Removal of As, Cd, Cr, Cu, Ni and Zn from polluted water using an iron based sorbent

In this study fixed-bed sorption filters are filled with an iron based sorbent (ferrosorp plus, FP) and used to remove a range of heavy metals (i.e. As, Cd, Cr, Cu, Ni, and Zn) from polluted water. It is found that FP is very effective at simultaneous removal of the heavy metals, and the magnitude of heavy metal removal in a decreasing order is Cd, Ni, Cr, Zn, Cu and As. Furthermore, the effect of humic acid (HA) and light on the heavy metal removal is also tested. The data show that both the presence of 100 mg/L HA and the absence of light suppress the removal, with the suppression due to HA being more significant. A mathematical model (i.e. Thomas model) is employed to study the data further and to predict the breakthrough adsorption capacities. Accordingly, capacities of 10.57, 21.85, 15.96, 12.86, 17.54, and 11.07 μmol/g are found for As, Cd, Cr, Cu, Ni and Zn, respectively, at an average inflow pH of 6.8 and heavy metal concentration of ≈2.8 μM. It is concluded that FP has high affinity to heavy metals and it can be used (e.g. as a filter medium) to treat waters containing a wide range of heavy metals, e.g. stormwater, industrial wastewater.