Wheat straw biochar-supported nanoscale zerovalent iron for removal of trichloroethylene from groundwater

PLoS One. 2017 Mar 6;12(3):e0172337. doi: 10.1371/journal.pone.0172337. eCollection 2017.

Abstract

This study synthesized the wheat straw biochar-supported nanoscale zerovalent iron (BC-nZVI) via in-situ reduction with NaBH4 and biochar pyrolyzed at 600°C. Wheat straw biochar, as a carrier, significantly enhanced the removal of trichloroethylene (TCE) by nZVI. The pseudo-first-order rate constant of TCE removal by BC-nZVI (1.079 h-1) within 260 min was 1.4 times higher and 539.5 times higher than that of biochar and nZVI, respectively. TCE was 79% dechlorinated by BC-nZVI within 15 h, but only 11% dechlorinated by unsupported nZVI, and no TCE dechlorination occurred with unmodified biochar. Weakly acidic solution (pH 5.7-6.8) significantly enhanced the dechlorination of TCE. Chloride enhanced the removal of TCE, while SO42-, HCO3- and NO3- all inhibited it. Humic acid (HA) inhibited BC-nZVI reactivity, but the inhibition decreased slightly as the concentration of HA increased from 40 mg∙L-1 to 80 mg∙L-1, which was due to the electron shutting by HA aggregates. Results suggest that BC-nZVI was promising for remediation of TCE contaminated groundwater.

MeSH terms

  • Adsorption
  • Anions / chemistry
  • Charcoal* / chemistry
  • Groundwater* / chemistry
  • Hydrogen-Ion Concentration
  • Iron*
  • Kinetics
  • Trichloroethylene*
  • Triticum* / chemistry
  • Water Pollutants, Chemical*

Substances

  • Anions
  • Water Pollutants, Chemical
  • biochar
  • Charcoal
  • Trichloroethylene
  • Iron

Grant support

The author, HL, received the funding jointly provided by National Natural Science Foundation of China (grant number: 41273109, 51378208, 51578240), http://www.nsfc.gov.cn/; the National key research and development plan (2016YFC0206200), http://service.most.gov.cn/; Program for New Century Excellent Talents in University (grant number: NCET-13-0797), http://www.moe.gov.cn/; Fok Ying Tung Education Foundation (grant number: 141077), http://www.cutech.edu.cn/cn/index.htm; Innovation Program of Shanghai Municipal Education Commission (14ZZ059), http://www.shmec.gov.cn/; Innovation Program of Shanghai Municipal of Science and Technology Commission (grant number: 15DZ1205804), http://www.stcsm.gov.cn/; Fundamental Research Funds for the Central Universities (WB1313008, WB1516015, WB1616012), http://www.moe.edu.cn/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.