Key role of activated carbon fibers in enhanced decomposition of pollutants using heterogeneous cobalt/peroxymonosulfate system

BACKGROUND: The development of effective and green peroxymonosulfate (PMS) activation processes has attracted considerable attention and still remains a great challenge in the environmental field. Herein, the cobalt catalyst was innovatively supported onto activated carbon fibers (ACFs) to construct an outstanding heterogeneous catalyst, Co@ACFs, for PMS activation. RESULTS: Co@ACFs could effectively activate PMS to decompose dyes with about 100% removal rate in 35 min. Co@ACFs maintained its catalytic ability without detectable Co leaching during repeated batch experiments. More importantly, the catalyst presented an enhanced decomposition performance over most reported heterogeneous Co catalysts due to the significant role of ACFs: (i) high adsorption capacity in favor of the enhanced catalytic activity; (ii) ACFs as an electron donor to accelerate Coᴵᴵ/Coᴵᴵᴵ cycle thereby speeding up degradation. Combining electron paramagnetic resonance (EPR) with radical scavengers, it was found that both sulfate and hydroxyl radicals (SO₄ •‐, •OH) were responsible for the degradation of dyes. Unexpectedly, •OH was the dominant radical, different from the reported mechanism in typical Co/PMS. CONCLUSION: This study not only paves the way to further develop highly efficient and green PMS activation processes, but also provides a new practical method for application to wastewater remediation. © 2015 Society of Chemical Industry