Intensification of light green SF yellowish (LGSFY) photodegradion in water by iodate ions: Iodine radicals implication in the degradation process and impacts of water matrix components.

The results of this work showed that UV/IO oxidation process supplies good performance in the degradation of light green SF yellowish (LGSFY) dye in deionized water. This process generated reactive iodine radicals that make the degradation much faster than the sole UV irradiation. The assistance of UV-irradiation by 10 mM of iodate increased the LGSFY removal after 10 min from 36% to 90% for C = 10 mg/L and from 18% to 85% for C = 20 mg/L. In parallel, a 2.5 and 4.72-fold increase in the LGSFY initial degradation rate, as compared with UV alone, were recorded for, respectively, 10 and 20 mg/L of LGSFY. IO and IO played the most important role in the degradation of LGSFY by the UV/IO process. The degradation was not affected by the presence of chloride and nitrate ions even at high dosage levels (up to 0.1 M), whereas sulfate ions reduced the valuable effect of iodate to the half when they are present at 0.1 M. Correspondingly, humic acids, at usual concentrations as those measured in natural waters, did not affect significantly the LGSFY degradation upon photoactivated iodate process. These results revealed, in one part, that iodine radicals are selective oxidants and, in another part, that the process is likely to remove organic dyes from natural water which often contains mineral constitutes and humic substances.