The mobile phone is a fast-growing E-waste stream that includes hazardous substances and valuable metals. Smartphone touch screens (SPTS) contain a considerable amount of critical metals, such as indium and strontium that can be recovered from end of life devices as a secondary resource. Bioleaching is an emerging and environmentally friendly method for metal recovery from electronic waste. In the present study, bioleaching was assessed for the extraction of indium and strontium from organic light emitting diode type smartphone touch screens. A statistical approach based on the response surface methodology was successfully applied. The effects of influential variables: pH, ferrous sulfate, elemental sulfur, and solid content and their interactions on indium and strontium recovery using adapted Acidithiobacillus ferrooxidans were evaluated. Under optimum conditions (ferrous sulfate: 13.0 g/L; solid content; 3.0 g/L; elemental sulfur: 5.6 g/L; and initial pH of 1.1), a complete indium extraction was observed, with a concentration in solution of about 200 mg/L indium. As concerns strontium, a 5% extraction efficiency was observed, which, even if quite low, resulted in a relatively high strontium concentration in solution, around 3000 mg/L, due to its high content in the solid (2%). This work opens new perspectives in the application of clean technologies for the extraction of valuable metals, such as indium and strontium from smartphone screens.

Graphical abstract

中文翻译：

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使用适应的嗜酸细菌从废弃的 OLED 触摸屏中生物浸出关键金属

手机是一种快速增长的电子废物流，其中包括有害物质和有价金属。智能手机触摸屏 (SPTS) 含有大量关键金属，例如铟和锶，这些金属可以作为二次资源从报废设备中回收。生物浸出是一种新兴的环保方法，用于从电子废物中回收金属。在本研究中，对生物浸出法从有机发光二极管型智能手机触摸屏中提取铟和锶进行了评估。成功应用了基于响应面方法的统计方法。影响变量的影响：pH、硫酸亚铁、元素硫和固体含量及其相互作用对铟和锶回收率的影响评估了氧化亚铁酸硫杆菌。在最佳条件下（硫酸亚铁：13.0 g/L；固含量；3.0 g/L；元素硫：5.6 g/L；初始 pH 值为 1.1），观察到铟完全萃取，溶液中的浓度约为 200毫克/升铟。至于锶，观察到 5% 的提取效率，即使非常低，由于其在固体中的高含量 (2%)，导致溶液中的锶浓度相对较高，约为 3000 mg/L。这项工作为应用清洁技术从智能手机屏幕中提取有价金属（例如铟和锶）开辟了新的视角。

图形概要