title: Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry.
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.
authors.affiliation: Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan,. Electronic address: mori@gunma-u.ac.jp.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Mori
authors.affiliation: Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan.
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sugita
authors.affiliation: Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nagai
authors.affiliation: College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hirayama
authors.affiliation: Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Onozato
authors.affiliation: Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin-cho, Kiryu 376-8515, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Itabashi
keywords: Adsorption; Calcium alginate; Desorption; Enrichment; Flow system; Heavy metal