title: Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids.
abstract: Waste printed circuit boards (WPCBs) are attracting increasing concerns because the recovery of its content of valuable metallic resources is hampered by the presence of hazardous substances. In this study, we used ionic liquids (IL) to leach copper from WPCBs. [BSO3HPy]OTf, [BSO3HMIm]OTf, [BSO4HPy]HSO4, [BSO4HMim]HSO4 and [MIm]HSO4 were selected. Factors that affect copper leaching rate were investigated in detail and their leaching kinetics were also examined with the comparison of [Bmim]HSO4. The results showed that all six IL acids could successfully leach copper out, with near 100% recovery. WPCB particle size and leaching time had similar influences on copper leaching performance, while IL acid concentration, hydrogen peroxide addition, solid to liquid ratio, temperature, showed different influences. Moreover, IL acid with HSO4(-) was more efficient than IL acid with CF3SO3(-). These six IL acids indicate a similar behavior with common inorganic acids, except temperature since copper leaching rate of some IL acids decreases with its increase. The results of leaching kinetics studies showed that diffusion plays a more important role than surface reaction, whereas copper leaching by inorganic acids is usually controlled by surface reaction. This innovation provides a new option for recovering valuable materials such as copper from WPCBs.
authors: Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education, Southwest University of Science and Technology, 59 Qinglong Road, Mianyang 621010, China. Electronic address: kyling@swust.edu.cn.
authors: Mengjun
authors: M
authors: Chen
authors: Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education, Southwest University of Science and Technology, 59 Qinglong Road, Mianyang 621010, China.
authors: Jinxiu
authors: J
authors: Huang
authors: Program in Public Health, Department of Population Health and Disease Prevention, and School of Social Ecology, University of California, Irvine, CA 92697-3957, USA.
authors: Oladele A
authors: OA
authors: Ogunseitan
authors: Biogas Institute of Ministry of Agriculture, 13 4th Section Renmin South Road, Chengdu 610041, China.
authors: Nengming
authors: N
authors: Zhu
authors: School of Chemistry and Environmental Science, Shaanxi University of Technology, Hanzhong, Shaanxi 723001, China.
authors: Yan-min
authors: YM
authors: Wang
mesh_terms: D000143:Acids / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D059029:Electronic Waste / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D052578:Ionic Liquids / Q000737:chemistry*; D007700:Kinetics; D010316:Particle Size; D059027:Recycling / Q000379:methods*; D013464:Sulfuric Acids / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D000143:Acids; D052578:Ionic Liquids; D013464:Sulfuric Acids; D003300:Copper; C033158:sulfuric acid
keywords: Copper; Ionic liquids (ILs); Leaching kinetics; WPCBs; Waste electric and electronic equipment (WEEE)