Use of synthetic polymers of pumice for the removal of chromium in the tannery industry

Synthetic inorganic polymers are materials called geopolymers that have structural characteristics used for the removal of contaminants in wastewater. Thanks to its easy synthesis and low production costs, they have become one of the most studied materials in removal processes. In the tannery industry, huge amounts of water are used, which are mixed with chromium salts and whose final disposal is made directly on the water slopes, becoming a serious environmental problem for the world. In this work, geopolymer synthesized with pumice was used to determine the efficiency in the removal of chromium in the wastewater of a tannery in the city of Bucaramanga, Colombia. Initially, aqueous solutions were prepared to study the influence of the contact time, the pH of the initial solution and the dose of adsorbent, on the removal capacity of the metal. The maximum adsorption was presented at nine hours and at a pH value of 4, by comparing the adsorption percentages it was found that the geopolymer has better removal capacity than the precursor material, in turn a study of the sorption kinetics using the Langmuir and Freundlich isotherm model were made. Obtained geopolymer and raw material were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscope, before and after the adsorption process.