title: Rapid reduction of lead leachate from hazardous fly ash using microwave treatment with acid combination.
abstract: The novelty of this study is to rapidly reduce hazardous lead leachates from solid waste using microwave digestion treatment, which is an energy-saving and low greenhouse gas emission technology. The article presents the reduction of toxic characteristic leaching procedure-extractable lead concentration in the municipal solid waste incineration fly ash by the microwave digestion treatment in HNO3/H2SO4 combination, and focuses on the effects of treatment time and temperature. The results obtained from this study indicated a significant reduction efficiency of toxic characteristic leaching procedure-extractable lead concentration and showed sufficient reduction in leaching levels to render the treated fly ash safe in lead compound leaching characteristics. The reduction efficiency of toxic characteristic leaching procedure-extractable lead concentration can reach 98% in 15 minutes of treatment time. This is equivalent to the original toxic characteristic leaching procedure-extractable lead concentration of 46.2 mg L(-1) in raw fly ash being reduced down to less than 1.0 mg L(-1). Based on the experimental data obtained in this study, a useful correlation between reduction efficiency and treatment conditions is proposed. For engineering applications, the necessary minimum treatment time is solved using a graphic illustration method, by which the minimum treatment time (t(min)) is obtained if the desired reduction efficiency (η) and treatment temperature (T) are known. The effects of treatment time and temperature are discussed. Some problems caused by the microwave digestion treatment method are also delineated in this article.
authors.affiliation: Department of Environment and Property Management, Jinwen University of Science and Technology, Taipei, Taiwan, Republic of China.
authors.forename: Chih-Mei
authors.initials: CM
authors.lastname: Chou
authors.affiliation: Graduate Institute of Environmental Engineering and Management, National Taipei University of Technology, Taipei, Taiwan, Republic of China.
authors.forename: Li-Pang
authors.initials: LP
authors.lastname: Wang
authors.affiliation: Graduate Institute of Environmental Engineering, National Sun Yat-Sen University, Kaushiung, Taiwan, Republic of China.
authors.forename: Jimmy C M
authors.initials: JC
authors.lastname: Kao
authors.affiliation: Department of Environmental Engineering, National I-Lan University, I-Lan, Taiwan, Republic of China.
authors.forename: Kae-Long
authors.initials: KL
authors.lastname: Lin
authors.affiliation: Graduate Institute of Environmental Engineering and Management, National Taipei University of Technology, Taipei, Taiwan, Republic of China ymchang@ntut.edu.tw.
authors.forename: Yu-Min
authors.initials: YM
authors.lastname: Chang
mesh_terms: D060729:Coal Ash / Q000737:chemistry; D004785:Environmental Pollutants / Q000737:chemistry* / Q000528:radiation effects; D017745:Incineration; D007854:Lead / Q000737:chemistry* / Q000528:radiation effects; D008872:Microwaves; D059027:Recycling / Q000379:methods*; D062611:Solid Waste / Q000032:analysis*; D018505:Waste Management / Q000379:methods*
chemical_list: D060729:Coal Ash; D004785:Environmental Pollutants; D062611:Solid Waste; D007854:Lead
keywords: Microwave treatment; fly ash; lead; municipal solid waste incineration; toxic characteristic leaching procedure