Glutaraldehyde‐crosslinking for improved copper absorption selectivity and chemical stability of polyethyleneimine coatings

ABSTRACT Nano‐thin coatings of glutaraldehyde (GA)‐crosslinked polyethyleneimine (PEI) are extremely selective and effective in binding copper from seawater. Here it was demonstrated that GA‐PEI performs significantly different from PEI. The copper‐selectivity of self‐assembled PEI coatings on silicon substrates was greatly improved by GA‐crosslinking. After submersion in artificial seawater containing 200 ppb copper and equimolar amounts of 11 competing ions only copper and trace amounts of Zn were detected in the GA‐crosslinked coatings, while for non‐crosslinked PEI there was about 30% Zn present relative to copper. The coatings were demonstrated to be highly stable under acidic conditions and retained their copper‐binding selectivity after repeated cycles of binding and acid‐mediated elution. After self‐assembly of the GA‐crosslinked coating on mesoporous diatomaceous earth particles, significant amounts of copper could be extracted from 200 ppb in artificial seawater and eluted under acidic pH. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43954.