Photoreduction of Reactive Brilliant Red X-3B by Ultraviolet Irradiation/Potassium Borohydride/Sodium Bisulfite

Photoreduction of Reactive Brilliant Red X-3B in aqueous solution by ultraviolet irradiation/potassium borohydride/sodium bisulfite (UV/KBH 4 /NaHSO 3 ) was investigated. The effects of operational parameters including KBH 4 dosage, NaHSO 3 dosage, pH value, and temperature were studied. The reaction mechanism was also discussed. The preliminary results showed that UV and KBH 4 /NaHSO 3 had a significant synergy for the decolorization. At the conditions of 6-mg KBH 4 , 250-mg NaHSO 3 , pH 6.0, and room temperature, highest color removal percentage was achieved. From the mechanism discussion, we could conjecture that the mechanism of photoreduction was mainly caused by the production of sulfur dioxide anion radicals, and UV irradiation played a vital role during the process.