Ultrasonic improvement of catalytic decomposition of Rhodamine B in simulated wastewater by functional waste printed circuit boards via thermochemical conversion

Heterogeneous advanced oxidation processes are promising technology for cleaner treatment of recalcitrant organic contaminants in wastewater. Fabrication of heterogeneous catalysts using solid wastes is an attractive alternative and receives substantial attention. Thermochemical conversion of waste printed circuit board (PCB) was conducted to prepare a novel heterogeneous catalyst (TCPCB) used for catalytic decomposition of Rhodamine B (RhB). The catalytic performance, involving ultrasound, H2O2 concentration, TCPCB concentration, solution pH, RhB concentration and reusability, were investigated for RhB decomposition. TCPCB was examined by scanning electron microscope, N-2 adsorption and desorption, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectrum. The decomposition efficiency of RhB within 60 min reaches 94.45% under optimum conditions. TCPCB shows good catalytic performance over a wide pH range with better performance at neutral pH and has good reusability for RhB decomposition. Ultrasound notably improves the generation of hydroxyl radical, which is the major reactive specie for RhB decomposition. A plausible catalytic mechanism is proposed in the TCPCB/H2O2/ultrasound system. The potential application of the proposed process was also discussed. Conversion of solid wastes into functional materials opens a novel strategy for waste management. (C) 2019 Elsevier Ltd. All rights reserved.