Visible Light-Active CdS/TiO₂ Hybrid Nanoparticles Immobilized on Polyacrylonitrile Membranes for the Photodegradation of Dyes in Water

Abstract

Reusable photocatalytic polyacrylonitrile membrane-supported cadmium sulphide/titanium dioxide hybrid nanoparticles (CdS/TiO2-PAN) were prepared using a dry-wet phase inversion technique. Scanning electron microscopy (SEM) analysis revealed that the photocatalytic membranes had a porous sublayer, a compact top layer, and that, some of the nanoparticles were not encapsulated by the membranes. The average crystallite sizes of the CdS, TiO2, and CdS/TiO2 hybrid nanoparticles were 3.41 nm, 10.47 nm, and 12.17 nm, respectively. The combination of CdS and TiO2 nanoparticles led to a red shift (band gap; ca. 2.6 eV) of the absorption band and extended the optical absorption spectrum into the visible region relative to TiO2. The photocatalytic activity of CdS/TiO2-PAN membranes was explored in the degradation of methylene blue dye under visible light irradiation, and the results revealed that the best photocatalytic performance was achieved by 0.1 g CdS/TiO2-PAN photocatalytic membrane with 5% loading of the CdS/TiO2 hybrid nanoparticles, which degraded 66.29% of methylene blue in 210 minutes at 25°C and pH 8.5. It was found that the optimum loading of nanoparticles in the membranes was 0.1 g. All the photocatalytic membranes showed an insignificant decrease in the photocatalytic activity when used repeatedly. According to literature, CdS/TiO2-PAN photocatalytic membranes have not been prepared before for the purpose of treating simulated wastewater.

Visible Light-Driven Photocatalytic Rhodamine B Degradation Using CdS Nanorods

“…Among the semiconductor photocatalysts, cadmium sulfide (CdS) is the most extensively used photocatalyst in environmental remediation and one of the most important semiconductor materials (bandgap~2.4 eV), absorbs in the visible region [23,24]. However, the practical usage of CdS in photocatalysis is limited due to some serious shortcomings, including particle aggregation, photo corrosion, and a short lifetime of photo-generated carriers [25,26].…”

Synthesis of Group IIB and IVB Metal Complexes of 3‐Nitroaniline for Photocatalytic Degradation of Organic Dyes

“…Analysis of 1 c : See Figure 4(d), in literature the characteristic peak appeared at 996 cm −1 attributed with vibrations of Cd−S bond from CdS but in our spectrum this peak appeared at 991 cm −1 which indicated the presence of CdS [37] . The broad band appeared between 3000–3400 cm −1 due to starching vibrations of water molecule which was further confirmed by a peak appeared at 1636 cm −1 as a result of bending vibration of H−O molecule [38] . In general, absorption bands associated with C−H, C−C, C−N and other types of organic bonds related to the organic ligand used for the synthesis were observed in the spectrum because to some extent ligand are adsorbed on the surface of CdS NPs [39]…”

“…[37] The broad band appeared between 3000-3400 cm À 1 due to starching vibrations of water molecule which was further confirmed by a peak appeared at 1636 cm À 1 as a result of bending vibration of HÀ O molecule. [38] In general, absorption bands associated with CÀ H, CÀ C, CÀ N and other types of organic bonds related to the organic ligand used for the synthesis were observed in the spectrum because to some extent ligand are adsorbed on the surface of CdS NPs. [39]…”

DETERMINATION OF PHOTOCATALYTIC ACTIVITY FOR THE SYSTEM: CdS CHEMICAL BATH DEPOSITED THIN FILMS COATED WITH TiO2 NPs

“…The UV-Vis spectra of CdS films prepared by chemical bath deposition is shown in Figure 1a. The spectra exhibit a well-defined feature (peak) at ~527 nm, which is considerably blueshifted relative to the peak absorption of bulk CdS indicating quantum size effect [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”