Enhanced electro-catalytic generation of hydrogen peroxide and hydroxyl radical for degradation of phenol wastewater using MnO2/Nano-G|Foam-Ni/Pd composite cathode

doi:10.1016/j.electacta.2018.06.075

Electrochimica Acta

Volume 282, 20 August 2018, Pages 416-426

https://doi.org/10.1016/j.electacta.2018.06.075 Get rights and content

Highlights

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A two-layer type MnO₂/Nano-G|Foam-Ni/Pd composite cathode was prepared.
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MnO₂/Nano-G|Foam-Ni/Pd cathode had high electro-catalytic degradation performance.
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Cyclic voltammetry test was used for measuring the degradation performance.
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MnO₂ nanorods accelerated the production of OH from the dissociation of H₂O₂.
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Pd metal trees/crystals improved the generation of H₂O₂ by O₂ reduction.

Abstract

To improve the electro-catalytic degradation efficiency of the cathode in electrochemical advanced oxidation processes, MnO₂ modified Nano-graphite (MnO₂/Nano-G) and Pd loaded Foam-Ni (Foam-Ni/Pd) composites were prepared by the chemical redox and electro-deposition methods, respectively, and a two-layer type MnO₂/Nano-G|Foam-Ni/Pd composite cathode was prepared with the chitosan as a binder. The composites were characterized by X-ray diffraction, scanning electrons microscopy and X-ray photoelectron spectroscopy. Results showed that the mix-crystal structural MnO₂ (α-MnO₂ and γ-MnO₂) nanorods with length of 80–200 nm and width of 20–50 nm were uniformly loaded on the Nano-G surface, and the three-dimensional Pd° metal trees/crystals were tightly deposited on the Foam-Ni substrate. The as-prepared cathode was applied to the electro-catalytic degradation of phenol wastewater, and the reaction parameters were optimized. Compared with MnO₂/Nano-G|Foam-Ni and Nano-G|Foam-Ni cathodes, the degradation efficiency of phenol by MnO₂/Nano-G|Foam-Ni/Pd cathode was significantly improved. The removal efficiencies of phenol and total organic carbon (TOC) by MnO₂/Nano-G|Foam-Ni/Pd cathode reached 98.7% and 85.3% after 120 min electrolysis under oxygen aeration condition, respectively. The optimal reaction parameters were current density of 39 mA cm⁻², electrolyte (Na₂SO₄) concentration of 0.1 mol L⁻¹, electrode distance of 4 cm and initial pH of 7. By determining the variations of H₂O₂ and radical dot OH content in the cathode chamber, it was found that Pd metal crystals improved the reduction of O₂ to H₂O₂ and MnO₂ nanorods accelerated the dissociation of H₂O₂ to OH, producing more H₂O₂ and OH to oxidize phenol and eliminate TOC in wastewater. The results in this study provide useful information for the control of refractory organic pollutants with electrochemical advanced oxidation in wastewater treatment.

Graphical abstract

Introduction

Phenol is not only an essential raw and intermediate material but also a common by-product in various industries of chemical, plastic, leather, pharmaceutical and petroleum, etc [[1], [2], [3], [4]]. The global demand of phenol has annually increased and is expected to exceed 11 million kilograms by 2020 [1]. However, phenol is a highly hazardous chemical, which has been listed as a priority pollutant by United States Environmental Protection Agency, due to its acute toxicity on living organisms and damage on ecological system even at low doses [[1], [2], [3]]. Phenol is a refractory pollutant in conventional treatment processes [[5], [6], [7]]. Conventional biological treatment is generally ineffective for the degradation of phenol wastewater with high concentration because of the inhibition or even inactivation effect of phenol on the activity of microorganisms [3,7]. Proposing an effective method for the treatment of phenol wastewater is important in wastewater treatment.

