Abstract: A process for treating produced water for removal of a majority of the water-insoluble petroleum oil components using an oil-adsorbent, such as an organophilic clay or an acid-activated smectite clay, such as acid-activated calcium bentonite clay, to provide a reduced-oil produced water in a first or pretreatment step; and then treating the reduced-oil produced water with a macroreticular adsorbent resin, such as styrene cross-linked with divinylbenzene, or a polyvinyl pyridine resin to remove marginally water-soluble petroleum oil components, such as C.sub.6 + carboxylic acids, phenolics, naphthenic carboxylic acid compounds, and aromatic carboxylic acids, such as benzene carboxylic acids.

Abstract: A method for encapsulating hazardous cations is provided comprising supplying a pretreated substrate containing the cations; contacting the substrate with an organo-silane compound to form a coating on the substrate; and allowing the coating to cure. A medium for containing hazardous cations is also provided, comprising a substrate having ion-exchange capacity and a silane-containing coating on the substrate.