Breaking single‐ion limits: Charge compensation enables concurrent Li/Br recovery and LiBr enrichment in produced water

Abstract

Abstract Produced water from oil and gas fields contains Li + and Br − resources, but their low concentrations and complex coexisting ions make efficient recovery difficult. A charge‐compensated dual‐electrode system is developed for simultaneous Li + /Br − recovery and LiBr enrichment. LiMn 2 O 4 (LMO) serves as the Li + capture electrode, while rGO 20 ‐BOB is used for Br − capture. Introducing rGO regulates the growth and assembly of BiOBr (BOB) nanosheets, forming a microflower‐like structure with improved Br − accessibility and conductivity. In the optimized L 1−x MO/rGO 20 ‐BOB 1−x electrode system, Li + and Br − extraction capacities reach 25.1 and 137.1 mg g −1 , respectively. In actual produced water from Zigong, Li + and Br − adsorption capacities reach 21.3 and 20.9 mg g −1 , and approximately 0.5 mmol LiBr is obtained in a single adsorption/desorption cycle. This system shows potential for coupling efficient Li + /Br − recovery with LiBr enrichment from complex produced water, offering a simplified route for high‐value utilization of oil and gas fields produced water.