A high-performance polyurethane sponge for the detection, adsorption and separation of Cu2+ ions

Article abstract of DOI:10.1039/c4ra01981d

The simultaneous detection and separation of copper ions is important. In this study, a fluorescent chemosensor (a copper sensitive molecule), was prepared using 6-bromo-benzo[de]isochromene-1,3-dione as a precursor. The as-prepared fluorescent molecule contains a hydroxyl group and an aminoquinoline moiety. The hydroxyl group enables the fluorescent molecule to anchor to a porous polyurethane (PU) sponge. The chemosensors still retained their recognition ability after they were introduced to PU. Upon the addition of Cu²⁺ ions to the PU sponge, both the color and the fluorescence intensity changed, suggesting that the chemosensor-functionalized PU sponges could be used as a Cu²⁺ ion sensor. The copper ions could also accumulate and be enriched on the sponges. The adsorption capacity of the PU sponge (containing 2 wt% of the chemosensor) reached 97.26 mg g^-1, which was higher than that of the solid PU membranes (52.62 mg g^-1). These polymeric, highly sensitive chemosensors may potentially be applied in the detection of water pollution generated by sources such as electroplating and drain outflow.

Full text of DOI:10.1039/c4ra01981d

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A high-performance polyurethane sponge for the
detection, adsorption and separation of Cu2+ ions
Cite this: RSC Adv., 2014, 4, 18222
a
a
b
a
*
Yun Yu, Jianrui Wang, Jiansheng Lian and Xinjian Cheng
The simultaneous detection and separation of copper ions is important. In this study, a fluorescent
chemosensor (a copper sensitive molecule), was prepared using 6-bromo-benzo[de]isochromene-1,3-
dione as a precursor. The as-prepared fluorescent molecule contains a hydroxyl group and an
aminoquinoline moiety. The hydroxyl group enables the fluorescent molecule to anchor to a porous
polyurethane (PU) sponge. The chemosensors still retained their recognition ability after they were
introduced to PU. Upon the addition of Cu2+ ions to the PU sponge, both the color and the
fluorescence intensity changed, suggesting that the chemosensor-functionalized PU sponges could be
used as a Cu2+ ion sensor. The copper ions could also accumulate and be enriched on the sponges. The
Received 7th March 2014
Accepted 26th March 2014
adsorption capacity of the PU sponge (containing 2 wt% of the chemosensor) reached 97.26 mg gꢀ1
,
which was higher than that of the solid PU membranes (52.62 mg gꢀ1). These polymeric, highly sensitive
chemosensors may potentially be applied in the detection of water pollution generated by sources such
as electroplating and drain outflow.
DOI: 10.1039/c4ra01981d
www.rsc.org/advances
moiety. This chemodosimeter displayed highly selective
1. Introduction
behavior for Cu2+. Jung et al.14 developed a novel coumarin-
based uorescent chemosensor that showed a high selectivity
for Cu2+ and a suitable affinity for Cu2+ in biologic functions.
They also employed the chemosensor for the uorescent
detection of intracellular Cu2+ in cells. However, many of these
chemosensors only have a high sensitivity and selectivity for
The pollution caused by heavy metal ions, especially in aqueous
systems, is one of the most dangerous and serious environ-
mental problems owing to the bioaccumulation of these toxic
metal ions.1,2 Copper plays a vital role in various biological
processes3 and is a micronutrient essential to human health.4
However, copper causes oxidative stress and might be harmful
to liver and kidney function5 at high concentrations. Hence, the
upper limit of copper in drinking water is established at 1.3
ppm by the U.S. Environmental Protection Agency, and the
concentration of copper in blood is limited to 100–150 mg dLꢀ1
(15.7–23.6 mM).6 Therefore, a rapid and convenient method for
detecting copper is of importance due to water quality7,8 and
biological concerns.9,10
In many works, traditional methods of detecting copper
involved synthesizing small molecular chemosensors. For
example, Yang et al.11 reported three new rhodamine Schiff base
sensors. They provided Cu2+ selectivity and sensitivity through
the rhodamine ring-open approach and demonstrated the
uorescent imaging of Cu2+ in living cells. Lee et al.12 reported
novel rhodamine hydrazone derivatives containing an addi-
tional phenol group that showed a high selectivity for Cu2+ and
reversible colorimetric change with Cu2+. Yu et al.13 reported a
uorescent chemodosimeter based on the 1,8-naphthyridyl
detecting Cu2+ 15–17 they cannot separate Cu2+ from the solution
;
because the chemosensors are soluble or dispersible in water.
