Green Synthesis of Copper Nanoparticles Deposited on Polyester Filter for Antibacterial Applications

This study was conducted to evaluate the antimicrobial property of polyester filter cloth embedded with copper nanoparticles by a green chemical method. Copper nanoparticles were generated in situ on pieces of commercial polyethylene terephthalte (PET) filter cloth by reducing [Cu(OH)4]2- ions by ascorbic acid in aqueous solution. Elemental analysis using energy-dispersive X-ray (EDX) spectrum of the modified filter fabric confirmed the presence of copper (0.15-0.35 $\mu$g/mm2). Analysis of scanning electron microscope (SEM) images showed that the sizes of synthesized copper particles varied from less than 100 nm to over 500 nm. Increasing ascorbic acid concentrations while fixing cuprate ion concentration resulted in higher load and lower sizes of deposited copper nanoparticles. Antibacterial activity of the modified polyester filters was assessed by passing suspensions of Escherichia coli NBRC 14237 in phosphate-buffered saline (PBS) and in sterilized milk through these modified filters. Analyzing the effluent for viable bacteria showed that the antibacterial activity against E.coli in PBS was about 12 times more effective than that in milk. Moreover, increasing copper nanoparticles load on the filter resulted in increasing antibacterial effect toward E.coli. Leaching test showed that concentration of copper in the effluent after passing distilled water (1000 and 2000 m3/m2) through the modified filter was below the recommended limit for copper in drinking water (1 ppm).