Oxidation–microfiltration removal of Fe(II) from water

Abstract

We studied iron removal from water by oxidation and microfiltration. Water sample containing ferrous ion was oxidized by air at a constant flow rate and pH. The suspension was then subjected to crossflow microfiltration using mixed cellulose ester and polyvinylidene fluoride membranes. Results reveal that iron removal efficiency mainly depended on oxidation process conditions, and the filtration process enhanced iron removal efficiency. Oxidation process at pH 8 followed by microfiltration produced permeate containing iron at concentrations below 0.3 mg/L, while a slightly higher iron concentration was found at pH 7.5. Under laminar and turbulent flow conditions, permeate flux increased as the filtration pressure varied from 5 to 10 psi. Increasing crossflow velocity from 0.48 to 1.33 m/s increased the permeate flux. Cake resistance was the dominant resistance causing decline in flux under all filtration conditions. Cake resistance increased with filtration pressure and decreased with the increase in crossflow velocity. The presence of Mn(II) and humic acids (HA) decreased iron removal efficiency and permeate flux. Permeate flux increased with initial Mn(II) concentrations and decreased with increasing HA concentration.

Keywords:

• Humic acids
• Iron
• Manganese
• Microfiltration
• Oxidation
• Water

Acknowledgement

Lanny Setyadhi would like to acknowledge the full international scholarship awarded by the National Taiwan University of Science and Technology during her master’s degree.

Notes

Presented at the International Conference on Desalination for the Environment, Clean Water and Energy, European Desalination Society, 23–26 April 2012, Barcelona, Spain