Vol.2, No.10, 1066-1072 (2010) Natural Science
http://dx.doi.org/10.4236/ns.2010.210132
Adsorption studies of cyanide onto activated carbon
and γ-alumina impregnated with cooper ions
Liliana Giraldo1, Juan Carlos Moreno-Piraján2
1Facultad de Ciencias, Departamento de Química, Universidad Nacional de Colombia, Bogotá, Colombia;
2Facultad de Ciencias, Departamento de Química, Grupo de Investigación en Sólidos Porosos y Calorimetría, Universidad de los
Andes, Bogotá, Colombia;
Received 5 May 2010; revised 17 June 2010; accepted 20 June 2010.
ABSTRACT
In this research, adsorption of cyanide onto cata-
lyst synthesized with activated carbon and γ-
alumina used supported and cooper has been
studied by means of batch technique. Percent-
age adsorption was determined for this catalyst
in function of pH, adsorbate concentration and
temperature. Adsorption data has been interpret-
ed in terms of Freundlich and Langmuir equa-
tions. Thermodynamics parameters for the ad-
sorption system have been determined at three
different temperatures.
Keywords: Activated carbon; Alumina; Cyanide;
Isotherms; Thermodynamic
1. INTRODUCTION
Waste water discharged by industrial activities is often
contaminated by a variety of toxic or otherwise harmful
substances which have negative effects on the water en-
vironment. For example, of metal finishing industry and
electroplating units is one of the major sources of heavy
metals such as (Zn, Cu, Cr, Pb etc.) and cyanide pollu-
tants which contribute greatly to the pollution load of the
receiving water bodies and therefore increase the envi-
ronmental risk [1-4]. Cyanide present in effluent water of
several industries. Cyanidation has dominated the gold
mining industry. In view of the toxicity of cyanide, and
the fact that cyanide is fatal in small dosages, authorities
have been forced to tighten up plant discharge regulations.
It is therefore vital to recover as much cyanide as possi-
ble, not only to meet standard requirements, but to strive
towards obtaining lower levels of free cyanide (CN-) in
tailing and plant effluent [4-8]. The solubility of gold in
cyanide solution was recognized as early as 1783 by
Scheel (Sweden) and was studied in the 1840s and 1850s
by Elkington and Bagration (Russia), Elsner (German)
and Faraday (England) [9]. Elkington also had a patent
for the use of potassium cyanide solutions for electro-
plating of gold and silver [9]. Cyanide is a singly-charged
anion containing unimolar amounts of carbon and nitro-
gen atoms triply-bounded together. It is a strong ligand,
capable of complexing at low concentrations with virtu-
ally any heavy metal. Because the health and survival of
plants and animals are dependent on the transport of
these heavy metals through their tissues, cyanide is very
toxic. Several systems have been adopted for the reduc-
tion of cyanide in mill discharges. There are SO2 assisted
oxidation, natural degradation, acidification volatiliza-
tion-reneutralization, oxidation and biological treatment.
However, in the first three processes, cyanide reduction
does not appear to meet the strict regulatory requirements,
and as for the fourth process, it is limited to certain cli-
mate conditions. The next best process used, is the oxi-
dation with hydrogen peroxide where the cyanide con-
centration is reduced to low enough levels, but this pro-
cess requires an expensive reagent which cannot be re-
used [10-16]. Activated carbon was used for the removal
of free cyanide from solution, but observed that copper-
impregnated carbon yielded far better cyanide removal
[17]. However, did not test other metal impregnated car-
bons or different metal loadings on the carbon. The use
of a metal impregnated carbon system would therefore
be more effective in reducing cyanide concentrations in
solution. Due to the problem mentioned above, the study
on using activated carbon in the removal of free cyanide
is being done in our laboratory [18,19]. The adsorption
onto activated carbon has found increasing application in
the treatment of wastewater, as well as for the recovery
of metals from cyanide leached pulps. Activated carbon
has a great potential for cyanide waste treatment both in
gold extraction plants and effluent from metal finishing
plants and hence, it forms a subject studied in the present
work. Characterization of activated carbon shows that
surface area has an effect although the reactivity of the
surface as a result of oxygenated functional groups, e.g.

