Oxalic acid leaching and eggshell wastes adsorption for recycling of solar cells

• Main Author: Lee, Tong
• Other Authors: Nripan Mathews
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/156292
• Institution: Nanyang Technological University

Increasing climate change and global warming have risen concerns and drive the search for alternative energy sources, preferably greener and renewable. Photovoltaics (PV) is one of the promising candidates as it is clean and generates no hazardous emission. The industry has grown drastically ever since, as many switch from traditional energy source to PV to exploit its benefits. Combined with government policies to promote PV as an energy alternative, the growth has been further catalysed. With the increasing number of installations and the limited lifespan of 25-30 years, it is essential that proper waste management for End-of-Life (EoL) panels is in place to deal with the large, expected volume of wastes. Many raw materials are present in the solar panel wastes and it is crucial to extract and repurpose these materials. Metal extraction/dissolution has been usually carried out with strong acids and/or bases such as nitric acid (HNO3), hydrofluoric acid (HF) and sodium hydroxide (NaOH). The utilisation of these harsh chemicals can have detrimental effects on the users and environment. Noxious gases like NOx can get released in the process of extracting metal ions using HNO3, while HF and NaOH are highly corrosive and have adverse effects to environment if not properly treated before discharge. Therefore, it is necessary to strategize an environmentally friendlier leaching approach. This project focus on the utilization of oxalic acid in replacement for strong inorganic acids for leaching, and eggshell as biosorbent to remove aluminium (Al) from the leachate solutions. Herein, we evaluated the potential of oxalic acid as leaching reagent for solar cell waste as well as demonstrated eggshell as biosorbent to remove Al from the collected leachate solution.