Copper-based catalyst from waste printed circuit boards for effective Fenton-like discoloration of Rhodamine B at neutral pH

Abstract

The carbonized waste printed circuit board (c-PCB) was used as novel copper-based catalyst for Fenton-like discoloration of Rhodamine B (RhB). The elemental ingredients, structure and morphology of the catalyst was investigated by multi-techniques. The catalytic activity of c-PCB for RhB discoloration was evaluated in the presence of H2O2, examining the factors of catalyst dosage, H2O2 dosage, solution pH, RhB concentration and temperature. RhB discoloration is improved with increasing catalyst dosage (0–2.0 g L−1), H2O2 dosage (0–0.15 mol L−1), solution pH (4.66–9.36) and temperature (30–50 °C). We found that c-PCB shows excellent catalytic activity for RhB discoloration in a broad pH range. RhB removal of 95.78% is obtained within 6 h at neutral pH (6.70). RhB discoloration is well described by the first-order kinetics, and the activation energy is calculated to be 87 kJ mol−1. The dominant role of OH radical in the c-PCB/H2O2 system is identified by quenching tests. The plausible pathway for RhB discoloration is discussed based on the time-dependent UV–vis spectra. The possible catalytic mechanism in the c-PCB/H2O2 system is also presented. Good reusability of c-PCB is verified by three cycles. This work opens a new strategy of “waste treating waste”, facilitating management of hazardous solid wastes and cleaner treatment of textile wastewater.