L. Giraldo et al. / Natural Science 2 (2010) 1066-1072
106
1067
carboxylate and phenolate is thought to be significant in
the sorption of metal cations. Pore size distribution has
been used to describe the internal structures and adsorp-
tion capacities of activated carbons [20]. The highly ac-
tive surface properties of the activated carbon are attrib-
uted to the chemical functional groups and the internal
surface areas, which typically range from 500 to 3000
m2/g [21]. The effect of copper was studied in the ad-
sorption of cyanide onto activated carbon. It was found
that the removal capacity was highly improved by the
presence of copper [18-21]. It is the aim of this research
to use of activated carbon (obtained from cassava peel)
[22,23] and alumina impregnated with cooper for obtain
catalyst for the removal of cyanide for dilute solutions.
The pertinent parameters that influence adsorption such
as initial cyanide (CN-) concentration, agitation time, pH
and temperature were investigated. Adsorption isotherms
at three different temperatures (i.e. 283 K, 313 K, 323 K)
have been studied. The adsorption data have been inter-
preted using Freundlich and Langmuir isotherms. Vari-
ous thermodynamic parameters including the mean en-
ergy of adsorption have been calculated.
2. EXPERIMENTAL
All reagents used in the experimental work were of
analytical grade (E.MERCK)® Argentmetric (largely
AgNO3) titrations were employed for CN- determination
[8]. Stock solution of cyanide (1000 mg.L-1) was pre-
pared by dissolving Sodium cyanide in distilled water.
The concentration range of cyanide prepared from stock
solution varied between 10 to 80 mg.L-1.
2.1. Preparation of Catalysts
The activated carbon used in this study was prepared
for by pyrolysis of cassava peel in presence of chloride
zinc (chemical activities) by our research group. Cassava
peel from Colombian Cassava cultives were impregnated
with aqueous solutions of ZnCl2 following a variant of
the incipient wetness method [22,23] with a specific sur-
face area of 1567 m2.g-1.
One of them was obtained commercial (Sasol™) sam-
ple of γ-alúmina.
2.1.1. Impregnation
Catalysts (activated carbon with cooper was labeled
Cu-AC and γ-alúmina with cooper was labeled Cu-A)
were formulated using a solution of Cu(NO3)2.3H2O (5
wt.(%) Cu) as a precursor of the active agent because of
its water solubility, lower cost, and lack of poisonous
elements. Activated carbons from cassava peel and γ-al-
úmina were used as supports. There are two well known
methods of loading the metal precursor on the support:
incipient wetness impregnation and soaking method. In
this case, the second one was used; the activated carbon
and γ-alúmina were soaked in a copper nitrate solution
for 8 days under agitation until the equilibrium was rea-
ched. The ratio solid/solution (weight base) was equal to
6. The impregnated solids were filtered and scurried
during 24 hours. Then, they were dried at 378 K for 24
hours 12.
2.1.2. Thermal Treatment
The objective of this step is to transform the copper
salt (cupric nitrate) in copper oxides, which are the ac-
tive catalytic agents. The high temperature used descom-
poses the nitrate releasing nitrogen oxides. The reactor
must work in a nitrogen atmosphere to avoid the com-
bustion of the support. The catalysts were treated in the
activation reactor, at 830 K for 24 hours. After that, a
nitrogen flow was maintained until the reactor reached
room temperature 12.
2.2. Characterization
Nitrogen adsorption-desorption isotherms were per-
formed using an Autosorb-3B (Quantachrome) equip-
ment. Samples of 0.100 g were oven-dried at 378 K
during 24 hours and outgassed at 473 K under vacuum
for 10 hours. The final pressure was less than 10–4 mbar.
Textural parameters were derived from adsorption data.
The specific BET surface area was estimated 15. The
specific total pore volume (VT) was determined from the
adsorption isotherm at the relative pressure of 0.99,
converted to liquid volume assuming a nitrogen density
of 0.808 g.cm–3. The specific micropore volume (VDR)
was determined using the Dubinin-Radushkevich mode
l16. The pore size distribution (PSD) was analyzed using
the BJH method [17,21-24].
Acidity and basicity determinations of the support were
made by titrating the acid sites with a strong basic solu-
tion and the basic sites with a strong acid solution, fol-
lowing the protocol detailed by Giraldo et al. [22,23].
