| Room temperature fluorescence of smectite clay minerals is reported for the first time. This fluorescence is shown to be directly related to iron content. Irradiation of a 1,000 ppm suspension of clay in water at 240 nm produces fluorescence exhibited at several wavelengths in the visible and near-UV region. A log-log plot of the iron content vs. the 408/240 nm peaks results in a linear plot. This allows determination of both the iron content of an unknown sample and the concentration of a known clay sample. The work used a variety of natural smectites, a synthetic smectite, a palygorskite and a kaolinite.;Absorbent clays (24/48 LVM-MS and 24/48 LVM-GA) treated to maintain a high surface area and porosity and yet retain their particle integrity in water were treated with n-octadecyldimethylchlorosilane. The exterior surfaces become hydrophobic and can remove organic materials from aqueous solution. The mechanism operates via partitioning, i.e. the less soluble the organic the more it is sorbed by the clay.;Anion exchange, chelation and cation exchange properties can all be increased with the use of functional silanes. The same absorbent clays as above were treated with different silanes functionalized to perform as ion exchange media. n-Trimethoxysilylpropyl-N,N,N-trimethylamunonium chloride (TMA) provided anion exchange functionality. N-(trimethoxysilylpropyi)ethylenediaminetri-acetic acid (EDTrA) provided chelating functionality. A grafted and subsequently hydrolyzed (10-carbomethoxydecyl)-dimethylchlorosilane (COD) provided weak cation exchange functionality. Exchange capacities and chelation were improved over untreated clay. TMA and EDTrA silanes exhibited ion exchange capacities less than predicted from the grafted amount measured gravimetrically. COD showed expected cation exchange capacity.;While exact effects remains unclear, trans-fatty acids have been implicated as having potential negative health effects. This section addresses isomerization of a singly unsaturated fatty acid, oleic acid, and its trans isomer, elaidic acid. Acid was irradiated with or without the presence of catalytically active clays. Addition of clay to oleic/elaidic acid had no effect. UV irradiation causes both isomerization and degradation. Air-, CO2- or Ar-saturated solutions showed little effect on either degradation or isomerization. With elaidic acid as starting material, up to 30--35% of non-degraded acid could be converted to oleic acid after 1 hour of irradiation without clay. |
