The adsorption of chloridazon (5-amino-4-chloro-2-phenylpyridazin-3(2H)-one) on a new type of material formed by kerolite/stevensite bearing lithofacies and on a bentonite, desiccated at 110 degreesC from aqueous solution at 25 degreesC has been studied by using batch experiments. In addition, column experiments were carried out with these samples using aqueous solutions of chloridazon at a concentration (C) of 45 x 10(-4)cmol dm(-3). The experimental data points have been fitted to the Langmuir equation to calculate the adsorption capacities (X-m). Values for X-m ranged from 0.072 cmol kg(-1) for bentonite up to 1.30 cmol kg(-1) for kerolite. The removal efficiency, R, ranged from 17.1% for bentonite up to 85.1% for kerolite. The batch experiments show that the kerolite is more effective than bentonite in adsorbing chloridazon. The column experiments show that kerolite might be reasonably used in removing chloridazon, the data indicating that a readily available and inexpensive Spanish kerolite can be employed as a filter for contaminated waters with chloridazon, so controlling its release to the environment.