Mechanochemical destruction of decabromodiphenyl ether into visible light photocatalyst BiOBr

Article abstract of DOI:10.1039/c3ra47738j

In the present study, mechanochemical (MC) treatment of polybrominated diphenyl ethers (PBDEs), a kind of emerging persistent organic pollutant (POPs), was performed using a high energy ball mill. With Bi₂O₃ as co-milling reagent, deca-BDE was effectively destroyed and no hazardous intermediates or organic products were observed in the MC reaction. Meanwhile, BiOBr, a promising visible light photocatalyst, was proved to be the final product which could be utilized in further steps. Neither excessive Bi ₂O₃ nor unreacted deca-BDE was left after the reaction as they were originally added at stoichiometric ratio for BiOBr formation. FITR and Raman analyses demonstrate the collapse of deca-BDE skeleton and the cleavage of C-Br bonds with the generation of inorganic carbon, revealing the mechanism of carbonization and debromination. The gaseous products at different reaction atmosphere were also analyzed, showing that mostly CO₂ with a fraction of CO were released during the MC process. The reaction formula of deca-BDE and Bi₂O₃ was then proposed based on the identified final products. Besides, the photocatalytic activity of the generated BiOBr was evaluated using methyl orange as the model pollutant. A good degradation performance from BiOBr was achieved under both simulated sunlight and visible light irradiation, indicating the possibility for its further utilization. This journal is the Partner Organisations 2014.

Full text of DOI:10.1039/c3ra47738j

RSC Advances
View Article Online
View Journal | View Issue
PAPER
Mechanochemical destruction of
decabromodiphenyl ether into visible light
photocatalyst BiOBr
Cite this: RSC Adv., 2014, 4, 14719
a
a
Kunlun Zhang, Jun Huang, Haizhu Wang,a Gang Yu,a Bin Wang,a Shubo Deng,a
*
Junya Kanob and Qiwu Zhangb
In the present study, mechanochemical (MC) treatment of polybrominated diphenyl ethers (PBDEs), a kind
of emerging persistent organic pollutant (POPs), was performed using a high energy ball mill. With Bi2O3 as
co-milling reagent, deca-BDE was effectively destroyed and no hazardous intermediates or organic
products were observed in the MC reaction. Meanwhile, BiOBr, a promising visible light photocatalyst,
was proved to be the final product which could be utilized in further steps. Neither excessive Bi2O3 nor
unreacted deca-BDE was left after the reaction as they were originally added at stoichiometric ratio for
BiOBr formation. FITR and Raman analyses demonstrate the collapse of deca-BDE skeleton and the
cleavage of C–Br bonds with the generation of inorganic carbon, revealing the mechanism of
carbonization and debromination. The gaseous products at different reaction atmosphere were also
analyzed, showing that mostly CO2 with a fraction of CO were released during the MC process. The
reaction formula of deca-BDE and Bi2O3 was then proposed based on the identified final products.
Besides, the photocatalytic activity of the generated BiOBr was evaluated using methyl orange as the
model pollutant. A good degradation performance from BiOBr was achieved under both simulated
sunlight and visible light irradiation, indicating the possibility for its further utilization.
Received 18th December 2013
Accepted 10th March 2014
DOI: 10.1039/c3ra47738j
www.rsc.org/advances
in the environment into lower brominated congeners, which
themselves are POPs.11,12
1. Introduction
In terms of the sound disposal of PBDEs wastes, mechano-
chemical (MC) method has been proved to be an effective alter-
native instead of combustion technologies.13 Via high energy ball
milling, the MC reactions between pollutants and co-milling
reagents are initiated by the mechanic force such as impact,
fraction, stress, deformation,14 resulting in the destruction of
pollutants into non-hazardous products. Compared with PBDEs
wastes combustion which could possibly release toxic PBDD/Fs,15
MC destruction happens at low temperature and normal pres-
sure and can avoid this kind of secondary pollution.16 Most
previous MC studies focused on the destruction of chlorinated
POPs such as DDT,17 PCBs,18 PCDD/Fs19 and few attention was
paid on non-chlorinated pollutants. Our recent studies has
shown that MC method was as well effective for the destruction
of brominated and peruorinated pollutants.20,21 However in
most cases, excessive co-milling reagents (represented by CaO
which is the mostly used) were required to ensure high reaction
speed and complete destruction.22 Additionally, the nal prod-
ucts and the residual reagents aer reaction cannot be utilized
and further treatment such as landll is still needed. Therefore,
it is necessary to seek for new co-milling reagents that are used
in the required amount for reaction rather than excessive,
and the nal products are expected to have proper utilization
as well.
