Eichhornia crassipes based carbon materials for constructing a CQDs-TiO2/activated carbon composite: a novel dual-functional material for wastewater treatment

Abstract

The recycling and reuse of agricultural waste have attracted significant attention, owing to the serious environmental pollution caused by its improper disposal. Inspired by the principles of the “circular economy,” a dual-functional material composed of a CQDs-TiO₂/activated carbon (CTAC) composite has been successfully developed for the adsorption and degradation of rhodamine B (RhB). The as-prepared CTAC composite exhibits good adsorption capacity and excellent photocatalytic degradation performance. The adsorption quantity (q_t) of RhB with CTAC is about 5.99 mg g⁻¹ after adsorption equilibrium and almost 100% of RhB can be degraded after 300-W xenon lamp light irradiation for 45 min. Meanwhile, the CTAC composite exhibits a high specific surface area, good light-harvesting ability, good carrier migration and good separation capacity, resulting in improved photocatalytic activity. In addition, the morphology, characteristic functional groups, and physicochemical features of the photocatalyst are investigated in detail. The results of reactive species trapping experiments imply that e⁻, h⁺, and ˙OH are the major reactive species in the photocatalytic process. This work provides a novel insight into the full utilization of the value of Eichhornia crassipes in wastewater treatment.