Characterisation of transition metal removal from mechanical pulps by chelating with DTPA in a displacement system

Chelation in a displacement system (displacement chelation) is an effective way to remove transition metal ions from pulp fibres. The breakthrough cur ves of manganese removal were studied as functions of process variables: te mperature, superficial velocity and DTPA concentration. It was found that t hese three parameters did not affect the manganese breakthrough curves. The se results are explained by the hypothesis that the displacement chelation process is neither a kinetic nor diffusion controlled process, and that it is governed by the flow characteristics of the pulp pad.