Degradation of 2,4-Dinitrophenol by Photo Fenton Process

Abstract

2,4-Dinitrophenol (2,4-DNP) is a priority pollutant that may enter environment from petrochemical, textile and dye stuff manufacturing. Due to ineffectiveness of biological processes in treatment of such a waste, advanced oxidation process (AOP) as a promising alternative has been introduced. Photo-Fenton process is an advanced oxidation process that we considered in this study. An 8.3 L cylindrical photo reactor equipped with 2 UV lamps, these two lamps with nominal power of 110 W emits radition at 254 nm. The photon flux of the reactor was 12 μ Einstein S^-1. The results show 100 % disappearance of the 2,4- DNP during 40 min reaction time was obtained when H₂O₂ concentration of 75 mg L^-1 was used. The elimination of all 2,4-DNP was combined with 21 % TOC removal. Also raising the initial H₂O₂ concentration direct to more oxidation of the contained organic matter. 50 % of COD conversion was obtained when 75 mg L^-1  H₂O₂ was used, while it reached to 61 % when H₂O₂ was increased to 100 mg L^-1 . Increasing the initial Fe²⁺ from 45 to 75 mg L^-1  direct to increase 2,4-DNP degradation from 54 up to 87 %. However, it was noticed that, the reaction reach a concentration at which catalytic reaction effect is weak and addition of the iron salt above this point (75 mg L^-1) did not improve the degradation, but rather perceptible decrease in the degradation rate occurred.