One of the promising ways involves the electrochemical reduction of carbon dioxide into useful gases in the presence of a suitable catalyst mostly metal. However, there exist certain limitations to the excessive use or this technique due to the need for a catalyst to function at high overpotential and the growing price of metals.
The use of a disposed electroplating sludge which comprises of certain organic compounds and metals as electrocatalysts has shown huge potential in electrolytic reaction. The successful use of the electroplating sludge could actually be cost-effective.
A microbial electrolysis cell is often classified as a potential source for renewable energy applications, as they have the ability to convert organic compounds into energy. The microbial electrolysis cell which also adapts a proton exchange membrane also has the ability to reduce high overpotential during electrochemical process. Hence, a means of using electroplating sludge in a microbial electrolysis cell could definitely achieve some positive results.
In a recent paper published in Electrochimica Acta, Professor Yong Yuan at Guangdong Institute of Eco-Environmental and Soil Sciences and Professor Haoran Yuan and Lifang Deng and their colleagues at Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, in China investigated the feasibility and efficiency of a thermally treated electroplating sludge as electrocatalysts for reduction of carbon dioxide to wanted products while considering a microbial electrolysis cell.
At first, the authors confirmed the presence of certain metallic compounds responsible for initiating carbon dioxide reduction when analyzing the thermally treated electroplating sludge.
The thermally treated electroplating sludge possessed high positive potential for carbon reduction compared to the previously reported ones. They also revealed a high catalytic activity during the conversion process.
At a certain potential, the thermally treated electroplating sludge performed efficient reduction of carbon dioxide in the microbial electrolysis cell as six main products; methane, ethylene, carbon monoxide, hydrogen and acetate were produced while methane had the highest production rate.
The thermally treated electroplating sludge when compared with the thermally treated municipal sludge and thermally dyeing sludge possessed the highest current densities and Faraday efficiencies for the converted products. The thermally treated electroplating sludge showed excellent stability in the microbial electrolysis cell during the conversion process of carbon dioxide.
The authors also provided a possible pathway mechanism for reduction of carbon dioxide with the use of the thermally treated electroplating sludge catalyst. They found that carbon dioxide was first reduced to a carbonate ion before being protonated by bicarbonate ions to produce methane, ethylene, carbon dioxide and acetate.
This study developed successfully a platform where electroplating sludge can be recycled as a useful catalyst for conversion of carbon dioxide into wanting gases.
Yuan, H.1,3,4, Deng, L.1,3,4, Cai, X.2, Zheng, T.1,3,4,5, Zhou, S.2, Chen, Y.1, Yuan, Y.2 Recycling Electroplating Sludge to Produce Sustainable Electrocatalysts for the Efficient Conversion of Carbon Dioxide in a Microbial Electrolysis Cell, Electrochimica Acta 222 (2016) 177–184.Show Affiliations
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China
- Key Laboratory of Renewable Energy, Chinese Academy of Sciences, Guangzhou 510640, China
- Guangdong Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
- Green Biomanufacturing Research Institute, Jiangsu University of Science and Technology, Zhenjiang, 212003, China
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