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

Abstract

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 photocatalysts 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.