Electronic Supplementary Material
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Magnetization of a Cu(II)-1,3,5-benzenetricarboxylate metal-organic framework for efficient
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solid-phase extraction of Congo Red
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Yan Xu,a, * Jingjie Jin,a Xianliang Li,b Yide Han,a Hao Meng,a Chaosheng Song,a Xia Zhanga, *
a
Department of Chemistry, College of Science, Northeastern University, Shenyang, Liaoning 110819, China
b
College of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang,
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Liaoning 110142, China
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*Corresponding Authors: xuyanjlu@126.com (Yan Xu);xzhang@mail.neu.edu.cn (Xia Zhang); Fax:
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+86-024-83684533; Tel.: +86-024-83684533.
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Fig. S1 FT-IR spectra of Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2-Cu-BTC (Note: The peak at 570 cm-1 is a
-1
14 characteristic peak of Fe3O4. The peaks at 1094 cm
and 3406 cm-1 can be assigned to the Si–O and –OH groups.
-1
15 Various peaks observed in the region of 600–800 cm
are attributed to the out-of-plane vibrations of BTC. The
-1
-1
16 peaks at 1370 cm
and 1440 cm as well as the peaks at 1580 cm-1 and 1630 cm-1 correspond to the symmetric
17 and asymmetric stretching vibrations of the carboxylate groups in BTC [1–2]).
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Fig. S2 N2 adsorption-desorption isotherms of as-prepared MOF Cu-BTC.
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Fig. S3 DLS curve of Fe3O4@SiO2.
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Table S1 Figures of merit of recently reported methods for determination or preconcentration of Congo Red
Material/method used
Removal Optimum
efficiency
pH
Interferences
Ref.
Ionic liquid (IL)/Liquie-liquid extraction
―
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A: pH
B: Type and amount of
IL
C: Initial concentration
of dye
D: Type and volume of
solvent
E: Concentration of salt
[3]
Bifunctional moleculary imprinted
polymer/Solid-phase extraction
―
―
―
―
[4]
Hierarchical NiO spheres
93 %
―
440
―
[5]
Porous Pr(OH)3 nanostructures
―
―
873.4
―
[6]
Polyaniline-lignocellulose composite
99.85 %
4.29
1672.5
A: pH
B: Temperature
C: Initial concentration
of dye
[7]
Starch-AlOOH-FeS2 nanocomposite
―
5
346
A: pH
B: Temperature
C: Initial concentration
of dye
D: Contact time
[8]
Graphene oxide/chitosan/silica fibers
89.8 %
3
294.12
A: pH
B: Initial concentration
of dye
C: Contact time
D: Adsorbent dose
[9]
Calixarene-functionalized
nanofiber membranes
> 80 %
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30-35
―
[10]
―
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89.95
A: pH
B: Initial concentration
of dye
[11]
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―
A: Adsorbent dose
B: Extraction time
C: CR concentration
D: Ionic strength
E: pH
polyacrylonitrile
Mesoporous TiO2-graphene oxide core-shell
microspheres
Fe3O4@SiO2-Cu-BTC/Magnetic solid-phase
extraction
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Adsorption
capacity
(mg g-1)
> 90 %
This
work
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Fig. S4 Effects of (a) extraction time, (b) initial CR concentration, (c) ionic strength, and (d) pH value on the
adsorption of CR on magnetic Fe3O4@SiO2-Cu-BTC
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Fig. S5 Structure of CR with (a) pH < 5.5, and (b) pH > 5.5
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Fig. S6. Adsorption isotherm by using (a) Freudlich, (b) Langmuir, and (c)Temkin models.
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Table S2. Isotherm parameters of CR adsorption on magnetic Fe3O4@SiO2-Cu-BTC materials
Initial CR qe (exp)
(mg L-1) (mg g-1)
60
19.10
90
28.71
150
47.16
KF
9.47
Freundlich
1/n
0.761
R2
KL
0.953
0.0477
Langmuir
qL(mg g-1)
171.82
R2
bT
0.963
0.1022
Temkin
KT
0.8258
R2
0.998
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Note: 28 mg of Fe3O4@SiO2-Cu-BTC (14 mg MOF Cu-BTC and 14 mg Fe3O4@SiO2) is used as adsorbent on MSPE of
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7 CR in aqueous solution with various concentrations (60 mg L , 90 mg L
and 150 mg L-1) in the exeperiment.
