آی اس آی پیپر

دانلود رایکان مقاله انگلیسی ISI با موضوع بررسی تلفیق ازونی فتوکاتالیستی مورد استفاده برای تصفیه آب و فاضلاب

عنوان فارسی مقاله:

بررسی تلفیق ازونی فتوکاتالیستی مورد استفاده برای تصفیه آب و فاضلاب

عنوان انگلیسی مقاله:

A review on photocatalytic ozonation used for the treatment of water and wastewater

دانلود رایگان مقاله ISI با فرمت PDF:

مشاهده توضیحات کامل و خرید ترجمه فارسی با فرمت ورد تایپ شده:

بخشی از مقاله انگلیسی :

2. Mechanisms of photocatalytic ozonation

The presence of photocatalysts (in addition to ozone) in the oxidation medium and the adsorption of ozone and pollutants on its surface can essentially change oxidation mechanisms which indicates photocatalytic ozonation is a different process from ozonation in the absence of a photocatalyst. Principally, photocatalytic reactions commence by photoexciting the surface of photocatalyst with UV–Vis radiation, which can provide the appropriate band gap energy to generate photoactivated electron–hole pairs (R1). In parallel, ozone molecules can adsorb on the surface of the photocatalyst via three different interactions: physical adsorption, formation of weak hydrogen bonds with surface hydroxyl groups, and molecular or dissociative adsorption into Lewis acid sites [35], each interaction resulting in the production of active oxygen radicals ð OÞ (R2). Huang and Li [36] showed these active oxygen radicals react with water molecules to produce hydroxyl radicals (R10) which play a key role in photocatalytic ozonation processes. Furthermore, by employing wavelengths shorter than 300 nm, molecules of ozone and hydrogen peroxide would also absorb these wavelengths, producing active oxidising reagents (R3) and (R4) [37]. Hydrogen peroxide molecules are generated as an intermediate in ozone decomposition chain reactions (R14)–(R16). In addition, Beltran [38], Garcia-Araya et al. [39] and Mena et al. [40] described the possibility of hydrogen peroxide formation from the direct reaction of ozone with aromatic compounds, unsaturated carboxylic acids and methanol, respectively.