Technological applications of organo-montmorillonites in the removal of pyrimethanil from water: adsorption/desorption and flocculation studies

14 páginas.-- 7 figuras.-- 5 tablas.-- r eferencias.-- Electronic supplementary material The online version of this article(doi:10.1007/s11356-017-9016-3) contains supplementary material,which is available to authorized users

Pyrimethanil (2-aniline-4, 6-dimethylpyrimidine, PRM) is used in fruit packing plants to control fungal infections and diseases. The effluents greatly polluted with this fungicide, as a point source contamination, need to be technologically treated for their regeneration before they reach water bodies. This work evaluates the use of organo-montmorillonites, synthetized in our laboratory, for their application in adsorption and coagulation/flocculation processes for the removal of PRM from water. The adsorption-desorption performance of PRM in a raw montmorillonite (Mt) and several organo-montmorillonites (organo-Mt) obtained by different amounts and types of exchanged surfactants (octadecyltrimethylammonium (ODTMA) and didodecyldimethylammonium (DDAB) bromides and benzyltrimethylammonium chloride (BTMA)) was studied. The PRM adsorption on raw Mt was assigned mainly to an interlayer occupancy, while hydrophobic interactions between PRM and the surfactants in the exchanged samples increased PRM adsorption, which was correlated with the surfactant loading. PRM desorption showed irreversible behavior in raw Mt, which changed to reversible for organo-Mt samples, and was also correlated with the increase of surfactant loading. Two of the organo-Mt with high surfactant loading (twice the CEC) were assayed for the removal of commercial PRM in coagulation/flocculation tests, and their performance was compared to that of the native clay (Mt). The use of the organo-Mt produced flocculation at a very low ratio (0.5 g L−1), whereas no flocculation was observed with Mt. These results proved the feasibility of the use of organo-Mt for the treatment of wastewater contaminated with PRM using a low organo-Mt/liquid ratio

Financial support of the Argentine Ministry of Science, Technology and Innovation—FONARSEC FS-Nano 008 and the Spanish Ministry of Economy and Competitiveness (Ref. CTM2013-42306-R, supported by funds from the European Regional Development Fund) and the Spanish Agency for International Cooperation for Development—Spanish Ministry of Education A/023433/10-09 is gratefully acknowledged. R.M.T.S. is a member of the National Council of Scientific and Technological Research (CONICET) and F.M. Flores acknowledges CONICET and Argentine (BEC.AR) fellowships.

Peer reviewed