Even aer combining with Cu2+, they still remain in the water.
To overcome this drawback, a novel method was created that
immobilized the chemosensor on macromolecules. This strategy
not only retained the chemosensor sensitivity, but also improved
its operability and convenience for the separation of heavy metals.
In this work, a new chemosensor was synthesized and
introduced to porous PU sponge. The chemosensor-function-
alized PU sponge (FPU) could selectively detect and separate
Cu2+ ions. The small molecule was rst synthesized by the
reaction of 6-bromo-benzo[de]isochromene-1,3-dione with
ethanolamine and 8-aminoquinoline, introducing the quino-
line and hydroxyl groups. The FPU sponge was then formed via
reaction of the hydroxyl groups on the chemosensor and the
isocyanate groups of 2,4-tolylene diisocyanate (TDI). The PU was
foamed by adding a suitable amount of water and then heated
and aged to obtain the porous FPU sponge. This FPU sponge
showed excellent detecting and separating ability for Cu2+
concentrations as low as 10ꢀ7 mol Lꢀ1. It is better than func-
tional solid membranes due to the higher specic surface area.
The functional sponge has potential applications in the detec-
tion and separation of Cu2+ pollutants.
aSchool of Chemistry and Materials Science, South-Central University for
Nationalities, Wuhan, 430074, China. E-mail: chxj606@163.com
bLMB, South China Sea Institute of Oceanology, Chinese Academy of Sciences,
Guangzhou, 510301, China
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The chemosensor, HQD, was added at different weight
percentages (0.5, 1, 1.5, and 2 wt%), and the obtained samples
were extracted with ethanol to wash and remove the residual
small molecules and catalysts.
2. Experimental section
2.1 Materials
A precursor for the uorescent co-monomer, 6-bromo-benzo[de]-
isochromene-1,3-dione, was purchased from J&K China Chem-
ical Ltd. and recrystallized twice with chlorobenzene. Ethanol-
amine, 8-aminoquinoline and tri(dibenzylideneacetone)
dipalladium(0) (Pd2(dba)3) were bought from J&K China
2.5 Synthesis of solid FPU membranes
The process of preparing solid PU membranes was as follows:
different amounts of HQD (0.5, 1, 1.5, and 2 wt%) and THF (30
mL) were added to 1.5 : 1 ratios of TDI to PEG. Aer stirring for
2 h at 60 ꢁC, the solution was poured onto a glass slide and dried
at room temperature, yielding the solid PU membranes.
Chemical
Ltd.
(+/ꢀ)-2,20-Bis(diphenylphosphino)-1,10-
binaphthyl (BINAP) and sodium tertiary butoxide were products
of Aladdin Chemical Co., Ltd.
All metal salts (Cr3+, Co2+, Pd2+, Zn2+, Hg2+, Mn2+, Ni2+, Pb2+,
Cu2+, Fe2+ and Fe3+) were purchased from Aladdin Chemical
Co., Ltd. and used as received.
2.6 Characterization
FTIR and 1H NMR measurements. Fourier transform
infrared spectra (FTIR, 4000–500 cmꢀ1) were collected on a
Nicolet NEXUS 470 spectrometer. The samples were pressed
into KBr pellets for measurements. Nuclear magnetic resonance
(1H NMR) was measured in DMSO on an AVANCE III-400
(Bruker) spectrometer.
Fluorescence measurements and uorescence imaging.
Fluorescence spectra were collected on a Perkin Elmer lambda
35 spectrometer using an excitation wavelength of 446 nm.
Fluorescence images were photographed with a Bx61 uores-
cence microscope.
2,4-Tolylene diisocyanate (TDI) and poly(oxyethylene) (PEG
600) with a molecular weight of 600 were from Aladdin Chem-
ical Co., Ltd, and dibutyltin dilaurate, triethanolamine, abso-
lute ethanol, toluene and tetrahydrofuran (THF) were
purchased from J&K China Chemical Ltd. Ultrapure water (>17
MU cmꢀ1) from a Milli-Q water system was used throughout the
experiments.
