[Effect of phenol in aqueous solutions on toxicity ofnano-TiO2 and nano-Fe/TiO2 particles]

ABSTRACT

Specific and unique characteristics of nanoparticles may entail specific and unique hazards. In addition, they may also exhibit toxicity under certain conditions. This study was conducted to investigate the toxicity of phenol-exposed and phenol-unexposed nano-TiO[2] and nano-Fe/TiO[2] particles. Stock solutions of the afore-mentioned nanoparticles were prepared at different concentrations and a sample of each was exposed to phenol. This was followed by exposing Daphnia Magna to the phenol- and non-phenol-exposed nanoparticles. LC[50], NOEC and the concentrations at which mortality rates were 100% were determined 12 to 96 hours after exposure, while for the determination of the mortality rate of Daphnia the Probit model in SPSS version16 software was used. The results revealed that [1]. The 48-hr LC[50] values for phenol-unexposed nano-TiO[2] and nano-Fe/TiO2 particles were 2705 and over 15000 mg/m[3], respectively. The corresponding values for the phenol-exposed samples were 414 and 1253. [2]. The 48-hr NOEC values for the phenol-exposed TiO[2] and FeTiO[2] were 41 and 789, respectively, the corresponding values for unexposed samples being 1253 and over 15000 mg/m[3]. [3]. In addition, the 48-hr 100% mortality rates for phenol-unexposed nano-TiO[2] and nano-Fe/TiO2 particles were, respectively, 1253 and over 15000 mg/m[3], while for the phenol-exposed samples the corresponding rates were 1090 and over 2108. With regard to 48-hr LC[50], the findings show that the toxicity of both nano-Fe TiO[2] and TiO[2] increases as a result of exposure to phenol, the increase being 12-fold for the former and 6.5-fold for the latter. In general, however, based on LC[50], it can be said that the toxicity of FeTiO2 nanoparticles, which has better catalytic characteristics, is lower in comparison to TiO[2] nanoparticles. Thus, using FeTiO2 in preference to pure TiO[2] should be investigated further, as it will be less hazardous to the environment