Preparation of H1.6Mn1.6O4/Chitosan Composite Microsphere and Its Adsorption Properties of Lithium

Abstract

AbstractLi1.6Mn1.6O4 was synthesized by soft chemical synthesis and solid‐phase calcination. Then it was compounded with chitosan (CTS) to form composite microsphere by Epichlorohydrin used as a cross‐linking agent. Subsequently, 0.5 mol ⋅ L−1 sodium persulfate was used as an eluent, and the lithium ion sieve adsorbent (H1.6Mn1.6O4) was prepared. The influencing factors of the preparation conditions for the lithium ion sieve precursor were investigated, and the results showed that when the mixed salt solution was 100 mL (molar ratio of lithium manganese for 4 : 1), added 5 mL H2O2 and calcined at 400 °C for 5 hours, the relatively pure Li1.6Mn1.6O4 could be obtained. Aimed at the composite microsphere, the influencing factors of its preparation conditions was investigated. The results showed that the ratio of CTS to lithium ion sieve powder was 1 : 2, the amount of cross‐linking agent was 2 mL and the time were 30 min was the best condition. The adsorption effect was tested by eluting Li1.6Mn1.6O4 and composite microsphere with a variety of eluents. The results showed that the adsorption effect of Li1.6Mn1.6O4 was best when 0.5 mol ⋅ L−1 hydrochloric acid was used as the eluent, and its adsorption capacity was 32.34 mg ⋅ g−1, the dissolution loss rate of Mn is 1.61 %; the composite microsphere had the best effect when 0.5 mol ⋅ L−1 sodium persulfate was used as the eluent, its adsorption capacity was 13.29 mg ⋅ g−1, the dissolution loss rate of Mn was only 0.91 %, moreover it had better repeatability, with only a 20.83 % drop in performance after the tenth runs. Ion selectivity experiments showed that the adsorption selection was in the order of Li+≫K+>Mg2+>Ca+>Na+, and the composite adsorbent was highly selective for Li+.