Chinese Journal of Chemical Engineering ›› 2020, Vol. 28 ›› Issue (9): 2312-2318.doi: 10.1016/j.cjche.2020.05.006

• Separation Science and Engineering • Previous Articles     Next Articles

Preparation and evaluation of α-Al2O3 supported lithium ion sieve membranes for Li+ extraction

Feng Xue, Xiaoxian Zhang, Yue Niu, Chenhao Yi, Shengui Ju, Weihong Xing   

  1. College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
  • Received:2019-11-28 Revised:2020-04-20 Online:2020-09-28 Published:2020-10-21
  • Contact: Shengui Ju
  • Supported by:
    This work was financially supported by National Key Research and Development Program (2018YFE0203502), China; Primary Research and Development Plan of Jiangsu Province (BE2019117), China and National Students' Platform for Innovation and Entrepreneurship Training (201910291051Z), China.

Abstract: Spinel lithium manganese oxide ion-sieves have been considered the most promising adsorbents to extract Li+ from brines and sea water. Here, we report a lithium ion-sieve which was successfully loaded onto tubular α-Al2O3 ceramic substrates by dipping crystallization and post-calcination method. The lithium manganese oxide Li4Mn5O12 was first synthesized onto tubular α-Al2O3 ceramic substrates as the ion-sieve precursor (i.e. L-AA), and the corresponding lithium ion-sieve (i.e. H-AA) was obtained after acid pickling. The chemical and morphological properties of the ion-sieve were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Both L-AA and H-AA showed characteristic peaks of α-Al2O3 and cubic phase Li4Mn5O12, and the peaks representing cubic phase could still exist after pickling. The lithium manganese oxide Li4Mn5O12 could be uniformly loaded not only on the surface of α-Al2O3 substrates but also inside the pores. Moreover, we found that the equilibrium adsorption capacity of H-AA was 22.9 mg·g-1. After 12 h adsorption, the adsorption balance was reached. After 5 cycles of adsorption, the adsorption capacity of H-AA was 60.88% of the initial adsorption capacity. The process of H-AA adsorption for Li+ correlated with pseudo-second order kinetic model and Langmuir model. Adsorption thermodynamic parameters regarding enthalpy (ΔH), Gibbs free energy (ΔG) and entropy (ΔS) were calculated. For the dynamic adsorption- desorption process of H-AA, the H-AA exhibited excellent adsorption performance to Li+ with the Li+ dynamic adsorption capacity of 9.74 mg·g-1 and the Mn2+ dissolution loss rate of 0.99%. After 3 dynamic adsorption-desorption cycles, 80% of the initial dynamic adsorption capacity was still kept.

Key words: Lithium, α-Al2O3 tube, Ion sieve, Adsorption, Li4Mn5O12