Novel and versatile TiO2 thin films on PET for photocatalytic removal of contaminants of emerging concern from water

Abstract

The current work presents new and versatile photocatalytic surfaces designed to remove contaminants of emerging concerns (CECs) from water. Photocatalytic thin films of titanium dioxide (TiO2) were deposited on a polyethylene terephthalate (PET) surface (PET-TiO2) and photosensitized by a natural and non-hazardous curcumin (turmeric). The nanocrystalline TiO2 thin film was deposited in a single stage and solvent-free process, without thermal post treatment, using the high power impulse magnetron sputtering (HiPIMS) technique. The photocatalytic film was characterized by different techniques (SEM/EDS, STEM, AFM, UV-Vis spectroscopy, and wettability via water droplet contact angle measurements). The photocatalytic activity was assessed by the degradation of two model CECs: the fungicide carbendazim (CBZ), used in different crops around the world (coffee, rice, fruits, etc.), and the anthropogenic pollution tracer caffeine (CAF). Removal of these model CECs of up to 39% were achieved under 2 combined UV and visible irradiation under 7 h photocatalytic treatments. The degradation process was further studied by organic carbon dissolved analysis, with 80% removal achieved, and acute ecotoxicity tests with Aliivibrio fischeri bacteria, indicating reduction of toxicity or non-change. The PET-TiO2 surfaces remained stable for 5 consecutive cycles of use, with similar kinetic rates. Finally, the species involved in photocatalytic reactions were investigated by use of h + , HO • and • O2trapping agents for the degradation reactions, both in the presence and absence of turmeric. The results were indicative of the fact that the addition of the turmeric led to an increase in photogenerated • O2radicals due to a synergistic effect between the photocatalyst and photosensitizer. The results demonstrate the potential of the PET-TiO2 surfaces as a straightforward solution for the removal of CECs in wastewater treatment plants (WWTP), using a flexible, scalable, reusable and environmental friendly photocatalytic material.

A Sustainable Recycling Alternative: Electrospun PET-Membranes for Air Nanofiltration

“…However, one of the challenges to produce these filter media is the adjustment and control of several parameters which influence fiber production, (explored in this work) [ 38 , 39 , 40 , 41 , 42 ]. Thus, the utilization of this technique to produce filter media from post-consumer PET bottles is a very promising and ecologically sustainable alternative because it highly contributes to the reduction of environmental pollution [ 6 , 43 ].…”

Self-Locked and Self-Cleaning Membranes for Efficient Removal of Insoluble and Soluble Organic Pollutants from Water

“…Titanium dioxide (TiO 2 ) has become an excellent heterogeneous photocatalyst because of its low cost, nontoxicity, mechanical robustness, and chemical resistance . Suspended TiO 2 nanoparticles are supposed to be the commonest application form as suspended slurries because vigorously mixing can maximally enhance mass transfer and light utilization, but such application is seriously limited by weak recyclability and extra energy cost and the possibility of accidentally discharging nanoparticles. , Alternatively, membranes modified with photocatalytic nanoparticles have shown their potential to address the aforementioned problems . A suitable membrane loaded with TiO 2 can adsorb and bring contaminants close to photocatalytic sites for utilizing the short-lived unselective reactive radicals more efficiently …”

“…14,15 Alternatively, membranes modified with photocatalytic nanoparticles have shown their potential to address the aforementioned problems. 16 A suitable membrane loaded with TiO 2 can adsorb and bring contaminants close to photocatalytic sites for utilizing the short-lived unselective reactive radicals more efficiently. 17 Compared to other membranes, electrospun nanofibrous membranes (NFMs) with selective superwettability have been considered as prominent photocatalytic substrates because of their high porosity, easily tunable structures, large specific area, three-dimensional networks with good connectivity, and so on.…”

Immobilization techniques of a photocatalyst into and onto a polymer membrane for photocatalytic activity

“…Recently, Marcelino et al 95 reported on the good photocatalytic activity of TiO 2 sputtered on polyethylene terephthalate (PET) in the removal of contaminants of emerging concern, specifically for the fungicide carbendazim (CBZ) and anthropogenic pollution tracer caffeine (CAF) up to 39% under a combination of UV and visible light irradiation. It is stated that TiO 2 was successfully deposited onto the PET flat sheet surface by using the high power impulse magnetron sputtering (HiPIMS) technique.…”