Over the last decades, polybrominated diphenyl ethers
(PBDEs) have been widely used as non-reactive additives in
polymers such as textiles, plastics and electronic products, to
improve their ame resistance and prevent re.1,2 There were
three main formulations of commercially used PBDEs in the
market, i.e., penta-, octa- and deca-BDE. Due to substantial
and long-term usage, PBDEs have been frequently detected in
humans, wildlife, and abiotic environment around the
world.3–6 As a consequence of their toxic, bioaccumulative
and persistent properties,7–9 more and more concerns about
this kind of chemicals have arisen. In 2009, the commercially
used penta- and octa-BDE were listed as persistent organic
pollutants (POPs) in the Annex A of the Stockholm Conven-
tion. In June 2013, deca-BDE was also proposed for the
inclusion in the convention as it was considered to meet the
screening criteria in Annex
D
for persistence, bio-
accumulation, long-range transport and adverse effects.10
Adding to this concern, deca-BDE can be degraded in biota or
aState Key Joint Laboratory of Environment Simulation and Pollution Control
(SKJLESPC), School of Environment, POPs Research Center, Tsinghua University,
Beijing 100084, P.R. China. E-mail: huangjun@tsinghua.edu.cn
bInstitute of Multidisciplinary Research for Advanced Materials, Tohoku University,
Sendai 980-8577, Japan
This journal is © The Royal Society of Chemistry 2014
RSC Adv., 2014, 4, 14719–14724 | 14719

View Article Online
RSC Advances
Paper
As MC reactions can take place directly in solid state, besides analyzed using a micro gas chromatograph system (Micro-GC
the destruction of POPs, it has also been used for the prepara- 3000A, Agilent, USA).
tion of new materials and running chemical reactions in
To identify the nal products aer MC reaction, X-ray
absence of solvents.23 Thus there should be a possibility to diffraction (XRD) measurement were performed by an X-ray
couple these two processes together, in which not only pollut- diffractometer (RINT-2200, Rigaku, Japan) equipped with a Cu
ants are destroyed but also the nal products can be useful.
Ka radiation from 2q ¼ 10ꢀ–60ꢀ at a speed of 10ꢀ minꢂ1. The
In the present study, Bi2O3 was selected as the co-milling thermogravimetric (TG) analysis was carried out using a TG8120
reagents for the destruction of PBDEs (represented by deca- analyzer (Rigaꢂk1u, Japan) in nitrogen ow with 10 mg sample
BDE) since the element of bismuth has a promising application and 10 ꢀC min heating rate from 25 ꢀC to 600 ꢀC. To gure out
in photocatalyst.24,25 With exactly the stoichiometric amount of the chemical changes during milling, the samples were char-
Bi2O3 and deca-BDE for reaction, deca-BDE was completely acterized by a Fourier transform infrared (FTIR) spectrometer
degraded and the nal product was proved to be a visible light (FTS3000, Digilab, USA) with the KBr disk method. Raman
photocatalyst BiOBr. The photocatalytic activity of the gener- spectra of the samples were also recorded using a Labspec
ated BiOBr was also evaluated using methyl orange (MO) as Raman spectrograph (HORIBA Jobin Yvon, France) with a He
model pollutant in the irradiation of simulated sunlight and laser beam at the 632 nm line.
visible light.
2.4. Photocatalytic experiments
2. Experimental
To evaluate the photocatalytic activity of the nal products aer
MC reaction, a series of experiments were carried out using a
projective photochemical reactor (PLSSXE300UV, Beijing
Trusttech Technology Co., China) with a 300 W xenon lamp as
simulated sunlight. The UV-CUT-400 lter was employed to
remove the incoming wavelengths shorter than 400 nm and
ensure visible light irradiation. A cooling device was equipped
and the infrared irradiation of the light was cut off to avoid
signicant temperature increase of the reaction system.
