Abstract In this work, a Colombian sodium bentonite geopolymer, montmorillonite type, activated with commercial sodium silicate, was synthesized for its later use as sorbent material of ammonium cations in leached waters from soils treated with PINAL, an ammonia-based herbicide of glufosinate used to eradicate the use of illicit crops. The raw material and geopolymer obtained are characterized by the Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy technique, to determine the structural difference between the bonds created during the geopolymerization process, as well as to know the transformation of the crystalline phases of the material. Through this analysis and study of dispersion spectroscopy, it was possible to establish the effect of the eliminated ammonium cation on the structure of the geopolymeric material and propose a sorption mechanism, in addition, an improvement in the removal capacity of these ions from the geopolymeric material was observed.