Tailoring the draw solution chemistry in the integrated electro-Fenton and forward osmosis for enhancing emerging contaminants removal: Performance, DFT calculation and degradation pathway

In situ generated iron oxide nanosheet on iron foam electrode for enhanced electro-Fenton performance toward pharmaceutical wastewater treatment

Electro-Fenton (EF) is considered to be an effective technology for the purification of organic wastewater containing antibiotics, but the construction of accessible and efficient heterogeneous EF catalytic materials still faces challenges. In this study, an iron foam-derived electrode (FeOx/if-400) was prepared by a simple method (chemical oxidation combined heat treatment). The fabricated electrode presented great EF degradation efficiency under wide pH range (almost completely removing 50 mg L-1 TNZ within 60 min) and maintained great stability after consecutive operation (>95% removal after six cycles). Also, the FeOx/if-400 electrode showed good purification ability for pharmaceutical wastewater as evaluated by the quadrupole time-of-flight mass spectrometry and the three-dimensional excitation-emission matrix fluorescence spectroscopy. Based on experimental results, characterization analysis, and density functional theory (DFT) calculations, the EF reaction mechanism of FeOx/if-400 electrode and the organics degradation pathways in simulated and real matrices were proposed. Significantly, the biotoxicity assessment of the degradation intermediate products was revealed by ECOSAR software and relative inhibition of E. coli, which fully proved the environmental friendliness of the EF process by the FeOx/if-400 cathode. This work provides a green and effective EF system, showing a promising application potential in the field of organic wastewater treatment containing antibiotic contaminants.

Recent advances in degradation of N,N-diethyl-3-toluamide (DEET)-an emerging environmental contaminant: a review

N,N-Diethyl-3-toluamide (DEET) is a commonly used insect repellent, which acts as an organic chemical contaminant in water and considered as an emerging contaminant which has been observed worldwide. It gets discharged into the environment through sewage waste. The various methods have been used to degrade DEET, such as UV based, ozonation, photocatalytic degradation, and biodegradation (based on the metabolic activity of fungi and bacteria). However, less research has been done on the degradation of DEET by deploying nanoparticles. Therefore, biodegradation and nanotechnology-based methods can be the potential solution to remediate DEET from the environment. This review is an attempt to analyze the routes of entry of DEET into the atmosphere and its environmental health consequences and to explore physical, chemical, and biological methods of degradation. Furthermore, it focuses on the various methods used for the biodegradation of the DEET, including their environmental consequences. Future research is needed with the application of biological methods for the degradation of DEET. Metabolic pathway for biodegradation was explored for the new potent microbial strains by the application of physical, chemical, and microbial genomics; molecular biology; genetic engineering; and genome sequencing methods.