Nickel (II) Removal from Aqueous Solution Using Yam Peel (Dioscorea rotundata) As BIO-Adsorbent Applied to a Fixed BED System

This research evaluated nickel (II) ions removal having yam peel as adsorbent material, applied to a fixed bed continuous system; in which adsorption tests were carried out with a 0.75 mL/s flowrate of polluted aqueous solution, at a concentration of 100 ppm. The variables for this experimentation were bed depth, particle size and temperature, and the results of final concentration for each sample were determined through the method of atomic absorption spectroscopy. Obtained results showed that the most influential variable was bed depth, followed by the particle size, which, in contrast to bed depth, it was inversely proportional. According to the variance analysis ANOVA carried out in STATGRAPHICS CENTURION 18.1.02, these two variables presented a significance value smaller than 0,05%. On the other hand, despite temperature wasn’t that meaningful to the adsorption process, it turned out to be directly proportional. The optimal answer for maximum removal percentage was obtained with 0.355 mm, 62 °C and 89.35 mm of particle size, temperature and bed depth, respectively. This fact may be justified inasmuch as the surface area and the contact time between the pollutant and the adsorbent improve the process; also, the hydroxyl and carboxyl groups present in the biomass. In this manner, yam peel is considered a potential waste to be used in nickel (II) ions removal, considering that these tests achieved removal percentages between 94% and 99%.