A solar light regenerated adsorbent by implanting CdS into an active covalent triazine framework to decontaminate tetracycline

Abstract

In this investigation, CdS samples with different morphologies (one-dimensional rod-shaped CdS-R, two-dimensional thin layer CdS-P, three-dimensional nanospheres CdS-S) were synthesized by hydrothermal and solvothermal methods, respectively. Then, a photocatalytic regenerated active carbon adsorbent was obtained by assembling the prepared CdS samples into an alkali-activated covalent triazine-base framework (ACTF). The structure, morphology and chemical states of CdS and CdS-ACTF were characterized by XRD, SEM, TEM and XPS. By estimating the decontamination of tetracycline, CdS-P/ACTF composite displays the best removal rate (99.7% for 20 mg·L−1 initial tetracycline under 90 min simulated solar light irradiation). In addition, compared with the single-phase CdS, the hybrid material presents a good reusability with a still 80% degradation rate at successive 300 min of 5 runs tests under solar light illuminating, indicating its excellent structural stability and photo-regenerated ability. An adsorption and photo-regenerated mechanism was proposed in which ACTF contributes to the strong adsorption of contamination due to its ultra-high specific surface area and CdS contributes to solar light decomposition with a strong photocatalytic oxidative activity. In addition, the regenerated ability was further enhanced by inhibiting carriers’ recombination through a quickly electron transport, ascribing to the well electronic conductivity of ACTF. Consequently, it is highly desirable that CdS-ACTF could be used as a promising adsorbent to eliminate tetracycline residues from the environment and easily to be regenerated with solar light.