Synthesis and characterization of a novel graft copolymer containing carboxyl groups and its application to extract uranium(VI) from aqueous media

Abstract

A novel poly(methacrylic acid)-grafted-cellulose/bentonite (Cellu-g-PMAAc/Bent) superabsorbent composite was prepared through graft copolymerization reaction among cellulose, methacrylic acid, and bentonite in the presence of N,N 0 -methylenebisacrylamide as a crosslinker and potassium peroxydisulphate as an initiator. The structural and morphological characteristics of the graft copolymer were determined using Fourier transform infrared spectra, scanning electron microscopeenergy dispersion analysis, and X-ray diffraction. The effectiveness of the Cellu-g-PMAAc/Bent, as adsorbent for the removal and recovery of uranium(VI) from aqueous media, was studied. The effects of pH, contact time, and initial sorbate concentration were studied to optimize the conditions for maximum adsorption. The adsorption process, which was pH dependent, shows maximum removal (>99.0% ) at pH 6.0. Kinetic study showed that 180 min of contact at 100 mg/L could adsorb about 99.2% of U(VI) onto Cellu-g-PMAAc/Bent. A pseudosecond-order kinetic model successfully described the kinetics of sorption of U(VI). Adsorption equilibrium data were correlated with the Langmuir, Freundlich, and Redlich-Peterson isotherm models. The best fit was obtained with Freundlich model. Desorption of U(UI) was studied by using 0.1M HCl. Adsorption/ desorption for more than six cycles showed the possibility of repeated use of this graft copolymer for the recovery of U(VI) from aqueous solutions.

Competitive photo-degradation performance of ZnO modified bentonite clay in water containing both organic and inorganic contaminants

“…The main reason for this selection is the susceptibility of layered clays to organic/inorganic modifications apart from their large internal surface area. But adsorption simply transfer contaminants from one phase to another which demands further chemical treatment for the recovery of the adsorbent material [13,14]. Also, excessive usage of adsorbents gradually leads to problems with landfill.…”

Extraction of uranium from seawater : design and testing of a symbiotic system

“…A recent review of uranium recovery technologies by Kim et al (2013b) identified uranium adsorption by chelating polymers to be the most promising in terms of cost, adsorption capacity, and environmental footprint (Zhang et al, 2003;Seko et al, 2003;Anirudhan et al, 2011). Other techniques, including membrane filtration, coagulation, and precipitation were found to have issues such as high operating costs, durability, or toxicity (Kanno, 1984;van Reis and Zydney, 2007;Tularam and Ilahee, 2007).…”

Extraction of Uranium from Seawater: Design and Testing of a Symbiotic System (Final Report)

“…Extraction of uranium from seawater has been researched for decades, with one of the first studies conducted by Davies et al (1964) after World War II in an effort to secure uranium supply for Britain at a time when the production of uranium was uncertain. A recent review of uranium recovery technologies by Kim et al (2013b) identified uranium adsorption by chelating polymers to be the most promising in terms of cost, adsorption capacity, and environmental footprint (Zhang et al, 2003;Seko et al, 2003;Anirudhan et al, 2011). Other techniques, including membrane filtration, coagulation, and precipitation were found to have issues such as high operating costs, durability, or toxicity (Kanno, 1984;van Reis and Zydney, 2007;Tularam and Ilahee, 2007).…”