Degradation of 2-Naphthol in Aqueous Solution by Electro-Fenton System with Cu-Supported Stainless Steel Electrode

Abstract

For the treatment of 2-naphthol wastewater, the homogeneous electro-Fenton process was considered as an effective method but some disadvantages greatly restrict its application. The three-dimensional electro-Fenton (3D-EF) system using a nano zero-valent iron-supported biochar (NZVIs-BC) particle electrode and a Cu-supported stainless steel electrode (Cu-SSE) was proposed to avoid the disadvantages of the homogeneous electro-Fenton. In this work, the 3D-EF system was developed, which consisted of a Cu-SSE (cathode), a graphite rod (anode) and a NZVIs-BC particle electrode. The effect of the ratio of ferrous sulfate heptahydrate (FS) to rice straw (RS), CuSO4•5H2O amount, initial pH of 2-naphthol wastewater and current intensity (the output current of the power supply) on the removal rate of 2-naphthol were investigated. It is noteworthy that more than 98.36% of the 2-naphthol in aqueous solution was removed by the 3D-EF system, and only about 60.09% of 2-naphthol was removed by the homogeneous electro-Fenton system. Furthermore, naphthalene, benzoic acid, β-naphthoquinone, 1, 2-naphthalenedione, phenol and aromatic hydrocarbon were the main degradation products of 2-naphthol by the 3D-EF system; the toxicity of 2-naphthol wastewater was also greatly reduced.

Stirling Engine-Inspired Parallel Triboelectric Nanogenerator Drives the Electro-Fenton Process

“…In this process, •OH is a kind of active oxygen species with a higher oxidation potential (E 0 (•OH,H + /H2O) = 2.72 V) than ozone under acidic conditions. 11,12 However, the conventional EF process generally needs an external power source to produce the active oxygen species 13−15 and it has become a hot topic to develop self-powered EF systems using generally available renewable mechanical energy. 16 As an emerging energy-converting technology, the triboelectric nanogenerator (TENG) is undergoing fast progress in both harvesting mechanical energy prevalent in the environ-ment 17,18 and developing electrochemical systems for environmental protection.…”

“…The main reactions are hydrogen peroxide (H 2 O 2 ) electrogeneration over the cathode and decomposition under the catalytic effect of Fe 2+ ions, forming a hydroxyl radical ( · OH), , along with the regeneration of Fe 2+ ions through Fe 3+ reduction on the cathode. In this process, · OH is a kind of active oxygen species with a higher oxidation potential ( E 0 ( · OH,H + /H2O) = 2.72 V) than ozone under acidic conditions. , However, the conventional EF process generally needs an external power source to produce the active oxygen species − and it has become a hot topic to develop self-powered EF systems using generally available renewable mechanical energy …”