Electrochemical advanced oxidation processes have been demonstrated to be an effective technology for degradation and/or mineralization of refractory organic wastewater with high concentration [8,9]. This technology has many advantages including high efficiency, simple operation, small occupation and environmental compatibility [10,11]. The degradation of organic pollutants is mainly depended on the production of the strong reactive oxygen species ( radical dot OH and H₂O₂) by electro-catalysis, which can oxidize a wide range of organics into CO₂, H₂O and/or small molecule products quickly and non-selectively [8,9,[11], [12], [13]]. The anode can oxidize H₂O to generate OH [8,11]. The cathode can catalyze the conversion of dissolved O₂ to H₂O₂ by two-electron reduction, which can be dissociated to radical dot OH [8,[14], [15], [16]]. Thus, the electrode is the most important factor for the generation of reactive oxygen species and electrochemical degradation efficiency. The degradation of organics are performed by using various anodes effectively, such as dimensionally stable anode (DSA), platinized titanium (Ti/Pt) anode, lead dioxide (PbO₂) anode, or boron-doped diamond (BDD) anode [[17], [18], [19], [20]]. Some of these anodes have been developed and applied to the actual wastewater treatment. The cathodes used in electrochemical advanced oxidation processes have principally focused on the titanium mesh [21], stainless steel [22,23], and various carbon materials (such as porous carbon, carbon felt, activated carbon fiber, and graphite) electrodes for their conductivity and low cost [[24], [25], [26], [27], [28], [29]].

Among these cathodes, the carbon materials electrodes with high yield of H₂O₂ are considered as the ideal cathodes [30]. The traditional graphite materials electrodes have been widely used as the cathode because of their chemical resistance [29,30]. As one of the graphite materials, the two-dimensional flake-like Nano-G, which is made up of ultrathin graphite sheet or even few-layer graphene, possesses not only the superior electrical conductivity and high chemical stability but also the large specific surface area and high surface energy [31]. Most importantly, Nano-G can be more easily and cheaply manufactured on a large scale compared with graphene [31]. Yu et al. [32] used ultrasound to disperse expanded graphite for producing the Nano-G and found that the electrochemical performances and electro-catalytic degradation efficiency of Nano-G cathode are superior to traditional graphite materials cathodes. To improve the electro-catalytic degradation efficiency, the cathode materials should be further explored. Typically, manganese oxide (MnO_x) and palladium (Pd) metal as the catalysts were successfully used for modifying carbon materials to enhance the electro-generation of H₂O₂ by O₂ reduction or dissociation of H₂O₂ to radical dot OH. Wang et al. [33,34] used the Pd metal to modify the activated carbon electrode and indicated that the presence of the Pd metal can accelerate the two-electron reduction of O₂ to H₂O₂ for effective degrading chlorinated phenols in wastewater. Fathy et al. [35] reported that the MnO₂ modified multi-walled carbon nanotube nanocomposite catalyzes greatly the dissociation of H₂O₂ to radical dot OH and shows high activity for the degradation of reactive blue 19 dye from wastewater. Furthermore, Roy et al. [36] and Goldestine et al. [37] also indicated that the MnO_x can effectively promote the dissociation of H₂O₂ to OH. However, to our best knowledge, there is still lack of a study in regard to cathode modified with MnO_x and Pd metal for simultaneously enhancing the generation of H₂O₂ and radical dot OH.

In recent years, the novel multi-layer composite cathodes were developed by researchers for wastewater treatment. Fan et al. [38] prepared a Fe-CHI/Foam-Ni|ACF|Fe-CHI/Foam-Ni sandwich cathode for electro-Fenton system, in which one piece of activated carbon fiber (ACF) was fixed between two pieces of Fe²⁺-chitosan loaded nickel foam (Foam-Ni). This cathode was very stable and could efficiently degrade rhodamine B by in situ generating both H₂O₂ and iron ions. In our previous study [39], a two-layer type Nano-G|Foam-Ni (Nano-G film layer and Foam-Ni layer) cathode was successfully synthesized, and showed a better electro-catalytic degradation performance in comparison with monolayer Nano-G cathode and Foam-Ni|Nano-G|Foam-Ni sandwich cathode. Furthermore, the unique three-dimensional cross-linked grid structure of the Foam-Ni can provide high porosity and surface area, which can also support the catalysts for increasing the contact areas between catalysts and reactants [40]. Therefore, to utilize the catalytic property of the Pd metal, Pd deposited Foam-Ni electrode may exhibit the advantage for the generation of H₂O₂.

