Homogeneous And Heterogeneous Activation Of Peroxymonosulfate With Iron-Based Catalysts
Citation:
Yang, Q., A. Rastogi, H. Choi, S. R. AL-ABED, AND D. D. DIONYSIOU. Homogeneous And Heterogeneous Activation Of Peroxymonosulfate With Iron-Based Catalysts. Presented at First International Conference From Nanoparticles And Nanodevices And Nanosystems (IC4N), Halkidiki, GREECE, June 15 - 19, 2008.
Impact/Purpose:
To investigate the degradation of PCBs using sulfate radical-based advanced oxidation technologies.
Description:
Polychlorinated biphenyls (PCBs) in the environment pose long-term risk to public health because of their persistent and toxic nature. This study investigates the degradation of PCBs using sulfate radical-based advanced oxidation technologies (SR-AOTs). SR-AOTs are attracting considerable attention due to the high oxidizing ability of sulfate radicals (SRs) to degrade various organic pollutants [1]. SRs could be generated through iron (Fe(II)) mediated activation of peroxymonosulfate (KHSO5, PMS). To the best of our knowledge, this study is the first instance for coupling of Fe(II) with PMS for PCB degradation. The effectiveness of the process was evaluated based on the degradation of a model polychlorinated biphenyl, 2-chlorobiphenyl (2-CIBP). In aqueous system, near complete removal of 2-CIBP was observed in 4 h with the mole ratio of 2-CIBP : Fe(II) : PMS at 1:10:10. Since nano zero valent iron (NZVI) has been shown to be effective in dechlorinating PCBs, attempts were made to extend the application of the homogeneous oxidation process using soluble iron ions to heterogeneous systems that immobilize iron in support materials. It has been documented that the activity of the heterogeneous catalyst is directly proportional to its surface area. This prompts the present investigation of systems with highly dispersed catalyst supported on a high surface area substrate like activated carbon. Meanwhile, the iron immobilization could also overcome the common problem faced with NZVI which is the spontaneous aggregation to micro-sized particles, resulting in loss of reactivity and mobility. This study showed that SRs could be effectively generated via the heterogeneous activation of PMS with NZVI dispersed on granular activated carbon and there exists an optimum iron loading (30%) for PMS activation.