With decreasing global rhenium resources,
it has become
important
to separate and purify rhenium in secondary resources, so a preparation
strategy for a chitosan-comodified surface-grafted thermosensitive
ion-imprinted composite membrane (CS-Re-TIICM) was developed in this
work. The key of this design was that the two ends of a poly(N,N-diethylacrylamide) (PDEA) chain were
grafted onto the imprinted polymer separating the layer matrix and
the surface of the membrane, respectively, which aimed to improve
the selectivity and desorption ratio of this material simultaneously.
The structure and morphology of this material were characterized by
FTIR and SEM, respectively. In addition, CS-Re-TIICM was applied to
the secondary leaching solution of the high-temperature alloy to test
the actual separation effect, and results showed that CS-Re-TIICM,
possessing thermoresponsive recognition sites, and the structure of
the imprinting cavity could be adjusted by temperature, which helped
this material achieve good selective separation and purification performance
for ReO4
–. The maximum adsorption capacity
was 0.1071 mmol/g at 35 °C. CS-Re-TIICM not only showed an excellent
selectivity (separation ReO4
–/MnO4
– of 3.90 in the presence of interfering
ion MnO4
–) but also presented an excellent
desorption performance (desorption ratio of 68.94%) and good reusability
(adsorption capacity of 0.0425 mmol/g, desorption ratio of 59.13%,
and separation degree of 1.24). When CS-Re-TIICM was applied to the
secondary leaching solution of high-temperature alloys, the purity
of Re was increased from 35.41% to 65.10% after one adsorption/desorption
cycle, which depicted a prospective application in the industrialized
separation of ReO4
– from a complex environment.