higher than other renewable sources, it should be kept in mind that WtE facilities serve a dual role of waste disposal and energy production. Although the cost per MW of capacity may be greater than other renewable sources, the benefits of waste management, energy and metals recovery, and reduction of GHG emission need to be considered.
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