Synthesis And Adsorption Properties Of H₂TiO₃ Adsorbent

The majority of lithium exists as lithium salt in brine with high concentration of Mg2+,which means the extraction process is complicated and high cost.One focus of the research field is lithium ion-sieve because of high performance and excellent selectivity.Herein,H₂TiO₃ adsorbent was obtained by acid-modifying adsorbent precursor Li2TiO3,which was synthesized by calcining products of hydrothermal reaction between TiO₂ and LiOH·H2O.The effects of calcination time,calcination temperature on structure and ion-exchange properties were investigated via XRD,SEM and kinetic experiment.Rate equations were used to investigate the adsorption process,and adsorption isotherm equations were fitted by the equilibrium data.The verified optimal calcination temperature and time are 500? and 2 h,respectively.For such prepared adsorbent,the maximum adsorption capacity reaches 36.16 mg g-1,the adsorption kinetic constants is 0.0339 g/?mg h?and the extraction rate of lithium is 98.8%after 5 h.Moreover,the adsorption process obeys a pseudo-second order equation,and the equilibrium data fits well to the Freundlich model.The separation coefficients of Li+ to Mg2+ reaches 154.17.In addition,molded adsorbent was synthesized to decrease mass loss of powder adsorbent.Adsorption capacity of FH and EH adsorbent were 9.7 mg g-1 and 26.6 mg g-1.EH adsorbent had higher adsorption capacity but weaker mechanical strength than FH adsorbent.