Int. Journal of Renewable Energy Development 7 (2) 2018: 163-169

P a g e | 163

Contents list available at IJRED website

Int. Journal of Renewable Energy Development (IJRED)
Journal homepage: http://ejournal.undip.ac.id/index.php/ijred
Research Article

Enhancing the Phenolic Content of Bio-Oil by Acid PreTreatment of Biomass
Nurgül Özbaya and Elif Yamanb*
a

Department of Chemical and Process Engineering, Bilecik Şeyh Edebali University, Bilecik, Turkey
b

Central Research Laboratory, Bilecik Şeyh Edebali University, Bilecik, Turkey

ABSTRACT. Pyrolysis of lignocellulosic biomass with acidic pre-treatment to produce valuable bio-chemicals has been carried out in an
integrated pyrolysis-gas chromatograph/mass spectrometry system. Three different waste biomasses (fir wood sawdust, pine wood
sawdust and nutshell) were subjected to acidic solution to specify the acid pre-treatment effect on biomass chemical structure, thermal
degradation profile and pyrolysis products. Post acid pre-treatments, the changes in the biomasses and thermal degradation profile were
studied through proximate, structure and ultimate analysis and thermogravimetric. The pre-treatment significantly reduced the
inorganic, cellulose and hemicellulose content in biomass samples. According to the pyrolysis experiment results, acid pre-treatment
provided the increasing of the amount of phenolic in the degradation products at 10 min pyrolysis time. All the results would assist further
understanding of thermal decomposition and thermo-chemical application for bio-fuels and bio-chemicals of fir wood sawdust, pine wood
sawdust and nutshell.
Keywords: Pyrolysis, lignocellulosic biomass, acid pre-treatment, renewable chemicals, fir wood sawdust, pine wood sawdust, nutshell
Article History: Received January 15th 2018; Received in revised form May 24th 2018; Accepted 7th June 2018; Available online
How to Cite This Article: Ozbay, N. and Yaman, E (2018) Enhancing the Phenolic Content of Bio-Oil by Acid Pre-Treatment of Biomass. Int.
Journal of Renewable Energy Development, 7(2), 163-169.
https://doi.org/10.14710/ijred.7.2.163-169

1.

Introduction

Pyrolysis is a promising thermochemical conversion
process which can be used to produce valuable gaseous,
liquid and solid products from biomass (Gvero et al. 2016).
Biomass is a sustainable and renewable energy and biochemical source if evaluate in sustainable way. In 2006,
5% of the world’s primary energy depletion provided from
renewable energy source and it is estimated that this ratio
will increase to 10% in 2030s (Gu et al. 2013). In addition
to that, renewable energy production from biomass can
provide substantial towards the aims of the Kyoto
Agreement in extinguish to the complications of climate
change (Bridgewater et al. 2004).
Agricultural biomass includes crop residues like as
leaf, stalk, shell, stem and stone. Typically, lignocellulosic
biomass consists of cellulose, hemicelluloses and lignin. It
also contains some proportions of inorganic species. The
amount of the ash originated from the inorganic quantity
varies from less than 1% to 15% in biomass and
agricultural residues (Đurić, et al. 2014; Yaman 2004).
Some recent studies show that additives act as catalyst to
produce higher yields of sugars (Zhuang et al. 2001; Lian
et al. 2010; Lian et al. 2013; Layton et al. 2011; Chi et al.
2013). However, presence of inorganics in biomass can
generally inhibit the production of levoglucosan and
phenolic compounds (Mourant et al. 2011; Patwardhan et
*

al. 2010; David et al. 2017). Inorganics content in biomass
structure can be reduced via acidic pre-treatment of
biomass. In literature, different types of biomasses
(pinewood, straw, hay and bagasse) were exposed to acidic
pre-treatment. This process provides the reducing
inorganic content from 600 mg kg-1 to 90 mg kg-1. In
addition to that, significant increase of the organic oil yield
is obtained compared to the untreated biomasses
(Oudenhoven et al. 2016; Pecha et al. 2015; Oudenhoven et
al. 2015).
Pyrolysis experiments based on determination of
gaseous and liquid product can be done by using a
simultaneous
technique,
pyrolysis–gas
chromatography/mass spectrometry (Py–GC/MS). PyGC/MS has been successfully carried out to estimate the
thermal decomposition behaviour and pyrolysis products
of biomass. The technique is highly sensitive, rapid and it
can separate and detect the complex mixture compounds
(Gu et al. 2013). Qiang et al. (2009), examined the sawdust
pyrolysis with Al/SBA-15 catalysts by using Py-GC/MS.
Jeon et al. (2013), utilized SBA-15 for catalytic pyrolysis
of cellulose, hemicelluloses and lignin with Py-GC/MS.
In literature, the studies about pyrolysis of untreated
and acid pre-treated fir wood sawdust, pine wood sawdust
and nutshell are uncommon. The objective of this study is
to specify the acid pre-treatment effect on biomass
chemical structure, and degradation behaviour of all