In the experiments, 0.2 g of the 2 h milled sample was added
into a cylindrical quartz reactor (160 mm length ꢁ 32 mm inner
diameter) with 100 mL MO solution at a concentration of 15 mg
Lꢂ1. A magnetic stirring apparatus was located at the bottom of
the reactor to ensure thoroughly mixing of the aqueous system.
The direct photolysis and control test in darkroom were also
simultaneously carried out for comparison. At each sampling
time, 2 mL of the suspension was taken and ltered by 0.45 mm
nylon membrane, aer which remaining MO in the ltrate was
determined by a Hitachi U-3310 UV-visible spectrophotometer.
2.1. Materials
2,20,3,30,4,40,5,50,6,60-Decabromodiphenyl ether (deca-BDE,
C
12Br10O 98% in purity), bismuth(III) oxide (Bi2O3, 99% in
purity), calcium oxide (CaO, 99% in purity) were provided by
Wako Pure Chemical Industries Ltd. The CaO and Bi2O3 were
heated at 450 ꢀC for 2 hours before use. Methyl orange (MO,
85% in purity) was purchased from Sinopharm Chemical
Reagent Co., Ltd. (China) and used as model pollutant in pho-
tocatalytic experiments. All the solvents (n-hexane, acetone)
used in the extraction and determination were of HPLC grade
(J.T. Baker Inc., USA) and the ultrapure water was prepared by a
Milli-Q system (Millipore, USA).
2.2. MC reaction
The MC experiments were performed using a planetary ball mill
machine (Pulverisette-7, Fritch, Germany). Two zirconia pots
with the volume of 45 cm3 and seven zirconia balls with the
diameter of 15 mm (approx. 10.5 g each) were employed in the
ball milling. In each experiment, 0.875 g deca-BDE was milled
with 2.125 g Bi2O3 (or CaO comparatively) as co-milling reagent,
keeping the molar ratio Bi–Br ¼ 1 : 1. The rotary speed of
machine disk was set as 700 rpm for 15 min intervals, aer
which there was a 15 min cooling period. The milled samples
were collected and then preserved in a hermetic and dry appa-
ratus for further use. For the 2 h milled sample of deca-BDE and
Bi2O3, the gas phase products at different reaction atmosphere
were also collected for composition analysis.
3. Results and discussion
3.1. Comparison of Bi2O3 with CaO as co-milling reagents
In order to investigate the performance of Bi2O3 in MC
destruction of deca-BDE, the comparison experiment with CaO
(as a representative of commonly used co-milling reagents) was
carried out with the same weight ratio (2.125 g Bi2O3 or CaO
with 0.875 g deca-BDE). The destruction efficiency of deca-BDE
by Bi2O3 or CaO and the GC-MS spectra of Bi2O3 milled samples
are shown in Fig. 1.
2.3. Determination and characterization
With the extension of milling time, the remaining deca-BDE
For deca-BDE determination, 0.05 g of each milled sample was quickly decreased roughly following a linear declination trend,
taken and extracted using 50 mL hexane–acetone (1 : 1, v/v) with showing that the MC method is effective for deca-BDE
10 min ultrasonic treatment. The solution was rstly ltered by destruction. Nearly all the deca-BDE was destroyed aer 1 h ball
0.45 mm polytetrauoroethylene (PTFE) membrane and then milling with Bi2O3 as co-milling reagent. Actually no peak could
subjected to instrumental analysis. A Shimadzu 2010 GC-MS be found in the GC-MS spectra of the 2 h milled sample, indi-
equipped with a DB-5HT column (15 m ꢁ 0.25 mm i.d., 0.10 mm cating a complete degradation of deca-BDE aer MC reaction.
lm thickness) was used and operated in negative ion chemical But when CaO was used as co-milling reagent, the performance
ionization (NCI) mode. The collected gas phase products were was less effective and there was still more than 15% deca-BDE
14720 | RSC Adv., 2014, 4, 14719–14724
This journal is © The Royal Society of Chemistry 2014

View Article Online
Paper
RSC Advances
and the results are shown in Fig. 2, labeled with the patterns of
the reagent and typical products.