The point of charge zero (PZC) of the catalyst were
determined for a procedure very similar [24], which are
described here. In a beaker were added 0.1 g of finely
ground catalyst in an agate mortar and 20 mL of a 0.01
M KCl-0.004 M KOH. The solution was kept under con-
stant stirring for 48 h. Then, titration was performed
with a 0.1 M HCl solution using a burette and a stream
of nitrogen to prevent carbon dioxide from the air is ab-
sorbed into the solution and the formation of CO3-2 and
HCO3-1. The titrant solution was added slowly 0.1 mL
and was recorded by adding the aggregate volume and
pH of the solution. Furthermore, the evaluation was car-
ried 0.01 M solution of KCl-0004 KOH under the same
conditions but without catalyst. The PCC of the catalyst
was determined by plotting the pH of the solution aga-
inst the volume of titrant solution to the solution without

L. Giraldo et al. / Natural Science 2 (2010) 1066-1072
1068
catalyst and the catalyst solution, the pH where these two
curves intersect corresponds to the PZC. Another way
interpret experimental data is to calculate the burden of
surface of the catalyst using the equations reported in
literature [24], in this case the pH at which the burden of
surface is zero corresponds to the PZC.
Studies of X ray diffraction (XRD) patterns were re-
corded at room temperature using a Rigaku diffractome-
ter operated at 30 kV and 20 mA, employing Ni-filtered
Cu Kα radiation (λ = 0.15418 nm). The crystalline
phases were identified employing standard spectra soft-
ware.
2.3. Adsorption Studies
The adsorption of CN- on activated carbon and γ-Alu-
mina impregnated with Cu was studied by batch-tech-
nique [9]. The general method used for these studies is
described below: A known weight (i.e., 0.5 g of the Cu-
AC or Cu-A) was equilibrated with 25 cm3 of the spiked
cyanide solution of known concentrations in Pyrex glass
flasks at a fixed temperature in a thermostated shaker
water bath for a known period of time (i.e. 30 minutes).
After equilibrium the suspension was centrifuged in a
stoppered tube for 5 minutes at 4500 rpm, was then fil-
tered through Whatman 41 filter paper. All adsorption
experiments except where the pH was varied were done
at pH 7.20, which was obtained naturally at solution to
adsorbent ratio of 50:1. To study the effect of pH, in one
set of experiments the pH of the suspensions was adjust-
ed by using NaOH/NH4OH and HNO3. The pH of solu-
tions was in the range of 3.0-12. The amount of cyanide
adsorbed, “X” and the equilibrium cyanide concentration
in the solution, “Ce” was always determined volumetri-
cally with standard silver Nitrate solution. Adsorption of
cyanide on Cu-AC and Cu-A was determined in terms of
percentage extraction. Amount adsorbed per unit weight
of the Cu-AC or Cu-A, X/m was calculated from the ini-
tial and final concentration of the solution, Adsorption
capacity for the adsorption of cyanide species has been
evaluated from the Freundlich and Langmuir adsorption
isotherms were studied at three different temperatures
(i.e. 283 K, 313 K, 323 K). The cyanide concentration
studied was in the range of 10 pmm to 80 ppm for 50:1
solution to the catalyst.
3. RESULTS AND DISCUSSIONS
3.1. Characterization
Nitrogen adsorption-desorption isotherms for the sup-
ports and catalysts are shown in Figures 1 and 2. The
textural parameters modeled from the adsorption data
are summarized in Table 1.
Both catalysts present lower surface area and pore vo-
lume compared to that of the corresponding support. This
is mainly due to a pore blocking effect, especially micro-
pores, which is evident from the analysis of the uptake
at low relative pressures in the adsorption-desorption iso-
therms for the catalysts compared to the supports. The
micropore volume and surface area using activated car-
bon is higher than that obtained from γ-alumina, as the
total pore volume for both materials.
The isotherms corresponding to both catalysts present
0.000 6.24712.494 18.741 24.987 31.234 37.481 43.728 49.975 56.222 62.469
Pore Width [Å]
DFT Differential Pore Volume Distribution
0.0029
0.0026
0.0023
0.0020
0.0017
0.0014
0.0012
0.0009
0.0006
0.0003
0.0000
Pore Volume [cc/μg]
Figure 1. Pore distribution for Cu-AC.
0.000 5.709 11.418 17.127 22. 836 28.545 34.255 39.964 45.673 51.382 57.09
1
Pore Width [Å]
DFT Differential Pore Volume Distribution
0.0091
0.0082
0.0073
0.0064
0.0055
0.0046
0.0036
0.0027
0.0018
0.0009
0.0000
Pore Volume [cc/μg]
Figure 2. Pore distribution for Cu-A.

L. Giraldo et al. / Natural Science 2 (2010) 1066-1072
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Table 1. Textural parameters of catalyst.
