A Novel Preparation and Vapour Phase Modification of 2D-open
Channel Bio-adsorbent Via ATRP for Uranium Separation
Mudasir Ahmad a, b, Jianquan Ren a,
Tao Xiu a, Mehraj-ud-din Naik c,
Qiuyu Zhang a, b, Baoliang Zhang a,
d, 11Corresponding author, Northwestern Polytechnical
University, Youyi Road 127#, Xi’an (710072), China. Email:
blzhang@nwpu.edu.cn
a School of Chemistry and Chemical Engineering,
Northwestern Polytechnical University, Xian, China, 710072.
b Xian Key laboratory of Functional Organic porous
materials, Northwestern Polytechnical University, China, 710129.
c Department of Chemical Engineering, College of
Engineering, Jazan University, Jazan 45142, Kingdom of Saudi Arabia.
d Shaanxi Engineering and Research Center for
Functional Polymers on Adsorption and Separation, Sunresins New
Materials Co. Ltd., Xi’an, 710072, China.
Abstract: An economical and highly uranium extraction from
seawater remains a crucial task for energy sources and environmental
safety. Aiming for improving mass transfer rate of uranium adsorption
from seawater, a new synthetic strategy was adopted for the fabrication
of 2D-open channel microporous bio-adsorbent for uranium extraction from
seawater. Herein, the in-situ ATRP grafting approach was adopted to
graft divinylbenzene, polyacrylonitrile onto the surfaces of microporous
frameworks via the vapour phase method. The post-synthetic
functionalization was carried out by hydrothermal method, where
amidoxime groups are structure-directing agents to trap uranium.
Further, amidoxime groups not only enhanced hydrophilicity but also
adjusts adsorbents pKa. AO-Fc faces minimum interference of competing
ions and achieves a high uranium adsorption capacity of 8.57±0.02 and
409±1 mg/g in seawater and simulated solution. Despite its stable
structure, AO-Fc exhibits a long life span and negligible weight loss
revealed AO-Fc could be applied as a potential adsorbent for
radionuclide.
Keywords: Microporous bioadsorbent; 2D-open channel;
vapor-phase modification; ATRP; uranium
Introduction
A rapid increase in energy demands has given rise to energy shortage,
nuclear energy with the advantage of low carbon emission play an
important role in sustainable energy source1,2.
Uranium plays a key role in nuclear energy sources, therefore its
extraction is very important for continuous energy
supply3-5. However, it is estimated uranium in the
terrestrial ores is limited and at the current usage, the terrestrial
resources might be ended at the end of the current
century6. Comparatively, it is estimated 4.5 billion
tons of uranium in seawater, which is a thousand times higher than
terrestrial ores7-9. Therefore, a new strategy needs
to develop to extract efficient uranium from seawater to fill the energy
gap, environmental protection and sustainable development. However, the
presence of competing ions, low uranium concentration (3.3 ppb) and
high-cost synthetic preparation hinder the development of materials for
the extraction of uranium from natural seawater10-14.
Various materials such as porous organic polymers
(POPs)15,16, covalent organic frameworks
(COFs)17-19, porous aromatic frameworks
(PAFs)3,20, metal-organic frameworks
(MOFs)21,22 and biopolymers23-25have been used for the extraction of uranium from seawater. Among all of
them, amidoxime-modified adsorbents are promising with the advantage of
high selectivity towards uranium in seawater26-29.
However, the development of most of the material is either expensive,
difficult to synthesize, poor stability and low uranium adsorption
efficiency in seawater. Recently, efforts have been devoted to
developing advanced materials via simple and facile methods from
inexpensive raw materials with ample uranium adsorption capacity.
Charcoal-based materials are highly interested due to their low cost,
porous structure, and environmentally friendly
nature1,30-32. Recently, amidoxime modified hollow
fibers were used for uranium adsorption33. Zhou et al.
reported 1D porous adsorbent from wood waste for adsorption of
polycyclic aromatic hydrocarbons34. Liao et al.
reported pig manure-based biochar for uranium
extraction35. Wang et al. reported 1D amidoxime
modified bamboo charcoal for uranium extraction from
seawater36. The drawbacks of already available
amidoxime modified charcoal-based adsorbents for uranium extraction are
as follows; (i) Regarding the analysis and reporting the adsorption
results, the experimental adsorption uncertainty is currently missing,
(ii) the preparation method is difficult or low functionalization yield
and or perform well under inert atmospheres, (iii) use of high cost
solvents for the preparation and purification process and (iv)
requirement of typical experimental procedure with critical conditions.
In this wok we could sort out these problems as well by carrying a
simple method by carbonization process in vacuum and subsequent vapor
phase modification via ATRP to obtain highly functionalized ultra-porous
material. Then after the post-synthetic modification was carried to
convert nitrile groups into amidoxime functional groups onto the surface
of 2D channels by hydrothermal method. The uncertainty in uranium
adsorption experiment was measurement by using classic concepts of error
propagation.