Effects of chemical oxidation on phenanthrene sorption by grass- and manure-derived biochars

Jie Jin; Ke Sun; Ziying Wang; Lanfang Han; Peng Du; Xiangke Wang; Baoshan Xing

doi:10.1016/j.scitotenv.2017.04.160

Effects of chemical oxidation on phenanthrene sorption by grass- and manure-derived biochars

Sci Total Environ. 2017 Nov 15:598:789-796. doi: 10.1016/j.scitotenv.2017.04.160. Epub 2017 Apr 27.

Authors

Jie Jin¹, Ke Sun², Ziying Wang³, Lanfang Han⁴, Peng Du⁵, Xiangke Wang⁶, Baoshan Xing⁵

Affiliations

¹ College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
² State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: sunke@bnu.edu.cn.
³ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
⁴ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
⁵ Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
⁶ College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China.

PMID: 28458195
DOI: 10.1016/j.scitotenv.2017.04.160

Abstract

The oxidation of biochar in the natural environment has been widely observed. However, its influence on the sorption of hydrophobic organic compounds (HOCs) by biochars, especially biochars with high contents of minerals, remains poorly understood. In this study, sorption of phenanthrene (PHE) by grass straw-based biochars (GRABs) and animal waste-based biochars (ANIBs) produced at 450°C before and after oxidation with HNO₃ was investigated. The biochar samples were characterized using elemental analysis, X-ray photoelectron spectroscopy, ¹³C nuclear magnetic resonance, and CO₂ adsorption. Characterization results demonstrate that HNO₃ treatment of biochars caused O enrichment, loss of alkyl C, and rise of aromaticity. The organic C-normalized surface area (CO₂-SA/OC) of both GRABs and ANIBs generally increased after oxidation. The sorption nonlinearity of PHE by the biochars was weakened after HNO₃ treatment. The sorption capacity of PHE by oxidized GRABs was consistently elevated compared with the untreated samples, indicating that the high sorption capacity of PHE by GRABs may be maintained for a long time after being added into soils. By contrast, PHE sorption by ANIBs was unchanged or attenuated after oxidation. Polar groups facilitated the sorption of PHE by GRABs, while inhibited that by ANIBs. Pore-filling and π-π electron donor-acceptor interactions regulated PHE sorption by GRABs. Our results imply that GRABs are promising sorbents for environmental applications in view of their long-lasting sorption capacity.

Keywords: Biochar; Feedstocks; HNO(3) oxidation; Phenanthrene; Sorption.