Sample BET surface area (m2.g–1) Pore volume (VT)
(cm3.g–1) Specific micropore volume (VDR) (cm3.g–1)
AC 1567 0.6641 0.6245
Cu-AC 1245 0.5478 0.6042
γ-Alúmina 245 0.2454 -
Cu-A 207 0.2087 -
a hysteresis loop. The uptake at high pressure rises signi-
ficantly for Cu-A, which indicates a considerable pres-
ence of mesoporous. The BJH pore size distribution (Fi-
gures 1 and 2) shows important mesoporosity in the range
of 40-90 Å for both catalysts, especially in Cu-AC, in
agreement with its hysteresis loop.
Figures 3 and 4 show the curves obtained in the point
of zero charge determinations using the mass titration
method. All these results, pH, acidity, basicity and pzc,
-0,05
-0,03
-0,01
0,01
0,03
0,05
67891011121314
pH
surface charge,(C/m
2
)
Figure 3. PZC for Cu-A catalyst.
-0,08
-0,06
-0,04
-0,02
0
0,02
0,04
0 24 6 8101214
pH
surface charge,(C/m
2
)
Figure 4. PZC for Cu-AC catalyst.
demonstrate that the surface of both supports are stro-
ngly basic (Table 2).
The X Ray diffraction patterns for both catalysts, Cu-
AC and Cu-A respectively are shown in Figures 5 and 6.
The profiles obtained show that the main oxidized metal
compound corresponds to CuO. The signals of Cu2O and
Cu are also present in the spectra, specially the last one.
The presence of CuO was expected because the metal
appears as divalent ion in the precursor salt. The reduced
species (Cu+ and CuO) could be produced by the reduc-
ing action of the carbon surface during the thermal treat-
ment at high temperatures.
The adsorption of cyanide on the catalyst Cu-AC and
Cu-A were studied as a function of shaking time in water
Bath shaker (Labconco 3535 US), pH, adsorbate concen-
tration and temperature for known cyanide concentration
at 313 K. The results are interpreted in terms of percent-
age adsorption. The variation of % adsorption with dif-
ferent intervals of time ranging from 2 minutes to 48
hours is illustrated by Figure 7 which shows that the
adsorption of cyanide at 25 ppm as well as 50 ppm con-
centration on Cu-AC and Cu-A is rapid at 313 K and
equilibrium reached instantaneously after mixing cya-
Table 2. Physicochemical characteristics of the catalyst.
SupportpH Acidity
(mmol.g–1) Basicity (mmol.g–1)pH
PZC
Cu-AC8.6 0.27 0.81 9.0
Cu-A 5.8 0.20 0.45 6.0
0
5000
10000
15000
20000
25000
30000
0 102030405060708090
2 Theta
Intensity, u.a.
Figure 5. DRX for Cu-AC catalys.

L. Giraldo et al. / Natural Science 2 (2010) 1066-1072
1070
0
1000
2000
3000
4000
5000
6000
7000
8000
0 102030405060708090
2 Theta
Intensity,u.a.
Figure 6. DRX Cu-A catalyst.
58
63
68
73
78
83
88
93
98
103
015 3045 6075 90105120135150
Tim e,mi nutes
%age Adsorption
Cu-A25
Cu-AC50
Cu-A50
Cu-AC25
Figure 7. Effect of shaking time % age Adsorption at 25 ppm
and 50 ppm for the synthesized catalyst.
nide solution with the catalyst. However, an equilibri-
umis reached faster with the catalyst of Cu-AC than with
Cu-A; that is associated with the greatest amount of
copper that is achieved on the activated carbon adsorb
taking into account their surface properties and specific
chemical the PZC allowing CN ions adsorb more rapidly
on the catalyst surface Cu-AC on the Cu-A.
No significant change in % adsorption values was ob-
served up to 48 hours, which indicates that surface pre-
cipitation as well as ion exchange may be the possible
adsorption mechanism. Therefore, equilibrium time of
20 minutes was selected for all further studies. The ad-
sorption is pH dependent, a much greater adsorptive ca
pacity for cyanide was observed in neutral solution for
both catalyst; moreover it is more higher adsorption ca-
pacity for Cu-AC, i.e., pH 7- 8.0 (Table 3 and Table 4).
