Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry

Masanobu Mori; Toshinobu Suzuki; Tsuyoshi Sugita; Daisuke Nagai; Kazuo Hirayama; Makoto Onozato; Hideyuki Itabashi

doi:10.1016/j.aca.2014.06.015

Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry

Anal Chim Acta. 2014 Aug 20:840:42-8. doi: 10.1016/j.aca.2014.06.015. Epub 2014 Jun 12.

Authors

Masanobu Mori¹, Toshinobu Suzuki², Tsuyoshi Sugita², Daisuke Nagai², Kazuo Hirayama³, Makoto Onozato², Hideyuki Itabashi²

Affiliations

¹ Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan,. Electronic address: mori@gunma-u.ac.jp.
² Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan.
³ College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642, Japan.

PMID: 25086892
DOI: 10.1016/j.aca.2014.06.015

Abstract

This study aimed to evaluate the heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel (CaAD) and incorporate this biosorbent into a flow analytical system for heavy metal ions using flame atomic absorption spectrometry (FAAS). The biosorbent was synthesized by electrostatically coating calcium alginate onto diethylenetriamine (dien)-silica gel. Copper ion adsorption tests by a batch method showed that CaAD exhibited a higher adsorption rate compared with other biosorbents despite its low maximum adsorption capacity. Next, CaAD was packed into a 1mL microcolumn, which was connected to a flow analytical system equipped with an FAAS instrument. The flow system quantitatively adsorbed heavy metals and enriched their concentrations. This quantitative adsorption was achieved for pH 3-4 solutions containing 1.0×10(-6) M of heavy metal ions at a flow rate of 5.0 mL min(-1). Furthermore, the metal ions were successfully desorbed from CaAD at low nitric acid concentrations (0.05-0.15 M) than from the polyaminecarboxylic acid chelating resin (Chelex 100). Therefore, CaAD may be considered as a biosorbent that quickly adsorbs and easily desorbs analyte metal ions. In addition, the flow system enhanced the concentrations of heavy metals such as Cu(2+), Zn(2+), and Pb(2+) by 50-fold. This new enrichment system successfully performed the separation and determination of Cu(2+) (5.0×10(-8)M) and Zn(2+) (5.7×10(-8) M) in a river water sample and Pb(2+) (3.8×10(-9) M) in a ground water sample.

Keywords: Adsorption; Calcium alginate; Desorption; Enrichment; Flow system; Heavy metal.