The adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) by two powdered co
al activated carbons was studied in aqueous solution. The modelling of the
adsorption equilibrium showed that the adsorption of 2,4-D fitted a Langmui
r isotherm. Adsorption was influenced by the activated carbon type, adsorbe
nt concentration and solution characteristics. The adsorption was found to
decrease with an increase in pH over the range 1.5-9. Maximum adsorption oc
curred at pH approximate to 2.5, which corresponds to the 2,4-D pK(a) value
. The amount of 2,4-D adsorbed was also found to depend on the NaCl concent
ration.