Removal of arsenic(V) ions from aqueous media by adsorption on multiwall carbon nanotubes thin film using XRF technique

Abstract

A solid phase extraction using multiwalled carbon nanotubes, modified with a tertiary amine, ALIQUAT 336, has been developed as a preconcentration technique for the determination of trace amounts of As(V) in water samples. After “batch-based mode” As(V) adsorption on ALIQUAT 336-Multiwalled carbon nanotubes, determinations were made directly on the solid by X-Ray Fluorescence spectrometry, which reduces the number of reagents used and minimizes the sample handling.The method herein described combines the advantages of solid phase extraction with the benefits of any X-Ray Fluorescence method associated to the large areas held by the carbon nanotubes, which make them a promising solid sorbent for preconcentration procedures.The enrichment factor was calculated considering that the thin film obtained from the 100mL solution of 1000μgL−1 As had a final thickness of 0.04mm and a final diameter of 16.7mm, the volume deposited on the pellet was 0.0088cm3. Thus the preconcentration factor obtained was 104 fold, which represented a highly satisfactory value for trace analysis by X-Ray Fluorescence.Satisfactory results were obtained for the determination of arsenic in samples of the standard reference material “NIST 1643e—Trace Elements in Water and drinking water”.