Research Article, Issue 1
Analytical Methods in Environmental Chemistry Journal
Journal home page: www.amecj.com/ir
AMECJ
Introduction
The most Pollutants such as volatile organic
compounds (VOCs, BTEX)and semi-volatile
compounds (SVOCs, Di-nitrotoluene) release to
air and environment by various industrial processes
and human activity such as petrochemical facilities,
motor vehicles, metal processing/finishing
industries, gas stations, and energy sectors.
Transport-derived emissions of volatile organic
compounds (VOCs) have decreased owing to
stricter controls on air pollution. The high fraction
of volatile chemical products (VCP) emissions is
consistent with observed urban outdoor and indoor
air. VCP contribute fully one-half of emitted VOCs
in industrialized cities. Based on previous study,
the toluene concentration was the most predominant
among all the targeted compounds in air. So, removal
of toluene from air is very important [1-5]. These
compounds (VOCs) are associated with allergies
and adverse respiratory effects [6] and some of them
have been classified as carcinogenic to humans
(benzene, formaldehyde) by the International
Agency for Research on cancer[7] . A complex
Cobra Jamshidzadeh a and Hamid Shirkhanloo b,*
a Occupational Health Engineering Department, School of Public Health, Kerman University of Medical Sciences, Kerman, Iran
b,Research Institute of Petroleum Industry, West Entrance Blvd., Olympic Village, P.O. Box: 14857-33111, Tehran, Fax: +98 21 48251
A new analytical method based on bismuth oxide-fullerene
nanoparticles and photocatalytic oxidation technique for
toluene removal from workplace air
* Corresponding Authors: Hamid Shirkhanloo
Email: hamidshirkhanloo@gmail.com
https://doi.org/10.24200/amecj.v2.i01.55
A R T I C L E I N F O:
Received 28 Nov 2018
Revised form 4 Feb 2019
Accepted 5 Mar 2019
Available online 29 Mar 2019
------------------------
Keywords:
Toluene
Air removal
Bismuth oxide nanoparticles
Bulky fullerene nanoparticles
UV-photocatalytic
Solid gas phase extraction
A B S T R A C T
A new sorbent based on mixture of bismuth oxide-fullerene nanoparticles
(Bi2O3-NF) was used for degradation/removal of toluene from workplace
and artificial air by UV-photocatalytic oxidation method (UV-PCOM).
By set up of pilot, standard gas of toluene was generated with difference
concentrations, and then was passed through UV lamp-glass quartz cell
accessory(UV-GQC) by SKC pump at optimized flow rate. Following the UV
irradiation, the electrons and holes can undergo redox reactions with toluene
on the Bi2O3 surface that lead to the formation of toluene intermediates and
toluene. Toluene and intermediates was physically and radically absorbed
on the 200 mg of NF at room temperature and then, desorbed from it at 185
OC before determined by GC/FID. In optimized conditions, the adsorption
capacity and removal efficiency of NF were obtained 212 mg g-1 and
more than 95%, respectively. The chemically absorption mechanism of
toluene on NF was mainly obtained due to radically group of NF (OHo,
COo) with methyl of toluene (CH2
o) and physically adsorption depend on
characterization of NF. In addition the flow rate and temperature had highly
impact on NF for removal efficiency and absorption capacity of toluene
from workplace and artificial air.
Analytical method for toluene removal from air; Cobra Jamshidzadeh, et al
Analytical Methods in Environmental Chemistry Journal Vol 2 (2019) 73-86
74 Analytical Methods in Environmental Chemistry Journal; Vol. 2 (2019)
combination of physicochemical and biological
phenomena takes place to finally convert pollutants
into innocuous compounds (mostly CO2, H2O and
biomass)[8].The accumulation of VOCs is the
greatest problem in air atmospheric pollutions with
cars or industrial activity. The BTEX pollutants
(benzene, toluene, ethylbenzene and xylenes)
generated in air by gasoline combustion in car
engines and caused a risk to human health[9]. The
BTEX have a carcinogens effect in humans. They
readily volatilized and distributed over large regions
of air and have important role in photochemical
oxidants and organic aerosols[10]. Among various
types of VOCs, toluene is one of the most commonly
used substances in industry and commerce as a
solvent in paints, siliconesealants, many chemical
reactants, rubber, printing ink,adhesives (glues),
lacquers, leather tanners, and disinfectants[11, 12].
Most of VOCs are regarded as toxic compounds
for human beings and the environment. symptoms
associated with exposure to VOCs include eye
irritation, nose and throat discomfort, headache,
allergic skin reaction, nausea, fatigue, or dizziness,
nervous system effects, liver toxicity, cancer[13,
14]. If inhaled or contacted, toluene can cause
dermatitis (dry, red, cracked skin) and damage
the nervous system and kidneys[12, 15]. The 8-h
time-weighted average (TWA) for occupational
exposure to toluenein accordance with ACGIH,
OSHA, NIOSH methods is respectively 50,
200 and 100 ppm. Therefore, toluene emission
control has become more stringent. Growing
concerns on exposure to toxic air pollutants has
led to intensive search for the best available
technology for remediation of air pollutants[16,
17]. A number of physical, chemical and biological
technologies such as membrane separation[14]
adsorption[18], catalytic oxidation[19] and
advanced oxidation[20] have been developed to
remove VOCs successfully. The control of toluene
emission is often accomplished by catalytic
oxidation or adsorption. The adsorption process is
widely used as a simple and effective operation[21].
