Nano-iron based coated biomass as packing material in fixed-bed reactors for Lead removal from wastewater: experimental and mathematical modelling

The lead pollution of natural environments is considered a severe issue due to the high toxicity and mobility of lead ionic species. The present study deals with the removal of Pb(II) ions from synthetic wastewater by means of iron-based coated olive stones, used as packing material in lab-scale fixed bed columns. The biomass was coated through the direct precipitation of nano-iron oxide nanoparticles and demonstrated a notable Pb(II) sorption capacity. In detail, the continuous experiments showed a Pb(II) removal efficiency of 80% at an initial Pb(II) concentration of 50 mg/L, a bed height of 12 cm and an inlet flowrate of 4 mL/min. Different operating parameters values were varied (initial Pb(II) concentration, inlet flowrate and bed height) at pH>pH of zero charge of the packing material. The obtained breakthrough curves were fitted by suitable dynamic models, to obtain the regressed model parameter values for a subsequent pilot-scale process simulation and scale-up.