Micellar-enhanced ultrafiltration process (MEUF) for removing copper from synthetic wastewater containing ligands

Abstract

The effects of the type and concentration of ligands on the removal of Cu by micellar-enhanced ultrafiltration (MEUF) with the help of either anionic or cationic surfactants were investigated. The removal efficiency of copper by anionic surfactant-(SDS-) MEUF depends on the ligand-to-Cu ratio and the ligand-to-Cu complexation constant. At fixed ligand-to-Cu ratio, the Cu removal efficiency decreases in the order of citric acid > NTA > EDTA, which is the reverse order of Cu–ligand complexation constants for these ligands. Increasing SDS–ligand ratios from 12 to 60 at fixed ligand concentration did not improve copper removal efficiency. The cationic surfactant, CPC, enhances Cu removal efficiency in systems with condition of ligand–copper ratios higher than 1.0, where Cu removal is not very efficient using SDS-MEUF process. The Cu removal efficiency with CPC-MEUF depends on both the ligand-to-Cu ratio and the type of ligands.