Comparative study of Fe/HO and Fe/persulfate systems on the pre-treatment process of real pharmaceutical wastewater.

Advanced oxidation technologies based on hydroxyl radical (•OH) and sulfate radical (SO) are two common types of advanced oxidation technologies, but there are not many reports on the application of advanced oxidation methods in actual wastewater pretreatment. This article compares the pre-treatment performance of Fe/HO and Fe/Persulfate systems in actual pharmaceutical wastewater, and combines EEM, GC-MS, and toxicity testing results to explore the differences in TOC, COD, and NH-N removal rates, optimal catalyst dosage, applicable pH range, toxicity of effluent after reaction, and pollutant structure between the two systems. The results indicate that the Fe/HO system has a higher pollutant removal rate (TOC: 71.9%, COD: 66.9%, NH-N: 34.1%), but also requires a higher catalyst (Fe) concentration (6.0 g/L), and its effluent exhibits characteristic peaks of aromatic proteins. The Fe/Persulfate system has a wider pH range (pH ≈ 3-7) and is more advantageous in treating wastewater containing more cyclic organic compounds, but the effluent contains some sulfur-containing compounds. In addition, toxicity tests have shown that the toxicity reduction effect of the Fe/Persulfate system is stronger than that of the Fe/HO system.