Adsorption of a Reactive Dye by Modified Celluloses

The equilibrium adsorption of commercial Procion Brilliant Red 2BS by acid‐modified cellulosie fibres and by standard cellulose altered by the specific action of different oxidising agents is studied. The equilibrium adsorption by all the fibres decreases rapidly in the initial stages of the action of acid, but tends to level off with further hydrolysis. The extent of the decrease depends mainly on the rate of removal of the hydrolysable fraction and the extent of crystallisation of the cellulose chains during the action of the acid. The reduction in dye uptake is more marked when primary alcoholic groups are converted into carboxyls than when secondary alcoholic groups are similarly oxidised.