Efficient removal and recovery of copper by liquid phase catalytic hydrogenation using highly active and stable
Minghui Li1, Yuhan Sun1, Yuqiong Tang1
1State Key Laboratory of Pollution Control and Resource Reuse, State Experimental Teaching Demonstration Center for Environmental Science and Engineering, School of the Environment, Nanjing University, Nanjing 210023, PR China.
Abstract:
In this work, we coated carbon nanotubes (CNT) supported Pt catalyst by conductive carbon layers (labelled as Pt/CNT@C) and the catalyst was further functionalized by surface oxidation (denoted as Pt/CNT@Oxi-C). The textural properties of the catalysts were extensively characterized and liquid phase catalytic hydrogenation reduction of Cu2+ was conducted. Results showed that Pt particles of Pt/CNT@C and Pt/CNT@Oxi-C were completely embedded beneath carbon overcoatings. Furthermore, contrary to Pt/CNT no CO chemisorption was observed on both Pt/CNT@C and Pt/CNT@Oxi-C, indicative of the absence of exposed Pt particles in carbon-coated Pt/CNT. Effective Cu2+ reduction and metallic Cu deposition by catalytic hydrogenation were achieved on catalyst surface. Surface oxidation of Pt/CNT@C resulted in increased surface wetting and functionality content, leading to noticeable enhancement in catalytic activity for Cu2+ reduction. Additionally, Cu2+ reduction on Pt/CNT@Oxi-C proceeded through the Langmuir-Hinshelwood model, suggesting that the reduction of Cu2+ adsorbed on catalyst surface was the rate-determining step. Carbonization of overcoatings exhibited a volcano-type relationship between carbonization temperature and catalytic activity of Pt/CNT@C for Cu2+ reduction. As for catalyst reuse, Pt/CNT lost 92 % of initial activity after five consecutive reaction cycles, whereas Pt/CNT@Oxi-C maintained a high catalytic activity without remarkable deactivation.
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