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Showing 2 results for Polycyclic Aromatic Hydrocarbons
Comparison of adsorption isotherms and kinetics of naphthalene and phenanthrene atactivated carbon bedsin the organic n-hexane solution
F. Golbabaei, R. Moradi Rad, L. Omidi, S. Farhang Dehghan, S. Roshani,
Volume 5, Issue 2 (7-2015)
Abstract

Introduction: Polycyclic aromatic hydrocarbons (PAHs) are one of the most significant current environmental issues. Phenanthrene and naphthalene adsorption at activated carbon beds prevent the release of these compounds into the environment. The objective of this research was to compare the amounts of phenanthrene and naphthalene adsorption at activated carbon beds in the n-hexane solution.

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Material and Method: This discontinuous experimental study was conducted in the laboratory scale batch and in the n-hexane solution containing phenanthrene and naphthalene.PH values were adjusted by adding hydrochloric acidand 1 N NaOH. The initial and residual phenanthrene and naphthalene concentrations were spectrophotometrically measured at 270 and 266 nm, respectively.

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Results: Findings showed that the maximum adsorption of naphthalene was obtained at pH=5 and contact time of 8 hours (7.4 mg/gr). The maximum adsorption was reached at pH=7 and contact time of 11 hours for phenanthrene (8.34 mg/gr).Improvement in the adsorption capacity was happenedby the increases in contact time and initial phenanthrene and naphthalene concentrations. The adsorption kinetics of these two compounds followed pseudo-second-order and Freundlich isotherm model.

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Conclusion: Freundlich isotherm model showed a strong association with PAHs adsorption process. A weak correlationwas observed between Langmuir theory and the results of the adsorption at activated carbon beds in the organic n-hexane solution.


Synthesis and Characterization of Zn3 (BTC)2 Nanoporous Sorbent for Sampling from Benzo[a]pyren using Needle Trap in the Air
Shiva Soury, Abdulrahman Bahrami, Saber Alizadeh, Farshid Ghorbani Shahna, Davood Nematollahi,
Volume 10, Issue 2 (5-2020)
Abstract
Introduction: In this study, Zn3(Btc)2 (metal organic framework) sorbent was introduced for sampling of Benzo[a]pyren from the air. The purpose of this study was to develop the sampling and analysis method by needle trap, with no sample preparation step.
Material and method: Zn3(Btc)2 sorbent was electrochemically synthesized and its properties were specified by FTIR, FE-SEM, and PXRD techniques. A glass chamber with a temperature of 120°C was used to make the certain concentration of Benzo[a]pyren. Factors affecting the efficiency of needle trap were evaluated and optimized using a response surface method considering a specific operating interval to achieve the highest efficiency. The performance of the proposed method was also investigated using the real samples.
Results: The highest desorption efficiency of Benzo[a]pyren was obtained when using the needle trap containing Zn3 (Btc)2 sorbent at 379°C and 9 min retention time. No significant reduction was observed in the analyte concentration by maintaining the sampler for 60 days. The limit of detection and limit of quantification of Benzo[a]pyren were obtained 0.01 and 0.03 mg/m3, respectively. The percentage of standard deviation of the measured values of Benzo[a]pyren in diesel exhaust was calculated 4.1%.
Conclusion: The highest desorption efficiency of Benzo[a]pyren was obtained when using the needle trap containing Zn3 (Btc)2 sorbent at 379°C and 9 min retention time. No significant reduction was observed in the analyte concentration by maintaining the sampler for 60 days. The limit of detection and limit of quantification of Benzo[a]pyren were obtained 0.01 and 0.03 mg/m3, respectively. The percentage of standard deviation of the measured values of Benzo[a]pyren in diesel exhaust was calculated 4.1%.

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