Water purification from organic pollutants by optimized micelle-clay systems

Removal of anionic pollutants (imazaquin, sulfentrazone, sulfosulfuron) and neutral pollutants (alachlor, acetochlor, chlorotoluron, bromacil) from water by micelles preadsorbed on montmorillonite was studied. Micelles of octadecyltri-methylammonium and benzyldimethylhexadecylammonium (BDMHDA) were used. The micelle-clay systems (1% w/w) removed 87-99% of the pollutants from their water solutions containing 1-33 mg/L of herbicide. The nature of the headgroup of the organic cation, which forms the micelles, is critical. Desorption of imazaquin and acetochlor from 0.3% (w/w) suspension of BDMHDA-clay complex after 24 h was around 7% in the range of adsorbed amounts from 0.6 to 15.3 mg/g. These results indicate rather slow rates and small extents of release of pollutants from micelle-clay complexes. Column filters (25 cm) made of a mixture of quartz sand and BDMHDA micelle-clay complex at 100:1 w/w ratio removed at least 99% of above pollutants from initial solutions containing 10 mg/L; 99.5 and 97% of sulfosulfuron and alachlor were removed from their initial solutions containing 200 and 5 mu g/L, respectively. These data indicate that micelle-clay complexes are very efficient for water purification from organic contaminants.