Recycling of Brewer's Spent Grain as a Biosorbent by Nitro-Oxidation for Uranyl Ion Removal from Wastewater

Yi Su; Marco Wenzel; Silvia Paasch; Markus Seifert; Wendelin Böhm; Thomas Doert; Jan J Weigand

doi:10.1021/acsomega.1c00589

Recycling of Brewer's Spent Grain as a Biosorbent by Nitro-Oxidation for Uranyl Ion Removal from Wastewater

ACS Omega. 2021 Jul 19;6(30):19364-19377. doi: 10.1021/acsomega.1c00589. eCollection 2021 Aug 3.

Authors

Yi Su¹, Marco Wenzel¹, Silvia Paasch², Markus Seifert¹, Wendelin Böhm³, Thomas Doert⁴, Jan J Weigand¹

Affiliations

¹ Chair of Inorganic Molecular Chemistry, TU Dresden, 01062 Dresden, Germany.
² Chair of Bioanalytical Chemistry, TU Dresden, 01062 Dresden, Germany.
³ Chair of Food Chemistry, TU Dresden, 01062 Dresden, Germany.
⁴ Chair of Inorganic Chemistry II, TU Dresden, 01062 Dresden, Germany.

Abstract

Developing biosorbents derived from agro-industrial biomass is considered as an economic and sustainable method for dealing with uranium-contaminated wastewater. The present study explores the feasibility of oxidizing a representative protein-rich biomass, brewer's spent grain (BSG), to an effective and reusable uranyl ion adsorbent to reduce the cost and waste generation during water treatment. The unique composition of BSG favors the oxidation process and yields in a high carboxyl group content (1.3 mmol/g) of the biosorbent. This makes BSG a cheap, sustainable, and suitable raw material independent from pre-treatment. The oxidized brewer's spent grain (OBSG) presents a high adsorption capacity of U(VI) of 297.3 mg/g (c ₀(U) = 900 mg/L, pH = 4.7) and fast adsorption kinetics (1 h) compared with other biosorbents reported in the literature. Infrared spectra (Fourier transform infrared), ¹³C solid-state nuclear magnetic resonance spectra, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis were employed to characterize the biosorbents and reveal the adsorption mechanisms. The desorption and reusability of OBSG were tested for five cycles, resulting in a remaining adsorption of U(VI) of 100.3 mg/g and a desorption ratio of 89%. This study offers a viable and sustainable approach to convert agro-industrial waste into effective and reusable biosorbents for uranium removal from wastewater.