Lignin combined with polypyrrole as a renewable cathode material for H2O2 generation and its application in the electro-Fenton process for azo dye removal. (1st January 2018)

• Record Type: Journal Article
• Authors: Huang, Hailan; Han, Chunlei; Wang, Guanwen; Feng, Chunhua
• Is Part Of: Electrochimica acta. Volume 259(2018)
• Page Start: 637
• Page End: 646
• Publication Date: 2018-01-01
• Subjects: Electropolymerization -- Advanced oxidation process -- Quinonoid group -- Lignin -- Oxygen reduction reaction; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.11.014
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: The development of renewable, low-cost, and high-efficiency cathode materials for oxygen reduction to H2 O2 is desirable for use in electro-Fenton systems for the oxidative treatment of wastewater. In the present study, we report the synthesis of a renewable biopolymer with lignin (lig) interpenetrated into a polypyrrole (PPy) framework via a simple one-step electropolymerization method. This allows the formation of PPy/lig composites that are uniformly coated on a graphite felt (GF) substrate, having large surface area, increased mechanical stability, and abundant CO (including quinone-type) groups. These features improved the electrocatalytic activity of the PPy/lig-GF cathode for oxygen reduction to H2 O2 when an optimal cathodic potential (−0.5 V vs. SCE) was applied, as evidenced by the observed higher H2 O2 electro-generation yield and efficiency compared to the raw GF and PPy/ClO4 − -GF cathodes. Electro-Fenton systems equipped with the GF cathodes (either modified or unmodified) for the decolorization and mineralization of AO7 (an azo dye) followed a pseudo-first-order kinetic model. The PPy/lig-GF cathode achieved substantially higher rate constants and degradation efficiencies. In addition, the incorporation of lignin significantly improved the cycling stability of the cathode material. Graphical abstract: Highlights: Pyrrole was electropolymerized on the GF substrate with lignin as the dopant. PPy/lig composites have abundant CO (including quinone-type) groups. PPy/lig-GF cathode is electrocatalytically effective in oxygen reduction to H2 O2 . Decolorization and mineralization of AO7 was achieved in the electro-Fenton system.