Adsorption of VOCs by activated carbon (AC)
has proven to besustainable, environmentally
friendly, economical and efficient which makes it
the most commonly used technique[22]. Toluene
removal by adsorption is the traditional method
for cleaning air contaminants [23-25]. However,
the use of adsorbents just transfers pollutants
from the gaseous phase to the solid phase and
causes a disposal and regeneration problem[15].
Many studies have been done to remove toluene
using carbon adsorbent such as activated
carbon fibers (ACFs)[22], NaOCl oxidized
carbon nanotubes[26], Zeolite[15],Nano-
graphene modified by ionic liquid[27] .
Buckminsterfullerene(C60) a hydrophobic
molecule comprise a class of nanomaterials that
are made of a newly discovered allotrope of carbon
and composed of 60 carbon atoms arranged in a
hollow spheres, ellipsoids, or tubes spherical shape,
has gained wide application in many industries,
including biomedical technology, electronics,
optics, and cosmetics[28-30]. In recent years,
advanced oxidation processes have been considered
as a way to pollute organic pollutants. These
methods are based on the production of highly active
species such as hydroxyl radicals (OH0) that can
oxidize a wide range of organic pollutants. Among
the advanced oxidation processes, heterogeneous
photocatalytic are used as a successful method
for the analysis of organic pollutants[31-33].
Degradation of volatile organic compounds
such as, o-xylene, n-hexane, n-octane, n-decane,
methylcyclohexane and 2,2,4-trimethylpentane in
the gas phase by heterogeneous photocatalysis with
titanium dioxide/ultraviolet light was achived at 52-
62OC. in this way, devices based on heterogeneous
photocatalysis do not need flame for VOC oxidation,
this will allow it to be installed safely even in areas
vulnerable to fire and explosion[34, 35]. In this
study, the UV-PCOM based on Bi2O3-NFwas used
for efficient removal of toluene from air. The Bi2O3/
UV irradiation increased the removal efficiency of
toluene from air by chemically adsorption of NF.
Experimental parameters such as concentration,
UV irradiation, temperature, the value of Bi2O3-
NF, flow rate, contact time, desorption, absorption,
and repeatability were studied and optimized.
75
Analytical method for toluene removal from air; Cobra Jamshidzadeh, et al
The performance of the proposed method was
evaluated.
2. Experimental
2. 1. Instrumental:
Gas chromatography (GC) was used for
determination of toluene in air (Agilent,
Netherland). The FID detector was selected for
toluene analysis in air/gas. The polyethylene tubes
(PET) are simple devices that introduce a pure air
stream from electro air cleaner (EAC, Canada,
model HEPA 600M) into bags. Adjusted valves
are used to control of gas flow rate from Germany.
For sampling, the air bags, septum port and air
sampling apparatus were used. GC equipped with
a split/splitless injector, FID, and a column coated
with cross-linked polydimethylsiloxane gum
(50 m × 0.2 mm id.). For determining of toluene
with GC, The temperature of injector and detector
was adjusted to 200°C and 2700°C, respectively.
The temperature of oven was tuned from °C to
40°C which was held for 10 min. Hydrogen as the
carrier gas was used at a flow rate of 1.0 mL min-1
with split ratio of 1:100. The different volumes of
glass vials (10-200 mL, Aldrich, Germany) with
air tight cap (PTFE) were used in batch or static
system. The polyethylene tubes and bags were
used as a transport and storage of air in static/
dynamic system. TGS 2180 (China) and Dräger
Pac 3500 (Lübeck, Germany) detectors were used
for continuous measurement of H2O vapor and
O2 concentrations in gas fluid, respectively. The
TGS detector has high sensitivity to water vapor
and its conductivity depends on absolute humidity
(0.7~150 gm-3). Preheat of tubes and bags caused to
capture water droplets. The toluene evaporated from
chamber accessory, mixed with purified air and
introduced to bags. For validation of methodology,
the concentration of toluene in polyethylene bags
was determined by GC-MS before and after passed
through Bi2O3-NF. The quartz glass tube (QGT,
10 cm) as a column sorbent was used for Bi2O3-
NF. In this study, QGT with 0.4 cm diameter and
10 cm length was filled with 200 mg of Bi2O3-
NF. The gas tight syringes (SGE) were used for
sampling of toluene and injection to GC. In this
study, toluene generation system, QGT, PET, bags,
electric power supply accessory (50-280 VAC, 10A,
20-800 oC, Italy), pneumatic valves (Germany) and
Ar gas were used for evaluation of toluene removal
from air. The accuracy of results was achieved by
injecting a standard concentration of toluene in the
chamber accessory before determined by GC-FID/
GC-MS.
2.2. Reagents and solutions
All reagents with high purity and analytical grade
were purchased from Merck and sigma Aldrich
(Darmstadt, Germany). All aqueous solutions were
cm-1) from Milli-Q plus water purification system
(Millipore, Bedford, MA, USA). The analytical
grade of toluene solution was purchased from
Sigma Aldrich, Germany (CAS N: 108-88-3,
99.8%). For calibration of toluene, the approximate
concentrations of toluene in methanol were prepared
by 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, and 5.0% (v/v).
