One-step microwave synthesis of magnetic biochars with sorption properties
관리자2018-05-03조회 2355
Adsorption is one of the best methods for wastewater purification. The fact that water quality
is continuously decreasing requires the development of novel, effective and cost available
adsorbents. Herein, a simple procedure for the preparation of a magnetic adsorbent from
agricultural waste biomass and ferrofluid has been introduced. Specifically, ferrofluid mixed
with wheat straw was directly pyrolyzed either by microwave irradiation (900 W, 30 min) or
by conventional heating (550°C, 90 min). Magnetic biochars were characterized by X-ray
powder diffraction, Mössbauer spectroscopy, textural analysis and tested as adsorbents of
As(V) oxyanion and cationic methylene blue, respectively. Results showed that microwave
pyrolysis produced char with high adsorption capacity of As(V) (Qm= 25.6 mg g–1 at pH 4),
whereas conventional pyrolysis was not so effective. In comparison to conventional pyrolysis,
one-step microwave pyrolysis produced a material with expressive microporosity,
having a nine times higher value of specific surface area as well as total pore volume. We assumed
that sorption properties are also caused by several iron-bearing composites identified
by Mössbauer spectroscopy ([super] paramagnetic Fe2O3, α-Fe, non-stoichiometric Fe3C,
γ-Fe2O3, γ-Fe) transformed from nano-maghemite presented in the ferrofluid. Methylene
blue was also more easily removed by magnetic biochar prepared by microwaves (Qm=144.9
mg g–1 at pH 10.9) compared to using conventional techniques.
첨부파일
- ▲ 윗글 Determination of nickel and cadmium in fish, canned tuna, black tea, and human urine samples after extraction by a novel quinoline thioacetamide functionalized magnetite /graphene oxide nanocomposite
- ▼ 아랫글 Dispersion stability of polyelectrolyte-wrapped carbon black particles in a highly fluorinated solvent