In this work, we prepared the MnO₂ modified Nano-G (MnO₂/Nano-G) and Pd loaded Foam-Ni (Foam-Ni/Pd) composites by the chemical redox method and electro-deposition method, respectively, and then used them to construct a two-layer type MnO₂/Nano-G|Foam-Ni/Pd composite cathode for the electro-catalytic degradation of phenol wastewater. The morphology, structure and element chemical state of the MnO₂/Nano-G and Pd/Foam-Ni composites were analyzed. The degradation efficiencies of phenol and TOC with MnO₂/Nano-G|Foam-Ni/Pd composite cathode were investigated, and the reaction parameters were optimized. Finally, the roles of the MnO₂ and Pd metal on the phenol degradation by MnO₂/Nano-G|Foam-Ni/Pd composite cathode and the cathodic catalysis mechanisms were revealed. As expected, the as-prepared MnO₂/Nano-G|Foam-Ni/Pd composite cathode exhibited high H₂O₂ and radical dot OH yields and electro-catalytic degradation performance.

Section snippets

Materials and chemicals

Natural flake graphite was purchased from Heilongjiang Oyu Graphite Group Co., Ltd. Foam-Ni (99.9%) was purchased from Changsha Liyuan New Material Co., Ltd. Phenol, glutaraldehyde and palladium chloride were purchased from Sinopharm Chemical Reagent Co., Ltd., China. Chitosan was purchased from Aladdin Reagent Co., Ltd. Potassium permanganate, manganese acetate and perchloric acid were purchased from Tianjin Xinyuan Chemical Co., Ltd., China. All chemicals used in our work were analytical

Characterization of the cathode materials

The crystalline structure of the cathode materials (MnO₂/Nano-G and Foam-Ni/Pd) was characterized by XRD technique. Fig. 1a shows the XRD pattern of the MnO₂/Nano-G composite. As exhibited in Fig. 1a, the sharp diffraction peaks at 2θ = 26.5° and 54.7° were assigned to the characteristic peaks of (002) and (004) crystal faces of the graphite (JCPDS No. 08-0415) [41], respectively. The two sharp peaks implied that the Nano-G was perfectly crystallized and the original Nano-G crystal was not

Conclusions

The two-layer type MnO₂/Nano-G|Foam-Ni/Pd composite cathode was prepared for the degradation of phenol wastewater. The MnO₂ nanorods with length of 80–200 nm and width of 20–50 nm were uniformly loaded on the Nano-G surface, and presented the mix-crystal structure of α-MnO₂ and γ-MnO₂. The three-dimensional Pd° metal trees/crystals were tightly deposited on the Foam-Ni substrate. The optimal current density, electrolyte (Na₂SO₄) concentration, electrode distance and initial solution pH were

Acknowledgments

This work was supported by the State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology) (No. 2016DX11), and the National Science and Technology Major Projects for Water Pollution Control and Treatment (Grand NO. 2017ZX07201003).

References (62)

N. Boonrattanakij et al.
Treatability of phenol-production wastewater: rate constant and pathway of dimethyl phenyl carbinol oxidation by hydroxyl radicals
J. Environ. Manag.
(2017)
L. Ren et al.
Phenol biodegradation and microbial community dynamics in extractive membrane bioreactor (EMBR) for phenol-laden saline wastewater
Bioresour. Technol.
(2017)
M. Pimentel et al.
Phenol degradation by advanced electrochemical oxidation process electro-Fenton using a carbon felt cathode
Appl. Catal. B Environ.
(2008)
G. Pan et al.
Hybrid gel reinforced with coating layer for removal of phenol from aqueous solution
Chem. Eng. J.
(2008)
F.C. Moreira et al.
Electrochemical advanced oxidation processes: a review on their application to synthetic and real wastewaters
Appl. Catal. B Environ.
(2017)
C.A. Martínez-Huitle et al.
Decontamination of wastewaters containing synthetic organic dyes by electrochemical methods: a general review
Appl. Catal. B Environ.
(2009)
C. Comninellis
Electrocatalysis in the electrochemical conversion/combustion of organic pollutants for waste water treatment
Electrochim. Acta
(1994)
X. Guo et al.
Study on preparation of SnO₂-TiO₂/Nano-graphite composite anode and electro-catalytic degradation of ceftriaxone sodium
Chemosphere
(2016)
F.C. Moreira et al.
Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes
Water Res.
(2015)
H. Luo et al.
Electrochemical degradation of phenol by in situ electro-generated and electro-activated hydrogen peroxide using an improved gas diffusion cathode
Electrochim. Acta
(2015)

H. Wang et al.

Degradation mechanism of diethyl phthalate with electrogenerated hydroxyl radical on a Pd/C gas-diffusion electrode

J. Hazard. Mater.

(2010)

M. Zhou et al.

Treatment of high-salinity reverse osmosis concentrate by electrochemical oxidation on BDD and DSA electrodes

Desalination

(2011)

S. Belkacem et al.

Study of oxytetracycline degradation by means of anodic oxidation process using platinized titanium (Ti/Pt) anode and modeling by artificial neural networks

Process Saf. Environ. Protect.