2.2 Preparation of 6-bromo-2-(2-hydroxy-ethyl)-benzo[de]-
isoquinoline-1,3-dione (BHD)
BHD was prepared by a modied method according to the
literature21 using the following procedure: 6-bromo-benzo[de]-
isochromene-1,3-dione (0.2 g, 0.7 mmol) was reacted with
ethanolamine (0.06 mL, 0.7 mmol) by reuxing for 4 h in 35 mL
of absolute ethanol. Aer cooling to room temperature, the
suspension solution was ltered and washed with ethanol. The
crude compound was further puried by recrystallization form
ethanol and dried to give the pale yellow product BHD (0.21 g)
with a 90% yield.
UV-Vis experiments. Solid and liquid samples were analyzed
with a Perkin Elmer lambda 35 UV-Vis spectrometer.
Atomic absorption spectrometry (AAS). Metal ion solutions
were prepared in water while HQD solutions were prepared in
DMF. Copper concentrations (below 10 mg Lꢀ1) were deter-
mined by an AA-6300 atomic absorption spectrometer.
X-ray photoelectron spectroscopy (XPS) measurements. XPS
analysis was carried out with a Thermo VG Multilab 2000
spectrometer using an Al Ka X-ray source (300 W PE 25 eV).
2.3 Synthesis of 2-(2-hydroxy-ethyl)-6-(quinolin-8-ylamino)-
benzo[de]isoquinoline-1,3-dione (HQD)
3. Results and discussion
3.1 Synthesis and characterization of chemosensor HQD
A dried round-bottom ask was charged with BHD (0.1 g, 0.3
mmol), 8-aminoquinoline (0.086 g, 0.6 mmol), BINAP (7 mg),
Pd2(dba)3 (5 mg), and sodium tertiary butoxide (120 mg). Toluene
(50 mL) was added and the solution was degassed under a nitrogen
atmosphere, stirred for 1 h in an ice bath, and heated to 90 ꢁC for
48 h. The reaction mixture was cooled and ltered through a Celite
pad and washed with dichloromethane. The residue concentrated
in vacuo was puried by ash column chromatography (ethyl
acetate–hexane ¼ 4 : 1) to give HQD (57 mg, 48% yield).
HQD was prepared using the procedure shown in Scheme 1(a).
Based on the property of 4-bromo-naphthalic anhydride, the
amidation reaction of the anhydride was conducted moderately
easily. The desired small molecule was synthesized by a Pd-
catalyzed (BINAP, Pd2(dba)3 and sodium tertiary butoxide) aryl
amination between 6-bromo-2-(2-hydroxy-ethyl)-benzo[de]iso-
quinoline-1,3-dione and 8-aminoquinoline. The chemosensor
HQD was obtained in 48% yield aer purication by ash
column chromatography. Fig. 1 shows the FT-IR spectra of the
small molecule (HQD) and the starting material. The strong C–O–
C peaks at 1778 cmꢀ1 and 1733 cmꢀ1 disappeared and new peaks
at 1698 cmꢀ1 and 1663 cmꢀ1 were determined by comparison
2.4 Synthesis of chemosensor functionalized PU sponge
(FPU sponge)
The porous FPU sponges were prepared by the condensation with the peaks of 6-bromo-benzo[de]isochromene-1,3-dione. The
reaction of TDI isocyanate groups with PEG hydroxyl groups at a C–Br peak at 556 cmꢀ1 disappeared and a new C–N peak of 1366
ratio of 1.5 : 1. Different amounts of HQD were added at room cmꢀ1 emerged. This means that the Pd-catalyzed aryl amination
temperature. The catalysts dibutyltin dilaurate (1 wt%) and reaction between 6-bromo-2-(2-hydroxy-ethyl)-benzo[de]iso-
triethanolamine (1 wt%) were added aer stirring for 10 quinoline-1,3-dione and 8-aminoquinoline was successful.
minutes. Finally, water (0.1 mL) was added as a foaming agent.
