Zeolitic Imidazolate Framework-67 Functionalized Chitosan Aerogel
for Efficient Removal of Dye
Xiang Li
, Hong Shao
, Qianli Ma
, Wensheng Yu
and Xiangting Dong
School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun, China
School of Petrochemical Technology, Jilin Institute of Chemical Technology, Jilin, China
School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun,
Keywords: ZIF-67, Chitosan, Aerogel, Adsorption, Congo Red.
Abstract: As an efficient adsorbent, metal-organic framework (MOF) has been used in dye wastewater treatment.
However, the morphology of MOF powder has some disadvantages, such as poor recoverability and complex
operation process. The zeolitic imidazolate framework-67@chitosan aerogel (ZIF-67@CSA) was prepared
by alkali freezing-thawing method, freeze drying and in situ growth method to remove dye congo red. The
load mass ratio of ZIF-67on CSA is as high as 41.2 wt% ZIF-67@CSA was used to adsorb dye congo red,
and the removal rate is more than 89.3%. This strategy provides an effective and universal way to prepare
high loaded MOF natural polysaccharide aerogel, thus expanding its application in the field of pollutant
Industries such as textiles, leather and paper produce
a large amount of dye wastewater serious impact on
the natural environment.
However, in order to prevent water pollution and
protect human health and safety, it is necessary to
properly treat dye wastewater before discharge
(Yang, Han, Li, Zhu, Shi, Tang, Wang, Yue, Li, 2019,
Shao, Yin, Li, Ma, Yu, Dong, 2021).
Metal-organic frameworks are regular crystalline
structures supported by metal nodes and organic
ligands. It has excellent properties such as large
specific surface area, low density, good
biocompatibility, chemical modifiability, and
topological diversity (Liu, Yu, Zeng, Li, Sun, Hu, Su,
2020). Due to its exists in powder form, it cannot be
used directly in practical application, resulting in
different operations, resource waste and secondary
pollution (Ma, Lou, Chen, Shi, Xu, 2019). In order to
solve these problems, some researchers often
combine polymer materials with MOF crystal.
Chitosan is one of the common natural polymer
materials, which has good biocompatibility,
renewability, biodegradability and economy (Wang,
Zheng, Luo, Liu, Zhang, Li, Sun, Shen, Han, Wang,
2018). Chitosan aerogels have large specific surface
area, high porosity, and macroporous 3D network
structure, and they have excellent adsorption
properties for printing and dyeing wastewater
treatment (Zhao, Ma, Zhao, Rong, Tian, Zhu, 2020).
However, the affinity of chitosan based adsorbent is
insufficient, which limits its practical application
(Qiu, He, 2019), therefore, functional modification of
chitosan aerogel is needed to improve its adsorption
Herein, we reported a ZIF-67@CSA material is
prepared by alkali lyophilization, freeze drying and in
situ growth method to remove dye congo red. In
addition, ZIF-67@CSA was characterized by X-ray
diffractometry. The adsorption properties and
selectivity of aerogels were investigated with dye
Congo red as the model.
2.1 Materials and Characterization
Chitosan (CS), Epichlorohydrin (ECH, 99.5%),
Congo red (CR), 2-methylimidazole (2-MI, 98%),
cobalt nitrate (Co(NO
O, 99%) were acquired
Li, X., Shao, H., Ma, Q., Yu, W. and Dong, X.
Zeolitic Imidazolate Framework-67 Functionalized Chitosan Aerogel for Efficient Removal of Dye.
DOI: 10.5220/0011507900003443
In Proceedings of the 4th International Conference on Biomedical Engineering and Bioinformatics (ICBEB 2022), pages 1264-1267
ISBN: 978-989-758-595-1
2022 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved
from Aladdin. X-ray diffraction (XRD) spectra of
samples were obtained on an X-ray diffractometer
(D/Max 2500, Rigaku, Japan). The CR
concentrations were measured at 497 nm by using an
ultraviolet-visible spectrophotometer (UV-vis, UV-
2501, Shimadzu, Japan).
2.2 Preparation of the ZIF-67@CSA
2.2.1 Preparation of the CSA
Chitosan aerogel (CSA) was fabricated according to
the following procedure (Song, Zhu, Zhu, Zhao,
Yang, Miao, Ren, Ma, Qian, 2020). A 3 wt% chitosan
solution was prepared in a pre-cooled
LiOH/KOH/urea (4.5 wt %/7 wt %/8 wt%) solution.
