Browsing by Author "P. Thiravetyan"

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    Air-borne xylene degradation by Bougainvillea buttiana and the role of epiphytic bacteria in the degradation
    (Academic Press, 2016) S. Sangthong; P. Suksabye; P. Thiravetyan; P. Thiravetyan; School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand; email: paitip.thi@kmutt.ac.th
    The efficiency of xylene removal from contaminated air by thirteen perennial plants was studied. The results showed that Bougainvillea buttiana had the highest xylene removal efficiency. Different parts of B. buttiana such as stems, epicuticular waxes, and plant stomata (including microorganism-associated plant leaves) can uptake xylene 53.1�1.9%, 32.3�0.9, and 14.6�0.0%, respectively. Metabolite products found in treated plants may result from stress or defense compounds triggered by exposure to xylene. Moreover, possible degradation products in B. buttiana stems were analyzed after treatment with xylene at 100. ppm. Various metabolites in B. buttiana stems such as 2,6-dimethoxyphenol, 4-hydroxy-3,5-dimethoxy benzoic acid, 1-isopropyl-4-methylbenzene, p-tolualdehyde, 2,5-dimethoxy-4-methylbenzaldehyde, 2,4-dihydroxy-2,5-dimethyl-3(2H)-furanone, 3-methyl-2-butenal, dihydroxy acetone, propanedial, and many organic acids are related to the xylene degradation pathway. In addition, microorganism-associated B. buttiana leaves especially Enterobacter cloacae LSRC11, Staphylococcus sp. A1 and Pseudomonas aeruginosa enhanced the plant resulting in quicker xylene removal. � 2015 Elsevier Inc.
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    The capacity of activated kaolins to remove colour pigments from rice bran oil: The effects of acid concentration and pre-heating prior to activation
    (Mineralogical Society, 2014) L.L. Aung; E. Tertre; N. Worasith; P. Suksabye; P. Thiravetyan
    This study focuses on the effects of both thermal treatment (between 80 and 700¡C) and chemical activation (concentration of sulfuric acid between 0.3 and 2 M) of natural Ranong kaolins (ground or not) from Thailand to remove the undesirable colour of rice bran oil. The mineralogical, physical and physicochemical properties of the initial and activated kaolins are discussed in relation with the bleaching effectiveness of the activated sample investigated. Generally, the greater the temperature used before the activation step and the concentration of sulfuric acid used during activation, the greater the structural degradation of the kaolinite; Al is removed from the octahedral sheet of kaolinite and amorphous SiO2 dominates the samples. The measured maximum bleaching capacity is not necessarily obtained when using the activated kaolin having the highest specific surface area and pore volume; rather, the bleaching capacity is dependent on both alumina contents and proportion of kaolinite in the samples. Indeed, the partial preservation of the kaolinite structure is crucial to obtain a good bleaching capacity of kaolin in relation to the preservation of the aluminol sites which are likely to be involved in the adsorption of unsaturated molecules present in the rice bran oil. Moreover, as previously demonstrated, a partial leaching of Al from octahedral sheets of kaolin is also an important factor in order to obtain good bleaching capacities. Finally, the optimal preheating temperature and concentration of sulfuric acid which permit the best bleaching capacity of kaolin are reported. © 2014 Mineralogical Society.