Fabrication and Characterization of N−TiO2/C/ATP Composite with Enhanced Visible‐Light Photocatalytic Performance for the Degradation of Polyacrylamide in Wastewater

Abstract

AbstractA novel N−TiO2/C/attapulgite (N−TiO2/C/ATP) composite photocatalyst was prepared by sol‐gel method using ATP supported o‐phenanthroline modified TiO2. The as‐prepared samples were characterized by X‐ray diffraction (XRD), fourier transform infrared (FT‐IR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), ultraviolet‐visible diffuse reflectance spectroscopy (UV‐vis DRS) and N2 adsorption–desorption measurements. The activity of these photocatalysts was tested by degrading polyacrylamide (PAM) under visible light irradiation while N−TiO2/C/ATP shows significant photocatalytic enhancement compared to pure TiO2. The optimal ratio of N−TiO2/C/ATP photocatalyst is n (TiO2): n (o‐phenanthroline)=20 : 1 and the m (N−TiO2/C): m (ATP)=1 : 1. When the initial concentration of PAM is 300 mg/L and the catalyst dosage is 1.5 g/L, the removal rate of chemical oxygen demand (COD) reaches 86.3 % at pH 2 under 2 h of visible light. The enhanced performance can be attributed to the C element in o‐phenanthroline is modified on the TiO2 surface as a surface sensitizer and the N element may enter anatase TiO2 lattice and replace to form O−Ti−N bond. Meanwhile, some TiO2 particles were permeated into the layer of ATP, which made the composite photocatalyst more stable and the N−TiO2/C/ATP composite exhibits good stability after three times recycling. In addition, the possible photocatalytic mechanism is proposed at the end.