Corresponding author: elif.yaman@bilecik.edu.tr

© IJRED – ISSN: 2252-4940, July 15th 2018, All rights reserved

Citation: Yaman, E and Ozbay, N. (2018) Enhancing the Phenolic Content of Bio-Oil by Acid Pre-Treatment of Biomass.. Int. Journal of Renewable Energy Development,
16(2), 163-169, doi.org/10.14710/ijred.7.2.163-169

P a g e | 164
samples during pyrolysis process. For this purpose,
pyrolysis of untreated and acid pre-treated fir wood
sawdust, pine wood sawdust and nutshell have been
carried out by using pyrolysis–gas chromatography/mass
spectrometry (Py–GC/MS). The feature that distinguishes
this study from other similar Py-GC/MS studies is that the
pyrolysis reaction time is 10 min. Another aim of the
present study is to increase the formation of phenolic
content by extending the pyrolysis time.

The biomass and acid pre-treated method that were
used in this study are described in this section. The
experimental apparatus for the biomass preparation,
determination of their properties and Py-GC/MS
apparatus are also specified.

reflection-Fourier transform infrared spectroscopy (ATRFTIR, Perkin Elmer, Spectrum100) with built-in diamondgermanium ATR single reflection crystal. Baseline
correction was applied before each measurement. FTIR
spectrums of FS, PS, NS, A-FS, A-PS and A-NS samples
were obtained using an average of 128 scans over the
range between 380 cm-1 and 4000 cm-1 with a spectral
resolution of 4 cm-1.
Thermal decomposition behaviours of the samples were
specified using Thermogravimetric Analysis (TGA,
SETARAM, Labsysevo). Mass changes of FS, PS, NS, AFS, A-PS and A-NS to the temperature were quantified
and recorded. A sample mass of 10±3 mg in the Al2O3
100µL crucible was used for each run. Nitrogen was flowed
20 mL min-1 as carrier gas. The samples were heated from
ambient temperature to 1000 °C at heating rate 10°Cmin1.

2.1 Materials

2.4 Py-GC/MS experiments

Fir wood sawdust (FS), pine wood sawdust (PS) and
nutshell (NS) were chosen as biomass feedstock from
Trabzon, located in North of Turkey. All biomass samples
were air-dried at room temperature and then ground in a
high speed rotary cutting mill (8000 rpm) and sieved. 425600 µm sized samples were used for all experiments in the
study. Prior to the characterization studies, acid pretreatment experiments and Py-GC/MS experiments,
biomasses were dried at 105 °C for 24 h and kept in a
desiccator.

Pyrolysis experiments were performed by using PyGC/MS System (Frontier Py-2020is pyrolyzer, Shimadzu
QP2010 GC/MS) to separate and detect degradation
products. Pyrolysis temperature was 550 °C and reaction
time was 10 min. Frontier Ultra Alloy column (30 m×0.25
mm×0.25 µm film thickness) was used to chromatic
separation of volatile products. Temperature of the
column and injection part was 40 °C and 320 °C,
respectively. Carrier gas was Helium which flowed 1.0 mL
min-1. NIST mass spectral library was used to
identification of peaks from pyrolysis products.

2.

Materials and Methods

2.2 Acid pre-treatment of biomass
1 M sulphuric acid (H2SO4) solution was added to 1 g of
each FS, PS and NS individually. Agitation of acid and
biomass sample proceeded for 1 hour at the room
temperature using a magnetic stirrer. After pretreatment, the samples were washed with ultra-pure
water until pH of the supernatant was equal to pH of ultra
pure water. Before the Py-GC/MS experiments, the
samples were filtrated, dried for 24 h at 105 °C and kept
in a desiccators. Acid pre-treated FS, PS and NS were
labelled A-FS, A-PS and A-NS, respectively.

