Singlet oxygen-dominated peroxydisulfate activation by sludge-derived biochar for sulfamethoxazole degradation through a nonradical oxidation pathway: Performance and mechanism
| Autor: | Juanshan Du, Qinglian Wu, Huazhe Wang, Jo Shu Chang, Nanqi Ren, Wanqian Guo, Renli Yin |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Singlet oxygen
General Chemical Engineering Radical Chemical process of decomposition 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Industrial and Manufacturing Engineering 0104 chemical sciences chemistry.chemical_compound Aniline Adsorption Reaction rate constant chemistry Peroxydisulfate Environmental Chemistry Degradation (geology) 0210 nano-technology |
| Zdroj: | Chemical Engineering Journal. 357:589-599 |
| ISSN: | 1385-8947 |
| DOI: | 10.1016/j.cej.2018.09.184 |
| Popis: | In this study, sludge-derived biochar (SDBC) was prepared and applied in peroxydisulfate (PDS) activation for sulfamethoxazole (SMX) degradation. Compared to the slight adsorption (16.5%) by SDBC alone and low direct oxidation (10.1%) by PDS alone, the SMX degradation rate was drastically increased to 94.6% in the combined SDBC/PDS system, suggesting that SDBC can successfully and efficiently activate PDS. The observed rate constant of the combined SDBC/PDS system was 48.3 times those of both PDS alone and SDBC alone processes. Material characterization and comparative experiments showed nitrogen doping and iron loading into the carbon layer might be the important active sites of the graphene-like SDBC material in PDS activation for SMX degradation. More importantly, singlet oxygen (1O2), instead of traditional sulfate radicals or hydroxyl radicals, was the predominant reactive species of the SDBC/PDS system, which involved a new nonradical oxidation method for PDS activation by SDBC. The SMX degradation pathways by the nonradical 1O2 oxidation were first studied by combining density functional theory (DFT) calculations with experimental results. Different from the well-known pathways of SMX through the cleavage of the sulfanilamide bond by the attack of radicals, the 1O2 was likely to attack the aniline ring of SMX to initiate and accelerate the decomposition process. Finally, the energy cost analysis of the SDBC/PDS system further demonstrated the possible and economic application of the SDBC/PDS technique for SMX degradation. Thus, this study proposed a novel and economic method for PDS activation through a new nonradical oxidation pathway predominated by 1O2, which also promoted the safe and efficient transformation of antibiotics or other contaminants by PDS activation processes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect