(545o) Catalytic Removal of Polybrominated Diphenyl Ethers (PBDEs) in Effluent Gas from Thermal Desorption Treated Soils

Over the past three decades, polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in various customer products, such as electronics, electronic appliances, furniture, and textile [1, 2]. Generally, PBDEs are simply blended with the materials, and thus are likely to leak out during the production, usage and disposal of the products [3]. Due to the high hydrophobicity, persistence and bioaccumulation, PBDEs released from the products have caused serious environmental problems and threats to human health.

Up to now, several methods such as photochemical method, biological method, reduction by zero-valent iron and thermal desorption have been applied to degrade PBDEs [4-6]. Among them, thermal desorption was the preferred remediation method for PBDEs-contaminated soils due to its high removal efficiency and stable reaction process. However, the effluent-gas containing PBDEs were usually collected by activated carbon, which has several drawbacks, such as need of secondary treatment, complex operation and high cost. Therefore, it is important to develop an effective and feasible method for eliminating gaseous PBDEs rapidly and completely. Catalytic degradation was considered as a promising method for PBDEs removal due to its high treatment efficiency, low price and easy to operate.

In this study, a plate-type γ-Al₂O₃/Al monolithic support was prepared through anodization technology [7, 8], and its catalytic performance for removal of gaseous PBDEs was studied. It was found that the structured support could not remove PBDEs effectively. However, Fe/γ-Al₂O₃/Al catalyst was proved to have good activity for gaseous PBDEs elimination. As such, a series of Fe-based/γ-Al₂O₃/Al catalysts with different iron loadings were further prepared by impregnation method, and the effects of Fe loading on the activity of catalysts were extensively investigated. The results show that the proper amount of iron loading could enhance the catalytic performance, and thus remove PBDEs significantly. In addition, based on the analysis of intermediate products, the degradation pathway and removal mechanism of PBDEs over Fe-based catalyst were speculated.

References

[1] L. Tan, S.Y. Lu, Z.Q. Fang et al., Appl. Catal., B 200 (2017) 200-210.

[2] D.M. Orihel, T. Bisbicos, C.T.R. Darling et al., Environ. Toxicol. Chem., 35 (2016) 573-583.

[3] Y.H. Peng, M.K. Chen, Y.H. Shih, J. Hazard. Mater., 260 (2013) 844-850.

[4] K.L. Chow, Y.B. Man, N.F.Y. Tam et al., J. Hazard. Mater., 322 (2017) 263-269.

[5] J.H. He, K.R. Robrock, L. Alvarez-Cohen, Environ. Sci. Technol., 40 (2006) 4429-4434.

[6] F. Yang, Q.Q. Li, G.J. Su et al., Chemosphere, 150 (2016) 445-452.

[7] F.Y. Fan, Q. Zhang, X. Wang et al., Fuel, 186 (2016) 11-19.

[8] F.Y. Fan, Q. Zhang, H. Hou, Ind. Eng. Chem. Res., 57 (2018) 2426-2433.