2018-Sustainable Industrial Processing Summit
SIPS2018
Volume 6. New and Advanced Materials and Technologies
| Editors: | F. Kongoli, F. Marquis, P. Chen, T. Prikhna, N. Chikhradze |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2018 |
| Pages: | 392 pages |
| ISBN: | 978-1-987820-92-8 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
CD shopping page
Dehalogenation of Organohalogen Compounds in Water by Using Raney Nickel Catalysts Prepared by Combustion Synthesis
Ryuichi Tomoshige1; Masashi Nishida1;1SOJO UNIVERSITY, Kumamoto, Japan;
Type of Paper: Regular
Id Paper: 260
Topic: 43
Abstract:
Today, many harmful chemicals such as volatile halogenated organics and defatting cleaners are still being used. The former has been used for mechanical metal parts or dry cleaning detergents, and the latter has been for agrichemicals and pesticide or industrial materials.<br />Unfortunately, they are thought as origins of pollution in groundwater and soil. In addition, their usage is restricted, or at least reduced to a degree that no longer causes health disasters for humans, due to their harmful effects on hepatic function and cancer generation, according to guidelines on drinking water quality by the World Health Organization (WHO). The acceptable limit of halogenated organics in water is determined based on Japan's laws on the environmental quality standards of wastewater. Since toxicity of halogenated organics can be reduced by dehalogenation of the substituent, dehalogenation that utilizes the chemical or biological process must be effective in eliminating toxicity. For example, in the biological process, dehalogenation by a few kinds of fungus has been reported. On the other hand, it was known that the chemical process is more effective on the dehalogenation reaction than the biological one on the decomposition rate of industrial wastewater dehalogenation. Furthermore, the chemical process has effects that can be utilized even under environments that would be inadequate for the biological process, i.e. under high halogen concentration. <br />In material science fields, many kinds of processes have been developed to make porous materials. Combustion synthesis has been known as one of the processes, which is an exothermic reaction for preparing intermetallic compounds and ceramics with very high temperatures. One of the characteristics of combustion synthesis is self-propagating reaction, which occurs by heating an end of a compact consisting of raw material metal and/or nonmetallic powders, and the other is to utilize the residual heat with sintering effect after completion of the combustion synthesis. One of the authors has produced various alloy and composites by using combustion synthesis [1-3].<br />In this paper, Raney catalysts obtained from NiAl intermetallic compounds prepared by combustion synthesis have been provided to evaluate a performance as purification treatment for industrial wastewater. It is reported concretely that dehalogenation reaction in the case of using 2,4,6-trichlorophenol (TCPh) of 50 ppm was investigated by column method using the NiAl alloy.<br />As a result, from the relationship between the flowing volume of TCPh solution and TCPh concentration, it was found that the TCPh concentration was reduced to a value lower than the quantification limit (<0.1 ppm) of high performance liquid chromatography (HPLC), when the flowing volume was up to 200 mL. Correspondingly, Ph was generated, and dichlorophenol (DCPh) and chlorophenol (CPh), which have been predicted as intermediate products, were not observed. As a result, the dehalogenation amount of TCPh per 1 g of catalyst was found to be 174 mg / g (0.881 mmol / g). The industrial wastewater standard value of TCPh is considered to be 0.3 ppm in Japan. Also, the flow rate of this experiment was 0.1 mL / min (S.V. = 87.0 in terms of space velocity), which was a industrially high processing speed. Therefore, it is considered that the Raney nickel catalyst can be fully applied to industrial wastewater.