CellUSorb: A high-performance, radiation functionalized cellulose based adsorbent for Uranium (VI) remediation in ground water

Abstract

A state of the art, phosphate functionalized cotton cellulose based green U(VI) adsorbent has been synthesized via single step, 60Co gamma radiation mediated simultaneous irradiation grafting process, wherein bis(2-methacryloxyethyl) phosphate (B2MEP) was grafted onto cotton cellulose fabric. Samples were characterized using 13C NMR, FTIR, EDXRF, XRD and SEM techniques. Poly(B2MEP)-g-cellulose adsorbent (CellUSorb) was tested for removal of Uranyl (U(VI)) ions from water, adsorption capacities being 79.9 mg.g−1 and 135.9 mg.g−1 in batch and column modes, respectively. The equilibrium adsorption data were analyzed using Langmuir, Freundlich and Redlich-Peterson isotherm models, and kinetic data using pseudo first order, pseudo second order, intra-particle diffusion and Boyd’s models. The adsorbent viability was enhanced through regeneration achieved using ammonium oxalate as eluent, ensuring reusability for five cycles with < 20 % attrition loss/cycle. A standalone, portable water treatment set up, housing a ∼ 100 g CellUSorb cartridge (maximum theoretical U(VI) adsorption capacity ∼ 27,200L for [U(VI)] = 500 µg.L−1), has been conceptualized, fabricated and successfully tested for U(VI) removal to < 30 µg.L−1 (WHO permissible limit) from contaminated water. With potential upscaling for large scale, onsite U(VI) remediation, CellUSorb is a promising prospect that spotlights the role of cellulose in accomplishing UNO’s Sustainable Development Goal of “clean water for all” (SDG6).