Adsorptive capture of uranium (VI) onto a novel nanocomposite of reduced graphene oxide@titanium dioxide@carboxymethylcellulose

Abstract

Uranium is a hazardous radionuclide metal with serious consequences on human health and therefore, efforts must be properly established to safely design uranium removal processes from wastewater. The present study is aimed at taking advantage of reduced graphene oxide (rGO) as a unique 2-D structure with selective functional groups for loading nanotitanium dioxide (TiO2) and sodium carboxymethylcellulose (CMC) to create a newly designed nanocomposite (Nano-rGO@TiO2@CMC) via facile microwave heating technique. The average particle size of this nanocomposite was determined by XRD as 16.88 nm. Several major influencing parameters were optimized to assess U(VI) capture and uptake by Nano-rGO@TiO2@CMC. At the optimum pH 6.0, the maximum U(VI) capture were 93.2 % (30 mg L−1), 94.1 % (15 mg L−1) and 97.6 % (5 mg L−1). Rapid U(VI) recovery was established (5–10 min) and the pseudo-second order was referred as the appropriate model to represent the adsorptive capture of U(VI) (R2 0.9999). Langmuir model was highly applicable providing linear R2 = 0.9976 and nonlinear R2 = 0.9815. The thermodynamic results indicated that U(VI) adsorptive capture was based on both exothermic and spontaneous behaviors. The investigated Nano-rGO@TiO2@CMC was highly stable to regeneration and reuse for five successive cycles. This study confirmed the capability of Nano-rGO@TiO2@CMC as an effective nanocomposite for U(VI) capture from various waters, providing percentage recovery values from 93.5 to 99.5 %. Therefore, Nano-rGO@TiO2@CMC nanocomposite can be demonstrated as an amazing for proficient multi-recapture of U(VI) from water.