Investigation of p-nitrophenol degradation in a rotating packed bed reactor in the presence of Fenton reagent

In this paper, the degradation of p-nitrophenol (PNP) by high gravity technology in the presence of Fenton reagent is investigated. In this process, a rotating packed bed reactor with a blade packing consisting of twelve blades was used. The purpose of this study was to investigate the effect of pH (3, 4, and 5), as well as the rotational speed of the rotating packed bed (600, 800, 1000, and 1200 rpm), the flow rate of inlet liquid (50 and 100 l/h), the dosage of hydrogen peroxide (1.25, 2.25, 3.25 and 4.25 ml) and the concentration of ferrous sulfate (0.1, 0.3, 0.4, 0.5 and 0.6 mM) on the PNP degradation. The initial solution contains 100 mg / l PNP. The results showed that excessive increase of rotational speed (more than 800 rpm) and increase of liquid inlet flow rate to 100 l/h did not contribute to the degradation of pollutant and reducing PNP removal efficiency. Increasing the amount of hydrogen peroxide from 1.25 to 3.25 ml improves the degradation of the pollutant, but increasing this amount to 4.25 does not help to improve the PNP removal process. Increasing the concentration of ferrous sulfate from 0.1 to 0.5 mM reduces the degradation time of the contaminant, but increasing the concentration to 0.6 mM has the opposite effect. In the best case, ie pH 5, the rotational speed of 800 rpm, the liquid inlet flow rate of 50 l/h, Fe2 + concentration of 0.5 mM, and H2O2 of 3.25 ml, PNP in 70 minutes destroyed completely (100%).