Study on the ferric iron adsorption from acid mine drainage on Lewatit resin in a fixed bed column

Abstract

The study aimed to determine the effect of the acid mine drainages` flow rate on the iron adsorption by ion-exchange resin LEWATIT MonoPlus TP 207 in a fixed-bed column and to evaluate which widely used models describe that process better. The ferrous iron was preliminary chemically oxidised by H2O2 and Na2CO3 addition and increased pH to 3.50 combined with the solution purging with air. After assembling fixed-bed columns, their bed volume (BV) was determined. The treated mining solution was delivered to fixed-bed columns by a peristaltic pump at 2.0, 3.0, and 4.0 BV flow rates. The iron adsorption efficiency on the LEWATIT resin was studied depending on the applied flow rate and the volume being treated. The experimental data obtained were modelled using the Bohart-Adams, Thomas, Yoon-Nelson, and Clark models. The results showed that at constant experimental conditions (temperature, ferric iron concentration, and pH), the applied flow rate had a significant effect on the parameters which are important from a practical (efficiency of iron removal, (Y); equilibrium iron and equilibrium copper contents of the resin, (qeq)) and a theoretical point of view (rate constants (kBA, kTh, kYN, r); time of breakthrough (τ)). The Yoon-Nelson and Clark models were the models that best fitted the experimental results.