The FPU sponge was obtained aer heating at 60 ꢁC and aging. is shown in Fig. 2. It can be seen that the peaks ranging from 8.2
To further verify the structure of HQD, the 1H NMR spectrum
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Scheme 1 (a) The synthetic route of chemosensor HQD and (b) preparation of the FPU sponge.
to 8.7 ppm represent the H in the naphthalene ring, and the membrane and the PU sponge upon adsorption of Cu2+. In order
peaks at about 4.3 ppm and 3.8 ppm represent the two –CH2– to conrm the polymerization of the TDI isocyanate groups with
groups (the red line in Fig. 2). Compared to the spectrum of BHD, the BHD hydroxyl groups, Br was analyzed aer the polymerization
that of HQD (the lower line in Fig. 2) portrays that the new reaction of TDI, PEG and BHD. As shown in Fig. 3a and b, the
quinoline peaks appeared between 6.7 ppm and 7.3 ppm and at small molecules were successfully polymerized onto polyurethane.
5.8 ppm. Moreover, the naphthalene ring H peaks are reduced by When the FPU sponge was analyzed by XPS, the N peaks could not
about 0.3 ppm owing to the introduction of the quinoline ring.
be easily distinguished because both HDQ and PU contain N
atoms. The BHD-containing PU was analyzed to conrm that
sensitive molecules could be introduced to PU using this method.
The FPU sponge containing Cu2+ (indicated by a color change from
yellow to green) was extracted, rinsed and evaporated. Subsequent
analysis by XPS indicated the presence of Cu atoms (Fig. 3c and d),
further conrming the formation of the Cu–PU sponge.
3.2 Synthesis and characterization of polyurethane sponges
TDI and PEG are usually used to prepare polyurethane lms and
foams.18–20 The process for the preparation of the FPU sponge is
shown in Scheme 1(b). The FPU sponge was synthesized with a
simple and quick method that used water as the foaming agent
under catalysis without solvent. Fig. 3 shows the XPS scans of PU
The uorescence imaging (Fig. 4) further conrmed that the
chemosensor was introduced into the PU sponge and displayed
Fig. 1 The FT-IR spectrum of the starting material (black line) and the Fig. 2 The 1H NMR spectrum of BHD (red line) and the chemosensor
chemosensor (HQD) (red line).
HQD (black line).
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Fig. 3 XPS spectra of (a) PU membrane containing small molecule BHD, (b) Br on the PU membrane, (c) adsorption Cu2+ of the FPU sponge, and
(d) Cu2+ on the FPU sponge.
uorescence without Cu2+ ions. The uorescence was enhanced (containing no chemosensor) were treated in this way, they were
upon the addition of copper ions.
observed to have no adsorption affinity for Cu2+ ions. These
results indicated that the color change was only caused by the
interaction between HQD and Cu2+ ions. The color change
could be seen by the naked eye even at Cu2+ ion concentrations
3.3 Detection of Cu2+ by PU sponges
As shown in Fig. 5a, the PU sponges bearing 1.0 wt% HQD were
cut into pieces (1 cm ꢂ 1 cm ꢂ 1 cm) and soaked in solutions
containing different concentrations of Cu2+ (10ꢀ2 mol Lꢀ1, 10ꢀ3
mol Lꢀ1, 10ꢀ4 mol Lꢀ1, 5 ꢂ 10ꢀ5 mol Lꢀ1, 10ꢀ5 mol Lꢀ1, 10ꢀ6
mol Lꢀ1, and 0 mol Lꢀ1). The color of the PU sponges changed
obviously from yellow to green (Fig. 5b and c). In order to avoid
overlap in color between the yellow sponge and the blue Cu2+
ions, some control experiments were also performed. Under the
same conditions, PU sponges were placed into blue ink and a
solution of Cd2+. It can be seen that the color (yellow) of the PU
sponges did not undergo any changes. When pure PU sponges
as low as 5 ꢂ 10ꢀ5 mol Lꢀ1
.
The optical properties of the PU sponge determined by UV-Vis
spectroscopy are displayed in Fig. 6. The introduction of the che-
mosensor obviously enhanced the absorbance of the FPU sponge
between 500 nm and 800 nm, and the new absorbance at about
680 nm appeared and increased with the concentration of Cu2+.
