「だんだんエコ玉」の制作とそのヒ素吸着能力(予報)

　“Dan Dan Eko Dama”, a ceramic ball made of Kawatsu red clay from Matsue is used for arsenic adsorption from water. The balls are made of a mixture of red clay and sludge from the granite sand widely produced in the Okuizumo district. The red clay is characterized by high contents of Fe2O3 (15 wt%) and Al2O3 (30 wt%) because it is a weathering product of basalts in the Miocene Matsue Formation. The granite sand sludge also has a high concentration of Al2O3 (20 wt%). The sludge is a waste of industrial activities and which previously has not been utilized as a resource. Column experiments showed the potential of adsorption of arsenic from solution. Arcenic content of water (0.1 mg/L) can be declined below the environmental guide line (0.01mg/L) under the high hydraulic conductivity (k = 10-2 m/s). Ceramic balls of red clay and mixtures of red clay and sludge can be used as an environmental material for removal of arsenic from natural water.