Arsenate adsorption onto Fe-TNTs prepared by a novel water-ethanol hydrothermal method: mechanism and synergistic effect

Yanqi Wang; Wen Liu; Ting Wang; Jinren Ni

doi:10.1016/j.jcis.2014.10.036

Arsenate adsorption onto Fe-TNTs prepared by a novel water-ethanol hydrothermal method: mechanism and synergistic effect

J Colloid Interface Sci. 2015 Feb 15:440:253-62. doi: 10.1016/j.jcis.2014.10.036. Epub 2014 Nov 4.

Authors

Yanqi Wang¹, Wen Liu², Ting Wang¹, Jinren Ni³

Affiliations

¹ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Water and Soil Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, 712100 Shaanxi, P.R. China; The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
² The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
³ The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China. Electronic address: nijinren@iee.pku.edu.cn.

PMID: 25460713
DOI: 10.1016/j.jcis.2014.10.036

Abstract

Arsenate adsorption onto Fe2O3 was highly restricted at acidic condition due to dramatic dissolution. To overcome this difficulty, iron oxide nanoparticle-grafted titanate nanotubes (Fe-TNTs) were synthesized by a facile one-step water-ethanol hydrothermal method and used to remove As(V) from aqueous solutions. This new adsorbent was acid-resistant, and showed a large As(V) adsorption capacity of 90.96 mg/g determined by two-site Langmuir model, which was almost 3 times of the original TNTs. Fe2O3 was proved to bonded to the surface of TNTs by TEM and XRD analysis and synergy of Fe2O3 and TNTs was of great help to excellent As(V) adsorption. Load of Fe2O3 greatly enhanced the point of zero charge. Moreover, tubular TNTs not only inhibited dissolution of Fe2O3 at low pH, but also maintained good sedimentation property. The hydroxyl groups on Fe-TNTs surface played the most important role in As(V) adsorption. Electrostatic interaction followed by complexation was confirmed to be the primary adsorption mechanism by means of XPS analysis. Desorption capability and reuse performance of Fe-TNTs were also investigated, and satisfactory As(V) adsorption was further found with NaOH desorbed even after three reuse cycles.

Keywords: Arsenate; Complexation; Fe-TNTs; Synergistic effect; Two-site Langmuir.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adsorption
Arsenates / chemistry*
Ethanol / chemistry*
Iron Compounds / chemistry*
Microscopy, Electron, Transmission
Water / chemistry
X-Ray Diffraction

Substances

Arsenates
Iron Compounds
Water
Ethanol
arsenic acid