The analytical grades of other reagents such as,
HNO3, HCl, methanol, ethanol and acetone were
prepared from Merck (Germany). Bismuth nitrate
(Bi (NO3).5H2O), sorbitol and distilled water used
for the preparation of Bi2O3 nanoparticles. Bismuth
nitrate (CAS N: 383074) and sorbitol (CAS N: 50-
70-4) were purchased from Sigma Aldrich. The
solutions were freshly prepared and stored just in
a fridge (4 °C) to prevent decomposition. All the
laboratory glassware and plastics were cleaned by
soaking in nitric acid (10%, v/v) for at least 24 h
and then rinsed with deionized water before use.
2.3. Synthesis bismuth oxide and fullerene
nanoparticles
Bismuth oxide nanoparticles (BONPs) were
prepared by special solid dispersion evaporation
technique (SDAT) with carrier solutions such as
sorbitol and flame sprays pyrolysis technique
(FSPT) by organodimethicone (ODIM). By
SDAT Synthesis, 5 g of solid bismuth nitrate [Bi
(NO3).5H2O] dissolve in carrier solutions (5 ml)
and stirred for 20 min at room temperature followed
76 Analytical Methods in Environmental Chemistry Journal; Vol. 2 (2019)
by sonication at 25 ºC in an ultrasonic bath (40 kHz
and 100 W). The mixture was diluted with 10 mL
of distilled water and put on heater magnet stirrer
plate for 30 min. The pH of sample solution was
optimized up to 7 and no precipitation was occurred
during processes. The oven provided programmable
heating up to 90–110 ºC for 50 min. Then dark
brown sediment was formed after the evaporation
of water. After 1 hour yellow sediment was formed
in 550–600 ºC and nano particles is decomposed at
800 -1200 ºC. In order to obtain pure BONPs and
remove the metal nanocatalysts, the product was
stirred in 18% HCl solution for about 16 h at an
ambient temperature. Then, the sample was washed
repeatedly (10N) with deionized water until the
solution became neutral. The treated product was
finally dried in oven at 100 ºC. So, bismuth nitrate,
sorbitol and distilled water used for the preparation
of Bi2O3 nanoparticles medical grade by proposed
procedure. For synthesis of fullerene (NF), fullerene
soot (FS) was purchased from Sigma-Aldrich and
pure fullerene (NF) was achieved with activated
carbonand silica gel (TEM size: 30-100 nm) [36].
The pure fullerene (C60) from fullerene soot (FS)
was done by two methods. By first procedure,
a Soxhlet extractor with toluene was used for
separation of light and heavy fullerenes (Fig. 1).
The electric arc was used for producing of FS with
low purity up to 7%. The second way was obtained
by column chromatography with stationary phase
and mobile phase of activated carbon/ silica gel and
chlorobenzene, respectively.
2.4. Characterization
The morphology of the mesh sorbent Bi2O3 and NF
was examined using scanning electron microscopy
(SEM, Phillips, PW3710, Netherland) and
transmission electron microscopy (TEM, CM30,
Philips, Netherland). The nanoparticle powder of
Bi2O3 is dissolved in water or ethanol with ultrasonic
bath and after drying, was prepared for TEM in
scale of 50-100 nm. The elemental composition
of the samples was tested by energy dispersive
X-ray microanalyser (EDX, QuanTax 200, Rontec,
Germany) which was attached to SEM. X-ray
diffraction (XRD) patterns for Bi2O3 nanoparticles
were recorded by a GBC MMA diffractometer
operating at 35.3 kV and 30 mA. FT-IR 8400
(Kyoto, Japan); UV–vis spectrophotometers
Scinco S-2100 (SCINCO, Twin Lakes, WI, USA),
NMR Jeol 90 MHz (JEOL Ltd., Tokyo, Japan),
and rotary evaporator (Heidolph Laborota 4000,
Schwabach, Germany) were used for nanofullerene
(NF) characterization.
2.5. Removal Procedure
The concentration of toluene vapor in pure air was
Fig. 1. The schema of light and heavy fullerenes
77
Analytical method for toluene removal from air; Cobra Jamshidzadeh, et al
prepared by pilot chamber (Fig. 2). The toluene
vapor was generated by and mixed with pure air
(210 mL of O2 per L; 2.5 mL of H2O per L) at 25oC.
This mixture was restored in polyethylene bag (5
Lit) and toluene was determined by GC-MS and
GC-FID. Based on producer, in bath scale set up,
10 mL of standard solutions of toluene (40-100 mg)
was convert to vapor gas and mixed to pure air and
then pass through silica gel and Bi2O3 nanoparticles
with flow rate of 500 mL min-1 at 10 min which was
irradiated by UV in quartz glass tube (QGT). Then,
toluene and intermediates was absorbed on NF by
physically and radically formation. Finally, toluene
and intermediates desorbed from NF at 185OC
before determined by GC/FID. For validation of
methodology, GC-MS and spike of sample was
used. This method can be applied for toluene
removal from artificial and workplace air.
