Study of Optimum Conditions for Adsorption Chromium in Aqueous Solution by Dragon Peel

This research was focused on optimum conditions determination for adsorption chromium (III) and chromium (VI) in aqueous solution by dragon peel (Selenicereus undatus). Effects of contact time (1-180 min), pH (2-8), adsorbents dose (0.5-20 g L^-1) and adsorption isotherm were studied. The results indicated that the optimal set of conditions for chromium adsorption was contact time of 120 min, the pH values of 2.4-5.0 and 2.0 for chromium (III) and chromium (VI), when using adsorbent doses of 10 and 20 g/L respectively, increasing the amount of dragon peel increased the adsorption capacity. From isotherm study, adsorption of chromium (III), chromium (VI) and chromium (III) mixed with chromium (VI) were found that all corresponded to the Freundlich model (R2 = 0.970, 0.989 and 0.991 respectively), which is multilayer adsorption and heterogeneous surface adsorption.