title: Arsenic transformation and volatilization during incineration of the hyperaccumulator Pteris vittata L.
abstract: Safe incineration of harvested hyperaccumulators containing high content of heavy metals to avoid secondary environmental pollution is a problem for popularizing phytoremediation technology. The As volatilization behavior and its mechanism during incineration of Pteris vittata, an As-hyperaccumulator, was investigated. Incineration results reveal that 24% of total As accumulated by P. vittata (H-As) containing high As content (1170 mg/kg) is emitted at 800 degrees C, of which 62.5% of the total emitted As is volatilized below 400 degrees C. A study of the extended X-ray absorption fine structure (EXAFS) shows that part of As(III) was identified in the thermal decomposition residue of dried P. vittata (H-As), As2O5 + P. vittata (L-As) containing low As content (14.7 mg/kg), and As2O5 + charcoal (C) at 200 degrees C, suggesting that carbon originating from biomass incineration might catalyze As(V) reduction. This speculation was tested through thermogravimetric experiments, in which either C or P. vittata (L-As) markedly catalyzed the volatilization of pure As2O5 at low temperature. Therefore, the reduction of As(V) to As(III) is responsible for As volatilization during incineration of P. vittata below 400 degrees C. This study provides important insights into As behavior during incineration of As-hyperaccumulators, which is helpful to safely dispose harvested biomass with high As content.
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Yan
authors.forename: Tong-Bin
authors.initials: TB
authors.lastname: Chen
authors.forename: Xiao-Yong
authors.initials: XY
authors.lastname: Liao
authors.forename: Ze-Chun
authors.initials: ZC
authors.lastname: Huang
authors.forename: Jia-Rong
authors.initials: JR
authors.lastname: Pan
authors.forename: Tian-Dou
authors.initials: TD
authors.lastname: Hu
authors.forename: Can-Jun
authors.initials: CJ
authors.lastname: Nie
authors.forename: Hua
authors.initials: H
authors.lastname: Xie
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D001711:Biotransformation; D017745:Incineration; D032495:Pteris / Q000378:metabolism*; D013057:Spectrum Analysis / Q000379:methods; D014835:Volatilization; D014965:X-Rays
chemical_list: D001151:Arsenic