Removal of chromium from alkaline wastewater with natural zeolite, in fixed bed adsorption column

Abstract

The technology of column of adsorption of fixed channel is evaluated, to laboratory scale, to neutralize and to reduce the concentration of ions chromate from alkaline industrial waste of the fibrocement Company "Armando Mestre" from Santiago, from Cuba, using a natural type mordenita zeolite (ZN) as adsorbent. To make the experiments, were carried out preliminary tests with channels of different grains, being selected an average size of particles of 0,85 mm. By coloidalchemistry tests it was determined that the point of zero load of this zeolite is of 7, 3; moving up to 7,7 when it enters in contact with a chromate solutions. This result, jointly with the SEM images, with the rupture curves that describe the pH neutralization processes and of adsorption of the chromium in the zeolita channel, as well as with the positions of the rupture points, they corroborated that the chromate’s ions were absorbed for the external surface of the zeolítico mineral by means of a process of specific polar adsorption. It was obtained experimentally, and was confirmed statistically, that the particle size is the variable that more influences in the position of the rupture point, being comparatively smaller the influence of the volumetric flow of the liquor. Finally, as a result of the carried out work it was proven that the technology of column of adsorption of fixed channel, with the employment of ZN as adsorbent, is appropriate for the purify and neutralization of alkaline industrial waste.