The adsorption capacity of adsorbent materials (organophilic clays) prepared from a homoionic clay was compared for the removal of nitrates and nitrites present in aqueous solution in batch systems at room temperature.The organophilic clays were obtained by replacing the exchange cations present in the precursor clays with quaternary ammonium cations. For this purpose, two precursor clays were used, a natural clay (FS) and the same clay exchanged with sodium (CP) and two ammonium cations with different structure: hexadecyltrimethylammonium (HDTMA) and benzyltriethylammonium (BTEA) with amounts equivalent to 1.5, 2.5 and 4.0 cation exchange capacity (C.E.C.). Ion exchange is important to obtain a good affinity between organoclay and anionic contaminants. The clays were characterized by XRD, FTIR and SEM-EDX. The maximum adsorption capacities of the CP-HDTMA-4.0 clay for nitrate and nitrit...

The present work was financed by the project 152-2006-CONCYTEC-OAJ granted by the National Council of Science and Technology to B.L. A.N. thank the H. McCracken doctoral scholarship at the New York University. The authors would also like to thank the Department of Chemistry of the Faculty of Sciences and Philosophy of the Cayetano Heredia University, the Section of Chemistry of the Department of Sciences of the Pontifical Catholic University of Peru and Norma Cuizano, Todd Kelly, Richard Buran and Paul Henkel for their contributions and critical comments concerning this research.

The authors thank the National Council of Science and Technology of Peru for the grant 152-2006-CONCYTEC-OAJ used in carrying out this work. We also wish to extend our grateful appreciation to Rosario Portales, Todd Kelly and Richard Buran for their contributions and critical comments regarding this research.

The authors gratefully acknowledge the financial support for this work provided by CONCYTEC (Project 371-2012-CONCYTEC-OAJ),