Functionalized polymeric architectures (FPAs) for uranium recovery from oceans: A review on adsorptive approaches, models and spectrophotometry for understanding the interaction mechanism

Abstract

Uranium is the prime source of nuclear power production. Seawater can serve as an open reservoir of nuclear fuel as it contains ∼4.5 billion metric tons of uranium; however, its low concentrations (∼3.3 ppb) make its large-scale selective extraction economically challenging. Adsorption via functionalized polymeric architectures (FPAs) has been efficient for sequestering uranium from ocean water because of their high affinity towards uranyl ions, chemical stability, and good mechanical strength. The review is focused on analyzing the uranium extraction ability of FPAs in real and artificial seawater matrix. It assesses the role of experimental variables, sorption models, and technical characterization studies from the perspective of understanding uranium binding mechanisms. The review indicated that the adsorption rate of FPAs in natural seawater ranged between 0.003 – 2.27 g kg−1 day−1. The bifunctional amidoximated three-dimensional fibers yielded maximum uptake capacity of 985 mg g − 1 while the Zn2+-poly(amidoxime) hydrogel membrane exhibited superefficient uptake kinetics ∼1180 mg g − 1. The sorption data demonstrated that the pseudo-second order model well captured the kinetics and that interparticle diffusion governed the mass transfer. The analytical characterization of Ur-loaded FPAs showed synergistic chelation of amidoxime and amine functional groups with uranyl ions from seawater. However, there is scant literature about the complex uranium adsorption behavior in dynamic conditions involving marine microorganisms and increasing temperature conditions. Therefore, future priorities should include marine applicability, durability, and life cycle sustainability impacts (LSCA) for measuring the commercial feasibility of FPAs for uranium recovery from oceans.

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