The removal of iron and manganese in groundwater by asymmetric nanofiltration membrane

Abstract

Iron and manganese are common elements in groundwater. Excessive content of both metals in the groundwater will cause aesthetical and operational problems to human. Oxidation, ion exchange and adsorption are some of the conventional methods used to remove the iron and manganese in groundwater. However, these methods have their own merits and limitations and could not remove this metal effectively. The efficiency of iron and manganese removal from groundwater was investigated in this research by means of asymmetric nanofiltration (NF) membrane separation technology. DR/2500 Laboratory Spectrophotometer was used to analyze the concentrations of samples obtained. The effects of evaporation time in the formation of asymmetric nanofiltration membrane using a simple dry/wet phase inversion technique were also determined. Employing the combination of solution-diffusion model (Spiegler-Kedem equation) and steric-hindrance pore (SHP) model, the membrane structural properties were determined and have been characterized for different cases of the formation parameter. The experimental and modeling showed very promising results in terms of membrane performance with interesting structural details. The best evaporation time for the removal of iron and manganese was determined to be in the range of 5 seconds to 7.5 seconds. The iron was found to be 90% successfully removed while the manganese was 75% removed in which these removals were observed to comply with the WHO standard guidelines for drinking water.