title: The migration and transformation behavior of heavy metals during the liquefaction process of sewage sludge.
abstract: Bio-oils and bio-chars were obtained from sewage sludge (SS) by liquefaction with ethanol (or acetone) as the solvent at the temperature of 280, 320 and 360°C. The migration and transformation of HMs as Pb, Zn, Cu and Ni during liquefaction were thoroughly investigated. Meanwhile, the environmental risk of HMs in the bio-oils and bio-chars was assessed according to the risk assessment code (RAC). The results showed that the liquefaction solvent and temperature significantly affected the redistribution of HMs. HMs distributed mainly into the bio-chars, with less than 10% into the bio-oils. Increasing liquefaction temperature would promote a higher HM content in bio-oils. The environmental risk of HMs in bio-chars was mitigated compared to SS, especially for Ni. However, the environmental risk of Zn and Ni in bio-oils was undesirably high in comparison with bio-chars. It was suggested that the bio-oil should be pretreated before utilization.
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Lijian
authors: L
authors: Leng
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China. Electronic address: yxz@hnu.edu.cn.
authors: Xingzhong
authors: X
authors: Yuan
authors: School of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330045, PR China.
authors: Huajun
authors: H
authors: Huang
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Hongwei
authors: H
authors: Jiang
authors: School of Business, Central South University, Changsha 410083, PR China.
authors: Xiaohong
authors: X
authors: Chen
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Guangming
authors: G
authors: Zeng
mesh_terms: D002606:Charcoal / Q000032:analysis; D005591:Chemical Fractionation; D004777:Environment; D019216:Metals, Heavy / Q000302:isolation & purification*; D009821:Oils / Q000032:analysis; D018570:Risk Assessment; D012722:Sewage / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D019216:Metals, Heavy; D009821:Oils; D012722:Sewage; C540010:biochar; D002606:Charcoal
keywords: Bio-char; Bio-oil; Heavy metal; Liquefaction; Sewage sludge