Adsorción de cromo hexavalente presente en aguas del Río Bogotá utilizando cáscara de café

Abstract

In this degree work, the efficiency of activated carbon made from coffee peel to eliminate hexavalent chromium present in the Bogotá River was evaluated. How the size of carbon particles affects their adsorption capacity was also investigated. The key steps include obtaining coffee husks, activation with potassium hydroxide, carbonization, grinding and separation into three particle sizes (0.6 mm, 0.85 mm and 1 mm). Water samples were then taken from the Bogotá River at three different locations and physicochemical analyzes were performed. All samples were within permitted limits. A UV-VIS spectrophotometry process was carried out before and after adding the activated carbon to the samples, using a reagent for hexavalent chromium in low ranges. Subsequently, adsorption isotherms were constructed to evaluate the performance of the activated carbon as a function of its particle size. The results were generally satisfactory, since no particle size had an adsorption capacity below 60%. A directly proportional relationship will be observed between the particle size and the adsorption capacity, with the largest particle (1 mm) being the one that had the highest adsorption capacity (75.42%), followed by the medium-sized particle (0 .85 mm) with 65.44%, and finally, the smallest particle (0.65 mm) with 60.57%.