Chemical Engineering Transactions (Apr 2019)
The Effect of Ph in Tannery Wastewater by Fenton Vs. Heterogeneous Fenton Process
Abstract
The present study reports about the development of heterogeneous Fenton process by means of nano zero-valent iron particles (nZVI) as heterogeneous catalyst for the treatment of a synthetic tannery wastewater (STW). The experimental tests were conducted using a pilot Fenton plant for the investigation of the scale-up possibility of the treatment process, studying the influence of initial pH (varied in the range 3-7) and catalyst/oxidant ratio (Cat/Ox wt%) on the overall efficiency of the process. The target wastewater prepared in laboratory, was characterized by a high initial COD0=1200 mg/L and the monitored parameters during the process were COD and hexavalent chromium (Cr(VI)) concentrations. Two different Cat/Ox ratios were tested (20 and 35%) whereas the H2O2 amount was fixed equal to 0.75*COD0. The treatment process was performed for the first 2 h in batch, whereas the remaining 8 h were conducted in continuous. The optimal operating parameters (Cat/OX=35%, pH=3) allowed to reach a COD removal efficiency of 70% and a total Cr(VI) removal.