Amorphous boron-doped sodium titanates hydrates: Efficient and reusable adsorbents for the removal of Pb2+ from water

Luigi di Bitonto; Angela Volpe; Michele Pagano; Giuseppe Bagnuolo; Giuseppe Mascolo; Valeria La Parola; Paola Di Leo; Carlo Pastore

doi:10.1016/j.jhazmat.2016.10.046

Amorphous boron-doped sodium titanates hydrates: Efficient and reusable adsorbents for the removal of Pb²⁺ from water

J Hazard Mater. 2017 Feb 15;324(Pt B):168-177. doi: 10.1016/j.jhazmat.2016.10.046. Epub 2016 Oct 20.

Authors

Luigi di Bitonto¹, Angela Volpe¹, Michele Pagano¹, Giuseppe Bagnuolo¹, Giuseppe Mascolo¹, Valeria La Parola², Paola Di Leo³, Carlo Pastore⁴

Affiliations

¹ CNR-IRSA, Via de Blasio 5, 70132 Bari (BA), Italy.
² CNR-ISMN, Via U. La Malfa, 153, 90146 Palermo (PA), Italy.
³ CNR-IMAA, Via S. Loja, Tito Scalo (PZ), Italy.
⁴ CNR-IRSA, Via de Blasio 5, 70132 Bari (BA), Italy. Electronic address: carlo.pastore@ba.irsa.cnr.it.

PMID: 27776867
DOI: 10.1016/j.jhazmat.2016.10.046

Abstract

Amorphous titanium hydroxide and boron-doped (B-doped) sodium titanates hydrates were synthetized and used as adsorbents for the removal of Pb²⁺ from water. The use of sodium borohydride (NaBH₄) and titanium(IV) isopropoxide (TTIP) as precursors permits a very easy synthesis of B-doped adsorbents at 298K. The new adsorbent materials were first chemically characterized (XRD, XPS, SEM, DRIFT and elemental analysis) and then tested in Pb²⁺ adsorption batch experiments, in order to define kinetics and equilibrium studies. The nature of interaction between such sorbent materials and Pb²⁺ was also well defined: besides a pure adsorption due to hydroxyl interaction functionalities, there is also an ionic exchange between Pb²⁺ and sodium ions even working at pH 4.4. Langmuir model presented the best fitting with a maximum adsorption capacity up to 385mg/g. The effect of solution pH and common ions (i.e. Na⁺, Ca²⁺ and Mg²⁺) onto Pb²⁺ sorption were also investigated. Finally, recovery was positively conducted using EDTA. Very efficient adsorption (>99.9%) was verified even using tap water spiked with traces of Pb²⁺ (50ppb).

Keywords: Adsorption; Ionic exchange; Metal removal; Pb(II); Titanium hydroxides.