Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 7, pp. 1200−1204.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
N.K. Luneva, L.I. Petrovskaya, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 7, pp. 1104−1108.
OF SYSTEMS AND PROCESSES
Effect of Some Ammonium Salts on Thermal Decomposition
of Impregnated Wood and Properties of Activated Carbons
N. K. Luneva and L. I. Petrovskaya
Institute of General and Inorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus
Received January 28, 2008
Abstract—Methods of chemical, thermal, IR spectral, and X-ray phase analysis were used to study the effect
of ammonium additives NH
Cl + NH
introduced into a phosphorus-nitrogen formulation on the thermal
decomposition of impregnated wood in the temperature range 20–700°C and on adsorption characteristics of the
resulting activated carbon.
Activated carbons are widely used in solution of vari-
ous ecological, technological, and chemical problems,
power engineering, and manufacture of various materials.
Wide industrial application of activated carbons requires
not only their high sorption parameters, porous structure
with pore size comparable with the diameter of sorbate
molecules, and acceptable kinetic parameters of sorption,
but also their low cost.
As a rule, activated carbons are produced from wood
in two stages: pyrolysis of wood to give a raw carbon at
500°C and its further activation at 850–950°C with steam
or another oxidizing agent [1, 2]. Recently, activated
carbons have been increasingly frequently produced by
a single-stage process including thermal treatment of
raw materials impregnated with zinc chloride, Lewis
acids, and potassium sulfate, followed by washing of
carbonized wood [3, 4]. The carbons produced by the
methods described above are rather expensive, which
strongly hinders their use.
It has been shown previously that a low-cost
activated carbon can be produced by single-stage
pyrolysis of impregnated sawdust. Readily soluble
phosphorus-nitrogen formulations with addition of nitrate
) have been used
as impregnating agents .
The aim of this study was to examine the process in
which activated carbon is formed in thermal decomposition
of wood impregnated with a phosphorus-nitrogen decom-
position catalyst to which ammonium salts NH
are added in various ratios and to analyze the
adsorption properties of the resulting carbons.
We studied the thermal decomposition of waste
produced by wood-processing industries: sawdust with a
particle size of 1–3 mm, impregnated with a phosphorus-
nitrogen formulation CO(NH
 with addition of ammonium salts (5 wt %) NH
at additive ratios of 1 : 2, 1 : 1, or 2 : 1,
and examined the adsorption properties of the resulting
activated carbons. The weight increment the impregnating
formulation was 170% relative to dry sawdust. The
thermal studies of impregnated samples were performed
with an MOM instrument (Hungary) at a heating rate of
20 deg min
and a sample mass of 200 mg. The initial
and thermally treated samples were analyzed for the
content of phosphorus and nitrogen. Phosphorus was
determined photocolorimetricaly by formation of
a Phosphorus-molybdenum Blue , and nitrogen, by the
procedure described in  in a Kjeldahl apparatus upon
wet burning of the samples in concentrated sulfuric acid.
X-ray diffraction patterns of the samples were obtained
using a Dron-3 instrument with Cu
radiation (Ni ﬁ lter)
at angles 2θ = 2–60°. IR spectra of the samples with a KBr
immersion medium were measured on a Perkin–Elmer
instrument in the frequency range 400–3900 cm
obtain activated carbons upon a thermal treatment of