2.3 Characterization of biomass and acid-treated biomass
samples
True density and bulk density of FS, PS, NS, A-FS, APS and A-NS samples were determined by using gas
pycnometer (Micromeritics-AccuPyc II 1340)
and
American Standard Test Method (ASTM E 873-82)
Proximate and structural analyses of samples were
applied to specify weight fractions of moisture, ash,
volatile matter, fixed carbon, extractives, hemicelluloses,
lignin and cellulose content. Ultimate analysis was
performed on samples to determine the elemental
composition. The weight fractions of carbon, hydrogen and
nitrogen were obtained by using Elemental Analyser (Leco
CHN628 Series). According to the ultimate analysis
results, H/C, O/C, and higher heating value (HHV) were
also determined.
The identity of functional groups involved in the
binding of biomass were specified using Attenuated total

3.

Results and Discussion

In this section, results from the characterization of the
biomass feedstocks and acid pre-treated biomass
feedstocks,
and
detailed
pyrolysis
product
characterization are presented and discussed.
3.1 Characterization of biomass and acid pre-treated
biomass samples
The results of true and bulk densities of biomass
samples were given in Table 1. True densities of FS, PS
and NS were not significantly change but bulk densities of
FS, PS and NS were drastically decreased by applying acid
pre-treatment. This behaviour showed that, the porosity
of the samples was increased by hydrolyzing the
carbohydrates present in the material structure,
especially the hemicelluloses (Li et al. 2004).
The results of proximate and structural analyses of
biomass samples were given at Table 2. The moisture
content of all untreated biomass samples were decreased
by applying acid pre-treatment.
Higher volatile matter content is desirable for pyrolysis
process. In addition, acid pre-treatment ensured in the
removal of minerals, as indicated by the lower ash content
of A-FS, A-PS and A-NS. Acid pre-treatment provided
increasing of volatile matter content from 80.74% to
87.15%; 81.96% to 85.21% and 72.78% to 79.17% for FS,
PS and NS, respectively. Acid pre-treatment was also
decreased hemicellulose and cellulose content, while
increased lignin content.

© IJRED – ISSN: 2252-4940, July 15th 2018, All rights reserved

Int. Journal of Renewable Energy Development 7 (2) 2018: 163-169
P a g e | 165
Table 1
True and bulk densities of biomass samples
FS
A-FS
PS
A-PS
True
density
[g/cm3]
Bulk
density
[g/cm3]

1.39
0.38

1.39
0.23

1.39
0.40

1.35
0.21

NS

A-NS

1.36

1.40

0.98

0.74

According to ultimate analysis (Table 3), carbon
content of FS and PS increased, while oxygen content
decreased after application of the acidic pre-treatment.
Carbon content of NS did not change significantly, even
oxygen content increased slightly. Higher heating value of
FS and PS, calculated using Dulong’s formula on ultimate
analysis data, increased from 14.76 MJ/kg to 18.59 MJ/kg
and 16.93 MJ/kg to 18.43 MJ/kg after acid pre-treatment.
Higher heating value of NS decreased from 18.21 MJ/kg to
16.47 MJ/kg because of the higher oxygen content of A-NS.
Lignocellulosic biomass usually has several absorption
bonds at 3300 cm-1, 2923 cm-1, 1466 cm-1, 1370 cm-1 and
1329 cm-1 in FTIR spectrum. Located absorption bands are
relevant with the lignocellulosic components such as
cellulose, hemicelluloses and lignin (Sim et al. 2012).
Cellulose includes glyosidic linkages, hydroxyl groups and
carboxyl. Hemicelluloses and lignin are mainly formed
ether bonds. In addition to this, hemicelluloses can be
characterized by high amount of carboxyl groups
(Taherzadeh and Karimi 2008).
Table 2
Proximate and structural analyses of biomass samples
Proximate
FS
A-FS
PS
ANS
Analysis
PS
(wt.%)
Moisture*
7.01
3.02
6.32
3.07
6.41
Ash **
0.21
0.07
0.72
0.08
1.46
Volatile
80.74 87.15 81.96 85.21 72.78
matter**
Fixed
12.04
9.76
11.00 11.64 19.35
carbon**
Extractive
12.51 18.89 11.30 19.37 14.56
Hemicellulose 24.90 13.21 23.42 14.17 23.82
Lignin
42.30 53.71 39.30 44.21 45.42
Cellulose
20.08 14.12 25.26 22.17 14.74

about 1700 cm-1, corresponding to the carbonyl functional
groups in hemicellulose, became less intense due to
efficient removal of hemicelluloses (Chen et al. 2017).
Table 3
Ultimate analysis of FS, PS, NS and acid pre-treated samples
Ultimate
Analysis
[wt.%]
C

