Coliform removal efficacy of polyurethane foam impregnated with chitosan nanoparticles and silver/silver oxide nanoparticles

Abstract

This study was intended to synthesise, characterise and evaluate the antibacterial activity and Escherichia coli removal efficacy of a novel polyurethane foam impregnated with nanochitosan and nanosilver/silver oxide (PFCA). The study also exposed the effectiveness of nanochitosan as a disinfectant and as a binder for AgNPs, which has not been explored so far. The E. coli removal mechanism and antibacterial activity of PFCA were established by FTIR spectroscopy, XRD pattern and SEM analysis. PFCA achieved complete removal of E. coli with sufficient reusing capacities and possessed 100% antibacterial efficiency in a bacterial suspension of 5 × 106 CFU/mL. The study also showed that varying pH from 5 to 9 did not make any significant changes in the removal of E. coli. The presence of co-existing ions and organic matter did not reduce the efficiency of PFCA. The elution of silver ions (a very common limitation in treatment processes involving silver ions) was found to be much less, well below the drinking water limit. The study proved excellent potential of PFCA in removing E. coli, making it a viable disinfectant for water/wastewater treatment. HIGHLIGHTS Developed a novel and reliable sorbent cum disinfectant, PFCA by loading nanochitosan and nanosilver/silver oxide on PUF.; PFCA achieved complete removal of coliforms with sufficient reusing capacities.; The elution of silver ions was found to be much less, well below the drinking water limit.; Performance was unaffected in the presence of co-existing anions and organic matter.; No pH adjustment is required.;

Keywords

• antibacterial activity
• e. coli
• impregnation
• nanochitosan
• nanosilver/silver oxide
• polyurethane foam