For 0 h mixture of deca-BDE and Bi2O3, only the diffraction
peaks of Bi2O3 (JCPDS Card no. 74-1373, labeled as C) were
shown clearly in the XRD spectra. While aer 30 min milling, the
pattern of Bi2O3 quickly receded and another new group of
diffraction peaks with strong intensity started to appear. These
new peaks were indexed to the hexagonal structure of bismuth
oxybromide (BiOBr, JCPDS Card no. 73-2061, labeled as ;) which
was a promising visible light photocatalyst.28 Aer 2 h milling,
there was no longer any peaks of Bi2O3 in the spectra, remaining
only the pattern of BiOBr. This transformation from Bi2O3 to
BiOBr illustrates that deca-BDE was destroyed through the MC
reaction and the organic bromine was changed into inorganic
form as BiOBr, corresponding with the GC-MS results above.
It's worth mentioning that there was neither excessive Bi2O3 nor
unreacted deca-BDE remaining in the samples aer the MC
process. Therefore as expected, deca-BDE was effectively destroyed
with the stoichiometric amount of Bi2O3 rather than excessive.
Meanwhile, a promising visible light photocatalyst BiOBr was
prepared as the nal product and can be utilized again. This
process matches well with the concept of green chemistry in which
pollutants were destroyed and useful products were generated.
To ensure the destruction of deca-BDE and the formation of
BiOBr during MC treatment, thermogravimetric (TG) analysis of
the samples was also conducted as shown in Fig. 3.
Fig. 1 The destruction of deca-BDE together with GC-MS spectra of
Bi2O3 milled samples.
remaining in the solid even aer 2 h ball milling. Obviously, as
co-milling reagent, Bi2O3 showed better performance for PBDEs
destruction.
It was expected that there should be some intermediates from
the MC degradation of deca-BDE. However, unlike some other
degradation reactions such as photolysis,26 no obvious inter-
mediates or organic products of deca-BDE could be found in the
Bi2O3 milled samples (as shown in the GC-MS spectra in Fig. 1).
This suggests that the MC reactions between deca-BDE and
Bi2O3 should take place continuously and spontaneously, during
which few intermediates could be detected. This phenomenon
also happened in many previous studies on MC destruction.20,27
For 0 h mixture, an obvious weight change could be observed
during heating at the range of 325–425 ꢀC, which was owing to
the thermal decomposition of deca-BDE.29 The nearly 30% loss
also agreed well with the weight ratio of deca-BDE in the mixture
(0.875 g deca-BDE/total 3.0 g ¼ 29.2%). Aer 30 min ball milling,
the weight change around 325–425 ꢀC became much smaller,
indicating a large destruction of deca-BDE. Meanwhile there was
another weight loss at the range of 480–580 ꢀC starting to occur.
Since most organics would be decomposed at the temperature
above 450 ꢀC, this new weight loss could be attributed the
3.2. Products identication
For the products identication of deca-BDE and Bi2O3 aer MC
reaction, XRD analysis of the milled samples was carried out
ꢀ
thermolysis of the nal product. At above 500 C, BiOBr would
be easily decomposed into Bi2O3 (s) and BiBr3 (g),30 during which
the evaporation of BiBr3 at this temperature resulted in this large
weight loss (shown in eqn (1)).
Fig. 2 XRD spectra of the samples milled with Bi2O3 for different time. Fig. 3 TG analysis of the samples milled with Bi2O3 for different time.
This journal is © The Royal Society of Chemistry 2014
RSC Adv., 2014, 4, 14719–14724 | 14721

View Article Online
RSC Advances
Paper
480ꢂ580 ℃
3BiOBr
Bi O þ BiBr [
(1)
ƒƒƒƒƒƒ!
2
3
3
For the samples aer 2 h ball milling, there was no longer
weight change at 325–425 ꢀC, indicating that deca-BDE was
completely destroyed and transformed into inorganic form.
Correspondingly, there was a nearly 50% weight loss at 480–550 ꢀC
owing to the BiBr3 evaporation from the BiOBr decomposition.
This result again demonstrates that deca-BDE has just reacted with
the Bi2O3 during ball milling with the formation of BiOBr.
3.3. Characterization of the samples milled with Bi2O3
To better understand the chemical change of deca-BDE during
milling, Fourier transform infrared (FTIR) and Raman spec-
trometer were conducted on the milled samples. Fig. 4 shows
the FTIR spectra of the samples for different milling time.
