Influencing Factors Optimization of Pharmaceutical Wastewater Pretreatment Through a Microwave-assisted Fenton-like Process

A microwave-assisted Fenton-like process generated hydroxyl radicals and high iron complexes, which caused the oxidative degradation of organic pollutants. Ferric sulfate and hydrogen peroxide were introduced to the system as the catalyst and initial oxidant, respectively. An acidic microenvironment was generated by the microwave radiation in the reaction system. The flocculation of ferric salt was included in the process. As pretreatment method, when the microwave power was set at medium-high (539 W) for a reaction time of less than 6 min, with a hydrogen peroxide dosage of less than 5 mL and a ferric salt dosage of less than 1. 5 g in 1 L wastewater, the COD removal increased as the amount of each factor increased, and the toxicants or toxic molecular structures in the wastewater were removed well. The course of the entire reaction was separated into two stages. The different morphologies of flocculation were used by the first stage of the reaction, and the second stage of reaction had identical conditions. The morphology of flocculation that was generated in 2 min during the first stage of the reaction favored the second stage of the reaction. When the first stage exceeded 3 min, the second stage had low efficiency. The course of the microwave-assisted Fenton-like process was likewise studied using the oxidation-reduction potential. Oxidation was terminated after 6 min. Reaction times exceeding 6 min required the increased removal of COD by improving the effect of flocculation. The efficiency of treatment with the proposed technology was significantly higher than that with the traditional Fenton / Fenton-like process.