Porous spherical Cu2O supported by wood-based biochar skeleton for the adsorption-photocatalytic degradation of methyl orange

To treat dye-containing wastewater, p-type semiconductor Cu2O nanoparticles supported by wood-based biochar (MBC@Cu2O) were prepared in this work. Benefiting from the synergistic effects of the wood-based biochar skeleton and Cu2O, MBC@Cu2O efficiently degraded methyl orange (MO) dye via an adsorption-photocatalytic mechanism. A series of analytical results showed that the MO adsorption process was well-described by the pseudo-second-order kinetics model, and the maximum adsorption capacity was 1610 mg/g. The photocatalytic degradation efficiency of MO reached 94.5 % under visible light irradiation, and free-radical capture experiments confirmed that superoxide radicals (·O2-) and hydroxyl radicals (OH) were the main active species involved in this process. The photocatalytic efficiency of MBC@Cu2O remained above 80 % after five reuse cycles. In addition, the adsorption and photocatalytic mechanisms were explored. The comprehensive results indicate that MBC@Cu2O, as a bifunctional adsorption-based photocatalytic composite, has great potential for removing anionic azo dyes from wastewater.