Novel Fenton-like process (pre-magnetized Fe-0/H2O2) for efficient degradation of organic pollutants

摘要

A new modified Fenton-like process (pre-magnetization Fe-0/H2O2) was employed to enhance the degradation of organic pollutants and reduce reagents dosage, using azo dye of tartrazine as the model. Compared with Fe-0/H2O2 process, pre-magnetization Fe-0/H2O2 process could have 1.3-11.2 folds enhancement in the degradation rate of tartrazine at different Fe-0 dosages (0.5-4 mmol), initial pH levels (2-6.5) and H2O2 dosages (0.25-2 mmol) owing to the change of Fe-0 characteristics after pre-magnetization. The contact angle of pre-magnetization Fe-0 decreased from 58.4 degrees to 19.8 degrees enhancing the hydrophilicity and BET increased from 0.15 m(2)/g to 1.94 m(2)/g, which improved the corrosion of Fe-0 and accelerated the generation of Fe2+. Similar to the case of tartrazine, pre-magnetization Fe-0/H2O2 process had remarkable improvement on many refractory contaminants. The degradation rate constant of methyl orange, orange, methylene blue, 2,4-dichlorophenol (2,4-DCP), acetylsalicylic acid, phenol and tetracycline by pre-magnetization Fe-0/H2O2 process was 5.2, 21.3, 9.2, 5.6, 12.3, 9.5 and 3 folds of that by Fe-0/H2O2 process, respectively. The "magnetic memory" of pre-magnetization Fe-0 could last 24 h which was suitable for off-site application, and the lost some or all "magnetic memory" could be recovered after second pre-magnetization. Pre-magnetization Fe-0/H2O2 is a more promising and highly efficient Fenton process since it does not require any change of the present water and wastewater treatment process, and does not need an extra energy source and complex equipment but can widen pH range and save more than 75% Fe-0 and H2O2 dosages. (C) 2016 Elsevier B.V. All rights reserved.