Modified clays contg. organic cations - are heat-treated to form intercalated graphite phase, useful as adsorbents, esp. for water purificn.

摘要

New clays (I) have their cation-exchange capacity satd. by at least organic cations (i.e. by organic or a combination of organic and inorganic cations) and contain a graphite phase intercalated between the clay layers. Also claimed is the prodn. of (I) by treating clays to saturate their cation-exchange capacity with at least organic cations, and heat treating them in air at ca. 500 deg.C. Also claimed are clays (II) with their cation-exchange capacity satd. by organic and inorganic cations, for prodn. of (I). Pref. organic cations are quat. ammonium ions. Inorganic cations are metal polycations, esp. Al137+. In (II), at least 25% of the cations are inorganic. The heat-treated prod. may be further treated to saturate its cation-exchange capacity with at least organic cations. USE/ADVANTAGE - (I) are useful for purifying liquids contg. organic mols., esp. for removing low-polarity 'micropollutants', e.g. pesticides, herbicides and organic solvents, from drinking water. (I) have a high specific adsorption capacity for hydrophobic mols., have a high surface area (ca. 750 m2/g in water), and have good thermal stability, making regeneration a possibility.