One-step synthesis of N-doped metal/biochar composite using NH 3-ambiance pyrolysis for efficient degradation and mineralization of Methylene Blue

J Environ Sci (China). 2019 Apr;78:29-41. doi: 10.1016/j.jes.2018.06.014. Epub 2018 Jun 28.

Abstract

A series of new biochar-supported composite based on the combination of biochar and metallic nanoparticles (NPs) were produced through single-step pyrolysis of FeCl3-Ti(OBu)4 laden agar biomass under NH3 environment. The physiochemical properties of composites were characterized thoroughly. It has found that heating temperature and N-doping through NH3-ambiance pyrolysis significantly influence the visible-light sensitivity and bandgap energy of composites. The catalytic activities of composites were measured by degradation of Methylene Blue (MB) in the presence or absence of H2O2 and visible-light irradiation. Our best catalyst (N-TiO2-Fe3O4-biochar) exhibits rapid and high MB removal competency (99.99%) via synergism of adsorption, photodegradation, and Fenton-like reaction. Continuous production of O2- and OH radicles performs MB degradation and mineralization, confirmed by scavenging experiments and degradation product analysis. The local trap state Ti3+, Fe3O4, and N-carbon of the catalyst acted as active sites. It has suggested that the Ti3+ and N-doped dense carbon layer improve charge separation and shuttle that prolonged photo-Fenton like reaction. Moreover, the catalyst is highly stable, collectible, and recyclable up to 5 cycles with high MB degradation efficiency. This work provides a new insight into the synthesis of highly visible-light sensitized biochar-supported photocatalyst through NH3-ambiance pyrolysis of NPs-laden biomass.

Keywords: Biochar-supported photocatalyst; Methylene Blue; NH(3)-ambiance pyrolysis; N–TiO(2)–Fe(3)O(4)-biochar; Photocatalysis.

MeSH terms

  • Adsorption
  • Ammonia / chemistry*
  • Catalysis
  • Charcoal / chemistry*
  • Hydrogen Peroxide / chemistry
  • Methylene Blue / chemistry*
  • Models, Chemical*
  • Pyrolysis*
  • Titanium / chemistry
  • Water Pollutants, Chemical / chemistry*

Substances

  • Water Pollutants, Chemical
  • biochar
  • Charcoal
  • Ammonia
  • Hydrogen Peroxide
  • Titanium
  • Methylene Blue