For 0 h mixture of deca-BDE and Bi2O3, there was a strong
peak centered at 1350 cmꢂ1 in FTIR, which came from the n(CC)
chain vibration of the aromatic ring and could be regarded as
the indicator for deca-BDE molecule.31 The peak band at
960 cmꢂ1, 761 cmꢂ1 and 696 cmꢂ1 were the n(C–Br) stretching
vibrations, illustrating the existence of the organic bromine.32
The weak stretching band around 1210 cmꢂ1 was attributed to
the n(C–O–C) asymmetric vibration. For the spectra of 30 min
milled sample, these peaks quickly weakened, showing that the
deca-BDE was greatly destroyed. Actually aer 2 h ball milling
with Bi2O3, all the signal peaks of deca-BDE in FTIR were totally
disappeared, illustrating that both the skeleton of deca-BDE
was broken down and the organic bromine atoms were disso-
ciated from the molecule.
Fig. 5 Raman analysis of samples milled with Bi2O3 for different time.
With the ball milling ongoing, the intensity of the peaks from
deca-BDE largely decreased and two peak bands with the peak
around 1312 cmꢂ1 and 1582 cmꢂ1 started to appear and
strengthen. In Raman analysis, these two peak bands are
usually classied as the “D-band” (1330–1380 cmꢂ1) and
“G-band” (1540–1580 cmꢂ1) which are respectively the charac-
teristic for sp2-bonded atoms of disordered carbon and crystal
graphite.34 The appearance and intensication of “D-band” and
“G-band” declare the generation of disordered and graphite
carbon in the MC reaction.
Therefore, the collapse of deca-BDE skeleton and the
cleavage of C–Br bonds, together with the generation of inor-
ganic carbon, reveal that debromination and carbonization are
the main mechanisms for deca-BDE destruction. In this way,
the organic carbon and bromine in the molecule were trans-
formed into inorganic forms, eliminating the POPs properties
of deca-BDE.
Raman spectra of the samples milled with Bi2O3 are shown
in Fig. 5. Correspondingly with FTIR, the n(CC) aromatic ring
chain vibration of deca-BDE in Raman spectra was located at
1520 cmꢂ1 with strong intensity and the asymmetric n(C–O–C)
vibration showed around 1180–1240 cmꢂ1 31,33 The peaks of C–
.
Br bonds were observed over a wide range of 690–1090 cmꢂ1
.
3.4. Gas phase products identication
During the milling of deca-BDE with Bi3O3, evident gas
production could be observed aer the experiment. As a result,
the MC reactions in the atmosphere of air or argon were per-
formed for 2 h and the produced gases were collected for
analysis. The results of the gaseous products from 2 h milled
samples at different reaction atmosphere are shown in Table 1.
Through micro-GC analysis, CO2 (roughly 90%) and CO were
proved to be the gaseous products of the MC reaction. It should
Table 1 Gas products analysis for 2 h milled samples at different
reaction atmosphere
Components
Atmosphere
CO2
CO
N2
O2
Ar
Air
Argon
56.5%
54.7%
6.1%
5.8%
29.3%
—
7.6%
—
—
39.5%
Fig. 4 FTIR spectra of samples milled with Bi2O3 for different time.
14722 | RSC Adv., 2014, 4, 14719–14724
This journal is © The Royal Society of Chemistry 2014

View Article Online
Paper
RSC Advances
be pointed out that the atmosphere had few inuence on the
It can be observed that the direct photolysis of MO was
gas production. It is not difficult to understand because the MC negligible under both xenon lamp and visible light irradiation.
reactions are usually initiated by mechanic force and take place Meanwhile in the control experiment, there was a nearly 15%
in solid state at nearly room temperature, in which the gas decrease of MO concentration in the rst 60 min and keep
phase is seldom involved in the reactions.
unchanged aerwards. Since no irradiation existed in the
darkroom, this removal of MO was ascribed to the absorption
from the sample. Under xenon lamp irradiation with BiOBr,
there was a remarkable degradation of MO (20% aer 4 h
reaction) besides the absorption, indicating the occurrence of
photocatalytic degradation.35 The visible light irradiation with
BiOBr also showed a signicant effect with 15% MO degrada-
tion aer 4 h reaction, although the performance was not as
good as simulated sunlight irradiation.
