EFFECT OF FE-ZSM-5 ZEOLITE ON THE PHOTOCHEMICAL AND BIOCHEMICAL DEGRADATION OF 4-NITROPHENOL

This study presents a novel approach for the degradation of 4-nitrophenol using Fe-ZSM-5 zeolite (Fe-zeolite). The influence of temperature,light, H2O2 concentration and amount of 1.5% Fe-zeolite catalyst used during the reaction has been systematically studied. A solution containing 4-nitrophenol (3.6 X 10(-3) M), 1.5% Fe-zeolite (1.375g/l) and H2O2 (1.3 X 10(-2) M) photodegraded the pollutant in approximate to 8 h at 35 degrees C as seen by HPLC. The same solution needed > 12 h to attain complete mineralization as shown by TOC experiments. Therefore CO2 is the major oxidation product. The amount of H2O2 used in the reaction was monitored throughout. Based on NMR experimental results the OH radicals are considered to be reactive species responsible for the degradation reactions. Physical insight is given through a model for the surface reaction taking place. This model suggests that the degradation is partly due to the zeolite surface. Biodegradability of 4-nitrophenol was monitored by biochemical oxygen demand (BOD), chemical oxygen demand (COD) and dissolved organic carbon (DOC).