Photon Factory Activity Report 2004 #22 Part B (2005)
Materials Science

10C/2004G077

Environmentally-Concerned Heavy-Metal Distributionin Adsorbent Gels
Kazuhiro HARA1, Masaaki SUGIYAMA2, Masahiko ANNAKA3,45Yuji SOEJIMA and Toshihiro OKAJIMA
1

Institute of Environmental Systems, Faculty of Engineering, Kyushu University,
6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
2
Kyoto University Research Reactor InstituteKumatori-cho Sennan-gun, Osaka 590-0494, Japan3
Department of Chemistry, Fuculty of Sciences, Kyushu University
6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
4
Department of Chemistry, Fuculty of Sciences, Kyushu University
6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
5
Kyushu Synchrotron Light Research Center,
8-7 Yayoigaoka, Tosu, Saga 841-0005, Japan

Introduction
After the announcement from the Ministry of Healthand Welfare of Japan in 1968 that the cadmium
discharged from Kamioka mine in the Jintsu River
upstream was suspected to cause the Itai-itai disease, theheavy metal contamination had suddenly attracted muchattention. Triggered by this, the concern about heavymetal environment pollution increased greatly and theheavy metal effluence has been regulated severely. In
these conditions, the situation has been remarkably
improved on the heavy metal contamination. One may
have a view that the heavy-metal environmental pollution
has been already solved nowadays. However, they must
realize that harmful heavy metals which have alreadybeen flown out into the environment will not disappear
and that the polluted area will spread out by diffusion. In
order to prevent the heavy metals from spreading out intoa wide area, efficient recovery and fixation systems areindispensable, which should be easily handled andconducted without special equipments. Besides, after therecovery, heavy-metal adsorbed materials should be easily
conveyed. The authors expect that ionized gels havehighly potential applications to the heavy-metal recovery,
therefore, have been examining the heavy-metal
adsorption ability of several ionized gels and theirstructural change by the heavy-metal adsorption.
SAXS Observations of a Heavy-Metal Adsorbed Gel
In the present study, the authors have investigated ion
absorption effects on a nanostructure of an N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel.
IIIn order to examine Cu distribution in the dehydrated
IICu -captured NIPA/SA gel, the authors observed SAXS
profiles with changing incident-X-ray energy at BL-10C.
Figure 1 shows incident-X-ray-energy dependence ofdifference SAXS-profile distribution derived by deducing

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Users' Reporta SAXS profile at 9.04 keV (far from the Cu-K absorptionedge) from that observed at each incident energy in arange from around 8.90 to 9.06 keV. As can be easily seen,at the energy of the Cu-K absorption edge, the intensity
difference takes a minimum around the SAXS peak
position. Because the anomalous dispersion effect only
IIoccurs by Cu element, this characteristic feature directlyIIdemonstrates a close relation between the Cu distribution
and hydrophilic domain structure. This result indicates alocalized distribution of the cupper ions in the hydrophilic
domain.
* haratap@mbox.nc.kyushu-u.ac.jp

Fig.1. The incident-X-ray-energy dependence ofdifference SAXS-profile distribution derived bydeducing a SAXS profile at 9.04 keV (far from the CuK absorption edge) from that observed at each incident
energy in a range from around 8.90 to 9.06 keV..