CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
J Hazard Mater. 2016 Dec 15;320:393-400. doi: 10.1016/j.jhazmat.2016.08.054. Epub 2016 Aug 24.
Electronic wastes (E-wastes) contain a huge amount of valuable metals that are worth recovering. Bioleaching has attracted widespread attention as an environment-friendly and low-cost technology for the recycling of E-wastes. To avoid the disadvantages of being time-consuming or having a relatively low efficiency, biochar with redox activity was used to enhance bioleaching efficiency of metals from a basic E-waste (i.e., printed circuit boards in this study). The role of biochar was examined through three basic processes: Carbon-mediated, Sulfur-mediated and Iron-mediated bioleaching pathways. Although no obvious enhancement of bioleaching performance was observed in the C-mediated and S-mediated systems, Fe-mediated bioleaching was significantly promoted by the participation of biochar, and its leaching time was decreased by one-third compared with that of a biochar-free system. By mapping the dynamic concentration of Fe(II) and Cu(II), biochar was proved to facilitate the redox action between Fe(II) to Fe(III), which resulted in effective leaching of Cu. Two dominant functional species consisting of Alicyclobacillus spp. and Sulfobacillus spp. may cooperate in the Fe-mediated bioleaching system, and the ratio of these two species was regulated by biochar for enhancing the efficiency of bioleaching. Hence, this work provides a method to improve bioleaching efficiency with low-cost solid redox media.
电子废物（E-wastes）中含有大量有价值的金属，这些金属值得回收。生物浸出作为一种环保且低成本的技术，已经引起了人们对电子废物回收的广泛关注。为了避免耗时或效率相对较低的缺点，具有氧化还原活性的生物炭被用于提高从基本电子废物（即本研究中的印刷电路板）中金属的生物浸出效率。通过三种基本过程：碳介导、硫介导和铁介导生物浸出途径，研究了生物炭的作用。虽然在 C 介导和 S 介导系统中没有观察到生物浸出性能的明显提高，但生物炭的参与显著促进了 Fe 介导生物浸出，与无生物炭系统相比，其浸出时间缩短了三分之一。通过绘制 Fe(II)和 Cu(II)的动态浓度图，证明生物炭促进了 Fe(II)到 Fe(III)之间的氧化还原作用，从而有效地浸出了 Cu。由节杆菌属和硫杆菌属组成的两种主要功能物种可能在 Fe 介导的生物浸出系统中协同作用，而这两种物种的比例通过生物炭得到调节，以提高生物浸出效率。因此，这项工作提供了一种使用低成本固体氧化还原介质来提高生物浸出效率的方法。
