DECOLORIZATION KINETICS FROM COFFEE EFFLUENT WITH PHOTO-FENTON REACTION

Abstract

Coffee effluent contains a high amount of dark brown pigments. When this waste is released in the river, it
will block the sun ray and disturb the photosynthesis process. The decolorization of coffee effluent using
photo-Fenton and Fenton processes is presented in this paper. On the photo-Fenton reaction, UV light, ion
Fe(II) and H2O2 will produce •OH. This will react with organic contaminant, so the color of the effluent will
be changed from brown to yellow, and finally became a clear solution. On the Fenton process, reaction
occurred without the existence of UV light. The rate of this decolorization is slower than photo-Fenton
reaction. The reaction consists of three phases, the first phase happen when H2O2 is added to the reactor and
the color changes rapidly, the color of the solution start to be removed fast (second phase) and then it became
faster and there were no more changes in its color (third phase). The color removal rate for second phase at
the coffee effluent concentration of 250 ppm,300 ppm, 400 ppm were : r = -0,0322 (Abs)² ; r = -0,0271
(Abs)²; r = -0,0196 (Abs)², whereas the color removal rate for third phase at the coffee effluent concentration
of 250 ppm, 300 ppm, 400 ppm were : r = -0,0049 (Abs) ; r = -0,0211 (Abs) ; r = -0,005 (Abs)