[Study on mechanism of ceramic honeycomb-catalytic ozonation for the decomposition of trace nitrobenzene in aqueous solution].
The experiment investigated effects of the presence of hydroxyl radical inhibitor on degradation efficiency of trace nitrobenzene in aqueous solution in the processes of ozonation alone and ceramic honeycomb-catalyzed ozonation, including HCO3-, CO3(2-), HPO4(2-), H2PO4- and tert-butanol, and studied preliminarily on their mechanism. The results indicated that degradation rate of the two processes both increased firstly and decreased subsequently with the increase of the concentration of HCO3- (0 - 200 mg x L(-1)), and reached the climax at the concentration of bicarbonate ion 50 mg x L(-1) under the same experimental condition. The degradation rates of ozonation alone and ozonation/ ceramic honeycomb both declined by 16.57% and 27.52% with the increase of the concentration of CO3(2-) (0 - 20 mg x L(-1)), respectively, and decreased by 13.61% and 17.52% with the addition of the concentration of HPO4(2-) (0 - 12 mg x L(-1)), and reduced by 6.61% and 12.52% with the enhancement of the concentration of H2PO4- (0 - 120 mg x L(-1)), and dropped by 30.06% and 46.09% with the increasing of the concentration of tert-butanol (0 - 10 mg x L(-1)). The experimental results indicated that decomposition of nitrobenzene in both processes all followed the mechanism of oxidization by OH free radical, and tert-butanol is a more suitable indicator for the radical type reaction. The removal rate of ozonation alone rose with the increase of the concentration of pH (3.02 - 10.96), but that of ozonation/ceramic honeycomb process reached the maximum at pH = 9.23.
Zhao
Lei
L
School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Ma
Jun
J
Sun
Zhi-Zhong
ZZ
Liu
Zheng-Qian
ZQ
Yang
Yi-Xin
YX
Lu
Wei
W
D002384:Catalysis; D002516:Ceramics / Q000737:chemistry*; D009578:Nitrobenzenes / Q000032:analysis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000032:analysis
D009578:Nitrobenzenes; D014874:Water Pollutants, Chemical; D010126:Ozone; C036077:nitrobenzene