Fluorescence intensity of the PU sponge both with and
without Cu2+ ions was measured. Fig. 7a shows the uorescence
of HQD; it increased signicantly with increasing Cu2+
concentrations at about 516 nm (excited at 446 nm). The Stokes
Fig. 4 Fluorescence imaging of (a) the FPU sponge, (b) the FPU sponge with Cu2+ ions, and (c) the solid FPU membranes with Cu2+ ions.
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Fe2+, Fe3+, Hg2+, Zn2+, Mn2+, Cd2+, and Pb2+; Fig. 8a). The control
experiments (Fig. 8b) were performed in the presence of 10ꢀ4
mol Lꢀ1 Cu2+ mixed with 10ꢀ4 mol Lꢀ1 of other heavy metal
ions, such as Ni2+/Cu2+, Co2+/Cu2+, Fe2+/Cu2+, Fe3+/Cu2+, Cr2+/
Cu2+, Hg2+/Cu2+, Zn2+/Cu2+, Mn2+/Cu2+, Cd2+/Cu2+, and Pb2+
/
Cu2+. As shown in Fig. 8, Cu2+ was the only detected species and
no other metal ions interfered with the uorescence intensity.
By measuring IF/I0 at 516 nm (I0 represents the emission
intensity of the PU sponge without Cu2+ and IF corresponds to
the uorescence intensity), it could be seen (Fig. 8b) that IF/I0
had not been inuenced by other common wastewater ions in
the binary mixture of copper and other metal ions. The values of
IF/I0 remained almost the same. The results further indicated
that the FPU sponge had a high selectivity for Cu2+
.
3.4 The effect of pH on Cu2+ adsorption by the FPU sponge
The effect of pH on the FPU sponge was evaluated by testing
various pH values (2–12) on the adsorption of Cu2+ ions (3 mL, 7
mg Lꢀ1) by the FPU sponge. As shown in Fig. 9, the adsorption
capacity of the FPU sponge remained almost constant at pH
values from 4–10. At pH values below 4.0 and above 10, the
adsorption capacity decreased. Below pH 4, the protonation of
N atoms occurred, reducing the sponge's ability to complex
copper ions. In strong alkaline conditions (pH $ 12), the
adsorption capacity of the FPU sponge also decreased. This
might be attributed to the following two reasons: (1) at high pH,
Cu(OH)2 formed, decreasing the number of copper ions coor-
dinated to the chemosensors and (2) the porous PU sponges
collapsed at high pH, resulting in a reduction of specic surface
area and a decrease in adsorption ability. These results suggest
that this PU sponge could have a high copper ion adsorption
ability in the pH range of 4–10.
Fig. 5 (a) Photographs of the color changes in FPU sponges with
different concentrations of Cu2+ (10ꢀ2 mol Lꢀ1, 10ꢀ3 mol Lꢀ1, 10ꢀ4 mol
L
ꢀ1, 5 ꢂ 10ꢀ5 mol Lꢀ1, 10ꢀ5 mol Lꢀ1, 10ꢀ6 mol Lꢀ1 and 0 mol Lꢀ1, from
left to right), (b) photographs of the color change in the dry FPU
sponge without Cu2+ and (c) the dry FPU sponge with Cu2+
.
shi is at about 70 nm. Fig. 7b shows that the uorescence of PU
sponges bearing HQD has the same trend as in HQD. This
means that the performance of the chemosensor still remains
when co-polymerised into the PU sponges. Furthermore, the
concentration of Cu2+ ions could be detected by the uores-
cence intensity in concentrations as low as 10ꢀ7 mol Lꢀ1
.
