Antimicrobial Activities of Polyethylene Terephthalate-Waste-Derived Nanofibrous Membranes Decorated with Green Synthesized Ag Nanoparticles

Abstract

Thermoplastic polymers are one of the synthetic materials produced with high tonnage in the world and are so omnipresent in industries and everyday life. One of the most important polymeric wastes is polyethylene terephthalate (PET), and the disposal of used PET bottles is an unsolved environmental problem, and many efforts have been made to find practical solutions to solve it. In this present work, nanofibrous membranes were produced from waste PET bottles using the electrospinning process. The surface of membranes was modified using NaOH and then decorated with green synthesized Ag nanoparticles (10 ± 2 nm) using an in situ chemical reduction method. The morphology, size, and diameter of the Ag nanoparticles decorating the nanofibers were characterized through transmission electron microscopy (TEM), a field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and UV-visible spectroscopy techniques. Finally, the antimicrobial activity of the nanofibrous membranes was tested against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus using disc diffusion and colony-forming count methods. The growth of bacteria was not affected by the pure nanofibrous membranes, while the Ag-decorated samples showed inhibition zones of 17 ± 1, 16 ± 1, and 14 ± 1 mm for Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, respectively. The planktonic culture results of Pseudomonas aeruginosa showed that the membranes had a relatively low inhibitory effect on its growth. The obtained results showed that Pseudomonas aeruginosa has a relatively low ability to form biofilms on the nanostructured membranes too. A good agreement was observed between the data of biofilm formation and the planktonic cultures of bacteria. The plastic-waste-derived PET/Ag nanocomposite membranes can be used for wound dressings, air filters, and water purification applications.

A review of plastic waste nanocomposites: assessment of features and applications

“…Also, recycled polymers have been used as a source of plastic waste [ 8 , 19 , 27 , 29 , 33 ], indicating the quality to be close to high-quality industrial plastic waste rather than post-consumer plastic waste. Bottle waste have been source for recycled HDPE [ 21 ], PET [ 25 , 26 , 30 – 32 ] and PP [ 40 ], plastic bags and films for HDPE [ 13 , 21 , 22 ], packaging for PP [ 42 ], PS [ 37 , 38 ], HDPE [ 13 , 18 ], and EPS [ 45 ], cable tie waste for nylon 6,6 [ 48 ], and other plastic products for HDPE [ 20 ]. However, in most of the above-mentioned studies, the plastic waste is carefully selected, sorted, and purified before nanocomposite processing, characterizing the condition of post-industrial waste rather than post-consumer plastic waste.…”

“…Common methods to disperse nanomaterials into a virgin polymer matrix are melt blending, solution mixing, shear mixing, three-roll milling, ball milling, and in situ polymerization [ 9 , 10 ]. Common dispersion methods in the plastic waste nanocomposites observed in the current work have been melt blending with a twin-screw extruder [ 8 , 13 , 17 , 19 , 24 – 26 , 29 , 39 , 41 , 42 ], two-roll milling [ 20 – 22 , 43 ], solvent blending [ 10 , 23 , 31 , 33 , 38 ], and electrospinning [ 27 , 32 , 35 – 37 , 45 , 46 ], as well as other methods such as in situ polymerization [ 30 ]. Different processing methods are used as a secondary processing step to shape plastic waste nanocomposites into solid test specimens, foams, or nanocomposite fibers.…”

“…Unlike in other electrospinning studies considered in this review, Yasin et al [ 28 ] first converted PET waste into nanofibers in an electrospinning process, followed by addition of copper oxide (CuO) nanoparticles on the surface of PET nanofiber using a cross-linked solvent. Soltanolzakerin-Sorkhabi et al [ 32 ] prepared nanofibrous membranes from waste PET solution by electrospinning, which was followed by NaOH modification to assist the decoration with silver NPs using in situ chemical green synthesis. Mogharbel et al [ 47 ] created colorless polymer out of waste PC using a refining process followed by mechanical stirring with 20 wt% of pure PC, 1.5 wt% of plasticizer and up to 1.5 wt% of strontium aluminate NPs in DMF.…”

“…In the study of de Oliveira Santos et al [ 27 ], PET waste, castor oil and cellulose nanocrystals containing electrospun mats showed potential for filtration and biomedical applications. Likewise, electrospun nanofibrous membranes from PET waste decorated with silver NPs showed good antimicrobial and antibiofilm activity, making it a promising material for eradication of microbes, wound dressings, air filters, and water purification applications [ 32 ].…”