(Digital Presentation) Recovery of Copper from Wastewater By Electrodeposition Onto Nanocarbon Composites
Authors: Stando Grzegorz Jan , Hannula Pyry-Mikko , Kumanek Bogumiła , Lundström Mari , Liu Haitao , Janas Dawid 
Published: July 2022

The connection of carbon nanostructures such as graphene or carbon nanotubes with other materials like metals [1] or polymers [2] is often beneficial. For example, composites consisting of copper and nanocarbon materials have improved electrical [1] and mechanical [3] properties due to the synergy effect. Unfortunately, the integration between copper and nanocarbon is not an easy task because of the “cuprophobic” nature of nanocarbon [4]. Recently, many methods have been developed to accomplish this challenge. Out of all available techniques, physical (casting, spark plasma sintering or metal spinning) and electrochemical [5] gained a considerable share of attention. In particular, electrodeposition is a commonly employed strategy to deposit copper onto nanocarbon electrodes. In this method, nanocarbon surface plays the role of working electrode, onto which copper ions are reduced, thereby creating a Cu coating on the surface.

This study demonstrates the recovery of copper from industrial wastewater by thin films based on carbon nanotubes (CNTs). Such a substrate was found as an ideal surface for the electrodeposition of metallic particles. Single/multi-walled CNTs, oxidized CNTs, nitrogen-doped CNTs and graphene were combined to obtain nanocarbon-nanocarbon composite electrodes, which were then used as substrates in Cu electrodeposition [6].

To establish the coating process parameters, synthetic solution of CuSO4 was first used as a source of copper ions. Then, wastewater of complex composition was employed directly for the electrodeposition process. Besides the 40 ppm of Cu, the wastewater contained other elements like salts Fe, Mg, Al, Zn and As in much greater amounts. It was discovered that such nanocomposite materials may be an excellent substrate for electrochemical recovery of Cu also from such a problematic waste, while simultaneously giving a product of high added value. Interestingly, the product was free from other metals, and only copper was detected on the nanocarbon surface. After just 1-hour of electrodeposition at -0.1V vs. SCE, a nanocarbon-based composite evenly coated with Cu was manufactured. Thorough investigation of the microstructure, and chemical composition of the nanocomposites correlated with the properties of the Cu coated materials enabled us to deduce critical parameters needed to make the Cu coating process effective [7].

[1] C. Arnaud, F. Lecouturier, D. Mesguich, N. Ferreira, G. Chevallier, C. Estournès, A. Weibel, C. Laurent, High strength - High conductivity double-walled carbon nanotube - Copper composite wires, Carbon N. Y. 96 (2016) 212–215. doi:10.1016/j.carbon.2015.09.061.

[2] S.N. Beesabathuni, J.G. Stockham, J.H. Kim, H.B. Lee, J.H. Chung, A.Q. Shen, Fabrication of conducting polyaniline microspheres using droplet microfluidics, RSC Adv. 3 (2013) 24423–24429. doi:10.1039/c3ra44808h.

[3] R. Jiang, X. Zhou, Q. Fang, Z. Liu, Copper-graphene bulk composites with homogeneous graphene dispersion and enhanced mechanical properties, Mater. Sci. Eng. A. 654 (2016) 124–130. doi:10.1016/j.msea.2015.12.039.

[4] D. Janas, B. Liszka, Copper matrix nanocomposites based on carbon nanotubes or graphene, Mater. Chem. Front. 2 (2018) 22–35. doi:10.1039/c7qm00316a.

[5] A. Singh, T. Ram Prabhu, A.R. Sanjay, V. Koti, An Overview of Processing and Properties of CU/CNT Nano Composites, Mater. Today Proc. 4 (2017) 3872–3881. doi:10.1016/J.MATPR.2017.02.286.

[6] D. Janas, M. Rdest, K.K.K. Koziol, Free-standing films from chirality-controlled carbon nanotubes, Mater. Des. 121 (2017) 119–125. doi:10.1016/j.matdes.2017.02.062.

[7] G. Stando, P.-M. Hannula, B. Kumanek, M. Lundström, D. Janas, Copper recovery from industrial wastewater - Synergistic electrodeposition onto nanocarbon materials, Water Resour. Ind. 26 (2021) 100156. doi:10.1016/J.WRI.2021.100156.

G.S. and P.S. would like to thank the Ministry of Science and Higher Education of Poland for financial support of research (under Diamond Grant, grant agreement 0036/DIA/201948). G.S. also would like to thank European Union for thanks for financing the costs of the conference (European Social Fund, grant nr POWR.03.05.00-00-Z305) and National Agency for Academic Exchange of Poland (under the Iwanowska program, grant agreement PPN/IWA/2019/1/00017/UO/00001) for financial support during the stay at the University of Pittsburgh in the USA. G.S. and H.L. acknowledge NSF (CBET-2028826) for partial support of this work. G. S. and D.J. acknowledge the National Agency for Academic Exchange of Poland (under the Academic International Partnerships program, grant agreement PPI/APM/2018/1/00004) for supporting training in the Aalto University. G.S, B.K. and D.J. would like to thank the National Centre for Research and Development, Poland (under the Leader program, grant agreement LIDER/0001/L-8/16/NCBR/2017).