Pulse radiolysis of aqueous solutions of aromatic hydrocarbons in the presence of oxygen

Roder, M.; Wojnárovits, László; Földiák, G.

doi:10.1016/1359-0197(90)90236-b

“…The buffer acts as an OH• scavenger at the concentrations used in the present study, and we observed pseudo‐first‐order kinetics with our target PAH. Therefore, using Equation 5 and the reported second‐order rate constant for naphthalene reaction with OH• (9.4 × 10 9 /M/s [31]) and our proxy [OH•] ss value of 1.4 × 10 −16 mol/L, we estimate the contribution from OH• in GIN water for naphthalene to be 4.7 × 10 −3 /h. The sum of this calculated rate constant resulting from OH• production and the direct photolysis rate constant is 2.0 × 10 −2 /h.…”

Section: Resultsmentioning

confidence: 99%

Direct and indirect photolysis of polycyclic aromatic hydrocarbons in nitrate‐rich surface waters

Jacobs

¹

,

Weavers

²

,

Chin

³

2008

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

The photolysis of three polycyclic aromatic hydrocarbons (PAHs)-pyrene, phenanthrene, and naphthalene-were studied in waters taken from creosote-contaminated sites in Gary (IN, USA) and Wilmington (NC, USA). Direct photolysis of all PAHs was observed under simulated solar radiation, with pyrene degrading at a faster rate than either phenanthrene or naphthalene. Phenanthrene degradation, when compared to its direct photolysis rate, increased in Gary water but decreased in Wilmington water. Analysis of the waters for dissolved organic carbon (DOC) and nitrate revealed higher levels of DOC in the Wilmington sample (9.29 mg/L) compared with the Gary sample (6.73 mg/L), as well as significantly less nitrate (0.046 mM vs 0.205 mM for the Gary sample). The slightly lower rate of phenanthrene degradation observed for the Wilmington sample, corrected for light attenuation effects, is statistically the same as that in the direct photolysis experiments. Therefore, we attribute the lower rate of degradation in the presence of Wilmington water to light screening by DOC, but we believe the faster reaction rate observed for the Gary water results from hydroxyl radical (OH*) chemistry generated by nitrate photolysis. Indeed, degradation of the target compound increased when nitrate (at 0.2 and 0.4 mM) was added to the Wilmington sample, further corroborating this conclusion. Overall photoreaction rates decreased for the lower-molecular-weight PAHs, because the fastest naphthalene photolytic rate was roughly two orders of magnitude slower than that of pyrene.

show abstract

“…Complex molecules often undergo a series of intermediate reactions before they are completely destructed in plasma. Since the mechanism of C 6 H 6 destruction in DBD is unclear up to now, we would offer relative overall mechanism for C 6 H 6 destruction by referring to some related publications [20][21][22][23][24][25] and our experimental results in this work.…”

Section: The Mechanism Discussion Of C 6 H 6 Destruction In Dbdmentioning

confidence: 96%

“…by breaking the aromatic structure. Relative reactions and rate constants came from some other references [23][24][25] and were listed below.…”

Section: The Mechanism Discussion Of C 6 H 6 Destruction In Dbdmentioning

confidence: 99%

Feasibility of destruction of gaseous benzene with dielectric barrier discharge

Ye

¹

,

Zhang

²

,

Li

³

et al. 2008

Journal of Hazardous Materials

View full text Add to dashboard Cite

“…The buffer acts as an OH• scavenger at the concentrations used in the present study, and we observed pseudo-first-order kinetics with our target PAH. Therefore, using Equation 5 and the reported second-order rate constant for naphthalene reaction with OH• (9.4 ϫ 10 9 /M/s [31]) and our proxy [OH•] ss value of 1.4 ϫ 10 Ϫ16 mol/L, we estimate the contribution from OH• in GIN water for naphthalene to be 4.7 ϫ 10 Ϫ3 /h. The sum of this calculated rate constant resulting from OH• production and the direct photolysis rate constant is 2.0 ϫ 10 Ϫ2 /h.…”

Section: Resultsmentioning

confidence: 99%

Direct and Indirect Photolysis of Polycyclic Aromatic Hydrocarbons in Nitrate-Rich Surface Waters

Jacobs¹,

Weavers²,

Chin³

2007

Environ Toxicol Chem

4

0

View full text Add to dashboard Cite

The photolysis of three polycyclic aromatic hydrocarbons (PAHs)-pyrene, phenanthrene, and naphthalene-were studied in waters taken from creosote-contaminated sites in Gary (IN, USA) and Wilmington (NC, USA). Direct photolysis of all PAHs was observed under simulated solar radiation, with pyrene degrading at a faster rate than either phenanthrene or naphthalene. Phenanthrene degradation, when compared to its direct photolysis rate, increased in Gary water but decreased in Wilmington water. Analysis of the waters for dissolved organic carbon (DOC) and nitrate revealed higher levels of DOC in the Wilmington sample (9.29 mg/L) compared with the Gary sample (6.73 mg/L), as well as significantly less nitrate (0.046 mM vs 0.205 mM for the Gary sample). The slightly lower rate of phenanthrene degradation observed for the Wilmington sample, corrected for light attenuation effects, is statistically the same as that in the direct photolysis experiments. Therefore, we attribute the lower rate of degradation in the presence of Wilmington water to light screening by DOC, but we believe the faster reaction rate observed for the Gary water results from hydroxyl radical (OH*) chemistry generated by nitrate photolysis. Indeed, degradation of the target compound increased when nitrate (at 0.2 and 0.4 mM) was added to the Wilmington sample, further corroborating this conclusion. Overall photoreaction rates decreased for the lower-molecular-weight PAHs, because the fastest naphthalene photolytic rate was roughly two orders of magnitude slower than that of pyrene.

show abstract

Pulse radiolysis of aqueous solutions of aromatic hydrocarbons in the presence of oxygen

Cited by 14 publications

References 10 publications

Direct and indirect photolysis of polycyclic aromatic hydrocarbons in nitrate‐rich surface waters

Direct and indirect photolysis of polycyclic aromatic hydrocarbons in nitrate‐rich surface waters

Feasibility of destruction of gaseous benzene with dielectric barrier discharge

Direct and Indirect Photolysis of Polycyclic Aromatic Hydrocarbons in Nitrate-Rich Surface Waters

Contact Info

Product

Resources

About