Because when the pH is reduced, surface charge of the
particles becomes increasingly positive and because of
the competition of the hydrogen ions for the binding sites,
Table 3. Dependence of absorbance concentration relative to
CN- on Cu-A catalyst at 293 K.
pH Amount of CN-
in taken
Amount of CN- in
sol. At equilibrium
Amount of CN-
Adsorbed Adsorption
(ppm) (ppm) (ppm) (%)
2,06
4,57
6,54
7,28
9,14
11 , 3 4
12,75
20
20
20
20
20
20
20
6,48
5,44
4,11
2,13
4,11
6,55
7,76
13,52
14,56
15,89
17,87
15,89
13,45
12,24
67,60
72,80
79,45
89,35
79,45
67,45
61,20
Table 4. Dependence of absorbance concentration relative to
CN- on Cu-AC catalyst at 293 K.
pH Amount of
CN- in taken
Amount of CN- in
sol. At equilibrium
Amount of CN-
Adsorbed Adsorption
(ppm) (ppm) (ppm) (%)
2,06
4,57
6,54
7,28
9,14
11 , 3 4
12,75
20
20
20
20
20
20
20
5,35
3,34
1,23
0,99
2,02
4,66
5,55
14,65
16,66
18,77
19,01
17,98
15,34
14,45
73,25
83,30
93,85
95,05
89,90
75,70
72,25
metal ions tend to desorbs at low pH region, as well a
small decrease in cyanide adsorption was observed at pH
higher than 9.0. This behavior may be due to the forma-
tion of soluble cyanide complexes, which remain in so-
lution as dissolved component. Similarly adsorption of
cyanide as a function of its concentration was studied by
varying the metal concentration from 10ppm to 80 pmm,
% age adsorption values decreases with increasing metal
concentration (Table 5), which suggest that at least two
types of phenomena (i.e. adsorption as well ion-exchange)
taking place in the range of metal concentration studied,
in addition less favorable lattice positions or exchange
sites become involved with increasing metal concentra-
tion.
The adsorption in aqueous solutions and adsorption
isotherms at three different temperatures (i.e. 278 K, 298
K, 323 K) were obtained by plotting the amount of cya-
Table 5. Dependence of adsorbate concentration relative to
CN- on Cu-AC (this catalyst present major adsorption).
Amount of
Adsorbent
CN- in taken
Amount of
CN- taken
Amount of
CN- in soln.
at Equilibrium
Amount of
CN- AdsorbedAdsorption
(mg (ppm) (ppm) (ppm) (%)
500
500
500
500
500
500
500
5,00
10,00
20,00
40,00
60,00
80,00
100,00
2,42
3,12
1,41
15,65
37,98
41,09
54,58
2,58
6,88
18,52
30,35
38,44
38,91
45,42
51,60
68,00
92,60
75,88
64,06
48,63
45,42

L. Giraldo et al. / Natural Science 2 (2010) 1066-1072
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nide adsorbed on Cu-A and Cu-AC (mg/g) against metal
at equilibrium concentration “Ce” (mg/l). Adsorption of
cyanide decreases with increasing temperature. Two mo-
dels, Langmuir and Freundlich equations, were used to
describe experimental data for adsorption isotherms.
The linear form of the Freundlich isotherm model is
given by the following relation:
Log x / m = logKF + 1 / nlogCe (1)
where x / m is the amount adsorbed at equilibrium (mg/g),
Ce is the equilibrium concentration of the adsorbate
(mg/l), and KF and 1 / n are the Freundlich constants
related to adsorption capacity and adsorption intensity
respectively, of the sorbent. The values of KF and 1/n can
be obtained from the intercept and slope respectively, of
the linear plot of experimental data of log X / m versus
logCe. The linear form of the Langmuir isotherm model
can be represented by the following relation:
Ce / x / m = 1 / KLVm + Ce / Vm (2)
where Vm and KL are the Langmuir constants related to
the maximum adsorption capacity and the energy of ad-
sorption, respectively. These constants can be evaluated
from the intercept and slope of the linear plot of experi-
mental data of Ce / X / m versus Ce. The Freundlich and
Langmuir adsorption isotherms are shown in Figure 3
and Figure 4 (the isotherms linearizated not shown here).
The related parameters of Langmuir and Freundlich mo-
dels are summarized in Table 6. The results reveal that
both the Langmuir isotherm model adequately describes
better the adsorption data (See Figure 8).
