Plenary Lecture
Recycling Metals from Waste Solar Panels by Microbes
Professor Hong Hocheng
Co-authors M. V. Chakankar and C. H. Su
Department of Power Mechanical Engineering
National Tsing Hua University
Taiwan ROC
E-mail: hocheng@pme.nthu.edu.tw
Abstract: Renewable energy source is a world trend and becoming cross-national agenda. Solar electricity has been the major approach. Along with the fast growing use of solar cells, the increased demand for base and valuable metals diminishes the natural deposits and the impact of the waste solar panels to environment is not to ignore. Solar cells contain precious metals including silver, tellurium, and indium with other heavy metals such as copper, aluminum, lead, arsenic, cadmium, selenium which are hazardous to the ecosystem. The lifetime of solar cell module is about 25-30 years of power generation. Taking into account the rate at which the new solar cells are being installed and those which are approaching their end-of-life, the cumulative amount of solar cell waste in 2017 was about 800 tons, and the total amount of waste is estimated to increase to 2 million tons by 2040. Such a huge amount of waste is a challenge for future waste management. Establishing a technology for recycling is an urgent necessity not only for meeting the ever increasing demand of metals but also for avoiding environmental hazards. Some chemical methods are presented for recovery of metals from solar cells, there are few reports on the bioleaching for metal reclamation from solar cells, which is considered more environmental benign. In the current study, the recovery of metals from solar cells is investigated using various microbes. Some species can leach Cr, Mn and Cu 100%, while B, Mg, Si, V, Ni, Zn and the valuable metal Te, were recovered by other microbes with 100% efficiency. The recovery of aluminum reached to 89%. Bioleaching is found feasible to recover valuable and hazardous metals from spent solar cells and help resource recycling. Such a recycling process further maximizes the environmental benefits of the solar cells.
Brief Biography of the Speaker: Professor Hong Hocheng earned his PhD from UC Berkeley in US and Diplom-Ingenieur from TH Aachen in Germany. He is now the University Chair Professor at National Tsing Hua University in Hsinchu, Taiwan. He has published more than 160 journal papers and 40 patents in the area of manufacturing and recycling technology. His research interest lies in the new manufacturing and recycling processes. Recently he has made innovative research in achieving effective reclaim of hazardous and valuable metals from industrial wastes by microbes. He has been cited Outstanding Teaching by NTHU for teaching the undergraduate required courses of Manufacturing Processes and Technology. Prof. Hocheng served as the editorial board member of more than 15 international journals. He received National Academic Prize from Ministry of Education and Outstanding Research Awards from Ministry of Science and Technology in Taiwan. Prof. Hocheng is internationally recognized by Prof. Fryderyk Staub Golden Owl Award and William Johnson Award.