3.3 Uranium recovery in seawater
To analyze the uranium adsorption capacity of AO-Fc in real seawater,
adsorbent (7 mg) was added in a homemade adsorbent holder (syringe,
Figure S1) and exposed to 20 L seawater and the complete home-made
uranium adsorption set-up was shown in (Figure S1). The amount of
uranium adsorbed from seawater was analyzed by knowing uranium
concentration at different time intervals using (ICP-MS). For industrial
applications, the adsorbent can be directly used to lower surface
seawater for uranium extraction. The uranium adsorption kinetic results
revealed that AO-Fc showed 6.60 mg/g adsorption capacity within one
week, which was 75% of the total uranium adsorption. The maximum
adsorption capacity reached 8.57 mg/g with 100 % adsorption efficiency
after 11 days of the adsorption experiment (Figure 9ab). In comparison,
AO-Fc showed efficient uranium adsorption from seawater (Table 5).
Uranium adsorption capacity reflects the direct measurement of the
amount of uranium adsorbed by an adsorbent and the distribution
coefficient (Kd), determines the adsorbent affinity
towards adsorbate. These results indicated that the adsorbent retaining
high uranium adsorption capacity in presence of other coexisting ions
might have a correspondingly higher Kd value than other
coexisting ions in Figure 9c. Based on that, the evaluation of
Kd (L/g)is an important parameter for choosing the most
suitable adsorbent for further analysis.
Figure 9 Kinetics of uranium extraction (a,b) and distribution
coefficient (Kd) of various ions in natural seawater (b)
Table 5 Comparison of various adsorbents for uranium extraction in
seawater