Utilização de nanofibras de óxido de titânio (TIO2) para tratamento de água

Abstract

Titanium dioxide (TiO2) has been synthesized in the form of nanofibers for photocatalysis, photodegradation and water treatment applications. The use of silver nanoparticles, potentiates the catalytic effect of TiO2, favoring the degradation of organic pollutants and the antibacterial action. Thus, this work aimed at the production of nanofibers of TiO2 and TiO2 with silver nanoparticles for application in water treatment. TiO2 nanofibers were produced using titanium isopropoxide (TTIP) as an inorganic precursor and polyvinylpyrrolidone (PVP) and polyvinylacetate (PVAc) polymers as spinning agents. For TiO2 nanofibers with silver, silver nitrate was used. The nanofibers were produced by the solution blow spinning technique (SBS), calcined at temperatures of 550, 600 and 700oC and characterized by their thermal, morphological and crystallographic behavior. Escherichia coli and Staphylococcus aureus were used in the antibacterial test, the assay was performed with and without exposure to UV-A / 9W light (Ȝ = 315-400 nm) at times of 1 and 6 hours. The photodegradation tests were performed with the rhodamine B (RB) and

methylene blue (AM) dyes, altering the contact time and pH of the solution under UV- A / 9W light exposure. The variables TTIP concentration, pressure and ejection rate

did not present a statistically significant influence on the mean diameter of the fibers and that the combined use of low pressure, ejection rate and high TTIP content (12% v) promoted the production of fibers with reduced diameter. Nanofibers with 1.9% Ag inhibited the growth of colonies of E.coli and S. aureus even without irradiation of UV light, TiO2 nanofibers subjected to UV-A light inactivated E. coli and S. aureus. TiO2 nanofibers were efficient in the decomposition of AM and RB dyes under UV-A light, with 100% removal at the 4 and 8 hour times, respectively, being the best performance for the AM. TiO2 nanofibers with silver degraded the AM and RB dyes in the time of 2 hours. The studied nanofibers presented excellent antibacterial activities and a good photodegradation performance, exhibiting inactivation for E. coli and S. aureus, being indicated for study with water treatment.