3. Results
In this research, Bi2O3-NF was used for efficient
removal of toluene from air. The Bi2O3 based on UV
irradiation can be increased the removal efficiency
of toluene from air by radically adsorption. The
characterization of Bi2O3/NF such as TEM, SEM,
XRD, XRD and IR was prepared. The important
parameters include, toluene concentration, intensity
of UV irradiation, temperature, the mass of Bi2O3-
NF, flow rate, time and repeatability were studied
and optimized.
3.1. TEM, SEM, XRD and IR
The results of synthesis for Bismuth oxide
nanoparticles have been obtained in a series
of scanning electron microscope (SEM) and
transmission electron microscopy (TEM) images.
It was clarified that the size of nanoparticles are
obtained below 100 nm. The TEM and SEM images
of Bi2O3 have been demonstrated in figure 3 (a, b).
SEM and TEM of fullerene nanoparticles (NF) was
shown in figure 4(a, b) which was between 50-100
nm. The XRD of Bi2O3 and NF was shown in figure
5 a and 5b, respectively. The IR of NF (C60) was
shown in figure 6.
3.2. The effects of humidity
The concentration of toluene vapor in pure air was
prepared at 25oC (210 mL of O2 per L; 2.5 mL of
H2O per L). This mixture was restored in 5 Li of
polyethylene bag. Finally, toluene vapor in pure air
was removed from air by UV-PCOM method. By
procedure, the effects of humidity on adsorption
capacity of Bi2O3-NF in QGT were examined in
different humidity (10-60%). The value of humidity
in the pilot chamber was adjusted by the water
tank valve by auto electronic system in present of
silica gel. By increasing of humidity more than
40%, the removal efficiency of Bi2O3-NF was
Fig. 2. The pilot of toluene vapor generator in pure air and adsorption procedure
78 Analytical Methods in Environmental Chemistry Journal; Vol. 2 (2019)
Fig. 3a. TEM picture of Bi2O3Fig. 3b. SEM picture of Bi2O3
Fig. 4a. TEM picture of NF
decreased (Fig. 7). The Previous study showed
that the trap device packed with silica composite –
multi walled carbon nanotubes (MSN-MWCNTs)
prepared based on sol–gel technique was used
for evaluation of volatile organic compounds at
20% humidity. Increasing of humidity may be
reduced the adsorption active sites on NF which
was occupied by water (-OH). On the other hand,
the nanoparticles of NF stick together with water
molecules increase in size and decrease of surface
Fig. 4b. SEM picture NF
area. All examinations were achieved by toluene
concentration (40 mg L-1), flow rate (500 mL min-
1), temperature (25oC), and 200 mg of Bi2O3-NF.
In optimized condition, the 20% humidity had low
effects on toluene removal from air less than 5%.
Also, the results showed us, the humidity had lower
effect than temperature.
3.3. The effect of toluene concentration
By optimizing conditions, the toluene removal
79
Analytical method for toluene removal from air; Cobra Jamshidzadeh, et al
from air based on Bi2O3-NF was studied in different
toluene concentration from 10-100 ppm (mg L-1).
The high surface area in NF based on UV lamp-
glass quartz cell accessory (UV-GQC) caused to
increasing of the adsorption capacity for toluene
removal from air. At high concentration of toluene,
the Bi2O3-NF can be acted as a favorite sorbent.
The optimum of toluene concentration for removal
efficiency (>99%) with 200 mg of Bi2O3-NF, NF,
Bi2O3 was achieved, 42.4 mg L-1, 20.6 mg L-1
Fig. 5a. XRD spectra of NF
Fig. 5b. XRD spectra of Bi2O3
Fig. 6. The IR spectra of NF
80 Analytical Methods in Environmental Chemistry Journal; Vol. 2 (2019)
and 2.3 mg L-1 in 25oC, respectively. The results
showed, in optimized concentration, the Bi2O3-
NF had more adsorption capacity and removal
efficiency than others.
3.4. The effect of temperature
The temperature has a main factor for removal
efficiency of toluene from air by Bi2O3-NF. As
prevent to condensing toluene, the special thermal
accessory was used in pilot chamber for heat
controlling up to 115°C. The column of QGT was
used at below 45oC. The effect of temperature was
OC. The results showed us,
the absorption recovery of Bi2O3-NF was depended
to temperature. Desorption of toluene from Bi2O3-
NF was occurred at 185oC. In optimized conditions,
the removal recovery for toluene based on Bi2O3-NF
was more than NF up to 45oC (Fig. 8). Sone et al
showed that the adsorption of toluene was decreased
by increasing temperature. Increasing temperature
more than 50oC had negative effects on removal
efficiency of Bi2O3-NF and had more effected on
humidity. In this study, the adsorption capacity of
Bi2O3-NF and NF has obtained 212 mg g-1 and 99.6
mg g-1, respectively. Other parameters such as, the
surface area, flow rate, kind/ porosity/ source/ size
sorbent and chemical and physical adsorption can
be affected on removal of toluene from air. The
low adsorption capacity of nanosorbents related to
greater amounts of amorphous structure with low
surface area or increasing of temperature.
3.5. The effect of sorbent mass
The amounts of Bi2O3-NF (1:1) as a sorbent in the
range of 20 to 300 mg were tested on the recoveries
of toluene removal from air at 25oC. It was found
that 220 mg of Bi2O3-NF was sufficient for
quantitative recoveries of toluene removal from air.
