マンガン酸化物Mn₂O₃に対する水溶液中カドミウムの吸着

抄録

In the present study, the adsorption of cadmium on Mn₂O₃ in aqueous solution was investigated. The Mn₂O₃ was prepared by heating MnCO₃ at 300∼800°C for 4.5 hours.
The findings of the present study are as follows:
(1) The Mn₂O₃ showed the ability to adsorb and concentrate cadmium from aqueous solution to levels reaching 23.2∼46.6mg · g^-1 under the following conditions : heating temperature=300°C, solution pH=7, and cadmium concentration=1∼100mg · l^-1. The surface area of the Mn₂O₃ was 50m² · g^-1.
(2) The cadmium was eluted from the Mn₂O₃ by adding 0.5mol · l^-1 HNO₃, and the adsorption ability of the Mn₂O₃ recovered to nearly the previous level.
(3) We attempted to remove cadmium from a sample (1l) of mining effluent (0.117mg · l^-1 Cd) from the Yoshino mine in Akita prefecture, Japan using Mn₂O₃ (1g). The results showed that the cadmium concentration of the treated effluent decreased to under 0.001mg · l^-1 in 2.5 hours.