Synergistic charge-size trimetallic design PVDF@Mn-co/Al-LDH for efficient lithium selectivity from high-Mg/Li ratio brine

Mn-Co/Al-LDH enables efficient lithium capturing from Salt Lake Brines. • Fiber adsorbent exhibits excellent Li + selectivity, mechanical stability and durability. • PVDF@Mn-Co/Al-LDH design as fiber functionalization via wet spinning. • Dynamic uptake capacity of Li + 14.94 ± 1.23 mg·g −1 from Da-Qaidam Salt Lake. Lithium‑aluminum layered double hydroxides (LiAl-LDH) have been successfully used on a commercial scale to extract lithium from salt lake brine, their uncertain extraction procedure and inadequate Li + adsorption ability prevent further development of their uses. High selectivity of Li + has been achieved by the LDHs adsorption from high Mg/Li ratio salt lake brine, but zinc and titanium-based LDH adsorbents are unstable in acidic environments and pose environmental hazards. In this study, a novel trimetallic-based PVDF@Mn-Co/Al-LDH fibrous composite material with tunable properties is compared to bimetallic-LDHs. Density Functional Theory (DFT) is used to optimize the composite design and adsorption sites calculations. To approach the industrial application of Mn-Co/Al-LDH powder, it was further fabricated into porous nature fiber by wet spinning technology with cost effective PVDF form as strong binder with hydrophilicity exhibited Li + maximum adsorption capacity by 50% Mn-Co/Al-LDH fiber composition of 16.73 ± 1.02 mg.g −1 from Li + brine and the dynamic adsorption capacity is 14.94 ± 1.23 mg·g −1 with a 93% elution rate and 4–5% dissolution rate of Mn/Co ions. This synthetic fibrous composite adsorbent highlights a promising approach for evaluating LDH's potential in lithium extraction from rich‑lithium high Mg/Li ratio brine resources, due to its superior selectivity, adsorption/desorption performance and cyclic stability. Download: Download high-res image (139KB) Download: Download full-size image