Extra mass of Bi2O3-NF had no significant effect
on the efficient removal of toluene vapor in air. So,
200 mg of Bi2O3-NF was selected as an optimized
mass sorbent by UV-PCOM. Also, the Bi2O3 and
NF and Bi2O3-NF had maximum recovery up to
5.1% and 48.4% and more than 95%, respectively.
These results confirm that the radically group of
NF (OHo, COo) with methyl of toluene (CH2o) had
important role for removal of toluene in present of
Bi2O3 by UV-PCOM.
3.6. The effect of flow rate
The flow rates were optimized in order to obtain
the maximum recovery by proposed method. So,
the effect of different flow rates between 100 to
1000 mL min-1 was examined by Bi2O3-NF at room
temperature. The flow rate was measured by a digital
rotameter in input and output of QGT in optimized
conditions. The results showed us, the removal
efficiency and adsorption capacity of Bi2O3-NF
Fig.7. The effects of humidity on toluene adsorption by silica gel/ Bi2O3-NF
81
Analytical method for toluene removal from air; Cobra Jamshidzadeh, et al
was decreased in more than 550 mL min-1 of flow
rate. So, 500 mL min-1 of flow rate was selected as
optimum flow rate for removal of toluene in air.
Higher flow rate was significantly decreased the
adsorption recovery of Bi2O3-NF. Based on results,
the maximum of toluene adsorption by exterior and
interior sites of NF was obtained at less than 500
mL min-1. Figure 9 show the effects of difference
flow rate on the removal efficiency and adsorption
capacity in optimized conditions.
3.7. Method Validation
Due to obtained Results, the Bi2O3-NF was
selected as a novel sorbent for removal of toluene
vapor from air. By proposed method, a mixture of
by pilot, storage in PE bag (5 L). Then, the mixture
of toluene in artificial air moved to Bi2O3-NF in
present of argon gas as a carrier gas. The different
standard of toluene (mg) in air was validated by
high sensitive and accurate GC-FID/GC-MS before
using by UV-PCOM. Since no certified reference
Fig. 8. The effects of temperature on toluene adsorption and desorption from Bi2O3-NF
Fig. 9. The effects of flow rate on toluene removal by Bi2O3-NF and NF
82 Analytical Methods in Environmental Chemistry Journal; Vol. 2 (2019)
material (CRM) for toluene in air are currently
available, the spiked of toluene concentration (10-
100 ppm) were used for validation of proposed
method. At optimized conditions in 5 and 10
minute, 20 ppm and 40 ppm of toluene vapor in
air was almost removed by Bi2O3-NF, respectively
(bag 5 L). The efficient recovery of spiked samples
is satisfactorily reasonable which indicates the
power ability of UV-PCOM based on Bi2O3-NF for
removal of air toluene. After thermal desorption of
Bi2O3-NF in QGT, the toluene concentration was
on-line determined by GC-FID. The validation of
methodology was confirmed using GC-MS (Table
1, 2).
4. Discussion
Volatile organic compounds (VOCs) are released
from various sources such as chemical processing
industries involved with the manufacturing,
handling, and the distribution of paints, lubricants,
and liquid fuels and are unsafe for human health are
known to have and environmental functions[37].
The numerous VOC treatment technologies have
emerged, such as incineration, condensation,
biological degradation, absorption, adsorption, and
catalysis oxidation. One of the common techniques
to monitor BTX in ambient air is the use of a
sorbent/solvent for the trapping and extracting of
VOCs from air or gas[38]. In this study, the toluene
removal from air was investigated based on mixture
of bismuth oxide-fullerene nanoparticles (Bi2O3-
NF) by UV-photocatalytic oxidation method (UV-
PCOM). The obtained results showed that flow
rate and temperature had highly impact on NF
for removal efficiency and absorption capacity of
toluene from air. Many researchers investigated
on toluene removal from air based on various
absorbents. The removal of toluene from air
through Nano-graphene modified by ionic liquid
(NG-IL) was studied. In this study the effect of
different conditions such as; toluene concentration,
humidity, and temperature on the adsorption were
investigated. The results showed the adsorption
Table 1. Method validation based on by spike of toluene concentration in artificial air by Bi2O3-NF/GC-FID (mg L-1)
Tolene aBag of pilot Spike of toluene Results b Recovery (%)
1.0 0. 93 ± 0.04 1.0 1..79 ± 0.05 96.2
5.0 4.58 ± 0.27 5.0 8.89 ± 0.46 97.1
10.0 9.43 ± 0.53 5.0 14.19 ± 0.65 101.2
15.0 14.39 ± 0.75 10.0 22.54 ± 1.23 94.6
20.0 19.70 ± 0.96 10.0 28.57 ± 1.33 98.2
25.0 24.65 ± 1.14 15.0 40.11± 2.16 102.7
a (Floe rate 500 mL min-1, Peak Area of GC-FID, 200 mg, T=45oC)
b (Mean of three determinations ± confidence interval, P = 0.95; n = 5)
Table 2. Comparing of Bi2O3-NF, Bi2O3 and NF for removal of toluene from artificial air by GC-FID/GC-MS (mg L-1)
Sorbent* Bag Added GC-FID a GC-MS aGC-FIDRecovery (%) GC-MS Recovery (%)
NF 5.0 ----- 2.34± 0.02 2.45± 0.02 46.8 49.0
5.0 4.53± 0.03 4.78± 0.04 43.8 46.6
10.0 6.68± 0.04 7.09± 0.05 43.4 46.4
Bi2O3-NF 5.0 ----- 4.88± 0.05 4.93± 0.06 97.6 98.6
5.0 9.71± 0.09 9.77± 0.10 96.6 96.7
10.0 14.95± 0.15 14.64± 0.16 101.1 97.1
Bi2O35.0 ----- 0.74± 0.03 0.77± 0.04 1.5 1.5
5.0 1.43± 0.07 1.51± 0.05 1.4 1.5
10.0 2.24± 0.12 2.33± 0.09 1.5 1.6
a (Mean of three determinations ± confidence interval , P = 0.95; n = 5)
* (500 mL min-1 air flow rate, 200 mg, T=45oC)
83
Analytical method for toluene removal from air; Cobra Jamshidzadeh, et al
capacity was decreased by raising the sorbent
humidity above 50 percent and the toluene capture
capacity for NG-IL was 126 mg g-1 which was
lower than Bi2O3-NF [27]. By UV-photocatalytic
oxidation method, the capacity of toluene
absorption with Bi2O3-NF was 212 mg g-1 which
was depended to UV-photocatalytic oxidation.