In addition to Cu2+, the possibility of other heavy metal ions
interfering with the uorescence intensity of FPU sponges was
investigated (Fig. 8). The uorescence intensities of FPU
sponges were clearly enhanced by Cu2+ ions while there was no
obvious response to other heavy metal ions (Ni2+, Co2+, Cr2+,
3.5 Dynamic adsorption capacity of the FPU sponge
Dynamic adsorption capacity with Cu2+ ions was measured. The
as-prepared PU sponge was xed in the middle of two PMMA
columns (Fig. 10). A series of same-volume solutions (100 mL)
containing different concentrations of Cu2+ (10ꢀ6 mol Lꢀ1, 10ꢀ5
mol Lꢀ1, and 10ꢀ4 mol Lꢀ1) were poured into the PMMA column
and passed through the PU sponge. The elapsed time and
solution volume were recorded. The equilibrium concentrations
in the solutions passing through the PU sponge were quantied
by AAS. The adsorption capacity of Cu2+ on the PU sponge was
calculated by the following equation,
ðC0 ꢀ CeÞꢂV
q ¼
(1)
W
where q represents the absorptivity capacity (%), C0 and Ce
represent the concentration of Cu2+ ions before the adsorption
experiment and the equilibrium concentration of Cu2+ in
mg Lꢀ1, respectively. V is the volume of the Cu2+ solution and W
is the weight of the PU sponge.
Equilibrium concentrations of the solutions passing through
the FPU sponge are listed in Table 1. Under the same contin-
uous ow and time conditions, the adsorption capacity was
signicantly enhanced with increasing Cu2+ concentration.
Fig. 6 UV-Vis spectra of the dry FPU sponge and non-FPU sponge
(the non-functionalized PU sponge, blue line).
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Fig. 7 Fluorescence spectra of the chemosensor (a) and the dry FPU sponge (b).
Fig. 8 The florescence response of the FPU sponge containing 1 wt% HQD to metal ions for (a) the single metal ions (10ꢀ4 mol Lꢀ1) and (b) the
mixture of Cu2+(10ꢀ4 mol Lꢀ1) and other metal ions (Ni2+, Co2+, Cr2+, Fe2+, Fe3+, Hg2+, Zn2+, Mn2+, Cd2+, and Pb2+; 10ꢀ4 mol Lꢀ1).
In addition, static adsorption capacity was measured using
an FPU sponge and a solid FPU membrane. They were put into
Cu2+ solutions with the same volume and concentration and
Fig. 9 The adsorption capacity of the FPU sponge for Cu2+ ions (3 mL,
Fig. 10 Schematic diagram of the dynamic adsorption procedure of
Cu2+ ions from solution using the fabricated FPU sponge as a filter.
7 mg Lꢀ1) at varying pH (2–12).
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Table 1 Dynamic adsorption capacity per unit content and unit time of the FPU sponge
Concentration of Cu2+ ions, C0 (mg Lꢀ1
)
0.1596
0.025
100
1.596
0.6280
100
7.88
6.215
100
15.96
14.275
100
Concentration of Cu2+ ions, Ce (mg Lꢀ1
Volume of Cu2+ ions V (mL)
)
Adsorption capacity per unit time (mg gꢀ1
)
8.87
53.77
92.48
93.57
Table 2 Static adsorption capacity per unit content and unit time of the FPU sponge and the solid FPU membrane
HQD content (1 wt%)
0.5
5
4.1693
100
46.15
1.0
5
3.7572
100
69.04
1.5
5
3.3967
100
89.07
2.0
5
3.2494
100
97.26
Solid membrane 2.0
5
4.0528
100
52.62
Concentration of Cu2+ C0 (mg Lꢀ1
)
Concentration of Cu2+ Ce (mg Lꢀ1
)
Volume of the Cu2+ solution V (mL)
Adsorption capacity per unit time (mg gꢀ1
)
then removed at the same time. The Cu2+ concentrations before
and aer removal were measured and listed in Table 2. It could
be seen that the content of HQD dramatically affected the
adsorption capacity of the FPU sponge. Higher HQD content
was associated with higher adsorption capacity per unit time.
However, the solid FPU membrane was inferior for Cu2+
adsorption compared to the FPU sponge. It may be attributed to
the high specic surface area of the FPU sponge which provided
more opportunities and spaces to complex and remove Cu2+
ions. These results suggest that the FPU sponge could be used
for ltration or purication of Cu2+-containing solutions.
3 L. S. Sarma, J. R. Kumar, K. J. Reddy and A. V. Reddy, J. Agric.
Food Chem., 2005, 53, 5492–5498.
4 M. A. Tarighat, M. R. Mohammadizadeh and G. Abdi, J. Agric.
Food Chem., 2013, 61, 6832.
