UV/H2O2/TiO2/Zeolite Hybrid System for Treatment of Molasses Wastewater

Abstract

Wastewater from molasses processing contains a large amount of coloured substances that give a recalcitrant dark brown colour and high organic load to the effluent. Photocatalytic decolourization of molasses wastewater was performed using titanium dioxide catalyst coated on the surface of South African natural zeolite using the solid-solid dispersion method. Addition of hydrogen peroxide as an oxidant was investigated and 30W UV-Clamp was used as source of irradiation. The Chemical Oxygen Demand (COD) of the wastewater treated was varied from 20 g/L to 1 g/L. Batch experiments were conducted in a thermostatic shaker fitted with the UV lamp. The effects of pH, catalyst loading, oxidant dosage and irradiation time on the COD reduction and decolourization of the Molasses Waste Water (MWW) were investigated in this study. The highest colour removal of more than 90% was achieved at pH = 4 and oxidant dosage of 1.47 mM, while low COD removal (< 20%) was observed during photodegradation. A H 2O2/UV/TiO 2 system achieved higher colour removal of 97% compared to a UV/TiO 2 system which achieved 44% while H 2O2 /UV system achieved 34% colour removal. The rate of decolourization was found to fitpseudo - first order reaction kinetics with the highest rate constant value of 1.36 x 10 -2 min -1 .