Development of new multifunctional filter based nonwovens for organics pollutants reduction and detoxification: High catalytic and antibacterial activities

Abstract

In this study, two polyester nonwovens (PET1 and PET2) were designed and functionalized by grafting PAMAM(NH2)4 as dendrimers (Dr) and 3-(aminopropyl)triethoxysilane (APTES) followed by the incorporation of copper (Cu) and silver (Ag) nanoparticles, with the aim of reducing toxic molecules, dissociated particles and bacteria. The obtained nonwovens PET1-Dr and PET2-APTES-Ag/Cu were fully characterized by SEM, FT-IR, XRD, ATG, DCO, optical microscopy and water contact angle. The results showed that hydrophilic hydroxyl/amino groups were successfully introduced onto the surface of both PET1-Dr and PET2-APTES-Ag/Cu nonwovens. UV–vis spectroscopy was employed to control the amount of mixture 4-NP and dyes, and compare the degradation of all toxic compounds, individually and mixed. Compared to the original PET nonwoven and several other reported nonwovens, PET2-APTES-Ag/Cu exhibited relatively high catalytic activity in the reduction of 4-nitrophenol (4-NP), methylene blue (MB), malachite green (MG) and remazol red (RR). The conversion rates reached 98.2% in 7 min and the kinetics of reduction and degradation were compared. Additionally, functional nonwoven demonstrated appreciable catalytic activity in the treatment of the mixture 4-nitrophenol and dyes. A mechanism of the catalytic activities was also proposed by referring to the above results and TGA spectrum after catalysis. At the light of these advantageous results, new filters based on three nonwoven layers as PET1-Dr|PET2-APTES-Ag/Cu|PET1-Dr were prepared and studied in the reduction of 4-NP, MB, MG, RR and their mixture. The results obtained demonstrate that PET1-Dr|PET2-APTES-Ag/Cu|PET1-Dr can be employed not only for toxic compounds removal but also to inhibit the growth of bacteria at normal conditions. This allows envisaging an advanced technology for designing and manufacturing highly effective and low-cost filters based on nonwovens for treating various polluted water.