title: A new technology for separation and recovery of materials from waste printed circuit boards by dissolving bromine epoxy resins using ionic liquid.
abstract: Recovery of valuable materials from waste printed circuit boards (WPCBs) is quite difficult because WPCBs is a heterogeneous mixture of polymer materials, glass fibers, and metals. In this study, WPCBs was treated using ionic liquid (1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM+][BF4-]). Experimental results showed that the separation of the solders went to completion, and electronic components (ECs) were removed in WPCBs when [EMIM+][BF4-] solution containing WPCBs was heated to 240 °C. Meanwhile, metallographic observations verified that the WPCBs had an initial delamination. When the temperature increased to 260 °C, the separation of the WPCBs went to completion, and coppers and glass fibers were obtained. The used [EMIM+][BF4-] was treated by water to generate a solid-liquid suspension, which was separated completely to obtain solid residues by filtration. Thermal analyses combined with infrared ray spectra (IR) observed that the solid residues were bromine epoxy resins. NMR (nuclear magnetic resonance) showed that hydrogen bond played an important role for [EMIM+][BF4-] dissolving bromine epoxy resins. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent environmental pollution from WPCBs effectively.
authors.affiliation: Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education and College of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, People's Republic of China. xhnzp@shu.edu.cn
authors.forename: P
authors.initials: P
authors.lastname: Zhu
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: L Y
authors.initials: LY
authors.lastname: Wang
authors.forename: G Y
authors.initials: GY
authors.lastname: Qian
authors.forename: M
authors.initials: M
authors.lastname: Zhou
authors.forename: J
authors.initials: J
authors.lastname: Zhou
mesh_terms: D001966:Bromine / Q000737:chemistry; D004581:Electronics; D004853:Epoxy Resins / Q000737:chemistry; D006358:Hot Temperature; D007093:Imidazoles / Q000737:chemistry*; D007220:Industrial Waste; D052578:Ionic Liquids / Q000737:chemistry*; D059027:Recycling / Q000379:methods*; D012037:Refuse Disposal / Q000379:methods*
chemical_list: C499119:1-ethyl-3-methylimidazolium tetrafluoroborate; D004853:Epoxy Resins; D007093:Imidazoles; D007220:Industrial Waste; D052578:Ionic Liquids; D001966:Bromine