Enhanced degradation of 4-nitrophenol by microwave assisted Fe/EDTA process.
A microwave assisted zero-valent iron oxidation process was studied in order to investigate the synergetic effects of MW irradiation on Fe/EDTA system (Fe/EDTA/MW) treated 4-nitrophenol (4-NP) from aqueous solution. The results indicated that the thermal effect of microwave improved the removal effect of 4-NP and TOC through raising the temperature of the system, as well as the non-thermal effect generated by the interaction between the microwave and the Fe resulting in an increase in the hydrophobic character of Fe surface. During the degradation of 4-NP in Fe/EDTA/MW system, the optimum value for MW power, Fe, EDTA dosage was 400 W, 2 g and 0.4 mM, respectively. The possible pathway for degrading the 4-NP was proposed based on GC/MS and HPLC analysis of the degradation intermediates. The concentration change course of the main bio-refractory by-products, the aminophenol formed in the degradation of 4-NP suggested a more efficient degradation and mineralization in Fe/EDTA/MW system. Finally, BOD(5)/COD(Cr) of the solution increased from 0.237 to 0.635 after reaction for 18 min, indicating that the biodegradability of wastewater was greatly improved by Fe/EDTA/MW system and would benefit to further treatment by biochemical methods.
Liu
Bo
B
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China. yongboliu@163.com
Li
Song
S
Zhao
Yongjun
Y
Wu
Wenfei
W
Zhang
Xuxiang
X
Gu
Xueyuan
X
Li
Ruihua
R
Yang
Shaogui
S
D001673:Biodegradation, Environmental; D004492:Edetic Acid / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D008872:Microwaves; D009596:Nitrophenols / Q000737:chemistry* / Q000528:radiation effects; D010084:Oxidation-Reduction; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
D009596:Nitrophenols; D012996:Solutions; D014874:Water Pollutants, Chemical; D004492:Edetic Acid; D007501:Iron; C024836:4-nitrophenol