Separation Science and Technology, Vol.42, No.7, 1505-1520, 2007
Fenton- and fenton-like AOPs for wastewater treatment: From Laboratory-to-plant-scale application
Fenton- and Fenton- like AOPs systems have been utilized for the oxidative degradation of some chlorinated pollutants such as chloral hydrate or 1,1,1-trichloroethane, and for the treatment of real industrial wastewaters. Both ferrous sulfate (FeSO4 center dot 7 H2O) and Mohr's salt (NH4)(2)Fe(SO4)(2)center dot 6 H2O have been used as Fe2+-ion sources. With Mohr's salt ( MS) the Fenton- and Fenton- like reaction has been successfully carried out under acidic ( pH 3) and neutral ( pH 7) reaction conditions. The new Fenton- like system utilizes zero-valent iron (Fe-o) instead of ferrous sulfate has been applied for the 1,1,1-trichloroethane and chloral hydrate degradation. Similarly, the application of catechol- and hydroquinone- driven Fenton reaction for the degradation of chloral hydrate under acidic and neutral pH is a new Fenton- like AOPs approach. The photo-Fenton- like reactions such as Fe3+/h nu, Fe2+/H2O2/h nu, and ferrioxalate system have been also studied for the degradation of chloral hydrate. As an irradiation source a daily light or sun light have been used. In comparison with photoreactor experiments the best system was observed to be Fe3+/h nu. In some experiments the influence of standing time prolongation after Fenton reaction on the final degradation efficiency due to hydrolysis of intermediates such as phosgene (CCl2=O) has also been studied. The Fenton reaction was successfully utilized for the treatment of real industrial wastewaters, in two cases even in plant-scale applications.
Keywords:fenton reaction;sludge separation;zero-valent iron;neutral pH use;1,1,1-trichloethane;chloral hydrate;industrial wastewaters