Then, 5 wt% ECH was added to the CS solution and
stirred at sub-zero to obtain a pre-crosslinked
solution. The pre-crosslinked solution was poured
into the mold and left to stand overnight at low
temperature. Finally, CSA was obtained by repeated
washing with deionized water and vacuum freeze-
2.2.2 Preparation of ZIF-67@CSA
ZIF-67@CSA was fabricated according to the
following procedure.
The CSA was immersed in 40 mL methanol
containing 1.098g Co(NO
O. Then, 0.656 g of
2-methylimidazole in 40 mL of methanol was added
to the above solution, ZIF-67 was grown in situ on
CSA at room temperature and left to stand overnight.
and the in-situ growth of ZIF-67 on CSA was
performed at room temperature for 24h. The ZIF-
67@CSA was washed with methanol, deionized
water and vacuum freeze-dried. ZIF-67@CSA was
obtained after repeated alternate washing with
methanol and deionized water, and vacuum freeze-
2.3 Batch Adsorption Experiments
The adsorption experiments were conducted as
follows: For all the experiments, the reacting
admixtures were mechanically stirred at 150 rpm.
10 mg adsorbent was added into 20 mL CR
solutions (50 mg·L
, pH=7.0 ).
The removal rate (%) onto the adsorbent was
listed as the following (Eq. (1)):
%100*rate Removal
Where A
is the absorbance of initial solution; A
is the absorbance of residual liquid.
3.1 Design of ZIF-67@CSA
From Fig. 1, the synthetic process of ZIF-67@CSA
was prepared by freeze-thaw method and in-situ
growth. Firstly, chitosan was dissolved under the
alkaline condition, and chitosan was dissolved by
freeze thaw method. Chitosan hydrogel was prepared
with ECH as crosslinking agent, and then freeze-
dried into CSA, ECH and chitosan molecules are
crosslinked in three different ways, as shown in Fig.
1. Then, CSA were immersed in the solution
containing metal ions Co
and 2-methylimidazole in
sequence, and ZIF-67 rhombic dodecahedrons was
generated in situ on the surface of CSA. This is
because the vacant orbitals of polyamino functional
groups on CSA can form coordination bonds with
, and then a large number of metal active sites are
generated on CSA. Further, dense layer ZIF-67 were
generated in CSA. Therefore, the ZIF-67@CSA has
a strong affinity for CR molecules and obtains
excellent adsorption performance.
Figure 1: Schematic fabrication process of ZIF-67@CSA.
Zeolitic Imidazolate Framework-67 Functionalized Chitosan Aerogel for Efficient Removal of Dye
3.2 Characterization
The structures of CSA, ZIF-67 and ZIF-67@CSA
were confirmed by XRD in Fig. 2. CSA have no
obvious diffraction, meaning that CSA are
amorphous peaks. The ZIF-67@CSA has the same
peaks as the synthesized ZIF-67, which indicates that
ZIF-67 are successfully grown on the surface of CSA.
Figure 2: The XRD of CSA, ZIF-67 and ZIF-67@CSA.
3.3 Adsorption Efficiency
As shown in Fig. 3, the adsorption capacity of ZIF-
67@CSA to CR is higher than that of CSA. This is
because ZIF-67 has a larger load on chitosan aerogel.
But the adsorption capacity of ZIF-67@CSA is lower
than that adsorption capacity of ZIF-67 to CR. This is
because the adsorption capacity of CSA is much
lower than that of ZIF-67. The adsorption capacity of
the composite aerogel in unit mass is lower than that
of ZIF-67. However, the preparation of ZIF-
67@CSA by powdered ZIF-67 can make the
adsorbent have good recyclable properties, simple
operation process and prevent secondary pollution.
Figure 3: Removal rate of CR by CSA, ZIF-67 and ZIF-67@CSA.
In conclusion, ZIF-67@CSA was obtained by a green
process of alkali dissolution, in situ growth and
freeze-vacuum drying. The structure of ZIF-
67@CSA was characterized by XRD. The results
showed that ZIF-67 was successfully grown on CSA.
The adsorption capacity of ZIF-67@CSA in CR was
much higher than that of CSA. The preparation of
aerogel from powdery ZIF-67 can make the adsorbent
have good recyclable properties, simple operation
process, and prevent Secondary pollution.
ICBEB 2022 - The International Conference on Biomedical Engineering and Bioinformatics
This work was supported by the National Natural
Science Foundation of China (52173155), the Natural
Science Foundation of Jilin Province
(YDZJ202101ZYTS130, YDZJ202101ZYTS059),
the Natural Science Foundation of Chongqing,
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