TY - JOUR
T1 - Sonolytic degradation of parathion and the formation of byproducts
AU - Yao, Juan Juan
AU - Gao, Nai Yun
AU - Deng, Yang
AU - Ma, Yan
AU - Li, Hai Jun
AU - Xu, Bin
AU - Li, Lei
PY - 2010/7
Y1 - 2010/7
N2 - Ultrasonic degradation of parathion has been investigated in this study. At a neutral condition, 99.7% of 2.9 μM parathion could be decomposed within 30 min under 600 kHz ultrasonic irradiation at ultrasonic intensity of 0.69 W/cm2. The degradation rate increased proportionally with the increasing ultrasonic intensity from 0.10 to 0.69 W/cm2. The parathion degradation was enhanced in the presence of dissolved oxygen due to formation of more {radical dot}OH, but was inhibited in the presence of nitrogen gas owning to the free radical scavenging effect in vapor phase within the cavitational bubbles. CO32 -, HCO3-, and Cl- exhibited the inhibiting effects on parathion degradation, and their inhibition degrees followed the order of CO32 - >HCO3- > Cl-. But Br- had a promoting effect on parathion degradation, and the effect increased with the increasing Br- level. Moreover, both the hydrophobic and hydrophilic natural organic matters (NOM) could slow the parathion degradation, but the inhibiting effect caused by hydrophobic component was greater, especially the strongly hydrophobic NOM. The three reaction pathways of parathion sonolysis were proposed, including formation of paraoxon, formation of 4-nitrophenol, and unknown species products. The kinetics tests showed that anyone of these pathways could not be overlooked, and the fractions of the parathion decomposed in the three pathways were 28.19%, 32.92% and 38.89%, respectively. In addition, 66.61% of paraoxon produced was degraded into 4-nitrophenol. Finally, kinetics models were established to adequately predict the concentrations of parathion, paraoxon and 4-nitrophenol as a function of time.
AB - Ultrasonic degradation of parathion has been investigated in this study. At a neutral condition, 99.7% of 2.9 μM parathion could be decomposed within 30 min under 600 kHz ultrasonic irradiation at ultrasonic intensity of 0.69 W/cm2. The degradation rate increased proportionally with the increasing ultrasonic intensity from 0.10 to 0.69 W/cm2. The parathion degradation was enhanced in the presence of dissolved oxygen due to formation of more {radical dot}OH, but was inhibited in the presence of nitrogen gas owning to the free radical scavenging effect in vapor phase within the cavitational bubbles. CO32 -, HCO3-, and Cl- exhibited the inhibiting effects on parathion degradation, and their inhibition degrees followed the order of CO32 - >HCO3- > Cl-. But Br- had a promoting effect on parathion degradation, and the effect increased with the increasing Br- level. Moreover, both the hydrophobic and hydrophilic natural organic matters (NOM) could slow the parathion degradation, but the inhibiting effect caused by hydrophobic component was greater, especially the strongly hydrophobic NOM. The three reaction pathways of parathion sonolysis were proposed, including formation of paraoxon, formation of 4-nitrophenol, and unknown species products. The kinetics tests showed that anyone of these pathways could not be overlooked, and the fractions of the parathion decomposed in the three pathways were 28.19%, 32.92% and 38.89%, respectively. In addition, 66.61% of paraoxon produced was degraded into 4-nitrophenol. Finally, kinetics models were established to adequately predict the concentrations of parathion, paraoxon and 4-nitrophenol as a function of time.
KW - 4-Nitrophenol
KW - Kinetics model
KW - Paraoxon
KW - Parathion
KW - Ultrasonic irradiation
UR - http://www.scopus.com/inward/record.url?scp=77953564052&partnerID=8YFLogxK
U2 - 10.1016/j.ultsonch.2010.01.016
DO - 10.1016/j.ultsonch.2010.01.016
M3 - Article
C2 - 20303819
AN - SCOPUS:77953564052
SN - 1350-4177
VL - 17
SP - 802
EP - 809
JO - Ultrasonics Sonochemistry
JF - Ultrasonics Sonochemistry
IS - 5
ER -