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.

The main objectives of this study were to study the simultaneous heavy metal (i.e. As, Cd, Cr, Cu, Ni, and Zn) removal using FP columns and to elucidate the effect of HA and light on the removal. Using the data obtained from the column experiments and Thomas model, the following conclusions are drawn: • The results suggest that FP is highly efficient for simultaneous adsorption of As, Cd, Cr, Cu, Ni, and Zn from aqueous solutions with estimated breakthrough capacities of 10.57, 21.85, 15.96, 12.86, 17.54, and 11.07 μmol/g for As, Cd, Cr, Cu, Ni and Zn, respectively. • The presence of 100 mg/L HA significantly suppresses the removal of all heavy metals, and the suppression is the highest for Cr with 81%. • The columns run at the dark demonstrated moderately suppressed heavy metal removal in the absence of HA, while the suppression was minor in the presence of HA. • It is concluded that FP can be developed as an effective filter media for the treatment of waters simultaneously containing heavy metals like As, Cd, Cr, Cu, Ni and Zn (i.e. stormwater and industrial wastewater).