Decolorizing kinetics of reactive black SRE by UV/TiO₂

Photocatalysis with TiO₂ (UV/TiO₂) was employed to treat Reactive Black SRE (RB SRE) in aqueous solution. The effects of TiO ₂ loading, initial concentration of RB SRE and pH on the photocatalytic activity were investigated. The RB SRE degradation intermediate products were analyzed by ultraviolet visible spectrum (UV-vis), gas chromatograpby-mass spectrometry (GC-MS), and ion chromatography (IC). The results show the optimum TiO₂ loading was 0.15 g L^-1 and acidic medium could improve the removal of RB SRE, and the rise of RB SRE initial concentration decreased color removal. The main intermediate products were 2,5-diritrobenzoic acid and 3,5,5-trimethylhexanoic acid. The primary inorganic ions were Cl^- NO₃^-, and SO ^2-₄. The photocatalytic degradation rate followed pseudo-first order at different loadings of TiO₂ and initial concentrations of RB SRE. On the basis of Langmuir model, the limiting rate of the reaction at maximum coverage (k_n) and the equilibrium constant for adsorption (K_e) of RB SRE are 1.129 mg L^-1 min ^-1 and 0.01789 L mg^-1, respectively.