FS

A-FS

PS

A-PS

NS

A-NS

41.34

46.34

46.60

48.22

49.81

49.11

H

6.86

7.71

6.38

7.04

6.24

5.54

N

0.24

0.18

0.34

0.25

0.62

0.23

O*

50.55

45.67

44.58

44.50

42.33

45.12

H/C

1.99

1.99

1.64

1.75

1.50

1.35

O/C

0.91

0.74

0.72

0.69

0.64

0.69

HHV
14.76
18.59 16.93 18.43 18.21 16.47
[Mj/kg]**
*By difference.
**Calculated by using the Dulong formula (Harker and
Backhurst, 1981).

ANS
4.52
0.03
79.17
16.28
11.44
18.21
57.12
13.20

Fig. 1 FTIR spectrum of FS and A-FS

*as received.
**dry basis.
***Fixed carbon= 100-(Moisture+Ash+Volatile matter)
****Cellulose=100–(Extractives + Hemicellulose +Lignin+ Ash)

FTIR spectrums of FS, PS, NS, A-FS, A-PS and A-NS
were given in Fig. 1, Fig. 2 and Fig. 3, respectively. The
absorption bands at 1157 cm-1, characteristic of glycosidic
linkages, were relatively more abundant in untreated
biomass samples. When compared the A-FS to the FS, the
bands based on aromatic skeletal of lignin at 1510 cm-1
and syringyl and guaiacyl condensed lignin at 1327 cm-1
increased slightly where the lignin content of A-FS
increased. When compared the PS to the A-PS, the peak
intensity at 1035 cm-1 referring to the removal of
crystalline cellulose were decreased sharply. The peak
intensity at around 900 cm-1 referring to the removal of
amorphous cellulose was decreased in acid pre-treated
biomass sample (Li et al. 2010). The peak intensity at

Fig. 2 FTIR Spectrum of PS and A-PS

© IJRED – ISSN: 2252-4940, July 15th 2018, All rights reserved

Citation: Yaman, E and Ozbay, N. (2018) Enhancing the Phenolic Content of Bio-Oil by Acid Pre-Treatment of Biomass.. Int. Journal of Renewable Energy Development,
16(2), 163-169, doi.org/10.14710/ijred.7.2.163-169

P a g e | 166

Fig. 3 FTIR Spectrum of NS and A-NS

3.2. Thermogravimetric analysis of biomass and acid pretreated biomass samples
Devolatilization step has a significant role for pyrolysis
process. Particularly, attention should be paid to the light
hydrocarbons which are produced at the end of thermal
degradation (Aboulkas et al. 2009). TGA studies have been
carried out to determine thermal characteristics of
materials such as thermal stability, degradation
temperatures, etc. The results of TG and dTG curves of the
FS, PS, NS, A-FS, A-PS and A-NS were given in Fig. 4,
Fig. 5 and Fig. 6, respectively. According to the TG
thermograms of biomass samples, the mass lose range can
be divided into three steps due to variable-slope curves.
The first step starts at about 50 °C and finishes at about
150 °C for all biomass samples. This could have been
owing to the vaporization of the moisture in consequence
of removal of physically adsorbed water of the sample.

Fig. 4 TG and dTG curves of (a) FS and (b) A-FS

Fig 5. TG and dTG curves of (a) PS and (b) A-PS

Following the TG curve the main devolatilization step
began at about 200 °C and finished at 420 °C. This step
indicated decomposition of hemicellulose and cellulose
referred as active pyrolysis zone, since mass loss rate is
high.
After 420 °C, passive pyrolysis zone started and mass
loss rate was lower. Then, no further essential weight loss
was detected. These thermal behaviours were clarified by
the components of FS, PS and NS. FS, PS and NS mainly
consisted of hemicellulose, cellulose and lignin like all
other lignocellulosic materials. The thermogravimetric
behaviour of these components have been studied before
and it is well known that hemicellulose, cellulose and
lignin accomplish their decomposition within the
temperature ranges of 210-325 °C, 310-400 °C, and 160900 °C, respectively (Açıkalın 2011). Based on these
temperature intervals, the minor and major reactions
observed in active pyrolysis zone can be attributed to
decomposition of hemicellulose and cellulose.
TG curves of A-PS and A-NS showed that the thermal
stability of biomass was increased by applying acid pretreatment. These results indicated that the catalytic effect
of inorganics on reactivity for pyrolysis of raw material
(Person et al. 2017; Raveendran et al. 1995; Asadieraghi et
al. 2014; Williams and Horne, 1994).

