title: Hydrothermal carbonization of sewage sludge: The effect of feed-water pH on fate and risk of heavy metals in hydrochars.
abstract: In this study, the effect of feed-water pH (pH=2-12) on fate and risk of heavy metals (HMs) in hydrochars (HCs) was investigated. Hydrothermal carbonization (HTC) of sewage sludge (SS) was carried out with different feed-water pH at 270°C. The research results showed that changing feed-water pH had a positive effect on accumulating Pb, Ni, Cd and Zn in HCs. Chemical forms of Cu and Cr converted from an unstable state to stable in the alkaline environment while in the acidic condition was opposite. The effect of feed-water pH on the chemical forms of HMs was variable but not significant. Risk assessments of Igeo, Er(i), RAC and RI were applied to evaluate the accumulation levels of individual metal, the potential ecological risks, the bio-availabilities and the comprehensive toxicity and sensitivity of HMs, respectively. The lowest pollution level of HMs was obtained at 270°C with pH=11.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China. Electronic address: ybzhai@hnu.edu.cn.
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Zhai
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Office of Scientific R&D, Hunan University, Changsha 410082, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Peng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Luo
authors.initials: L
authors.lastname: Zhu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Caiting
authors.initials: C
authors.lastname: Li
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
mesh_terms: D001709:Biotechnology; D002104:Cadmium / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D004787:Environmental Pollution; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis*; D009532:Nickel / Q000737:chemistry; D018570:Risk Assessment; D012722:Sewage; D013696:Temperature; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*; D015032:Zinc / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; D002857:Chromium; D007854:Lead; D002244:Carbon; D003300:Copper; D009532:Nickel; D015032:Zinc
keywords: Heavy metals; Hydrochar; Hydrothermal carbonization; Risk assessment; pH