Symbiotic Aerogel Fibers Made via In-Situ Gelation of Aramid Nanofibers with Polyamidoxime for Uranium Extraction

Abstract

The uranium reserve in seawater is enormous, but its concentration is extremely low and plenty of interfering ions exist; therefore, it is a great challenge to extract uranium from seawater with high efficiency and high selectivity. In this work, a symbiotic aerogel fiber (i.e., PAO@ANF) based on polyamidoxime (PAO) and aramid nanofiber (ANF) is designed and fabricated via in-situ gelation of ANF with PAO in dimethyl sulfoxide and subsequent freeze-drying of the corresponding fibrous gel precursor. The resulting flexible porous aerogel fiber possesses high specific surface area (up to 165 m2·g−1), excellent hydrophilicity and high tensile strength (up to 4.56 MPa) as determined by BET, contact angle, and stress-strain measurements. The batch adsorption experiments indicate that the PAO@ANF aerogel fibers possess a maximal adsorption capacity of uranium up to 262.5 mg·g−1, and the absorption process is better fitted by the pseudo-second-order kinetics model and Langmuir isotherm model, indicating an adsorption mechanism of the monolayer chemical adsorption. Moreover, the PAO@ANF aerogel fibers exhibit selective adsorption to uranium in the presence of coexisting ions, and they could well maintain good adsorption ability and integrated porous architecture after five cycles of adsorption–desorption process. It would be expected that the symbiotic aerogel fiber could be produced on a large scale and would find promising application in uranium ion extraction from seawater.

Robust Silica-Bacterial Cellulose Composite Aerogel Fibers for Thermal Insulation Textile

“…In particular, the number of BC nanofibers per unit volume was enhanced by secondary shaping, which further enhanced the adhesion of silica particles to the BC nanofibers. Based on the results of a BET test, the specific surface areas of the samples grew from 367.9 to 606.9 m 2 /g ( Table 1 ) with an increase in TEOS concentration, which is higher than that of PAO@ANF symbiotic aerogel fiber [ 28 ] and Kevlar aerogel fibers [ 25 ]. This is because a gel skeleton composed of inorganic oxide nanoparticles has a rougher surface compared to a gel skeleton composed of nanofibers or nanosheets.…”

“…The stress–strain curves of CAFs obtained from tensile tests showed that the breaking stress was in the range of 4.5–5.4 MPa. All the samples showed good tensile strength, which was much higher than that of native silica aerogel fibers, and it was comparable or even superior to those of CA/PAA-SF aerogel fibers [ 41 ] (3 MPa), SF/GO aerogel fibers [ 36 ] (3.2 MPa), and PAO@ANF aerogel fibers [ 28 ] (4.56 MPa). Moreover, the curves also showed that the elongation at break of the sample decreased from 6.8% to 1.1% with increasing precursor concentration.…”

“…Aerogel fibers not only enrich the morphology of aerogels but also expand the applicability of aerogels in different fields and contexts. In addition to thermal insulation applications [ 25 , 26 ], aerogel fibers could also be used in other fields, such as adsorption [ 27 , 28 , 29 ], biological sensing [ 30 ], and supercapacitors [ 31 ]. As a result of these potential advantages, it is essential to develop different strategies to obtain high-strength aerogel fibers.…”

Fabrication, Applications, and Prospects of Aramid Nanofiber

“…Commonly, acetone or a DMSO aqueous solution is used as the coagulation bath. Alternatively, as shown in Figure 12C, Li et al [ 80 ] selected a polyamidoxime (PAO)/DMSO solution as the coagulation bath to prepare a symbiotic PAO@ANF aerogel fiber by spinning an ANF/DMSO dispersion into a PAO coagulation bath and subsequently freeze drying it.…”

Bayberry tannin directed assembly of a bifunctional graphene aerogel for simultaneous solar steam generation and marine uranium extraction

“…For uranium extraction, the immobilization of specific chemical group on porous materials is the most promising method 9,10 . Plenty of porous materials have been utilized, such as mesoporous silica 11,12 , polymers 13,14 , carbon nanomaterials 15 , MOF 16 , and even MXene 17 . Much progress has been made on the improvement of performance of the SSG and uranium extraction.…”