Removal of organophosphorus insecticides from aqueous solution by adsorption on microporous pillared clays and mesoporous alumina aluminum phosphates
(EN)
Sakellarides, T. M.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Sakellarides, T. M.
(EN)
Al-pillared montmorillonite (ecaza), Fe-Al-pillared montmorillonite (ecfaza) and mesoporous alumina aluminum phosphates (AAPs) were contacted with aqueous solutions of organophosphorus insecticides, ethyl parathion, methyl parathion, fenitrothion and fenthion, at a concentration ranging between 1 and 10 mg l(-1), in batch equilibrium experiments, in order to determine their adsorption properties. The removal of organophosphorus compounds by the adsorbents increased in the following order: methyl parathion<fenitrothion<fenthion<ethyl parathion. In the case of ethyl parathion, the more lipophilic insecticide, the increased affinity allowed adsorption to occur much more efficiently than in the case of other compounds. At equilibrium ecaza montmorillonite adsorbed 96.4% of ethyl parathion, 92.3% of fenthion, 92.3% of fenitrothion and 87.6% of methyl parathion. The adsorption of selected organophosphorus insecticides on mesoporous AAPs was much less pronounced compared to the two clays but increased with the ratio of P/A1, as the surface acidity of those solids also increased. The AAP mixture with a ratio P/Al=0.6 adsorbed 81% of ethyl parathion, 83.1% of fenthion, 39.8% of fenitrothion and 61.4% of methyl parathion. The amounts of insecticides decomposed during the treatment increased in AAPs after 24 hours and especially in those with a higher P/Al ratio (=0.6) and reach 70.5% for ethyl parathion, 59.2% for fenthion, 32.5% for fenitrothion and 54.8% for methyl parathion.
(EN)