© IJRED – ISSN: 2252-4940, July 15th 2018, All rights reserved

Int. Journal of Renewable Energy Development 7 (2) 2018: 163-169
P a g e | 167

Fig. 7 Py–GC/MS detection of products evolved from pyrolysis of
FS and A-FS

Fig. 6 TG and dTG curves of (a) NS and (b) A-NS

3.3. Py-GC/MS analysis of biomass and acid pre-treated
biomass samples
In order to get some insights on the formation of
pyrolysis products and further understand the effect of
acid pre-treatment on the biomass pyrolysis process,
experiments were performed by using Py-GC/MS
equipment. The defined compounds were classified into
11 groups; aldehydes, alcohols, acids, phenols, aromatic
hydrocarbons, aliphatic hydrocarbons, ketones, furans,
polycyclic aromatic hydrocarbons (PAH) and oxygenates.
Compounds that could not be identified by the GC-MS
system were classified as unidentified. The results of
products derived from pyrolysis of FS and A-FS were given
in Fig. 7. It was shown that the Py–GC/MS results of FS
presented the formation of a large amount of furans and
oxygenates. When FS pre-treated with acid, phenolic
compound content rose up to 25.10%, oxygenates were also
decreased to 21.86%.
The amounts of aldehydes, alcohols, acids, phenols,
aromatic hydrocarbons, aliphatic hydrocarbons, ketones,
furans, PAH and oxygenates in the pyrolysis product of
untreated and pre-treated PS and NS were given in Fig. 8
and Fig. 9, respectively. It can be said that, in general, the
content of phenols, PAHs and oxygenates have higher
values in acid pre-treated samples. A significant reduction
in the amount of aromatic hydrocarbons and aliphatic
hydrocarbons were observed when the PS and NS were
pre-treated with acid. This result is clearly indicated that
acid pre-treatment had affected the thermal degradation
behaviour of the lignin.

Fig. 8 Py–GC/MS detection of products evolved from pyrolysis of
PS and A-PS

Fig. 9 Py–GC/MS detection of products evolved from pyrolysis of
NS and A-NS

Das and Sarmah (2005) and Person et al. (2017)
specified that phenolic compounds as lignin derivatives
were decreased when biomass exposed to acid pretreatment. But in their study, reaction time was 1 min and
2 s, respectively. Person et al. (2017), also indicated that
the pyrolysis time was an important parameter for
obtaining lignin derivatives. As seen from the Fig. 5 and

© IJRED – ISSN: 2252-4940, July 15th 2018, All rights reserved

Citation: Yaman, E and Ozbay, N. (2018) Enhancing the Phenolic Content of Bio-Oil by Acid Pre-Treatment of Biomass.. Int. Journal of Renewable Energy Development,
16(2), 163-169, doi.org/10.14710/ijred.7.2.163-169

P a g e | 168
Fig. 6, thermal stability of PS and NS were increased by
acid pre-treatment. In this study, reaction time was 10
min. According to the Py-GC/MS results, the reaction time
was suitable to overcome thermal stability of lignin.
4.

Conclusion

Pyrolysis is an efficient way to produce sustainable
value-added chemicals to utilize biomass in energy and
bio-chemical area. In this study, effect of acid pretreatment on the biomass physicochemical properties and
biomass pyrolysis process based on thermogravimetric
and Py-GC/MS analysis were investigated. Ash content of
biomass has decreased by applying acid pre-treatment.
Furthermore, thermal stability of acid pre-treated
biomass was higher than raw biomass in conjunction with
the catalytic effect of inorganics on reactivity for pyrolysis
of raw material.
The volatile product determination analysis of the
biomass and acid pre-treated biomass showed the relative
content variations of the final products, in particular, in
the decrease of aromatic hydrocarbons, and the increase of
phenols. According to the above-mentioned results, acidic
pre-treatment of lignocellulosic biomass with H2SO4 might
be suitable for production phenolic rich bio-chemicals.

