Abstract:
Biochar and activated carbon, as carbon-rich porous
materials, have wide
environmental applications. In the present research
, rice husk (RH) was used for
preparation of biochar at 400, 600, and 800 °C unde
r simple pyrolysis, physically-
activated carbon with water steam, chemically-activ
ated carbon with potassium
hydroxide (KOH), and physiochemically-activated car
bon with KOH and steam. Physical
and chemical properties of biochar and activated ca
rbons were characterized using
nitrogen adsorption–desorption isotherm, Fourier tr
ansform, infra-red analysis, and
Boehm method. The results showed that carbonization
temperature and activation agents
had significant effects on the characteristics of t
he samples. Activated carbon produced by
KOH activation
had the highest surface area (2201 m
2
g
-1
) and total pore volume (0.96
cm
3
g
-1
). High concentration of sodium (Na) is an importan
t limiting factor to reuse poor
quality water resources in arid and semiarid region
s. The sorption capacity of biochars
and activated carbons was investigated by performin
g batch sorption experiments using
Na as adsorbate. Na sorption was increased with inc
reasing surface area and pore
volume. The highest Na sorption capacity of 134.2 m
g g
-1
was achieved by the KOH
activated carbon, which has the highest surface are
a and pore volume. The kinetic data
were well-fitted to pseudo-first order and intra-pa
rticle diffusion models
.
Keywords:
Adsorbent, Diffusion models, Nitrogen isotherm, Ph
ysiochemical characteristics,
Sorption isotherm.
