Influence of TiO₂ nanostructures on anti-adhesion and photoinduced bactericidal properties of thin film composite membranes

Abstract

This work investigates the influence of TiO2 nanostructures on the anti-adhesion and photoinduced bactericidal properties of thin film composite (TFC) membranes. TiO2 nanostructures with different morphologies, nanoparticle size, and crystalline phase contents were incorporated within the membrane structure during the interfacial polymerization process. The membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and contact angle measurements. Bacterial anti-adhesion tests were performed using Escherichia coli. Bacteria suspensions were incubated in the presence of the modified membranes under three different conditions (dark, UV, and visible light) with the aim to induce photoactivation of the TiO2 nanostructures. The anti-adhesion properties of the membranes were confirmed by fluorescence microscopy using a live/dead bacterial viability kit. XRD, SEM, and EDX analyses confirmed that the TiO2 nanostructures were incorporated into the membrane. This incorporation resulted in TFC membranes exhibiting excellent bacterial anti-adhesion properties, as well as marked bactericidal activity. The anti-adhesion effect can be attributed to the physicochemical properties of the modified membrane surface (mainly hydrophilicity) and the bactericidal effect on the membrane surface was attributed to the photoactivation of TiO2 nanostructures upon irradiation, mainly by UV light. The influence of the morphology and the dispersion capacities of the TiO2 nanostructures on anti-adhesion and photoinduced bactericidal properties of TFC membranes were evidenced. The incorporation of a mixture of nanoparticles and nanorods into the TFC membrane reached higher hydrophilicity, lower roughness and uniform dispersion on the surface membrane improving the anti-adhesion capability and the bacterial degradation performance upon irradiationNational Fund for Scientific and Technological Development of the Government of Chile (FONDECYT) 1113025

Understanding the Phenomenon of Copper Ions Release from Copper-Modified TFC Membranes: A Mathematical and Experimental Methodology Using Shrinking Core Model

“…The PS support was fabricated using the phase-inversion method according to the previously reported synthesis [ 19 , 20 , 21 , 22 ]. A PS solution (15% weight) was prepared by dissolving a polysulfone pellet in DMF:NMP (4:1) mixture for 2 h at 65 °C.…”

“…A PS solution (15% weight) was prepared by dissolving a polysulfone pellet in DMF:NMP (4:1) mixture for 2 h at 65 °C. DMF was used as principal solvent and NMP was used as pore former agent [ 19 , 43 ]. Afterwards, the PS casting solution obtained was uniformly dispersed on a glass plate using a casting knife (BYK, Geretsried, Germany) with the knife gap at 200 m. The PS support was then immersed in water as coagulation bath at 25 °C.…”

“…Several studies oriented to the incorporation of inorganic and metallic nanoparticles (NPs) like Silver [ 11 , 14 , 15 ], Zinc oxide [ 16 , 17 ] or Titanium oxide [ 18 , 19 ] with antibacterial capacity in RO membranes have been developed. The incorporation of inorganic nanoparticles, with antimicrobial properties, has been reported as an effective route to enhance the antibiofouling capacity of the RO membranes [ 11 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. In particular, studies on the incorporation of copper-based nanoparticles (copper-based NPs) show a great capacity to induce toxic effects in bacteria, fungi and algae without depleting its permeability and salt rejection [ 20 , 26 , 27 , 28 ].…”

Anti-Biofouling and Desalination Properties of Thin Film Composite Reverse Osmosis Membranes Modified with Copper and Iron Nanoparticles

“…In order to avoid biofouling in the membranes, researchers have incorporated, on the PA layer, different inorganic nanoparticles (NPs) with antimicrobial properties, such as Ag, TiO 2 , and ZnO, among others [6,7,8]. However, some of these NPs are quite expensive because of the extraction process from the earth and are difficult to synthesize.…”

Biofouling of FeNP-Coated SWRO Membranes with Bacteria Isolated after Pre-Treatment in the Sea of Cortez

“…As biomass accumulates in the feed channel of membrane modules, this leads to technical problems (increases in the working pressure or reduction of permeate flux, as well as the need of more frequent chemical cleaning, among others), decreasing the process productivity, reducing the life span of membranes and increasing process costs [10,11]. To reduce the impact of biofouling problems, some research efforts have focused on coating the membrane surface with various nanoparticles (NPs) that are known to have antimicrobial properties, such as Ag, CuO, ZnO and TiO 2 [12][13][14][15]. In addition, NPs have been used as antifouling coatings in different marine industrial environments in order to prevent biofouling [16].…”