Nomenclature
A-FS
: Acid pre-treated fir wood sawdust
A-NS
: Acid pre-treated nutshell
A-PS
: Acid pre-treated pine wood sawdust
ATR-FTIR
: Attenuated total reflection-Fourier
transform infrared spectroscopy
dTG
: Derivative thermogravimetry
FS
: Fir wood sawdust
FTIR
: Fourier transform infrared
spectroscopy
HC
: Hydrocarbon
HHV
: Higher heating value
NS
: Nutshell
PAH
: Polycyclic aromatic hydrocarbon
PS
: Pine wood sawdust
Py–GC/MS
: Pyrolysis–gas chromatography/mass
spectrometry
TG
: Thermogravimetry
TGA
: Thermogravimetric Analysis
References
Aboulkas, A., Nadifiyine, M., Benchanaa, M., & Mokhlisse, A.
(2009). Pyrolysis kinetics of olive residue/plastic mixtures by
non-isothermal
thermogravimetry.
Fuel
Processing
Technology, 90(5), 722-728.
Açıkalın, K. (2011). Thermogravimetric analysis of walnut shell
as pyrolysis feedstock. Journal of thermal analysis and
calorimetry, 105(1), 145-150.
Asadieraghi, M., & Daud, W. M. A. W. (2014). Characterization of
lignocellulosic
biomass
thermal
degradation
and
physiochemical structure: effects of demineralization by
diverse acid solutions. Energy Conversion and Management,
82, 71-82.
Bridgewater, A. V. (2004). Biomass fast pyrolysis. Thermal
science, 8(2), 21-50.

Chen, Z., & Wan, C. (2017). Ultrafast Fractionation of
Lignocellulosic Biomass by Microwave-assisted Deep
Eutectic Solvent Pretreatment. Bioresource technology.
Chi, Z., Rover, M., Jun, E., Deaton, M., Johnston, P., Brown, R.
C., ... & Jarboe, L. R. (2013). Overliming detoxification of
pyrolytic sugar syrup for direct fermentation of levoglucosan
to ethanol. Bioresource technology, 150, 220-227.
Das, O., & Sarmah, A. K. (2015). Value added liquid products
from waste biomass pyrolysis using pretreatments. Science
of the Total Environment, 538, 145-151.
David, G. F., Perez, V. H., Justo, O. R., & Garcia-Perez, M. (2017).
Effect of acid additives on sugarcane bagasse pyrolysis:
Production of high yields of sugars. Bioresource technology,
223, 74-83.
Đurić, S. N., Brankov, S. D., Kosanić, T. R., Ćeranić, M. B., &
Nakomčić-Smaragdakis, B. B. (2014). The composition of
gaseous products from corn stalk pyrolysis process. Thermal
Science, 18(2), 533-542.
Gu, X., Ma, X., Li, L., Liu, C., Cheng, K., & Li, Z. (2013). Pyrolysis
of poplar wood sawdust by TG-FTIR and Py–
GC/MS. Journal of Analytical and Applied Pyrolysis, 102,
16-23.
Gvero, P. M., Papuga, S., Mujanic, I., & Vaskovic, S. (2016).
Pyrolysis as a key process in biomass combustion and
thermochemical conversion. Thermal Science, (00), 154-154.
Harker, J. H., & Backhurst, J. R. (1981). Fuel and energy. London
and New York, Academic Press, 1981. 373 p.
Jeon, M. J., Jeon, J. K., Suh, D. J., Park, S. H., Sa, Y. J., Joo, S.
H., & Park, Y. K. (2013). Catalytic pyrolysis of biomass
components over mesoporous catalysts using PyGC/MS. Catalysis Today, 204, 170-178.
Layton, D. S., Ajjarapu, A., Choi, D. W., & Jarboe, L. R. (2011).
Engineering ethanologenic Escherichia coli for levoglucosan
utilization. Bioresource technology, 102(17), 8318-8322.
Li, S., Xu, S., Liu, S., Yang, C., & Lu, Q. (2004). Fast pyrolysis of
biomass in free-fall reactor for hydrogen-rich gas. Fuel
Processing Technology, 85(8), 1201-1211.
Li, C., Knierim, B., Manisseri, C., Arora, R., Scheller, H. V., Auer,
M., ... & Singh, S. (2010). Comparison of dilute acid and ionic
liquid pretreatment of switchgrass: biomass recalcitrance,
delignification and enzymatic saccharification. Bioresource
technology, 101(13), 4900-4906.
Lian, J., Chen, S., Zhou, S., Wang, Z., O’Fallon, J., Li, C. Z., &
Garcia-Perez, M. (2010). Separation, hydrolysis and
fermentation of pyrolytic sugars to produce ethanol and
lipids. Bioresource technology, 101(24), 9688-9699.
Lian, J., Garcia-Perez, M., & Chen, S. (2013). Fermentation of
levoglucosan with oleaginous yeasts for lipid production.
Bioresource technology, 133, 183-189.
Mourant, D., Wang, Z., He, M., Wang, X. S., Garcia-Perez, M.,
Ling, K., & Li, C. Z. (2011). Mallee wood fast pyrolysis:
effects of alkali and alkaline earth metallic species on the
yield and composition of bio-oil. Fuel, 90(9), 2915-2922.
Oudenhoven, S. R. G., Westerhof, R. J. M., & Kersten, S. R. A.
(2015). Fast pyrolysis of organic acid leached wood, straw,
hay and bagasse: Improved oil and sugar yields. Journal of
analytical and applied pyrolysis, 116, 253-262.
Oudenhoven, S. R. G., van der Ham, A. G. J., van den Berg, H.,
Westerhof, R. J. M., & Kersten, S. R. A. (2016). Using
pyrolytic acid leaching as a pretreatment step in a biomass
fast pyrolysis plant: Process design and economic
evaluation. Biomass and Bioenergy, 95, 388-404.
Patwardhan, P. R., Satrio, J. A., Brown, R. C., & Shanks, B. H.
(2010). Influence of inorganic salts on the primary pyrolysis
products of cellulose. Bioresource technology, 101(12), 46464655.
Pecha, B., Arauzo, P., & Garcia-Perez, M. (2015). Impact of
combined acid washing and acid impregnation on the
pyrolysis of Douglas fir wood. Journal of Analytical and
Applied Pyrolysis, 114, 127-137.

