Content uploaded by Yuliusman Yuliusman
Author content
All content in this area was uploaded by Yuliusman Yuliusman on Oct 11, 2019
Content may be subject to copyright.
IP: 127.0.0.1 On: Fri, 20 Sep 2019 02:41:49
Copyright: American Scientific Publishers
Delivered by Ingenta
Copyright © 2017 American Scientific Publishers
All rights reserved
Printed in the United States of America
RESEARCH ARTICLE
Advanced Science Letters
Vol. 23, 5751–5755, 2017
Production of Activated Carbon from
Coffee Grounds Using Chemical and
Physical Activation Method
Yuliusman1, Nasruddin2, Muhammad Khairul Afdhol1, Farandy Haris1,
Rahmatika Alfia Amiliana1, Afdhal Hanafi1, and Imam Taufiq Ramadhan1∗
1Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia
2Department of Mechanical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia
Air pollution gives impacts to human’s health which is caused by the harmful gas components contained in
smokes, such as CO, NOx,SO
x, and aldehyde. CO, NOx,SO
xare also abundant in off gas produced by oil
refinery units. One of the innovation that could solve the problem is by using activated carbon from coffee
grounds residue as an adsorbent. Coffee grounds residue is selected as adsorbent because it contains good
lignocellulosic structure and is produced abundantly by the coffee industry; the production rate goes as high as
748,000 tons per year or about 6.6% from the world’s total production. This research aims to make activated car-
bon from coffee grounds. Coffee grounds residue, typically Robusta coffee grounds, is dried and then carbonized
at 300 C for 1 hour to reduce several components, such as steam, volatile compounds, and lignocellulosic so
that the carbon content will increase by the end of the process. Then, the product will be activated to improve
surface area of the charcoal. The method used to activate coffee residue is by using chemical activation with
ZnCl2on temperature 100 C, physical activation with CO2on temperature 600 C, and also a combination of
both. The best yield from those activation methods are resulted by chemical activation 92.97%, then physical
activation 82.8%, and combination of both is 79.5%. After activating the carbon, dip coating will be conducted
to coat the activated carbon on the surface layer of mask by adding TEOS compound. The characterization
involves SEM, EDX, and Iod Number to observe the topography of activated carbon and surface area as result
of activation. The best Iod number from those three activation method will be used to coat the mask. The best
surface, according to the testing of Iod Number, is produced by chemical activation by 432.60 mg/g equivalent
with 405.68 m2/g. In comparison, the Iod number for physical activation and chemical-physical activation are
196.61 mg/g and 259.47 mg/g.
Keywords: Activation, Activated Carbon, Characterization, Coffee Grounds.
1. INTRODUCTION
Activated carbon derived from organic substances is considered
to be a biosorbent that has a high adsorption rate which is pro-
duced through carbonization and either chemical physical, or
chemical-physical activation. Based on its structural pattern, acti-
vated carbon is an amorphous structure of carbon consisting
mostly of free carbon that has a deep surface layer which makes
it has a higher adsorption rate than most adsorbent. Activated
carbon can be used to adsorb harmful gases such as CO, NOx,
SOx, and aldehyde that are typically present in gas pollutant and
the off gas of oil refinery unit. Off gas contains a large amount of
lightweight hydrocarbon like CH4,C
2H6, and impurities in high
concentration: CO, SO2,NO
x,andH
2S.
∗Author to whom correspondence should be addressed.
Organic matters containing lignin, hemicellulose, and cellulose
can be used as a raw material for the production of activated
carbon because they are highly effective in regards to being an
adsorber. This research is done by utilizing another alternative,
which is using coffee grounds residue that is abundant in Indone-
sia as an alternative raw material for the production of activated
carbon. Coffee residue is a type of lignocellulose residue that is
produced in high numbers throughout Indonesia with the amount
of lands producing them totaling up to 1.3 million acres. Indone-
sia is the world’s third largest coffee producer after Brazil and
Vietnam. Indonesia is capable of producing at least 748,000 tons
of coffee per year or 6.6% of the world’s coffee production in
2012. Coffee grounds residue have a high surface area count
that ranges between 300–2,000 m2/g, therefore making it fair to
say that it has a high potential of being a sufficient adsorbent.
