Preparation of Size Controlled Silver on Carbon from E-waste by Chemical and Electro-Kinetic Processes

Authors: Mahmoud A. Rabah

Abstract:

Preparation of size controlled nano-particles of silver catalyst on carbon substrate from e-waste has been investigated. Chemical route was developed by extraction of the metals available in nitric acid followed by treatment with hydrofluoric acid. Silver metal particles deposited with an average size 4-10 nm. A stabilizer concentration of 10- 40 g/l was used. The average size of the prepared silver decreased with increase of the anode current density. Size uniformity of the silver nano-particles was improved distinctly at higher current density no more than 20mA... Grain size increased with EK time whereby aggregation of particles was observed after 6 h of reaction.. The chemical method involves adsorption of silver nitrate on the carbon substrate. Adsorbed silver ions were directly reduced to metal particles using hydrazine hydrate. Another alternative method is by treatment with ammonia followed by heating the carbon loaded-silver hydroxide at 980°C. The product was characterized with the help of XRD, XRF, ICP, SEM and TEM techniques.

Keywords: e-waste, silver catalyst, metals recovery, electrokinetic process.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1086581

References:

[1] Y. Sun, Y. Xia Shape-controlled synthesis of gold and silver nanoparticles Science, 298 pp. 2176-2179, 2002.
[2] B.R. Cuenya Synthesis and catalytic properties of metal nanoparticles: size, shape, support, composition, and oxidation state effects Thin Solid Films, 518 pp. 3127-3150 2010.
[3] S.S. Shankar, A. Rai, A. Ahmad et al. Controlling the optical properties of lemongrass extract synthesized gold nanotriangles and potential application in infrared-absorbing optical coatings Chem. Mater., 17, pp. 566-572 2005
[4] M. Goosey, R. Kellner, End-of Life Printed Circuit Boards, Intellect and the department of trade and industry, Makati City, 2002.
[5] S. Zhang, E. Forssberg, Mechanical separation-oriented characterization of electronic scrap, Resour. Conserv. Recycl. 21, 247-269, 1997.
[6] S. Zhang, E. Forssberg, B. Arvidson, W. Moss, Aluminum recovery from electronic scrap by high-force eddy-current separators, Resour. Conserv. Recycl. 23, 225-241, 1998.
[7] W.J. Hall, P.T. Williams, Separation and recovery of materials from scrap printed circuit boards, Resour. Conserv. Recycl. 51, 691-709, 2007.
[8] K. Gloe, P. Muhl, M.Knothe, Recovery of precious metals from electronic scrap, in particular from waste products of the thick-layer technique, Hydrometallurgy 25 99-110, 1990
[9] T. Oishi, K. Koyama, H. Konishi, M. Tanaka, J.C. Lee, Influence of ammonium salt on electro winning of copper from ammoniacal alkaline solutions, Electrochim. Acta 53, 127-132, 2006.
[10] D. Pilone, G.H. Kelsall, Prediction and measurement of multi-metal electro deposition rates and efficiencies in aqueous acidic chloride media, Electrochim. Acta 5, 3802-3808, 2006
[11] Young Jun Park*, Derek J. Fray, Recovery of high purity precious metals from printed circuit boards, Journal of Hazard. Mater. 164, 1152¬1158, 2009.
[12] P.A.Adhyapack, P.K. Khamora. J.W. Dadge and R.C. Alyer, Tuned optical properties of In-sito synthesized m-nitroaniline doped Ag/PVA nano-composites, J. of nanoscience &nanotechnology vol.6(7), 2141¬2146.
[13] I. Sondi, D.V. Goia and E. Matijevć, J. Colloid Interface Sci. 260, 75, 2003
[14] D. Wang, C. Song, Z. Hu and X. Zhou Synthesis of silver nanoparticles with flake-like shapes. Materials letters, Vol. 59(14-15}1760-1763, 2005
[15] Xianghua Song, P. Gunawan, R. Jiang, S. S.J. Leong, K. Wang and R. Xu, Surface activated carbon nanospheres for fast adsorption of silver ions from aqueous solutions, J. Hazard. Mater. Vol., 194, 162-168, 2011
[16] J. Cui and L. Zhang, Metallurgical recovery of metals from electronic waste; a review. J hazard. Mater. 158, 228-256, 2008.
[17] P. Mulvaney, Surface Plasmon Spectroscopy of Nanosized Metal Particles, Langmuir, 12 (3), pp 788–800, 1996
[18] R. Weast and M. Astle, “CRC handbook of chemistry and physics”, D 155, CRC Press, Boca Raton, Florida USA, 1980.
[19] M.A. Rabah, A.A. Abdul Azim and A. Ismail, "The role of impregnants in determining the behaviour of graphite anodes", J. Applied Electrochem. Vol. 11 49-54, 1989
[20] V.K. Shukla, S. R. Yaday, P. yadav and A.C. Pandey “Green synthesis of nanosilver as sensor for detection of hydrogen peroxide in water”. J. Hazard. Mater. 213-214, 161-166, 2012