The use of a glass fiber filter functionalized with a double-layer PEI/HA coating for removing trace levels of copper from artificial seawater

To avoid degrading the performances related to fuel consumption and maneuverability, an antifouling paint that contains Cu₂O as a source of biocidal Cu(II) are applied to the bottom of a ship. However, increasing the Cu(II) concentration around a dockyard located in an enclosed coastal area has been regarded as an environmental issue. The ability of humic acid (HA) and polyethyleneimine (PEI) for complexes with heavy metal ions was examined for removing Cu(II) from contaminated seawater. A glass fiber filter was functionalized by coating it with PEI and HA by taking advantage of the electrostatic character of these substrates. The resulting coated filter proved to be highly effective for removing Cu(II) from artificial seawater by simple filtration. The capacity and efficiency on Cu(II) removal for a filter coated with PEI was increased by further coating with HA. The removal of Cu(II) was dependent on the effectiveness of the coated area, suggesting that this functionalizing method could be applied to other forms of glass fiber materials.