Lillo-Ródenas showed that the removal percentage
for toluene also may depend on porosity and the
surface chemistry of adsorbent. They showed that
adsorption capacities for benzene and toluene was
obtained 34 g per 100 g activated carbon(AC) and
64 g per 100 g, respectively which is lower than
Bi2O3-NF by UV-PCOM [39]. Surface chemistry
of activated carbon has an important role on the
removal of aromatic compounds in air because it
affects both electrostatic and dispersive interactions
between adsorbents and adsorbates [40]. In
proposed method, the chemically absorption of
toluene on NF mainly obtain due to radically group
of NF (OHo, COo) with methyl of toluene (CH2o).
Rezaei et al. have been used as complex system
of nano-particles of titanium dioxide on exposing
them by ultraviolet radiation. The results showed
titanium dioxide nanoparticles when subjected to
ultraviolet radiation ,exhibit strong oxidizing and
regenerative properties and can be used to remove
toluene vapors in high concentrations but it need
more time for adsorption process and titanium
dioxide nanoparticles is expensive as compare to
carbon compounds [41]. In addition, the use of a
suitable adsorbent according to the type of sorption
can be helped for removal toluene from air. Ichiura
at el. has suggested a sorbent based on zeolite or
activated carbon as a photocatalyst bed to improve
the efficiency of adsorption with higher recovery
[42].
Shojaee showed that ZSM-5 has a porous surface
with surface area of 356.4 m2 per gram. That
after the calcination at temperature of 450°c it
decreased to 332.5m2 per gram. The results of the
photocatalytic degradation process showed that
the best performance of ZSM-5/TiO2 bed was
at concentration of ppm, so that was able to
remove toluene vapors which was lower than
Bi2O3-NF [43,44]. According to obtained results,
removal of toluene from air based on Bi2O3-NF /
UV-PCOM was very rapid and absorption capacity
increased up to 212 mg per gram. Rezaee et al.
studied on the potential of MnO/GAC and MgO/
GAC composites for toluene adsorption from
air stream. They showed that, by increasing inlet
toluene concentration from 100 to 400 ppm, the
breakthrough time of MgO/GAC and MnO/GAC
was decreased [45]. So, the proposed method based
on Bi2O3-NF had many advantages such as, high
efficiency, simple, low cost for toluene removal
from air as compared to other methods.
5. Conclusions
In this study, the removal of toluene from air was
obtained based on Bi2O3-NF and UV-PCOM.
By procedure, many advantages such as, high
efficiency, high capacity, low cost, simple and fast
adsorption was achieved. In optimized conditions,
toluene concentration, Bi2O3-NF mass, temperature
and flow rate were evaluated. The capacity of
sorbents, recovery, and removal efficiency of
Bi2O3-NF, Bi2O3 and NF was studied by CG-FID
and GC-MS. Based on the results, the recovery of
Bi2O3-NF was more than Bi2O3 and NF sorbents.
Also, the maximum adsorption of toluene was
achieved with 200 mg of Bi2O3-NF by flow rate
of 500 mL min-1 (450C). Thermal accessory was
used for toluene desorption from Bi2O3-NF at 180
oC. Due to characteristics of Bi2O3-NF based on
physically and radically adsorption, toluene was
efficient removed from air by proposed method.
6. References
[1] W. T. Tsai, Toxic volatile organic compounds (VOCs)
in the atmospheric environment: Regulatory aspects
and monitoring in Japan and Korea, Environ., 3
(2016) 23.
[2] M.A. Bari, W.B. Kindzierski, Ambient volatile
organic compounds (VOCs) in communities of the
Athabasca oil sands region: Sources and screening
health risk assessment, Environ. Pollut., 235 (2018)
602-614.
84 Analytical Methods in Environmental Chemistry Journal; Vol. 2 (2019)
[3] B.C. McDonald, J.A. de Gouw, J.B. Gilman, S.H.
