Efficient recycling of surface-plated metals from ABS plastic waste via ammonium persulfate system

[Display omitted] •Ammonium persulfate can be efficient for ABS plated plastic de-plating.•With central composite design (CCD) optimization, the de-plating rate reaches 99.23%.•98.35% Cu can be selectively recovered through electrolysis.•Ni can be recovered as Ni(NH)2(SO4)2 by low-temperature crystallization. Acrylonitrile-butadiene-styrene (ABS) plated plastic consists of a plastic substrate and surface-plated metals (Cu, Ni, and Cr), which has abundant reuse value. However, waste ABS plated plastic is essential to be de-plated before reuse. Therefore, an effective process for the de-plating of waste ABS plated plastic was proposed in this research. Ammonium persulfate ((NH4)2S2O8, APS) was used as the main active substance in the de-plating system. ABS samples can be de-plated with SO4•− radicals generated by thermal activation. The central composite design (CCD) of the response surface method (RSM) was used for the optimization of the de-plating parameters. The experimental results demonstrated that under optimal conditions, namely APS concentration of 0.6 mol/L, NaCl concentration of 0.35 mol/L, a duration of 40 min, a temperature of 64.5 °C, and a liquid-to-solid ratio (L/S) of 5 mL/g, the de-plating efficiency of ABS plated plastic reaches 99.23%. In addition, Cr, Cu, and Ni can be selectively recovered by filtration, electrochemical and low-temperature crystallization methods, respectively. The recovery rates of Cu and Ni can reach 98.35% and 92.57% under the optimal conditions. This research offers indispensable support for the green reuse and recycling process of waste ABS plated plastics.