On the grounds of its superfluous existence in Indonesia and its
Adv. Sci. Lett. Vol. 23, No. 6, 2017 1936-6612/2017/23/5751/005 doi:10.1166/asl.2017.8822 5751
IP: 127.0.0.1 On: Fri, 20 Sep 2019 02:41:49
Copyright: American Scientific Publishers
Delivered by Ingenta
RESEARCH ARTICLE Adv. Sci. Lett. 23, 5751–5755, 2017
moderate adsorption ability, it can be concluded that activated
carbon derived from coffee grounds residue is an acceptable alter-
native in terms of producing activated carbon for mask coating.
Chemical and physical activations are used within this research
as means to enhance the adsorption area. Chemical activation is
mediated by ZnCl2and physical activation is mediated by CO2
at temperature of 600 C.
2. EXPERIMENTAL DETAILS
2.1. Activated Carbon Production
Coffee grounds that are being used as raw materials in this
research come from coffee grounds residue of Robusta coffee
that is produced in high quantity in Indonesia. Pretreatments done
the ground coffee residue include heating it in the oven at 110 C
for 3 hours to dissipate the water molecules in the residue. The
production of activated carbon from coffee grounds residue is
done by carbonization that is done in temperature of 300 Cfor
1 hour. The resulting carbon is then grinded and sieved by using
a 100 mesh sieve. This process is done to acquire a more fine
and homogenized coffee grounds residue structure. After grind-
ing and sieving, the carbons are activated by using ZnCl2in the
chemical activation route and by carbon dioxide gas in the phys-
ical activation route. The ratio of activated carbon and ZnCl2that
was used in the chemical activation route is 1 gram of activated
carbon per 10 mL of ZnCl21 M. Meanwhile, physical activa-
tion is done by flowing carbon dioxide gas through the activated
carbon with a gas flow rate of 100, 150, and 200 mL/minute
within an activation reactor at high temperature that is set at the
temperature of 600 C for 2 hours.
A summation of the experiment is illustrated on Figure 1.
2.2. Characterization of Activated Carbon
Activated carbon characterization is done using Iod number test-
ing with the goal of measuring the adsorption capacity of acti-
vated carbon in an Iod solution. The first step is to mix the
activated carbon with an Iod solution and stir it for 1 hour to
give time for the activated carbon to adsorb the Iod. Iod that are
not adsorbed to the activated carbon will be titrated with Sodium
Thiosulphate (Na2S2O3until the color of the solution becomes
pale yellow, and then inserting an indicator that will change back
the color to black and start the titration process again until the
solution becomes transparent (colorless). The adsorption capac-
ity of the activated carbon increases with the decrease of Sodium
Thiosulphate usage. The equation used to calculate the Iod num-
berisasfollow:
Absorbed lodmg
g=10 −V1×N/01
W×1269 ×V2
10 (1)
Where, V1=Sodium Thiosulphate Usage (mL), V2=Vo l u m e
of the Iod Solution (mL), N=Normality of the Sodium Thiosul-
phate Solution, 12.69 =The amount of Iod needed for a 1 mL
solution of Sodium Thiosulphate 0.1 N, W=Sample’s weight
(gram).
To convert the Iod Number into surface area, a linear regres-
sion that refers to ASTM D-4607-94 is used. The equation is as
follow:
Iod Number =06366 ×Surface Area+17434 (2)
Fig. 1. Experiment details diagram.
Aside from Iod Number, this research also employs SEM +
EDX characterization to observe the morphology and composi-
tion of the activated carbon.
3. RESULTS AND DISCUSSION
3.1. Carbonization of Coffee Grounds Residue
Carbonization is used to produce a material with a higher-than-
average carbon concentration. Aside from that, carbonization
is also used to eliminate volatile compounds and water vapor
at temperature of 100–150 C, hemicellulose at temperature of
200–250 C, cellulose at temperature of 280–320 C, and lignin
at temperature of 400 C. Results of the coffee grounds residue
carbonization can be seen in Table I.
