Uptake and Speciation of Inorganic Arsenic with Cellulose Fibre Coated with Yttrium Hydroxide Layer as a Novel Green Sorbent

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Abstract

A novel adsorbent was developed by coating yttrium hydroxide precipitate layer on cellulose fibre. This material takes up ca. 98% of 5 µg·L−1 As(III) and As(V) at low pH (pH<7), while a favorable selectivity for As(V) was achieved within pH 11–12. In practice, a mini-column packed with Y(OH)3 precipitate layer coated cellulose fibre particles was incorporated into a sequential injection system for selective uptake of arsenate at pH 11.5. The retained arsenate was afterwards recovered with 50 µL of 0.8 mol·L−1 NaOH solution as eluent, followed by hydride generation in a reaction medium of 2.0 mol·L−1 HCl and 1.0% NaBH4 solution (W/V, in 0.5% NaOH) after pre-reduction of arsenate to arsenite by KI-ascorbic acid (5%, W/V), with detection by atomic fluorescence spectrometry. Total inorganic arsenic was quantitatively taken up at pH 6.0 by following the same procedure and arsenic speciation was performed by difference. With a sample volume of 1.0 mL, an enrichment factor of 16.4 was derived with a detection limit of 17 ng·L−1 within a linear range of 0.05–2.0 µg·L−1. A relative standard deviation (RSD) of 2.6% (0.5 µg·L−1, n=11) was achieved. The procedure was validated by analyzing arsenic in a certified reference material GBW 09101 (human hair), and speciation of inorganic arsenic in natural water samples. The entire process requires no organic solvents, thus Y(OH)3 coated cellulose fibre provides a green adsorbent.

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