Analysis of the degradation of m-cresol with Fe/AC in catalytic wet peroxide oxidation enhanced by swirl flow.

Catalytic wet peroxide oxidation (CWPO) enhanced by swirl flow (SF-CWPO) was developed for the first time to explore the degradation of m-cresol in 3%iron/activated carbon catalysed Fenton reaction. Under the conditions of catalyst dosage of 0.6 g/L, H2O2 dosage of 1.5 mL/L, pH = 6 and reaction time of 20 min, the degradation rate of m-cresol and total organic carbon in 100 mg/L m-cresol solution reaches 81.5% and 82%, respectively. The reaction speed in the SF-CWPO system with an independently designed cyclone reactor was two times faster than the traditional CWPO systems. In addition, via liquid chromatography-mass spectrometry analysis of the degradation product, the possible degradation pathway for m-cresol was proposed. The proposed SF-CWPO can potentially be an efficient and economical method to treat organic pollutants in wastewaters.

Pyrolyzed carbon derived from red soil as an efficient catalyst for cephalexin removal.

Red soil, a typical soil type in southern China, has been deemed infertile or nutrient-deficient. In this study, red soil was firstly utilized as a substrate for preparing catalysts, which were then successfully applied to the catalytic wet peroxide oxidation (CWPO) of cephalexin. The highest cephalexin removal was 95.23% and TOC removal was 60.58%, with the catalyst pyrolyzed at 500 °C (RC500). The high iron content and proportion of Fe(II) on the surface of RC500 was responsible for the decomposition of H2O2 into· OH. Moreover, the porous structure and existence of other minerals (such as SiO2 and Al2O3) in the catalyst were also significant for enhancing the catalytic activity of RC500. Afterwards, the influencing parameters, including temperature, pH, the dose of H2O2, and catalyst, were examined for cephalexin degradation. It was noteworthy that RC500 was efficient in treating hospital wastewater when using a self-design pilot device. A density functional theory analysis of cephalexin was conducted to establish the possible position attacked by ·OH, and the possibly ruptured one. Meanwhile, the intermediates generated during CWPO were identified. Finally, a reliable degradation pathway of cephalexin was proposed on the basis of the results.