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Study on the Formation of Byproducts and the Decomposition of o-Chlorophenol by Addition of NaOH in Supercritical Water  

Song, Byung-Joo (Environmental Engineering, Chonbuk National University)
Kim, Jong-Guk (Environmental Engineering, Chonbuk National University)
Lee, Geun-Hee (Environmental Policy Division, Busan Metropolitan City Hall)
Publication Information
Journal of Korean Society of Environmental Engineers / v.27, no.3, 2005 , pp. 273-279 More about this Journal
Abstract
The degradation of o-chlorophenol(o-CP) in the presence of NaOH and the byproducts formed were investigated in a supercritical water(SCW) destruction process. The conversion of o-CP in the absence of NaOH was less than 20%, however it showed 100% conversion in the presence of NaOH(mole ratio[NaOH]/[o-CP] over than 2) with a residence time of less than 1 second. The formation of PAHs and the phenolic compounds formed were decreased in the presence of NaOH. The results revealed that the formation of byproducts during the destruction of o-CP in SCW was effected by the addition of NaOH. Phenol, cresols, chlorinated phenols, PAHs, p,p'-dihydroxybiphenyl and oxygenated polyaromatic compounds such as 1-indanone, dibenzofuran and dibenzo-p-dioxin were detected in both conditions(presence and absence of NaOH). At the same time, in the presence of NaOH, 2-ethylphenol, o-hydroxyacetophenone, hydroquinone, 4-allylphenol, 3-phenoxyphenol and 4,4'-oxybisphenol were also detected. The observed results suggest that the destruction of o-CP in SCW with NaOH occurs through a number of complicated reaction pathways. Dibenzofuran and dibenzo-p-dioxin were also detected during destruction of o-CP by SCW. The above observation suggests that there may be a common relationship between the thermal incineration process and SCW decomposition process.
Keywords
Supercritical Water; Chlorinated Phenol Compounds; PCDF; PAHs; NaOH;
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