Development of ionic-imprinted polyesters of diallyl dicarboxylic acids (DAPY) for uranyl ion extraction (UO 2 2+ )
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Research Letter
Development of ionic-imprinted polyesters of diallyl dicarboxylic acids (DAPY) for uranyl ion extraction (UO2+ 2 ) Alejandro Ramos-Ballesteros and Emilio Bucio, Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, CDMX 04510, Mexico Address all correspondence to Alejandro Ramos-Ballesteros at [email protected] (Received 31 October 2018; accepted 4 December 2018)
Abstract Non-conventional uranium extraction sources are not the most used mainly due to high extraction costs associated with low concentrations and chemical forms that require extra purification processes. Therefore, efforts should focus on cheaper processes and develop more effective extraction materials. In this investigation, ionic-imprinted polymers were synthesized for the selective extraction of uranyl ions in aqueous solution, using polyesters of 2,5-bis((allyloxy)carbonyl)terephthalic acid and 4,6-bis((allyloxy)carbonyl)isophthalic acid as base materials and polymerized by gamma radiation. The extraction capacity (Q) of the resins was evaluated by varying parameters such as pH, temperature, extraction time, and ionic strength.
Introduction In coming decades, energy generation from nuclear reactors will invariably increase, which means that the demand for uranium-based fuels will become a matter of priority energy security.[1] Until now, the demand has been totally satisfied with terrestrial deposits (mines),[2] however, according to the current extraction dynamics, and without spending more than 30% of known reserves in the category of 7 fall to 80 mg/g and lower. When the system is purely basic (pH 11–12) polymers response is very similar, although the polymers still
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Figure 4. Effect of several parameters on the extraction capacity for IIP and NIP based on DAPY isomers polymerized al 80 kGy of absorbed dose: (a) temperature, (b) pH, and (c) extraction time.
manage to extract uranium (around 50 mg/g), its performance falls to the lowest level of all the pH range tested. As far as ionic imprinting is concerned, the uncertainty of both values overlaps, and it is not possible to conclude that there are significant differences under basic conditions.
Extraction time Finally, the time required for the material, under constant agitation, to reach the maximum analyte adsorption was determined [Fig. 4(c)]. The rapid initial adsorption is due to a low resistance to mass transfer, a higher density of binding sites and to the fact that the reaction only depends on the diffusion rate of the adsorbate in the medium. Maximum adsorption was observed after periods of 70 min for the NIP (polymer saturation), while imprinted resins took 10
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