Therefore, it is demonstrated that the generated BiOBr aer
the MC reaction had good photocatalytic activity under both
simulated sunlight and visible light irradiation. In this way, the
nal products aer the MC destruction of deca-BDE could be
utilized again as photocatalyst rather than discarded.
3.5. MC reaction formula
In terms of the nal products identied above (inorganic
carbon, BiOBr, CO2 or CO), the MC reaction between deca-BDE
and Bi2O3 should follow either of the following equations:
ball milling
ƒƒƒƒƒƒ!
5Bi O þ C Br O
10BiOBr þ 9C þ 3CO [ (2)
2
3
12
10
2
ball milling
5Bi O þ C Br O
10BiOBr þ 6C þ 6CO [ (3)
ƒƒƒƒƒƒ!
2
3
12
10
Since the rough ratio between CO2 and CO was 10 : 1, it can
be inferred that the reaction mostly followed eqn (2) and frac-
tionally went with eqn (3). Taking the experiment at air atmo-
sphere for example, the nal gas volume was about 108 mL
(25 ꢀC), in which there was 61.0 mL CO2 and 6.6 mL CO. Then
the generated CO2 and CO could be calculated into 2.49 mmol
and 0.27 mmol, corresponding to 0.798 g and 0.043 g deca-BDE
consumption following eqn (2) and (3). As a result, the calcu-
lated total deca-BDE consumption (0.841 g) agreed well with the
originally added amount (0.875 g), indicating that the gas
production can be well balanced with the initial concentration
of deca-BDE. Satisfyingly, there were no other gases or
hazardous products generated and the secondary pollution was
avoided.
4. Conclusion
The present study successfully combined MC destruction of
POPs with the preparation of catalyst. The main conclusions of
the study are as follows:
(1) MC reaction with Bi2O3 is shown to be an effective
method for the destruction of deca-BDE, with no hazardous
intermediates or organic products observed.
(2) Besides the deca-BDE destruction, the nal product aer
milling was a promising visible light photocatalyst BiOBr and
could be utilized in further steps, matching well with the
concept of green chemistry.
(3) With stoichiometric ratio for BiOBr formation, deca-BDE
had just reacted with Bi2O3, which economized the raw mate-
rials and saved the cost.
(4) Carbonization and debromination were found to be the
main reaction mechanisms for the destruction of deca-BDE.
(5) The generated BiOBr showed good photocatalytic activity
for MO degradation under both simulated sunlight and visible
light irradiation.
3.6. Photocatalytic activity of BiOBr
In order to evaluate the photocatalytic activity of the generated
BiOBr, the photocatalytic degradation of methyl orange (MO) in
water was performed under direct xenon lamp (simulated
sunlight) and visible light (l > 400 nm) irradiation. For
comparison, the direct photolysis of MO and the control test
with BiOBr in darkroom were also carried out. Fig. 6 shows the
variations of MO concentration (C/C0) at different conditions.
Acknowledgements
This work was supported by the High-tech Research and
Development Program of China (no. 2013AA06A305), the
National Natural Science Funds (no. 51278270; 51078212), and
the National Special Science & Technology Program for Non-
prot Industry, Ministry of Environmental Protection of China
(no. 201309001).
References
1 C. A. de Wit, Chemosphere, 2002, 46, 583–624.
2 M. Alaee, P. Arias, A. Sjodin and A. Bergman, Environ. Int.,
2003, 29, 683–689.
3 D. Chen and R. C. Hale, Environ. Int., 2010, 36, 800–811.
4 R. A. Hites, Environ. Sci. Technol., 2004, 38, 945–956.
Fig. 6 Variations of MO concentration at different conditions.
This journal is © The Royal Society of Chemistry 2014
RSC Adv., 2014, 4, 14719–14724 | 14723

View Article Online
RSC Advances
Paper
5 C. A. de Wit, D. Herzke and K. Vorkamp, Sci. Total Environ., 20 K. Zhang, J. Huang, G. Yu, Q. Zhang, S. Deng and B. Wang,
2010, 408, 2885–2918. Environ. Sci. Technol., 2013, 47, 6471–6477.
6 Q. Luo, Z. W. Cai and M. H. Wong, Sci. Total Environ., 2007, 21 K. Zhang, J. Huang, W. Zhang, Y. Yu, S. Deng and G. Yu,
383, 115–127. J. Hazard. Mater., 2012, 243, 278–285.
