Q-H Zhang, S-P Li, S-Y Sun, X-S Yin, J-G Yu
TiO2, nanoribbon lithium, ion-sieve, seperation
Low-dimensional TiO2-related nanomaterial with high morphology specificity, including nano-tube, -wire, -sheet, -fiber and -ribbon, had attracted particular interest in advanced applications as catalyst, solar-energy conversion semiconductor, gas sensor and electrochemical material, as it was discovered by Kasuga. However, doubts exist concerning the formation and construction of these materials, and the lithium selective adsorption into TiO2 ion-sieve from aqueous resources including brine or sea water has been rarely reported. Thus, the optimized synthesis, characterization and consequent lithium ion-sieve property of TiO2 were systematically studied in this work. First, the soft chemical hydrolysis of commercial TiO2 powder to quite uniform nanoribbons (with width about 20 nm and length about several micrometers) was realized at 448 K in 10 mol•l-1 NaOH solution, and the TiO2 ion-sieve with lithium selective adsorption property was accordingly prepared via a simple solid-state reaction between Li2CO3 and TiO2 nanoribbons, followed by the acid treatment process to extract lithium from the Li2TiO3 precursor; Second, the structure and texture were characterized by XRD, HRTEM/SAED and N2 adsorption at 77 K, and the formation mechanism was also discussed; Third, the selective adsorption property was studied by the batchwise adsorption isotherm with a series of alkaline and alkaline-earth metal ions.