Influence of the Nanotube Morphology and Intercalated Species on the Sorption Properties of Hybrid Layered Vanadium Oxides: Application for Cesium Removal from Aqueous Streams.

Delhia Alby,Clarence Charnay,Fabrice Salles,Jerzy Zajac

doi:10.3390/nano11092349

Abstract

The present paper examines the impact that the nanotube morphology and organic or inorganic intercalated species may have on the cesium sorption by layered vanadium oxides prepared with the use of hexadecylamine as a structure-directing agent. The hybrid material represented by a chemical formula of (V2O5)(VO2)1.03(C16H36N)1.46(H2O)x was achieved through accelerated microwave-assisted synthesis carefully optimized to ensure the best compromise between the scroll-like morphology and the hydrophobic character. To enhance its dispersibility in water, this sample was subsequently modified by progressive replacement of the C16H36N+ units by NH4+ cations. The final materials represented a stacking of lamellar sheets with a worse scroll-like morphology. Both the optimization procedure and the template removal were monitored on the basis of scanning and transmission electronic microscopy, X-ray diffraction, infra-red spectroscopy, inductively coupled plasma-optical emission spectrometry, X-ray photoelectron spectroscopy, and elemental analysis, supplemented by adequate simulations methods providing the reference IR spectra and XRD patterns for comparison or the textural parameters of the samples. The comparison of the cesium sorption from either a 4:1 ethanol–water mixture or aqueous solutions pointed toward the solubility of intercalated cations in the bulk solution as the main factor limiting their displacement from the interlayer space by the oncoming cesium ones. The sample obtained after 70% exchange with NH4+ exhibited a maximum sorption capacity of 1.4 mmol g−1 from CsNO3 aqueous solutions and its retention efficiency remained significant from low-concentration Cs solutions in river or sea water.

Highlights

Sorption processes occurring at the solid–liquid interface have gained substantial importance in remediation of liquid waste streams over the past decades since, in addition to fast operational readiness and easy handling, they may offer low-level discharge generation and significant reversibility of the removal process [1,2,3]
Layered vanadium oxide materials containing hexadecylamonium cations or a mixture of hexadecylammonium and ammonium cations in the interlayer space have proven efficient for cesium removal from some polar liquid media
A microwave-assisted synthesis pathway was successfully employed to speed up the preparation of well-structured vanadium oxide samples with a nanotube morphology by making use of hexadecylammine as a structure directing agent

Summary

Introduction

Sorption processes occurring at the solid–liquid interface have gained substantial importance in remediation of liquid waste streams over the past decades since, in addition to fast operational readiness and easy handling, they may offer low-level discharge generation and significant reversibility of the removal process [1,2,3]. The in situ removal of heavy metals from industrial wastewater still remains the first priority for the international scientific and technical community [4,5,6,7,8,9,10,11], though the sorption technology has attracted increasing attention in the field of ethanol purification for fuel usage [12,13]. Even in the elimination of heavy metals from ethanol extracts [14]. In many such cases, organic-mineral oxide hybrid materials are proposed, which should combine good removal efficiency and selectivity with sufficient dispersibility in appropriate liquid media.

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Results

Conclusion