There are three types of organoclays which are used in industry to remove oils, greases, surfactants, EDTA, anionic and cationic-type heavy metals. They are called nonionic, cationic and anionic organoclays. The nonionic ones are used primarily for non-polar, hydrophobic, low solubility compounds such as oil, grease and surfactant removal. The cationic types remove such compounds as chromate, arsenate, and humic and fulvic acids. The anionic types remove EDTA and other positively charged organics. Heavy metals are removed either by ion exchange on the clay portion of the organoclay, or by co-precipitation with iron. This presentation will describe the chemistry of organoclays and will show laboratory results. Case histories, relating to the use of organoclays for the treatment of wastewater, also will be presented.
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