Parametric Studies on Radiation Grafting of Polymeric Sorbents for Recovery of Heavy Metals from Seawater

Abstract

Uranium and vanadium are valuable trace metals in seawater. The economic viability of recovery of these metals depends on development of efficient sorbents. The radiation induced graft polymerization technique was adopted in this study to prepare metal chelate embedded polymers in sheet form in order to investigate the recovery the heavy metals from seawater, using different nonwoven substrate materials. In order to obtain more direct information on the grafting levels, the parametric studies to see the influence of cumulative dose, retention time in air, surrounding atmosphere, and reaction temperature on grafting yields were investigated using different electron beam energies. The grafted sorbents were verified by infrared spectroscopic measurements, and thermal properties were analyzed by scanning calorimetric methods. Metal sorption characteristics for uranium and vanadium were evaluated through in-field trials at seawaters of the Andaman and Nicobar Islands, Indian Ocean, and Arabian Sea along Indian coastal lines.

Synthesis, Development, and Testing of High-Surface-Area Polymer-Based Adsorbents for the Selective Recovery of Uranium from Seawater

“…Based on published reaction conditions for similar systems, a variety of reaction parameters were studied including grafting temperature (between 20 °C and 60 °C), grafting time, irradiation temperature, solvent mixtures, and additives (e.g., H 2 SO 4 ). ,− Our investigation began by grafting the TBR polymer fibers in a grafting solution composed of 50% DMSO and 50% comonomer solution (70/30 AN/MAA) at 20, 40, and 60 °C; however, an adsorbent capacity of uranium greater than 7 g U /kg ads could not be obtained versus 25 g U /kg ads of uranium from a sample donated by the JAEA of their nonwoven adsorbent, as shown in Figure S2a in the Supporting Information. Besides following the reported literature conditions, we attempted to use a reflux condenser in a shaker table, as well as longer degassing times, with the hopes of improving the grafting yield.…”

Technology to Harvest Uranium from Seawater and Its Estimation by Laser Fluorimetry

“…The quality assurance for grafting extent was done gravimetrically. The adsorbents formed were then used for extraction of uranium from seawater samples at laboratory as well as pilot scale [5].…”

“…Hence, research has been directed towards the recovery of uranium and other heavy metal ions from non-conventional sources such as phosphoric acid [2] and seawater [3][4][5][6]. Uranium is present in seawater at an average concentration of 3.3 ppb [7].…”

“…In India, research is on for the development of the most effective technology for recovery of uranium from seawater [3,5,6]. Polymer matrices have been synthesised by radiation grafting of acrylonitrile, making it suitable for uptake of uranium from seawater [3,[9][10][11].…”

The synthesis of a manganese dioxide–iron oxide–graphene magnetic nanocomposite for enhanced uranium(vi) removal

“…To date, several methods, such as chemical precipitation, solvent extraction, membrane separation, and adsorption, [3][4][5][6][7][8][9] have been extensively applied for the removal of uranium(VI) from aqueous solutions. Among them, adsorption is considered as an attractive method for the removal of heavy metals.…”