Zeolitic Imidazolate Framework-67 Functionalized Chitosan Aerogel

for Efficient Removal of Dye

Xiang Li

1,2

, Hong Shao

, Qianli Ma

, Wensheng Yu

and Xiangting Dong

1,3*

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,

China

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

treatment.

1 INTRODUCTION

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

properties.

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 EXPERIMENTAL

2.1 Materials and Characterization

Chitosan (CS), Epichlorohydrin (ECH, 99.5%),

Congo red (CR), 2-methylimidazole (2-MI, 98%),

cobalt nitrate (Co(NO

)

.6H

O, 99%) were acquired

1264

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

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-

drying.

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

)

·6H

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-

dried.

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

-1

, pH=7.0 ).

The removal rate (%) onto the adsorbent was

listed as the following (Eq. (1)):

%100*rate Removal

AA −

(1)

Where A

is the absorbance of initial solution; A

is the absorbance of residual liquid.

3 RESULTS AND DISCUSSION

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

1265

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.

4 CONCLUSIONS

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

1266

ACKNOWLEDGMENT

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,

(cstc2021jcyj-msxmX1076,cstc2021jcyj-

msxmX0798).

REFERENCES

C. Wang, T. Zheng, R. Luo, C. Liu, M. Zhang, J. Li, X. Sun,

J. Shen, W. Han, L. Wang, In situ growth of ZIF-8 on

PAN fibrous filters for highly efficient U(VI) removal,

ACS Appl. Mater. Interfaces. 10 (2018) 24164-24171.

H. Shao, D.D. Yin, D. Li, Q.L. Ma, W.S. Yu, X.T. Dong,

Simultaneous Visual Detection and Removal of Cu

with Electrospun Self-Supporting Flexible Amidated

Polyacrylonitrile/Branched Polyethyleneimine

Nanofiber Membranes. ACS Appl. Mater. Interfaces.

13 (2021) 49288-49300.

M. Qiu, C. He, Efficient removal of heavy metal ions by

forward osmosis membrane with a polydopamine

modified zeolitic imidazolate framework incorporated

selective layer, J. Hazard. Mater. 367 (2019) 339-347.

Q. Liu, H.H. Yu, F.M. Zeng, X. Li, J. Sun,X.L. Hu, Su, Z.M.

Polyaniline as interface layers promoting the in-situ

growth of zeolite imidazole skeleton on regenerated

cellulose aerogel for efficient removal of tetracycline.

Journal of Colloid and Interface Science, 579 (2020)

119-127.

R. Zhao, T.T. Ma, S. Zhao, H.Z. Rong, Y.Y. Tian, G.S. Zhu,

Uniform and stable immobilization of metal-organic

frameworks intochitosan matrix for enhanced

tetracycline removal from water, Chemical Engineering

Journal 382 (2020) 122893.

W.Q. Song, M. Zhu, Y.F. Zhu, Y.Z. Zhao, M.X. Yang, Z.C.

Miao, H.P. Ren, Q. Ma, L.W. Qian, Zeolitic imidazolate

framework-67 functionalized cellulose hybrid aerogel:

an environmentally friendly candidate for dye removal,

Cellulose 27 (2020) 2161-2172.

W.X. Yang, Y. Han, C.H. Li, L. Zhu, L.M. Shi, W.Z. Tang,

J.L. Wang, T.L. Yue, Z.H. Li, Shapeable three-

dimensional CMC aerogels decorated with Ni/Co-

MOF forrapid and highly efficient tetracycline

hydrochloride removal, Chemical Engineering Journal

375 (2019) 122076.

X.T. Ma, Y. Lou, X.B. Chen, Z. Shi, Y. Xu, Multifunctional

flexible composite aerogels constructed through in-situ

growth of metal-organic framework nanoparticles on

bacterial cellulose, Chemical Engineering Journal 356

(2019) 227-235.

Zeolitic Imidazolate Framework-67 Functionalized Chitosan Aerogel for Efﬁcient Removal of Dye

1267