Calculations of thermodynamic parameters:
Thermodynamic parameters such as Gibbs free energy
ΔG° (kJ/mol), change in enthalpy ΔH° (kJ/mol) and
change in entropy ΔS° (J.K-1mo l-1) for cyanide adsorp-
tion were calculated from the distribution constant K [10]
by using the following relations:
ΔG° = - RTlnK (3)
ΔG° = ΔH° - (4)
and
K = - ΔH° / RT + Constant (5)
Tables 7 and 8 show the values of thermodynamics
parameters ΔH°, ΔS°, ΔG° for Cu-AC and Cu-A catalyst
synthesized. The positive value of ΔH° = 6.234 kJ/mole
for Cu-AC and 4.897 kJ/mole, which is calculated from
Eq.5 and Figure 5, confirms the endothermic nature of
the overall adsorption process. The positive value of ΔS°
suggests increased randomness at the solid/solution in-
terface with some structural change in the adsorbate and
adsorbent and also affinity of the Cu-AC and Cu-A to-
wards CN-; the values more highest of entropy indicate
spontaneous process. A negative value of ΔG° indicates
Table 6. Parameters of Lagmuir and Freundlich for adsorption
of cyanide.
Langmuir Freundlich
Qo K R2 Kf n R2
Alumina221,9725 0,018648 0,99835 7,431714 1,477998 0,99653
Activated
Carbon 226,7673 0,0296200,99781 11,98697 1,6284590,99330
Cu-A 317,2252 0,0419560,99700 22,77397 1,759936 0,98713
Cu-Ac 297,2679 0,1649270,99646 58,15241 2,573350 0,97419
Table 7. Values of thermodynamic data for Adsorption of CN-
on Cu-AC.
Temperature
K
ΔH°
kJ/mol
ΔG°
kJ/mol
ΔS°
J/K.mol
278 6.234 -8.856 0.0543
298 6.234 -6.636 0.0432
323 6.234 -12.666 0.0585
Table 8. Values of thermodynamic data for Adsorption of CN-
on Cu-A.
Temperature
K
ΔH°
kJ/mol
ΔG°
kJ/mol
ΔS°
J/K.mol
278 4.897 -6.863 0.0423
298 4.897 -6.963 0.0398
323 4.897 -10.183 0.0467
Alumina
Activated Carbon
Cu-A
Cu-AC
Langmuir
Freundlich
0 1020304050607080
Ce, mg/g
0
50
100
150
200
250
300
x/m, mg/g
Figure 8. Langmuir and Freundlich models adjustment at 298
K.
the feasibility and spontaneity of the adsorption process,
where higher negative value reflects a more energetically
favorable adsorption process. The process of adsorption
Cu-AC is more favorable.

L. Giraldo et al. / Natural Science 2 (2010) 1066-1072
1072
4. CONCLUSIONS
Keeping the adsorptive nature of Cu-AC and Cu-A in
view it is felt desirable to select batch adsorption process
for removal of Cyanide from the industrial wastewater
using activated carbon and γ-alumina. The main advan-
tages of the procedure are:
1) The cost of starting materials for obtaining the cata-
lyst is low and easily available in country.
2) Ease and simplicity of preparation of the catalyst
due to non-corrosive and non-poisonous nature of
activated carbon and alumina.
3) Rapid attainment of phase equilibration and good
enrichment as well fitting of adsorption data with
Langmuir isotherms.
4) The positive value of ΔH° and negative values of
ΔG° indicate the endothermic and spontaneous na-
ture of the adsorption process.
5. ACKNOWLEDGEMENTS
The authors wish to thank the Master Agreement established between
Universidad de los Andes and Universidad Nacional de Colombia, and
the Memorandum of Understanding between Departments of Chemis-
try of both Universities. Additionally, special thanks to Fondo Especial
de la Facultad de Ciencias and Proyecto Semilla of Universidad de los
Andes for the partial financial of this research.
REFERENCES
[1] Abell, M.L. and Barselton, P.J. (1974) The maple V
handbook. AP Professional, New York.
[2] Contescu, C., Jagiello, J. and Schwarz, J.A. (1995) Pro-
ton affinity distributions: A scientific basis for the design
and construction of supported metal catalysts. Prepara-
tion of Catalysts VI, Scientific Bases for the Preparation
of Heterogeneous Catalysts, Elsevier Science, New York.
[3] Cooper, D. and Plane, A.R. (1966) Cyanide complexes of
copper with ammonia and ethylenediamine. Inorganic
Chemistry, 5, 1677-1681.
