Recovery of precious metals from mobile phone waste: Studies on leaching and adsorption by functionalized activated carbon

• Published in: Results in engineering 2024-06, Vol.22, p.102011, Article 102011
• Main Authors: Firmansyah, Mochamad Lutfi, Rizki, Intan Nurul, Amalina, Ilma, Abdul Jalil, Aishah, Ullah, Nisar
• Format: Article
• Language: English
• Subjects: Activated carbon; Electronic waste; Ionic liquid; Precious metals; Waste recycling
• ISSN: 2590-1230; 2590-1230
• DOI: 10.1016/j.rineng.2024.102011

In today's world, the utilization of electronic devices, particularly mobile phones, has seen a remarkable surge and they are a valuable source of recovery of precious metals. The current study reports on the physical and chemical processing of mobile phone waste into leachate, followed by recovery of precious metals, using ionic liquid functionalized activated carbon (ACF). The recovery process was explored both in batch and column study. The presence of base metals in the final leachate was minimized by employing multi-stage chemical leaching, leading to a more efficient purification process. Moreover, adjustment of HCl concentration in the leachate leads to decreased in other metals interference during adsorption. Following the batch adsorption results, a favorable interaction between IL and metal complexes leads to a quantitative adsorption of the precious metals. In addition, ACF also gave an excellent performance in the column adsorption process with the high bed depth and low flow rate of the leachate as the influential parameter. An increase in the bed depth and a decrease in leachate flow rate proportionally increases the values of kTh (rate constant), qe (adsorption capacity), and KYN (rate constant) and positively increases the 50% breakthrough time (τ). Moreover, the final purification of the adsorbed metals was performed selectively through sequential desorption, employing Na2S2O3, NH4SCN, and HNO3 solutions. Finally, the adsorption capability of ACF shown a negligible change after five repetitive adsorption-desorption cycles. Thus, the current study presents a method to process mobile phone waste and selectively recover the precious metals from the leachate. [Display omitted] •Activated carbon from palm kernel shell was functionalized with ionic liquid.•Mobile phone waste was physically and chemically process to extract precious metals.•ACF was able recover Au from a mobile phone leachate in batch and continuous system.•The separation of precious metals was done by sequential desorption.•ACF was able to maintain performance in a three adsorption-desorption cycles.