6533b7cefe1ef96bd1257953

RESEARCH PRODUCT

Influence of some aromatic and aliphatic compounds on the rate of photodegradation of phenol in aqueous suspensions of TiO2

subject

description

Abstract The influence of 3-nitrophenol, 4-nitrophenol, pentachlorophenol, ethanol, 2-propanol, ethanoic acid and ethanedioic acid on the photodegradation rate of phenol in an aqueous suspension of TiO2 (anatase) irradiated in the near-UV region was investigated. Binary mixtures of organic compound and phenol in molar ratios of 1:1 and 10:1 were used for the photoreactivity experiments performed in a batch reactor. The mineralization rate of all the mixtures was also monitored by measuring the total organic carbon (TOC) concentration. The reactivity results indicate that the photodegradation rate of phenol is mainly determined by the total amount of aromatic substrates present in the reacting medium independently of their nature, while it is scarcely affected by the presence of aliphatic compounds. The TOC results indicate that the mineralization rate of aromatic compound-phenol mixtures is sensitive to the mixture composition, and the simultaneous presence of phenol and aliphatic compounds negatively affects the mineralization rate. A tentative explanation of the above behaviour is proposed by taking into account (i) the similar manner of photoadsorption of phenol molecules and of the other aromatic compounds on the active surface site(s), (ii) the different sites of photoadsorption for aromatic and aliphatic substrates and (iii) the possible formation of stable intermediate compounds from the degradation products of phenol and aliphatic compounds.