(2017)

C. Wang et al.

Electrochemical degradation of enrofloxacin by lead dioxide anode: kinetics, mechanism and toxicity evaluation

Chem. Eng. J.

(2017)

Y. Samet et al.

Electrochemical degradation of chlorpyrifos pesticide in aqueous solutions by anodic oxidation at boron-doped diamond electrodes

Chem. Eng. J.

(2010)

X. Guo et al.

Preparation and electrochemical property of TiO₂/Nano-graphite composite anode for electro-catalytic degradation of ceftriaxone sodium

Electrochim. Acta

(2015)

D. Jager et al.

Degradation of reactive black 5 by electrochemical oxidation

Chemosphere

(2018)

T.X.H. Le et al.

Facile preparation of porous carbon cathode to eliminate paracetamol in aqueous medium using electro-fenton system

Electrochim. Acta

(2016)

S. Cotillas et al.

Use of carbon felt cathodes for the electrochemical reclamation of urban treated wastewaters

Appl. Catal. B Environ.

(2015)

Y. Gong et al.

Partial degradation of levofloxacin for biodegradability improvement by electro-Fenton process using an activated carbon fiber felt cathode

J. Hazard. Mater.

(2016)

R. Babaei-Sati et al.

Electrogeneration of H₂O₂ using graphite cathode modified with electrochemically synthesized polypyrrole/MWCNT nanocomposite for electro-Fenton process

J. Ind. Eng. Chem.

(2017)

Y. Wang et al.

Preparation and characterization of a novel KOH activated graphite felt cathode for the electro-Fenton process

Appl. Catal. B Environ.

(2015)

C.T. Wang et al.

Removal of color from real dyeing wastewater by Electro-Fenton technology using a three-dimensional graphite cathode

J. Hazard. Mater.

(2008)

Y. Lin et al.

Enhanced generation of H₂O₂ and radicals on Co₉S₈/partly-graphitized carbon cathode for degradation of bio-refractory organic wastewater

Electrochim. Acta

(2016)

D. Li et al.

Preparation and characterization of Nano-graphite/TiO₂ composite photoelectrode for photoelectrocatalytic degradation of hazardous pollutant

J. Hazard. Mater.

(2016)

H. Wang et al.

Comparative study on electrochemical degradation of 2,4-dichlorophenol by different Pd/C gas-diffusion cathodes

Appl. Catal. B Environ.

(2009)

H. Wang et al.

Preparation of multifunctional gas-diffusion electrode and its application to the degrading of chlorinated phenols by electrochemical reducing and oxidizing processes

Appl. Catal. B Environ.

(2012)

N.A. Fathy et al.

Oxidative degradation of RB19 dye by a novel g-MnO₂/MWCNT nanocomposite catalyst with H₂O₂

J. Environ. Chem. Eng.

(2013)

C.B. Roy

Catalytic decomposition of hydrogen peroxide on some oxide catalysts

J. Catal.

(1968)

J.R. Goldstein et al.

The kinetics of hydrogen peroxide decomposition catalyzed by cobalt-iron oxides

J. Catal.

(1974)

Y. Fan et al.

Design of an electro-Fenton system with a novel sandwich film cathode for wastewater treatment

J. Hazard. Mater.

(2010)

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Enhanced electro-catalytic generation of hydrogen peroxide and hydroxyl radical for degradation of phenol wastewater using MnO2/Nano-G|Foam-Ni/Pd composite cathode

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Materials and chemicals

Characterization of the cathode materials

Conclusions

Acknowledgments

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Enhanced electro-catalytic generation of hydrogen peroxide and hydroxyl radical for degradation of phenol wastewater using MnO₂/Nano-G|Foam-Ni/Pd composite cathode