title: Trichloroethylene decomposition and in-situ dry sorption of Cl-products by calcium oxides prepared from hydrated limes.
abstract: A comparison of CaOs produced by calcining two types of hydrated lime and calcium carbonate was made for decomposition of trichloroethylene and in-situ dry sorption of the decomposed Cl-products using a lab-scale gas flow type tubular packed bed reactor. About 20 mg of CaO sample was mixed with about 2 g of Al2O3 particles and packed in the reactor and allowed to react with a flowing standard gas containing 500 ppm of C2HCl3 (N2 balance) at 673 and 873 K, under the condition that the reaction of CaO with C2HCl3 might be completed within a few hours. It was found that no thermal decomposition of C2HCl3 at or below 673 K was observed in a reactor packed only with Al2O3 particles. However, a considerable amount of decomposition of C2HCl3 was obtained in a reactor packed with CaO and Al2O3, even at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 673 K, decomposition of 0.42 mol of C2HCl3 and in-situ absorption product of 0.53 mol of CaCl2 were obtained. At 873 K, about 46% of C2HCl3 was thermally decomposed. The total amount of C2HCl3 decomposed in CaO-Al2O3 particle bed at 873 K became nearly twice larger than that at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 873 K, decomposition of 0.59 mol of C2HCl3 and in-situ absorption product of 0.67 mol of CaCl2 were obtained. Small amounts of C2Cl2, C2Cl4, CCl4, etc. were detected during decomposition of C2HCl3 at 673 and 873 K. It was recognized that the data on decomposition of C2HCl3 as well as in-situ dry sorption of Cl-products in CaO particle bed were correlated with specific surface area of the CaO employed.
authors.affiliation: Yabashi Industries, Co. Ltd., 226 Akasaka-cho, Ogaki 503-2213, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Gotoh
authors.forename: Goichi
authors.initials: G
authors.lastname: Iwata
authors.forename: Kyaw
authors.initials: K
authors.lastname: Choh
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kubota
authors.forename: Hitoki
authors.initials: H
authors.lastname: Matsuda
mesh_terms: D000042:Absorption; D000537:Aluminum Oxide / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D010087:Oxides / Q000737:chemistry*; D013696:Temperature; D014241:Trichloroethylene / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D010087:Oxides; D014241:Trichloroethylene; C016538:lime; D000537:Aluminum Oxide