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Fig. S7 Adsorption kinetics of CR on Fe3O4@SiO2-Cu-BTC by using (a) pseudo-first order and (b)
pseudo-second order (adsorbent dose: 15 mg MOF Cu-BTC and 15 mg Fe3O4@SiO2; initial dye concentration:
-1
-1
-1
-1
4 30mg L , 60 mg L , 90 mg L , 150 mg L
and 200 mg L-1; initial pH: 7)
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Fig. S8 Intra-particle diffusion plots for the adsorption of CR on magnetic Fe3O4@SiO2-Cu-BTC material
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8 (adsorbent dose: 15 mg MOF Cu-BTC and 15 mg Fe3O4@SiO2; initial CR concentration: 30 mg L , 60 mg L ,
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9 90 mg L , 150 mg L
and 200 mg L-1; initial pH: 7; time: 1–20 min)
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Table S3. Kinetic parameters of CR adsorption for pseudo-first order, pseudo-second order and intra-particle
diffusionmodels
Initial CR
(mg L-1)
qe, exp
(mg g-1)
30
60
90
150
200
9.42
19.52
28.29
49.13
64.39
Pseudo-first order
qe1, cal
k1
R2
(mg g-1) (min-1)
6.22
0.2160 0.685
9.10
0.1970 0.659
10.29 0.1488 0.556
41.25 0.2376 0.968
57.25 0.2491 0.935
Pseudo-second order
Δq qe2, cal
k2
R2
(%) (mg g-1) (g·mg-1 min-1)
33.97 10.44
0.0422
0.993
53.38 20.74
0.0319
0.989
63.63 29.30
0.0252
0.985
16.04 54.59
0.0081
0.994
11.09 71.94
0.0059
0.992
Intra-particle diffusion model
Δq
C
k3
R2
(%) (mg g-1) (g mg-1 min1/2)
-10.83 1.42
2.3300
0.994
-6.25
6.02
3.4476
0.962
-3.57
8.87
6.0507
0.977
-11.11 8.92
11.7686
0.953
-11.73 16.79
12.7524
0.970
Note: To investigate the applicability of different kinetic models in fitting to data, a normalized standrard deviation, Δq (%),
is calculated as below:
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q (%) 
(qe , exp - qe, cal )
qe, exp
 100 %
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Fig. S9 Plot of lnKC versus 1/T for CR adsorption on Fe3O4@SiO2-Cu-BTC
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Table S4. Thermodynamic parameters for the adsorption of CR by Fe3O4@SiO2-Cu-BTC at different
temperature
Temperature CR
(K)
removal
(%)
317
85.0
325
87.5
331
88.2
ΔGΘ
ΔHΘ
ΔSΘ
-1
-1
(kJ mol ) (kJ mol ) (J mol K-1)
-4.61
-5.17
-5.59
17.70
70.37
Note: Concentration and volume of CR (90 mg L-1, 5 mL), adsorbent dose (5 mg MOF Cu-BTC and 5 mg Fe3O4@SiO2),
10 and the extraction time (10 min) are kept constant in the experiment.
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Fig. S10 Cycle measurement of Fe3O4@SiO2-Cu-BTC (15 mg Fe3O4@SiO2 and 15 mg MOF Cu-BTC) for the
4 adsorption and desorption of CR with pH of 7
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Table S5 Experimental data for cycle measurement of Fe3O4@SiO2-Cu-BTC (15 mg MOF Cu-BTC and 15 mg
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Fe3O4@SiO2) for the adsorption and desorption of CR (pH = 7).
Cycle time (i)
1
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3
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5
Removal
Cycle time
Removal
Cycle time
Removal
efficiency (%)
(i)
efficiency (%)
(i)
efficiency (%)
98.6
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97.6
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97.3
98.2
7
97.6
12
97.1
98.2
8
97.6
13
97.3
98.0
9
97.3
14
97.3
97.8
10
97.1
15
97.1
Fig. S11 XRD patterns of (a) Fe3O4@SiO2, (b) Fe3O4@SiO2-Cu-BTC, and (c) Fe3O4@SiO2-Cu-BTC after
fifteen time of MSPE of Congo Red.
Fig. S12 Structures of dye molecules used in the dye adsorption experiments.
Fig. 13 Removal efficiencies for cationic dyes: Methylene Blue (MB, 17 mg L-1), Basic Red 2 (BR2, 16 mg L-1),
and Crystal Violet (CV, 19 mg L-1); neutral dye: Methyl Red (MR, 12 mg L-1); anionic dyes: Methyl Orange
(MO, 15 mg L-1), Orange G (21 mg L-1), and Orange II (16 mg L-1)
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