Adsorption of Pb(II) in Water by Niobate/Titanate Nanoflakes

Abstract

A niobate/titanat nanoflakes (Nb/TiNFs) composite was synthesized via the hydrothermal method and used to remove Pb(II) from water. XRD, TEM, and SEM results indicate that Nb/TiNFs appear as nanoflakes, of which the primary crystal phase is tri-titanate. Nb/TiNFs show rapid adsorption kinetics and the result fits well with the pseudo-second order model. The key mechanism of adsorption is ion-exchange between metal and -ONa/H. According to the Langmuir isotherm model, the maximum capacity of Pb(II) is 488.323 mg·g⁻¹. The relatively low R _L values indicate that Nb/TiNFs exhibit favorable adsorption of Pb(II). Nb/TiNFs indicate high adsorption capacity over a broad pH range. Co-existing inorganic ions (Na⁺ and Ca²⁺) have a slight inhibition effect on adsorption, and HA moderately inhibits the adsorption of Pb(II) on Nb/TiNFs. Because of the simple method of synthesis and high removal efficiency for heavy metals, Nb/TiNFs are a promising material in remediation of heavy metal polluted water.

Keywords

Nb/TiNFs / Pb(II) / adsorption / ion-exchange