7 L.-H. Yu, X.-J. Luo, J.-P. Wu, L.-Y. Liu, J. Song, Q.-H. Sun, 22 W. Zhang, J. Huang, G. Yu, S. B. Deng and W. P. Zhu,
X.-L. Zhang, D. Chen and B.-X. Mai, Environ. Sci. Technol.,
2011, 45, 5125–5131.
Chemosphere, 2010, 81, 345–350.
23 L. Takacs, Chem. Soc. Rev., 2013, 42, 7649–7659.
8 P. B. Key, K. W. Chung, J. Hoguet, B. Shaddrix and 24 X. Chang, M. A. Gondal, Z. H. A. Yamani and G. Ji, in
M. H. Fulton, Sci. Total Environ., 2008, 399, 28–32. Bismuth-Containing Compounds, Springer, 2013, pp. 343–373.
9 S. D. Shaw, M. L. Berger, D. Brenner, K. Kannan, N. Lohmann 25 N. M. Leonard, L. C. Wieland and R. S. Mohan, Tetrahedron,
¨
and O. Papke, Sci. Total Environ., 2009, 407, 3323–3329.
2002, 58, 8373–8397.
10 UNEP, POPS/POPRC.9/2, 2013.
26 Y.-h. Shih and C.-K. Wang, J. Hazard. Mater., 2009, 165, 34–
11 A. C. Gerecke, P. C. Hartmann, N. V. Heeb, H.-P. E. Kohler,
38.
W. Giger, P. Schmid, M. Zennegg and M. Kohler, Environ. 27 Q. W. Zhang, H. Matsumoto, F. Saito and M. Baron,
Sci. Technol., 2005, 39, 1078–1083. Chemosphere, 2002, 48, 787–793.
12 M. J. La Guardia, R. C. Hale and E. Harvey, Environ. Sci. 28 K. Kalyanasundaram, Photochemistry, 2013, 41, 182.
Technol., 2007, 41, 6663–6670.
29 C. K. S. Pillai, V. S. Prasad, A. R. R. Menon, J. D. Sudha,
V. G. Jayakumari, M. B. Kumar, C. Pavithran, V. K. Tikku
and N. K. Pradhan, J. Appl. Polym. Sci., 1997, 66, 2157–2173.
30 Y. Feng, L. Li, J. Li, J. Wang and L. Liu, J. Hazard. Mater.,
2011, 192, 538–544.
13 S. A. Rowlands, A. K. Hall, P. G. McCormick, R. Street,
R. J. Hart, G. F. Ebell and P. Donecker, Nature, 1994, 367,
223.
14 J. J. Gilman, Science, 1996, 274, 65.
15 H. Duan, J. Li, Y. Liu, N. Yamazaki and W. Jiang, Environ. Sci. 31 M. Feng, R. Qu, L. Wang and Z. Wang, Chin. J. Struct. Chem.,
Technol., 2011, 45, 6322–6328. 2013, 32, 612–619.
16 X. Y. Guo, D. Xiang, G. H. Duan and P. Mou, Waste Manage., 32 L. G. Wade, Organic chemistry, Prentice Hall, New Jersey,
2010, 30, 4–10. 2003.
17 A. K. Hall, J. M. Harroweld, R. J. Hart and P. G. McCormick, 33 D. Lin-Vien, The Handbook of infrared and Raman
Environ. Sci. Technol., 1996, 30, 3401–3407.
characteristic frequencies of organic molecules, Academic
18 M. Aresta, P. Caramuscio, L. De Stefano and T. Pastore,
Waste Manage., 2003, 23, 315–319.
Press, 1991.
34 F. Tuinstra and J. L. Koenig, J. Chem. Phys., 1970, 53, 1126–
19 Y. Mitoma, T. Uda, N. Egashira, C. Simion, H. Tashiro,
1130.
M. Tashiro and X. Fan, Environ. Sci. Technol., 2004, 38, 35 X. Chang, J. Huang, C. Cheng, Q. Sui, W. Sha, G. Ji, S. Deng
1216–1220.
and G. Yu, Catal. Commun., 2010, 11, 460–464.
14724 | RSC Adv., 2014, 4, 14719–14724
This journal is © The Royal Society of Chemistry 2014