Inexpensive
porous activated biocarbons were prepared from biomass
and agriculture waste following the method of thermal and hydrothermal
carbonization and activation with superheated water vapor. The activated
biocarbons were characterized by nitrogen adsorption–desorption
at 77 K, SEM, XRD, Raman spectrometry, FTIR spectroscopy, determination
of particle size, and elemental composition by XRF. The specific surface
area was in the range of 240–709 m
2
/g, and the total
pore volume was from 0.12 to 0.43 cm
3
/g. The percentage
of microporosity in activated biocarbons was 89–92%. These
activated biocarbons have been used for CO
2
and heavy metal
sorption. Activated biocarbons based on pine cones and birch prepared
by thermal carbonization and activation with superheated water vapor
had the highest ability to capture CO
2
and amounted to
6.43 and 6.00 mmol/g at 273 K, as well as 4.57 and 4.22 mmol/g at
298 K, respectively. The best activated biocarbon was characterized
by unchanged stability after 30 adsorption and desorption cycles.
It was proved that the adsorption of CO
2
depends on narrow
micropores (<1 nm). Activated biocarbons have also been analyzed
as effective adsorbents for removing Cu
2+
, Zn
2+
, Fe
2+
, Ni
2+
, Co
2+
, and Pb
2+
ions from aqueous solutions. Activated biocarbons are effective
adsorbents for the removal of lead and zinc ions from aqueous solutions.