Fixation capability of recycling materials as potential additives for cesium immobilization in contaminated forest soil

The fixation capability of cesium on five recycling materials was compared through two sets of sorption experiments using the materials mixed with and without soil. The estimated Freundlich constant K and the distribution of sorbed cesium on the materials revealed a general order of the fixation capability as carbonized sludge > coconut shell biochar > incinerated sewage sludge ash > rice husk biochar > slag. Parametric strong positive correlations were found existent between the fixation capability of cesium and the property-related indexes of the materials such as cation exchange capacity, organic matter content and the potassium concentration.