Based on Table I, it can be seen that the average amount
of carbon in the coffee grounds residue formed is 30.18%
from the amount of carbon in the initial residue. Anita and
Adhityawarman’s2research stated that the average yield resulted
from coffee grounds residue carbonization ranges from 20% to
30%, ergo it can be concluded that the results achieved in this
Table I. Result of carbonization process.
Initial mass of coffee End mass of coffee
No. grounds residue (gram) grounds residue (gram) Yield (%)
1 50 14.46 28.92
2 100 31.24 31.24
3 150 45.32 30.21
4 200 60.76 30.38
Yield average (%) 30.18
5752
IP: 127.0.0.1 On: Fri, 20 Sep 2019 02:41:49
Copyright: American Scientific Publishers
Delivered by Ingenta
RESEARCH ARTICLEAdv. Sci. Lett. 23, 5751–5755, 2017
Table II. Result of chemical activation.
Initial mass of Mass of dried activated
No. carbon (gram) carbon (gram) Yield (%)
1 5 4.65 930
2 5 4.57 914
3 5 4.62 924
Average yield (%) 9227
research have acquired the optimum results of typical coffee
grounds residue carbonization process.
3.2. Activation of Coffee Grounds Residue
The activation of activated carbon is done to form macroporous
and microporous structure of activated carbon and in doing so,
increasing the surface area of the activated carbon. Carbon acti-
vation can be done via chemical activation or physical activation.
The chemical activation route involves the usage of ZnCl2, mean-
while the physical activation route involves flowing carbon diox-
ide gas through the activated carbon. Results from the activation
process by using ZnCl2can be seen in Table II.
Carbon activation using the chemical activation route resulted
in a 92.27% yield which is relatively constant in activation using
the same mass and operating condition. The high yield resulted
from chemical activation shows that ZnCl2is an activator that
can retain heat thus eliminating the chances of advance oxidation
occurring to the carbon. The high and constant yield signifies that
the operating condition used in this research’s activation process
is nearing its most optimum point.
In the physical activation route, carbon dioxide is used to oxi-
dize the activated carbon. CO2will react with carbon and release
carbon monoxide. Minor compounds and impurities will also be
released simultaneously in this process therefore opening up the
pores of the carbon and increasing adsorption capacity. Results
produced from the process with variations in the gas flow rate
can be seen in Table III.
It can be inferred from Table III that the mass of carbon after
activation decreases as the flow rate of carbon dioxide increases.
This is due to the fact that an increase of gas flow rate in the
activation process will result into the carbons reacting to the
carbon dioxide gas. An increase of gas flow rate will increase
the amount of erosion happening on the surface of carbon and
consequently the amount of carbon reacting becoming carbon
Table III. Result of physical activation.
Flow rate Initial mass of Mass of carbon after
(mL/minute) carbon (gram) activation (gram) Yield (%)
100 5 4.14 82.8
150 5 4.02 80.4
200 5 3.74 74.8
Table IV. 2nd result of physical activation.
Initial mass of Mass of carbon
No. carbon (gram) after activation (gram) Yield (%)
1 5 4.14 82.8
2 10 8.34 83.4
3 10 8.22 82.2
Average yield (%) 82.8
Table V. Result of Iod adsorption capacity test.
No. Activation method Iod number (mg/g) Surface area (m2/g)
1 Carbonization 330.32 24501
2 Chemical activation 432.60 40568
3 Physical activation 196.61 3545
4 Chemical-physical activation 259.47 13372
dioxide will also increase. The aforementioned phenomenon will
decrease the yield of activated carbon in the end product. There-
fore, this reaction is not highly desirable as it would damage the
resulting porous structure and thus reducing its surface area. In
conclusion, the optimum flow rate of carbon dioxide gas in this
form of activation is 100 mL/minute. Results of physical activa-
tion within an activation reactor at temperature of 600 Cand
with carbon dioxide flow rate of 100 mL/minute are shown in
Tab l e I V.
Results of the physical activation process shows constant yield
at the same operating condition regardless of different initial
mass. Although, a striking conclusion can be made in which
the yield resulted from the physical activation route is lower
than the highest yield in the chemical activation route. This is
due to the carbon dioxide used in the physical activation pro-
cess that reacted with the carbon and carried the byproducts that
was contained within the carbon. In contrast, ZnCl2used in the
chemical activation process impeded the advance oxidation from
Fig. 2. SEM characterization of chemical-activation-resulted pores (1000×
[above] and 2000×magnification [below]).
