One-pot synthesis of brewer's spent grain-supported superabsorbent polymer for highly efficient uranium adsorption from wastewater

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

High-efficient and fast adsorption of uranium is important to reduce the hazards caused by the uranium contamination of water environment due to the increased human activities. Herein, brewer's spent grain (BSG)-supported superabsorbent polymers (SAP) with different cross-linking densities are prepared as cheap and eco-friendly adsorbents for the first time via one-pot swelling and graft polymerization. A 7 wt% NaOH solution is used to swell BSG before grafting and subsequently neutralize the acrylic acid to control the reaction rate without producing alkaline wastewater. Compared with the traditional methods, swelling improves the grafting density and the utilization of raw materials due to the increased disorder degree of the BSG fibers. This results in the grafting of abundant carboxyl and amide groups onto the BSG backbone, forming a strongly hydrophilic polymer network of the BSG-SAP. Compared with the reference polymers without BSG, BSG-SAP presents higher adsorption capacity and enhanced reusability. The highly cross-linked BSG-SAP (BSG-SAP-H) shows an outstanding adsorption capacity of U(VI) (1465 mg/g at pH 0 = 4.6), a fast adsorption rate (81% of equilibrium adsorption capacity in 15 min), and a high selectivity in the presence of competing ions. Adsorption mechanism studies reveal the involvement of amide groups, a bidentate binding structure between UO 2 2+ and the carboxyl groups, and a cation exchange between Na + and UO 2 2+. More importantly, the adsorption capacity of BSG-SAP-H reaches 254.4 mg/g in the fixed-bed column experiment at a low initial concentration (c 0(U) = 30 mg/L) and keeps 80% of the adsorption capacity after four cycles, indicating a great potential for uranium removal from wastewater. This work shows a suitable approach to explore the untreated biomass to prepare SAP with enhanced adsorption performance via a general and low-cost strategy.

Details

Original languageEnglish
Article number113333
Number of pages15
JournalEnvironmental Research
Volume212 Part C
Publication statusPublished - Sept 2022
Peer-reviewedYes

External IDs

Scopus 85129460715
WOS 000800523200002
Mendeley b0e3316c-db5e-3b52-b04a-300485aa8a90
unpaywall 10.1016/j.envres.2022.113333
ORCID /0000-0001-7523-9313/work/142238671
ORCID /0000-0001-7323-7816/work/142257422

Keywords

Subject groups, research areas, subject areas according to Destatis

Keywords

  • Brewer's spent grain, Fixed-bed column, Reusable, Superabsorbent polymer, Uranium adsorption