Filtration by a novel nanofiber membrane and alumina adsorption to remove copper(II) from groundwater.

The elevated level of heavy metals in groundwater poses a substantial risk potentially to local resource users and the natural environment. Micellar-enhanced filtration (MEF) and alumina adsorption are considered from the viewpoint of copper(II) removal in groundwater, by taking copper(II) as an example. In MEF, copper(II) cations are collected electrostatically on micelles of sodium dodecyl benzene sulfonate (SDBS) and separated from the mother liquor by filtration using a novel nanofiber membrane prepared from chloridized polyvinyl chloride by high-voltage electrospinning process. After MEF with 10-layer filtration and SDBS concentration of 5 mmol/L, the removal of copper(II) in groundwater is above 70%. However, the final solution contains a large amount of surfactant causing serious second contamination in groundwater. This problem is overcome by alumina adsorption, where negatively charged surfactants are adsorbed on positively charged alumina particles and then recovered by conventional filtration. The hybrid process of MEF and alumina adsorption is successfully applied to removing almost 100% of copper(II) from groundwater. Finally, the characterization of the membrane and filtration mechanism are presented here.