Photolysis experiment let the IBP (0.87 mM initial concentration)
and TOC concentration unchanged. Similar results were observed for all ratios IBP–H2O2 after 24 h darkness. In contrast, UV–Vis/H2O2 process (0.32mM H2O2) showed an evident decrease in the concentration of IBP (0.87 mM initialconcentration). When solution was irradiated in presence of
0.32mMof H2O2, almost 40% of degradation occurred after 2 h.
In Fenton series, degradation of IBP (0.87 mM initial concentration)
ranged from 25 to 60% by use of 0.15–1.2mM Fe(II) respectively in presence of 0.32 mM of H2O2. In contrast, in photo-Fenton series, the degradation of IBP (0.87mM initial concentration) was direct proportional to the amount of hydrogen peroxide used between 80 and 100% for 0.04mMand
0.32mMof H2O2 respectively in presence of 1.2 mMof Fe(II). In regard to the mineralization, photo-Fenton reached 40% of TOC removal (0.87 mM initial IBP concentration; 0.32 mM of
H2O2 and 1.2 mM of Fe(II)) whereas in dark-Fenton conditions it was 10% (0.87mMinitial IBP concentration; 0.32mMof H2O2 and 1.2 mM of Fe(II)). Strong binding ability between iron and
IBP was observed and an important photolability of the Fe(III)–IBP coordinated complex promoted in strong manner the decarboxylation of IBP. Higher depletion of IBP through the carboxylic moiety was observed as higher Fe(III)–IBP coordinated complex presence. Complex formation and OH scavenger,as individual process or both at the same time, are responsible of the IBP and TOC depletion in photo-Fenton degradation. The main byproducts observed consisted mostly
of the decarboxylated and the hydroxylated byproducts of IBP.
Stable biodegradable final effluent showed a BOD5 increase of 25 mg L1. Thus a biological post-treatment can be suggested in order to diminish the environmental impact of IBP in surface waters.