[4] Gupta, A., Johnson, E.F. and Schlossel, R.H. (1987) In-
vestigation into the ion exchange of the cyanide com-
plexes of Zinc(II), Cadmium(II), and Copper(I) Ions. In-
dustrial Engineering Chemistry Research, 26, 588-597.
[5] Hogfeldt, E. (1982) Stability constants of metal-ion com-
plexes: Part A: Inorganic ligands, Pergamon Press, Oxford.
[6] Riley, T.C. and Semmens, J.M. (1994) Recovery of cad-
mium and cyanide using a combination of ion exchange
and membrane extraction. Plating and Surface Finishing,
81, 46-54.
[7] Tan, T.C. and Teo, W.K. (1987) Destruction of cyanides
by thermal hydrolysis. Plating and Surface Finishing, 74,
70-76.
[8] Tien, C. (1994) Adsorption calculations and modeling.
Butterworth-heinemann series in chemical engineering,
Butterworth Heinemann, Boston.
[9] Wedl, A.G. and Fulk, J.D. (1991) Cyanide destruction in
plating sludges by hot alkaline chlorination. Metal Finish,
89, 33-38.
[10] Gupta, C.G. and Murkherjee, T.K. (2001) Hydrometal-
lurgy in extraction process, CRC press, Florida.
[11] Zhou, C.D. and Chin, D.T. (1994) Continuous electro-
lytic treatment of complex metal cyanides with a rotating
barrel plater as the cathode and a packed bed as the an-
ode. Plating and Surface Finishing, 81, 70-81.
[12] Gill, J.B., Gans, P., Dougal, J.C. and Johnson, L.H. (1991)
Cyano and thiocyano complexation in solutions of noble
metals, Reviews in Inorganic Chemistry, 11, 177-182.
[13] Bhakta, D., Shukla, S.S. and Margrave, L.J. (1992) A
novel photocatalytic method for detoxification of cyanide
wastes. Environmental Science & Technology, 26, 625-
634.
[14] Bhargava, S., Tardío, J., Prasad, J., Föger, K., Akolekar,
D. and Grocott, S. (2006) Wet oxidation and catalytic wet
oxidation. Industrial & Engineering Chemical Research,
45, 1221-1234.
[15] Lei, L., Hu, X., Chen, G., Porter, J.F. and Yue, P.L. (2000)
Wet air oxidation of desizing wastewater from textile in-
dustry. Industrial & Engineering Chemical Research, 39,
2896-2905.
[16] Mantzavinos, D., Hellenbrand, R., Livingston, A.G. and
Metcalfe, I.S. (1996) Catalytic wet air oxidation of pol-
yethylene glycol. Applied Catalysis B: Environmental, 11,
99-107.
[17] Kolaczkowski, S.T., Plucinski, P., Beltran, F.J., Rivas, F.
J., and Mc Lurgh, D.B. (1999) Wet air oxidation: A re-
view of process technologies and aspects in reactor de-
sign, Chemical Engineering Journal, 73, 143-152.
[18] Luck, F. (1999) Wet air oxidation: Past, present and fu-
ture. Catalysis Today, 53, 81-89.
[19] Pintar, A. (2003) Catalytic process for the purification of
drinking water and industrial effluents. Catalysis Today,
77, 451-462.
[20] Fortuny, A., Bengoa, C., Font, J., Catells, F. and Fabregat,
A. (1999) Water pollution abatement by catalytic wet air
oxidation in a trickle bed reactor, Catalysis Today, 53,
107-112.
[21] Deiana, A.C., Granados, D., Petkovic, L.M., Sardella, M.
F. and Silva, H.S. (2004) Use of grape must binder to
obtain activated carbon briquettes. Brazilian Journal of
Chemical Engineering, 21, 585-592.
[22] Moreno-Piraján, J.C. and Giraldo, L. (2010) Study of
activated carbons by pyrolysis of cassava peel in the
presence of chloride zinc. Journal of Analytical and Ap-
plied and Pyrolysis, 87(2), 288-290.
[23] Moreno-Piraján, J.C. and Giraldo, L. (2010) Adsorption
of copper from aqueous solution by activated carbons
obtained by pyrolysis of cassava peel. Journal of Ana-
lytical Applied and Pyrolysis, 7(2), 188-193.
[24] Rodríguez-Reinoso, F. (1998) The role of carbon materi-
als in heterogeneous catalysis, Carbon, 36, 159-164.