Presentation Information
[3K0501-03-01]Layer stacking regulation of montmorillonite with Ca2+ to improve the capability as an adsorbent for arsenic
○Yusuf Olalekan Zubair1, Zhuangling Ye1, Hisanori Iwai1, Keishi Oyama2, Hayato Yodoya3, Yuuki Shimada3, Hiromichi Matsumoto3, Kohei Mitsuhashi3, Chiharu Tokoro1,4 (1. Waseda University, 2. Kyushu University, 3. Nittetsu Mining Co., Ltd., 4. The University of Tokyo)
Chairperson: ジョン サンヒ（秋田大学）、パク イルファン（北海道大学）
Keywords:
Ca-modified montmorillonite,Arsenic,Groundwater,Adsorption mechanism
Arsenic-bearing groundwater is recognized as one of the most severe global environmental problems, posing a significant threat to public health. Weathering of arsenic-bearing minerals and mining-related activities are the primary sources of arsenic contamination. This study investigates the arsenic removal mechanism of Ca-modified montmorillonite prepared using an ion-exchange process as a cost-effective adsorbent for groundwater treatment. The Ca-modified montmorillonite exhibited an arsenic adsorption capacity of approximately 0.20 mg/g, nearly four times higher than pristine montmorillonite, with adsorption equilibrium achieved within 2 hours. X-ray diffraction analysis combined with SEM-EDS and zeta potential measurements revealed that Ca²⁺ intercalation transformed the montmorillonite from a dispersed card-house structure to a more oriented face-to-face stacking configuration. This structural reorganization expanded the interlayer spacing and reduced the negative surface charge of montmorillonite. The modified face-to-face structure enhanced electrostatic attraction between AsO43– and the positively charged clay edges, facilitating efficient arsenic removal. Thus, this simple approach offers a cost-effective solution for arsenic remediation in contaminated groundwater.