Modified silicates and porous glass as adsorbents for removal of organic pollutants from water and comparison with activated carbons

It is demonstrated that a variety of modified silicate mineral sorbents can be utilized for the removal of organic pollutants from a water suspension or by a filter. Column filters filled with a mixture of quartz sand and organic micelle-montmorillonite (100:1 w/w) or zeolite were constructed. The micelle-clay filter removed 91% of ethylene dibromide (EDB) from an initial solution of 0.2 μg/L and 99.9% of the anionic pollutants sulfosulfuron, imazaquin, sulfentrazone and the neutral bromacil and chlorotoluron from an initial solution of 10 ppm. In contrast a filter filled with activated carbon at the same weight of the organic cation and sand, or without sand removed between 47.6% and 79% of these pollutants. Comparative capacity measurements yielded removal of sulfentrazone (75 ppm initial) at weights corresponding to 18.7% and 5.5% of the weights of the organic cation or activated carbon in the filter, respectively. For the antibiotic trimethoprim the micelle-clay system was not efficient; the clay mineral montmorillonite and the zeolite clinoptilolite yielded respectively 80% and 99.9% removal from its dispersion. A clinoptilolite/sand filter gave 91% removal. We also present varying degrees of efficiencies of removal of isoproturon, benzoic acid, and 1,2 dichlorobenzene by an organo-clay and by silica (controlled pore glass (CPG))-polycation immobilized micelles (SPIM) or without immobilized micelles.