Abstract
The sorption properties of cadmium on the bottom sediments deposited in the Lake Biwa etc. were investigated and estimated, especially in relation to both physical-chemical characteristics of the sediments and water quality. It was noticed that the particles of the sediments tend to become smaller in size with an increase in the water depth at sampling point. Besides, both moisture and CODcr increase as the particle becomes smaller. The sorption experiments in a batchwise method resulted in the adsorption isotherm expressed by Freundlich type formula. Three kinds of sediments were utilized for this experiment, i.e., wet, dry and heated ones. The parameters estimated from the adsorption isotherms were dependent on the pretreatment process of the sediments. This suggests the significance in both moisture and organic substaces. The effect of several coexisting ions like alkali metal etc. on the Cd sorption of the sediments was observed. Moreover, the effect of both DO and pH was also referred to. It was found that these factors are quite responsible for the change of the Cd sorption capacity.
