Adsorption behavior of Li+ onto nano-lithium ion sieve from hybrid magnesium/lithium manganese oxide

Magnesium (II) doped spinel lithium manganese oxide (LMS) was synthesized by soft chemical method and nanosized ion sieve manganese oxide (HMS) was prepared by extracting lithium and magnesium from LMS. The characteristics of HMS were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, surface areas and determination of pH at the point of zero charge. Experiments were performed to study the effects of pH, adsorbent dose, contact time and Li+ concentration. The competitive model was used to describe the competition between Li+–H+ and the applicability of different kinetic models was evaluated. The results showed that the pH at the point of zero charge of HMS was about 7.8. The recycle of HMS explained that it could be used as Li+ adsorbent with topotactical extraction of lithium. Under optimized batch conditions up to 99.2% Li+ could be recovered from solution within 24 h. The adsorption process followed the pseudo-second-order model and followed an intraparticle diffusion model at the beginning.