UV/Fe+3 Photolysis Process Optimization Using Response Surface Methodology for Decolorization of Reactive Red 120 Dye Simulated Wastewater

Decolorization of synthetic azo Reactive Red 120 (RR120) dye wastewater via UV/Fe+3 process was investigated. A preliminary study was conducted to understand the effect of various process variables like oxidant dose Fe+3 (0.25–2.75 mM)), initial dye concentration (100–200 mg/L), time (0–35 min), initial pH (1–11) on the decolorization of RR120. Response surface methodology (RSM) was employed to assess individual and interactive effects of critical process parameters on treatment performance in terms of colour removal efficiency. The photo-degradation of RR120 was investigated in a laboratory-scale batch photo-reactor equipped with low-pressure mercury lamp. Optimized process conditions for UV/Fe+3 treatment of RR120 suggested by RSM are Fe3+ = 2.35 mM, pH = 3.6, Initial dye concentration = 170 mg/L and reaction time = 55 min. Under these conditions, 92% colour removal was actually observed which is found to be very close to prediction given by fitted model. Treatment cost of UV/Fe+3 process was ~4 Rs/L.