© IJRED – ISSN: 2252-4940, July 15th 2018, All rights reserved

Int. Journal of Renewable Energy Development 7 (2) 2018: 163-169
P a g e | 169
Persson, H., Kantarelis, E., Evangelopoulos, P., & Yang, W.
(2017). Wood-derived acid leaching of biomass for enhanced
production of sugars and sugar derivatives during pyrolysis:
Influence of acidity and treatment time. Journal of
Analytical and Applied Pyrolysis, 127, 329-334.
Raveendran, K., Ganesh, A., & Khilar, K. C. (1995). Influence of
mineral matter on biomass pyrolysis characteristics. Fuel,
74(12), 1812-1822.
Sim, S. F., Mohamed, M., Lu, N. A. L. M. I., Sarman, N. S. P., &
Samsudin, S. N. S. (2012). Computer-assisted analysis of
fourier
transform
infrared
(FTIR)
spectra
for
characterization of various treated and untreated
agriculture biomass. Bioresources, 7(4), 5367-5380.
Taherzadeh, M. J., & Karimi, K. (2008). Pretreatment of
lignocellulosic wastes to improve ethanol and biogas
production: a review. International journal of molecular
sciences, 9(9), 1621-1651.
Qiang, L., Wen-Zhi, L., Dong, Z., & Xi-Feng, Z. (2009). Analytical
pyrolysis–gas chromatography/mass spectrometry (Py–
GC/MS) of sawdust with Al/SBA-15 catalysts. Journal of
Analytical and Applied Pyrolysis, 84(2), 131-138.
Williams, P. T., & Horne, P. A. (1994). The role of metal salts in
the pyrolysis of biomass. Renewable Energy, 4(1), 1-13.
Yaman, S. (2004). Pyrolysis of biomass to produce fuels and
chemical feedstocks. Energy conversion and management,
45(5), 651-671.
Zhuang, X. L., Zhang, H. X., Yang, J. Z., & Qi, H. Y. (2001).
Preparation of levoglucosan by pyrolysis of cellulose and its
citric acid fermentation. Bioresource Technology, 79(1), 6366.

© IJRED – ISSN: 2252-4940, July 15th 2018, All rights reserved