The experiments on the effect of contact time on the adsorption
of 2,4-D by CCAC were carried out by measuring the residual
2,4-D concentration at predetermined time intervals. Fig. 6 shows
the effect of contact time on the percent removal of 2,4-D by CCAC
for different initial concentrations of 2,4-D at 30 ◦C. The adsorption
increased with contact time and was rapid during the initial
stages followed by a slower uptake until