Lithium extraction from oil and gas produced water with spherical manganese-based lithium ion sieve: Preparation, adsorption mechanism, and fixed-bed application

To solve the problems of poor fluidity, difficult recovery, and cycle loss of lithium manganese oxide, this study used polyvinyl butyl aldehyde (PVB) and polyethylene glycol (PEG) to construct a physical blend system, and combined with the drop-phase conversion method to prepare precursor particles. Under the optimized conditions of 10% PVB, 7% PEG, 40℃, and a gel-powder ratio of 1:3, the porosity of spherical particles reached 65.23%, the average particle size was 1.35 mm. Under 25℃, with an initial Li-containing solution pH=10 and a Li + concentration of 100 mg/L, the adsorption capacity is 15.9 mg/g. This study constructed a pretreatment process of “Poly Aluminum Chloride (PAC) for Suspended Solids (SS) removal → NaOH+PAC/Polyacrylamide (PAM) for Mg 2+ removal”, reducing water quality interference. In the fixed-bed system, when the feed rate was 0.53 mL/min and the adsorbent was 0.8 g, the adsorption capacity reached 22.78 mg/g. For every 0.8 g of adsorbent desorbed with 150 mL of HCl, the Li recovery rate was 25% and the Mn dissolution rate was less than 1%. After 10 cycles, the adsorption capacity dropped to 18.16 mg/g. This study provided technical solutions for the industrialization of lithium manganese oxide from complex water bodies.