5753
IP: 127.0.0.1 On: Fri, 20 Sep 2019 02:41:49
Copyright: American Scientific Publishers
Delivered by Ingenta
RESEARCH ARTICLE Adv. Sci. Lett. 23, 5751–5755, 2017
happening resulting in a higher yield. Not only that, the activa-
tion temperature in the chemical activation route is also far lower
which is 80 C.
3.3. Characterization of Coffee Grounds Residue
3.3.1. Iod Number Test
Iod number testing is done to calculate the surface area of the
activated carbon by examining its adsorption capacity towards
Iod solution. The surface area and average results of Iod Num-
ber testing are shown in Table V. It can be seen in Table V that
the values of surface area are lower than those of Iod Numbers
due to the effect of correction factor being used. Results of Iod
Number testing showed that the best activation method is Chem-
ical Activation. The impact of the existence of ZnCl2is more
beneficial in the sense that more pores are created in comparison
to pyrolysis in high temperature of 600 C. It can also be con-
cluded that the worst form of activation according to Iod Number
Testing is physical activation. In accordance to the Iod Number
results, it can be inferred that activator ZnCl2creates more pore
than H3PO4and HCl.
3.3.2. SEM (Scanning Electron Microscopy)
Characterization
SEM characterization of activated carbon is done by using
SEM EVO 50 ZEISS to examine the surface pattern or surface
Fig. 3. SEM characterization of physical-activation-resulted pores (1000×
[above] and 2000×magnification [below]).
Fig. 4. SEM characterization of chemical-physical-activation-resulted pores
(1000×[above] and 2000×magnification [below]).
structure of the adsorbent, especially observing the pores that
were created by the end of the experiment. SEM characteriza-
tion is also done to examine the condition of the pores created
in the chemical activation, physical activation, and chemical-
physical activation process. Photographic representation of the
SEM characterizations can be seen in Figures 2–4.
It can be seen in the characterizations that pores have formed
in all of the activation method. But nevertheless, the number of
micro pores that is formed is seen highest within the activated
carbon resulted from the chemical activation route. This is again
due to the presence of ZnCl2in the activation process. During
the activation process, ZnCl2activates the carbon by dehydrat-
ing them. In the activation process by ZnCl2that is followed
by heating, the interaction between carbon atoms and Zn cre-
ated a significant widening of the carbon’s interlayers and cre-
ated pores within the carbon matrix. Meanwhile, the effect of
pyrolysis in physical activation is also able to create pore struc-
tures, although the pores that were created is relatively random in
terms of structure in comparison to the ones created by chemical
Table VI. SEM characterization of chemical-activation-resulted pores
(1000×and 2000×magnification).
COMgPSClKCaZn
76.33 19.05 0.39 0.58 0.28 0.15 0.34 0.53 2.34
5754
IP: 127.0.0.1 On: Fri, 20 Sep 2019 02:41:49
Copyright: American Scientific Publishers
Delivered by Ingenta
RESEARCH ARTICLEAdv. Sci. Lett. 23, 5751–5755, 2017
Table VII. SEM characterization of p hysical-activation-resulted pores
(1000×and 2000×magnification).
CONaMgAlPSKCaIn
86.99 9.75 0.11 0.64 0.01 0.49 0.13 0.89 0.47 0.52
activation. This is due to the initial form and particle size of
coffee ground residue which was in the form of very small pow-
der. Due to this small size, the heat transfer that ensued with
the temperature below the melting point of the activated carbon
was relatively very efficient ergo the activated carbon underwent
a sintering process in which solidification of the powder-form
activated carbon particle happened. It is because of this sinter-
ing process that the pores resulted from this particular activation
became non-conforming thus reducing the surface area of the
activated carbon.
3.3.3. EDX (Energy-Dispersive X-ray Spectroscopy)
Characterization
EDX characterization aims to determine the composition of the
activated carbon created in this research. The type of composi-
tion being observed is the weight composition of elements con-
tained within the activated carbon from the chemical activation,
physical activation, and chemical-physical activation route. EDX
characterization of each of the activation processes are shown in
Tables VI–VIII.
