Cr ( III ) removal from aqueous solutions : A straightforward model approaching of 2 the adsorption in a fixed - bed column 3 4 5 6 ANTONIO

22 23 Prediction of breakthrough curves for continuous sorption characterization is generally 24 performed by means of simple and simplified equations. These expressions hardly have 25 any physical meaning and, besides, do not allow extrapolation. A novel and simple 26 approach, based on unsteady state mass balances, is presented herein for the simulation 27 of the adsorption of Cr(III) ions from aqueous onto a low-cost adsorbent (leonardite). 28 The proposed model overcomes the limitations of the commonly used analytical 29 solution-based models without the need for complex mathematical methods. A set of 30 experimental breakthrough curves obtained from lab-scale fixed-bed columns was used 31 to calibrate and validate the proposed model with a minimum number of parameters to 32 be adjusted. 33 34