Abstract: A process for the production of an adsorbent suitable for use in the purification of edible oils such as soya oil comprising treating a layered clay mineral with a solution of a pillaring material such as a suitable aluminum cation so as to cause the adsorption of at least some of the pillaring material into the clay mineral and removing solvent to deposit pillaring material within the clay mineral, the process being characterized by the removal of at least some structural aluminum from the clay mineral by an acid treatment prior to contact with the pillaring material. The resulting pillared material, which can have a higher SiO.sub.2 :Al.sub.2 O.sub.3 ratio than normal as a result of the initial acid treatment can give chlorophyll adsorption capacity above 70% and even, in some instances, up to about 99%.