5 X. M. Wu, Z. Q. Guo, Y. Z. Wu, S. Q. Zhu, T. D. James and
W. H. Zhu, ACS Appl. Mater. Interfaces, 2013, 5, 12215.
6 H. D. Song, I. Choi, S. Lee, Y. I. Yang, T. Kang and J. Yi, Anal.
Chem., 2013, 85, 7980.
7 Z. L. Gong and Y. W. Zhong, Organometallics, 2013, 32, 7495.
`
8 H. Bessbousse, J. F. Verchere and L. Lebrun, Chem. Eng. J.,
2012, 187, 16.
9 S. L. Hu, Q. Zhao, Y. Dong, J. L. Yang, J. Liu and Q. Chang,
Langmuir, 2013, 29, 12615–12621.
4. Conclusion
10 M. H. Lee, J. H. Han, J. H. Lee, N. Park, R. Kumar, C. Kang
and J. S. Kim, Angew. Chem., Int. Ed., 2013, 52, 6206.
11 Z. Yang, M. She, J. Zhang, X. X. Chen, Y. Y. Huang, H. Y. Zhu,
P. Liu, J. L. Li and Z. Shi, Sens. Actuators, B, 2013, 176, 482.
12 H. Y. Lee, K. M. K. Swamy, J. Y. Jung, G. Kim and J. Yoon,
Sens. Actuators, B, 2013, 182, 530.
13 M. M. Yu, Z. X. Li, L. H. Wei, D. H. Wei and M. S. Tang, Org.
Lett., 2008, 10, 5115.
14 H. S. Jung, P. S. Kwon, J. W. Lee, J. I. Kim, C. S. Hong,
J. W. Kim, S. H. Yan, J. Y. Lee, J. H. Lee, T. Joo and
J. S. Kim, J. Am. Chem. Soc., 2009, 131, 2008.
In conclusion, a uorescent monomer, 2-(2-hydroxy-ethyl)-6-
(quinolin-8-ylamino)-benzo[de]isoquinoline-1,3-dione (HQD)
was synthesized and introduced to a solid FPU membrane and a
porous FPU sponge to form a macromolecular chemosensor for
Cu2+ ions. Aer the chemosensor was co-polymerised onto the
surfaces of the PU sponge, it still retained uorescence perfor-
mance. Compared to the PU solid membrane, the FPU sponge
had the advantages of greater specic surface area and
adsorption capacity. Furthermore, the as-prepared FPU sponge
can not only detect but also remove and recycle Cu2+ ions
without any complicated post-processing.
15 J. L. Yao, K. Zhang, H. J. Zhu, F. Ma, M. T. Sun, H. Yu, J. Sun
and S. H. Wang, Anal. Chem., 2013, 85, 6461.
16 C. Kar, M. D. Adhikari, A. Ramesh and G. Das, Inorg. Chem.,
2013, 52, 743.
Acknowledgements
17 J. H. Jang, S. Bhuniya, J. Kang, A. Yeom, K. S. Hong and
J. S. Kim, Org. Lett., 2013, 15, 4702.
18 H. W. Engels, H. G. Pirkl, R. Albers, R. W. Albach, J. Krause,
A. Hoffmann, H. Casselmann and J. Dormish, Angew. Chem.,
Int. Ed., 2013, 52, 9422.
The authors would like to thank the nancial support of
National Natural Scientic Foundation of China (NSFC
41240026) and Guangdong Natural Science Foundation
(S201210009845).
19 H. Y. Yang, X. M. Zhang, L. J. Duan, M. Y. Zhang, G. H. Gao
and H. X. Zhang, J. Appl. Polym. Sci., 2013, 846.
References
´
´
20 J. L. Vilas, J. M. Laza, C. Rodrıguez, M. Rodrıguez and
1 K. Zargoosh, H. Abedini, A. Abdolmaleki and M. R. Molavian,
Ind. Eng. Chem. Res., 2013, 52, 14944.
´
L. M. Leon, Polym. Eng. Sci., 2013, 744.
21 T. Chen, W. P. Zhu, Y. F. Xu, S. Y. Zhang, X. J. Zhang and
2 Y. A. Hu and H. F. Cheng, Environ. Sci. Technol., 2013, 47,
3752.
X. H. Qian, Dalton Trans., 2010, 39, 1316.
18228 | RSC Adv., 2014, 4, 18222–18228
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