Browsing by Author "Niramon Worasith"
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Item A reinvestigation of EXAFS and EPR spectroscopic measurements of chromium(VI) reduction by coir pith(2010) Parinda Suksabye; Niramon Worasith; Paitip Thiravetyan; Akira Nakajima; Bernard A. Goodman; B.A. Goodman; Health and Environment Department, Unit of Environmental Resources and Technologies, Austrian Institute of Technology, Seibersdorf A-2444, Austria; email: bernard_a_goodman@yahoo.comNew measurements using extended X-ray absorption fine structure (EXAFS) and electron paramagnetic resonance (EPR) techniques are consistent with Cr in the Cr(III) oxidation state as the main product from the adsorption of Cr(VI) on coir pith. These confirm the previous X-ray measurements, but differ from the results of previous EPR studies, which indicated that Cr(V) was the main form of Cr. The reason for this discrepancy is the presence of a broad signal from Cr(III) in an unsymmetrical environment that was missed previously; the Cr(V) component is in fact only a minor reaction product. As a result of this problem with spectral acquisition and interpretation, some simple recommendations are presented for conducting EPR investigations on natural systems. © 2010.Item Effect of alumina content and surface area of acid-activated kaolin on bleaching of rice bran oil(Springer Verlag, 2015) Lei Lei Aung; Emmanuel Tertre; Parinda Suksabye; Niramon Worasith; Paitip ThiravetyanThis study investigated the effect of kaolin acid activation on alumina losses, surface area changes and oil bleaching performance. Ground kaolin was treated with hydrochloric or citric acid, and bleaching tests were performed on rice bran oil. The adsorption studies showed that the optimal bleaching of ~83 or ~81 % were achieved by activation with 0.5 M hydrochloric or citric acid, respectively, whereas bleaching with a commercial clay was ~82 %. The highest bleaching value was not associated with the maximum clay surface area or porosity. X-ray fluorescence showed that alumina contents of 31-34 % were suggestive for optimum bleaching depending on the different acid used. Treating ground kaolin with the same hydrochloric acid strength by varying the acid concentration and clay/acid ratio also confirmed that the best Al3+ content was ~32 %, and a value lower than one indicated the extensively destruction of kaolinite proportions leading to a decrease in its bleaching capacity, even though it had the maximum surface area. The decrease in capacity was due to the reduction of alumina content, and the parallel formation of high amorphous silica was favorable for the adsorption of anionic pigments, such as chlorophyll-a. � 2014 AOCS.Item Erratum to: Effect of alumina content and surface area of acid-activated kaolin on bleaching of rice bran oil(Springer Verlag, 2015) Lei Lei Aung; Emmanuel Tertre; Parinda Suksabye; Niramon Worasith; Paitip Thiravetyan; P. Thiravetyan; Division of Biotechnology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkhuntien, Bangkok, 10150, Thailand; email: paitip.thi@kmutt.ac.th[No abstract available]