Nanoscale-controlled lithium ion-sieve based on MnO2·0.5H2O: Microfluidic synthesis and brine extraction performance

Manganese oxide lithium - ion sieves are among the most promising industrial adsorbents. This study is the first to apply membrane - dispersed microreactors for synthesizing monodisperse MnCO 3 nanoparticles, which is a problem that is coupled with novel two - stage thermal activation, which optimizes the Li 1.6 Mn 1.6 O 4 spinel structure with Li + diffusion channels. The results showed that the optimal adsorption conditions were identified as follows: pH = 10, initial Li + concenteation = 1000 mg/L, adsorption time = 12 h, and temperature = 25 °C, with a maximum capacity of 77.66 mg/g. The microfluidically synthesized MnO 2 ·0.5H 2 O exhibits superior Li + adsorption performance and exceptional Li + selectivity (order: Li + > Na + > Mg 2+ > K + ). Moreover, it retains an adsorption capacity of ≥ 58.67 mg/g after five cycles, highlighting the advantage of the microfluidic approach in enhancing material properties. The study offers technical assistance and theoretical guidance for the recovery of lithium from wastewater resources.