Abstract: The invention provides a range of modified organoclays comprising intercalated moieties to provide an effective mechanism for attracting organic compounds into the interlamellar spaces in close proximity to other intercalated reactants. The intercalated moieties provide three functions, namely (a) pillaring to create adequate interlamellar spacing to provide access for larger molecules, e.g. polychlorinated biphenyls and poly aromatic hydrocarbons, (b) organophilic attraction of like polarity organic compounds, and (c) a reactive environment in which the organic substrates can be permanently bonded to the clay surfaces and pillaring agents. The invention also resides in methods of treating soil or other materials with such modified organoclays in order to remove or bind hazardous organic molecules.