Jathar, A. Akherati, C.D. Cappa, J.L. Jimenez,
J. Lee-Taylor, P.L. Hayes, S.A. McKeen,
Volatile chemical products emerging as largest
petrochemical source of urban organic emissions,
Sci., 359 (2018) 760-764.
[4] Z. Cheng, B. Li, W. Yu, H. Wang, T. Zhang, J. Xiong,
Z. Bu, Risk assessment of inhalation exposure to
VOCs in dwellings in Chongqing, China, Toxicol.
Res., 7 (2018) 59-72.
[5] L. Zhong, F.-C. Su, S. Batterman, Volatile organic
compounds (VOCs) in conventional and high
performance school buildings in the US, Int. J.
Environ. Res. Public Health, 14 (2017) 100.
[6] J.C. Lerner, E. Sanchez, J. Sambeth, A. Porta,
Characterization and health risk assessment of
VOCs in occupational environments in Buenos
Aires, Argentina, Atmospheric. Environ., 55 (2012)
440-447.
[7] I.A.f.R.o. Cancer, IARC monographs on the
evaluation of carcinogenic risks to humans, agents
Retrieved from http7/monographs. Iarc, fr/eng/
[8] A.J. Wheeler, S.L. Wong, C. Khoury, J. Zhu,
Predictors of indoor BTEX concentrations in
Canadian residences, Health Rep., 24 (2013) 11.
[9] S.J. Lawrence, Description, properties, and
degradation of selected volatile organic compounds
detected in ground water, a review of selected
literature, 2006.
[10] X. Xu, P. Wang, W. Xu, J. Wu, L. Chen, M. Fu,
D. Ye, Plasma-catalysis of metal loaded SBA-15
for toluene removal: comparison of continuously
introduced and adsorption-discharge plasma
system, Chem. Eng. J., 283 (2016) 276-284.
[11] W.K. Boyes, M. Bercegeay, L. Degn, T.E. Beasley,
P.A. Evansky, J.C. Mwanza, A.M. Geller, C.
Pinckney, T.M. Nork, P.J. Bushnell, Toluene
inhalation exposure for 13 weeks causes persistent
changes in electroretinograms of Long–Evans rats,
Neurotoxicol., 53 (2016) 257-270.
[12] Y. Li, J. Miao, X. Sun, J. Xiao, Y. Li, H. Wang,
Q. Xia, Z. Li, Mechanochemical synthesis of Cu-
BTC@ GO with enhanced water stability and
toluene adsorption capacity, Chem. Eng. J, 298
(2016) 191-197.
[13] C.Y.H. Chao, C. Kwong, K. Hui, Potential use of
a combined ozone and zeolite system for gaseous
toluene elimination, J. Hazard. Mater., 143 (2007)
118-127.
[14] M. Salar-García, V. Ortiz-Martínez, F. Hernández-
Fernández, A. de Los Ríos, J. Quesada-Medina,
Ionic liquid technology to recover volatile organic
compounds (VOCs), J. Hazard. Mater., 321 (2017)
484-499.
[15] D. Romero, D. Chlala, M. Labaki, S. Royer, J.-
P. Bellat, I. Bezverkhyy, J.-M. Giraudon, J.-F.
Lamonier, Removal of toluene over NaX zeolite
exchanged with Cu2+, Catalysts, 5 (2015) 1479-
1497.
[16] Y.J. Tham, P.A. Latif, A.M. Abdullah, A. Shamala-
removal by activated carbon derived from durian
shell, Bioresour. Technol., 102 (2011) 724-728.
[17] NIOSH manual of analytical methods, NIOSH,
(1987).
[18] H. Sui, H. Liu, P. An, L. He, X. Li, S. Cong,
Application of silica gel in removing high
concentrations toluene vapor by adsorption and
desorption process, J. Taiwan Ins. Chem. Eng.,
(2017).
[19] Z. Sihaib, F. Puleo, J. Garcia-Vargas, L. Retailleau,
C. Descorme, L. Liotta, J. Valverde, S. Gil, A.
Giroir-Fendler, Manganese oxide-based catalysts
for toluene oxidation, App. Cat. B Environ., 209
(2017) 689-700.
[20] Z. Pengyi, L. Fuyan, Y. Gang, C. Qing, Z. Wanpeng,
A comparative study on decomposition of gaseous
toluene by O3/UV, TiO2/UV and O3/TiO2/UV, J.
Photochem. Photobiol., 156 (2003) 189-194.
[21] S. Wang, H. Sun, H.-M. Ang, M. Tadé, Adsorptive
remediation of environmental pollutants using
novel graphene-based nanomaterials, Chem. Eng.
J., 226 (2013) 336-347.
[22] G.B. Baur, O. Beswick, J. Spring, I. Yuranov, L.
85
Analytical method for toluene removal from air; Cobra Jamshidzadeh, et al
VOC removal from diluted streams: the role of
surface functionalities, Adsorption, 21 (2015) 255-
264.
[23] A. Faghihi-Zrandi, M. Akhgar, Volatile Organic
Compounds (VOCs) in the Ambient Air Of
Concentration Unit of Sar-Cheshmeh Copper
Complex, Environ. Sci. Technol., 18 (2016) 23-31.
