Reza Tajik, Hasan Asilian, Ali Khavanin, Ahmad Jonidi, Babak Eshrati, Ardalan Soleimanian,
Volume 6, Issue 17 (Summer 2012)
Abstract
Background: Poly chlorinated biphenyls (PCBS) are the groups of organic chemical material and toxic, persistent, bio accumulate and pose a risk of causing adverse effects to human health and the environment. PCB compounds are caused the different health effects in human depending of age, sex, route of entry, intensity and frequency exposure. This study was conducted to determine the effect of microwave rays, hydrogen peroxide, TiO2 catalyst and ethanol on the Decomposition of PCBS.
Methods: In this experiment used a MW oven, Pyrex vessel reactor (250ml volume), Pyrex tube connector and condensing system. A 900w domestic MW oven with a fixed frequency of 2450 MHZ was used to provide MW irradiation. Ray powers used in 540، 720 and 900w. The PCB were analyzed by GC-ECD
Results: The degradation of total PCBS in terms of 540, 720 and 900W was 85.03%, 90.32% and 96.87% respectively. The degradation of total PCB in terms of ratio to solvent with transformer oil in 1:1، 2:1 and 3:1 was 53.97%، 78.98% and 95.13% respectively. The degradation of total PCBs in terms of not using of H2O2/ TiO2 and using 20% of H2O2 and 0.05, 0.1, 0.15 and 0.2 g TiO2 was 68.78%, 93.97%, 95.13%, 96.18% and 96.87 % respectively.
Conclusion: The Microwave thermal reaction was applied for the dechlorination of PCBs and high efficiencies were obtained. Microwave power and amounts of reactants added are important factors influencing dechlorination efficiency.
Reza Tajik, Hasan Asilian, Ali Khavanin, Ahmad Jonidi Jafari, Babak Eshrati, Ardalan Soleimanian, Jaber Ghrehdaghi,
Volume 6, Issue 19 (Winter 2013)
Abstract
Background: Poly chlorinated biphenyls (PCBs) are a class of chlorinated organic chemicals that do not easily degrade in the environment. This study was conducted to determine the effect of microwave rays, hydrogen peroxide, dioxide titanium and ethanol solvent on the degradation of PCBs.
Methods: A 900w domestic MW oven with a fixed frequency of 2450 MHZ was used to provide MW irradiation. Ray powers were used in 540, 720, and 900w. A hole was made on the top portion of the oven and a Pyrex vessel reactor (250ml volume) was connected to condensing system with a Pyrex tube connector. The PCBs were analyzed by GC-ECD.
Results: The degradation of total PCBs was 54.62%, 79.71%, and 95.76% in terms of their ratio to solvent with transformer oil at 1:1, 2:1, and 3:1, respectively. The degradation of total PCBs was 84.27%, 89.18%, and 96.1% when using 540, 720, and 900W microwave radiation, respectively. The degradation of total PCBs was 70.72%, 93.02%, 94.16, 95.23% and 96.1% when not using H2O2/ Tio2 and using 20% H2O2 and 0.05, 0.1, 0.15, and 0.2g Tio2, respectively.
Conclusion: In the present study, the optimum conditions to decompose PCBs efficiently included 50 ml volume of ratio to solvent with transformer oil (3:1), sodium hydroxide solution (0.2N) 1 cc, use of 20% hydrogen peroxide of total volume of samples, dioxide titanium (0.2g), and irradiation for 9 minutes. Under these optimum conditions, efficiency of PCBs decomposition increased.