In all of the characterizations, it can be concluded that
carbon is the most dominant element. The amount of binded-
carbon within the activated carbons have also adhered to Indone-
sia’s National Standard which is a minimum of 65% from the
total weight. According to Kusuma’s research (2013), fixed car-
bon contained within coffee grounds residue ranges between
2.22–4.67% wt. Through activation process, the amount of car-
bon increases up to 86.99% in the physical activation route. The
increase of carbon signifies that the process of carbon activation
has gone smoothly. The different amount of carbon in each of the
activation routes is because the high temperature in the physical
activation process instigated a release of other elements from the
structure such as oxygen and impurities that stuck themselves on
the surface of the activated carbon. One distinct difference from
these routes is the existence of iron in the physical activation
route which came from the eroded tube wall of the activation
Table VIII. SEM characterization of chemical-physical-activation-
resulted pores (1000×and 2000×magnification).
COMgPSClKFeZn
84.08 9.61 0.3 0.58 0.99 0.2 0.86 0.12 3.26
reactor. Aside from that, in all three of the EDX characteriza-
tions, it can be seen that there are other minerals such as mag-
nesium, aluminum, sodium, potassium, and calcium with %wt.
ranging between 4.4–4.5% which are inert elements in the coffee
grounds residue.
4. CONCLUSION
Results of this research in light of producing activated carbon
from coffee grounds residue using chemical and physical activa-
tion are as follow:
1. Surface area of activated carbon based on Iod Number Test for
chemical activation, physical activation, and chemical-physical
activation route, respectively are 432.60 mg/g, 196.61 mg/g and
259.47 mg/g or equivalent to 405.68 m2/g, 35.45 m2/g, and
133.72 m2/g.
2. Adsorption rate of activated carbon with weight variation
equals to 2 grams, 4 grams, and 6 grams, respectively are
75.61%, 80.09%, and 84.6% with pollutant concentration reduc-
tion capacity of reducing the concentration CO 500 ppm to
121.93 ppm, 99.53 ppm, and 77 ppm, respectively.
3. Concentration variation of CO that comprises of 250, 500,
750, and 1000 ppm is able to be adsorbed by 6 gram of activated
carbon with the adsorption rate of 88.88%, 84.6%, 80.83%, and
77.31% consecutively and also the activated carbon has a CO
500 ppm adsorption capacity of just 2.65% lower than those of
its commercial counterparts.
References and Notes
1. Allwar, A. Noor, and M. Nawi, Journal of Physical Science 19, 93 (2008).
2. Anita and Adhityawarman, JKK 4, 50 (2015).
3. S. Z. Azna, Master Thesis Chemical Engineering Stocklom (2011).
4. M. C. Baquero, L. Giraldo, J. C. Moreno, and J. M. D. Tascon, Anal. Pyrolysis
70, 779 (2004).
5. R. Diansari, Undegraduate Thesis Chemical Engineering Universitas
Indonesia (2015).
6. M. J. B. Evans, Halliop, and MacDonald, Carbon 37, 269 (2004).
7. R. A. Gangga, Undegraduate Thesis Chemical Engineering Universitas
Indonesia (2013).
8. W. A. Kusuma, Sarwono, and D. N. Ronny, Jurnal Tehnik Pomits Institut
Teknologi Sepuluh Nopember (ITS) (2012).
9. N. Leddy, Centre for Microscopy and Analysis (2012).
10. O. E. Marina and H. Netti, Jurnal Teknik Kimia USU 4(2015).
11. K. Nakagawa and S. Nagamo, Japan Journal of Food Engineering 2, 141
(2004).
12. Rasdiansyah, Darmadi, and Supadan, Jurnal Teknologi dan Industri Pertanian
Indonesia 6(2014).
13. Setyowati, Karbon Aktif (Pengenalan dan Proses Pembuatannya), Jurusan
Teknik Industri, Fakultas Teknik, Universitas Sumatera Utara (2008).
Received: 12 December 2016. Accepted: 19 December 2016.
5755