Novel CdS/PANI/MWCNTs photocatalysts for photocatalytic degradation of xanthate in wastewater

In this paper, polyaniline (PANI) and multi-walled carbon nanotubes (MWCNTs) were introduced to hollow CdS spheres surfaces to fabricate CdS/PANI/MWCNTs nanocomposites. The novel CdS/PANI/MWCNTs photo-catalysts were used for photocatalytic degradation of sodium butyl xanthate (SBX) in wastewater. The morphology and structure of CdS/PANI/MWCNTs were characterized by XRD, SEM, TEM-EDS, UV-vis DRS. The optimal catalyst CdS/PANI/MWCNTs showed superior ultraviolet-light-driven photocatalytic performance for degradation of SBX with the degradation rate of 99.2 % in 70 min. The mechanism of photocatalysis was also discussed based on electrochemical impedance spectroscopy (EIS), transient photocurrent response, XPS, radical trapping experiments and electron paramagnetic resonance (EPR). The enhanced catalytic activity was related to two aspects: (1) the introduction of PANI facilitated the separation of the photogenerated electrons (e-) and holes (h+) preventing them from recombination; (2) MWCNTs promoted the catalyst surfaces adsorption of SBX and the migration of photogenerated electrons. Moreover, CdS/PANI/MWCNTs demonstrated good stability due to the inhibited photocorrosion of CdS.

Automated summary

Polyaniline (PANI) and multi-walled carbon nanotubes (MWCNTs) were incorporated into hollow CdS spheres to create CdS/PANI/MWCNTs nanocomposites. These nanocomposites were utilized as photo-catalysts for the degradation of sodium butyl xanthate (SBX) in wastewater. The optimized CdS/PANI/MWCNTs catalyst exhibited excellent ultraviolet-light-driven photocatalytic performance with a degradation rate of 99.2% in 70 minutes. The enhanced catalytic activity was attributed to the facilitated separation of photogenerated electrons and holes by PANI, as well as the promotion of SBX adsorption and electron migration by MWCNTs. The stability of CdS/PANI/MWCNTs was also demonstrated by the inhibited photocorrosion of CdS.