[24] G. Quijano, A. Couvert, A. Amrane, G. Darracq,
C. Couriol, P. Le Cloirec, L. Paquin, D. Carrié,
Potential of ionic liquids for VOC absorption and
biodegradation in multiphase systems, Chem. Eng.
Sci., 66 (2011) 2707-2712.
[25] F.G. Shahna, F. Golbabaei, J. Hamedi, H. Mahjub,
H.R. Darabi, S.J. Shahtaheri, Treatment of benzene,
toluene and xylene contaminated air in a bioactive
foam emulsion reactor, Chinese.Chem. Eng., 18
(2010) 113-121.
[26] F. Su, C. Lu, S. Hu, Adsorption of benzene, toluene,
ethylbenzene and p-xylene by NaOCl-oxidized
carbon nanotubes, Colloids Surface A, 353 (2010)
83-91.
[27] H. Shirkhanloo et al, Nobel Method for Toluene
Nano-Graphen, Iranian J. Occp. Health, 6 (2015)
1-5.
[28] M.R. Wiesner, G.V. Lowry, P. Alvarez, D. Dionysiou,
P. Biswas, Assessing the risks of manufactured
nanomaterials, Environ. Sci. Technol., 40 ( 2006)
4336-4345.
[29] Y. Li, Y. Wang, K.D. Pennell, L.M. Abriola,
Investigation of the transport and deposition of
fullerene (C60) nanoparticles in quartz sands under
(2008) 7174-7180.
[30] A.G.C. A.V. Rode, E.G. Gamaly, S.T. Hyde,
B. Luther Davie, carbon based magnetism, an
overview of the magnetism of metal free carbon-
based compounds and materials, Elsevier, (2006)
463-482.
water and air: advanced oxidation processes
(AOPs)-principles, reaction mechanisms, reactor
concepts, John Wiley & Sons, (2003).
[32] G.Y.M. Al-Nour, Photocatalytic degradation of
organic contaminants in the presence of graphite
particles, Nablus: An-Najah National University,
(2009).
[33] H.I. De Lasa, B. Serrano, M. Salaices, Photocatalytic
reaction engineering, Springer, 2005.
[34] C. Montalvo-Romero, C. Aguilar-Ucán, M.
Ramirez-Elias, V. Cordova-Quiroz, A Semi-Pilot
Photocatalytic Rotating Reactor (RFR) with
Supported TiO2/Ag Catalysts for Water Treatment,
Molecul., 23 (2018) 224.
[35] U.L. Rochetto, E. Tomaz, Degradation of
volatile organic compounds in the gas phase
by heterogeneous photocatalysis with titanium
dioxide/ultraviolet light, J. Air Waste Manag.
Assoc, 65 (2015) 810-817.
[36] H. Keypour, M. Noroozi, A. Rashidi, An improved
fullerene soot with activated carbon, celite, and
silica gel stationary phases, J. Nanostruct. Chem.,
3 (2013) 45.
[37] K. Patil, S. Jeong, H. Lim, H.-S. Byun, S. Han,
Removal of volatile organic compounds from
air using activated carbon impregnated cellulose
acetate electrospun mats, Environ. Eng. Res.,
(2018).
[38] X. Zhang, B. Gao, A.E. Creamer, C. Cao, Y. Li,
Adsorption of VOCs onto engineered carbon
materials: A review, J. Hazard. Mater., 338 (2017)
102-123.
[39] M. Lillo-Ródenas, D. Cazorla-Amorós, A. Linares-
Solano, Behaviour of activated carbons with
different pore size distributions and surface oxygen
groups for benzene and toluene adsorption at low
concentrations, Carbon, 43 (2005) 1758-1767.
[40] F. Villacañas, M.F.R. Pereira, J.J. Órfão, J.L.
Figueiredo, Adsorption of simple aromatic
compounds on activated carbons, J. Colloid.
Interface. Sci, 293 (2006) 128-136.
[41] H. Ichiura, T. Kitaoka, H. Tanaka, Removal of indoor
pollutants under UV irradiation by a composite
86 Analytical Methods in Environmental Chemistry Journal; Vol. 2 (2019)
TiO2–zeolite sheet prepared using a papermaking
technique, Chemosphere, 50 (2003) 79-83.
[42] Rezaee A., Pourtaghi Gh. H., Khavanin A., Saraf
Mamoori R., Hajizadeh E., Vali pour F., Elimination
of toluene by Application of ultraviolet irradiation
on TiO2 nano particles photocatalyst, Mil. Med., 9
(2007) 217-222.
[43] H. Asilian Mahabady, A. Khavanin, M. Nakhaei
pour, H. irvani, S. Aresoomandan, H. Shojaee fareh
removal of toluene vapour by titanium dioxide
nanoparticles immobilized on ZSM-5 zeolite, Iran
Occp. Health J., 15 (2018) 17-25.
Zeolite and Cooper Oxide Nanoparticles-
for Polluted Air BTX Removal, Iranian J. Health
Environ., 5 (2012).
[45] F. Rezaei, G. Moussavi, A.R. Riyahi Bakhtiari,
Y. Yamini, Toluene adsorption from waste air
stream using activated carbon impregnated with
manganese and magnesium metal oxides, Iranian J.
Health Environ., 8 (2016) 491-508.
