Polyacrylamide/Ni0.02Zn0.98O Nanocomposite with High Solar Light Photocatalytic Activity and Efficient Adsorption Capacity for Toxic Dye Removal

Abstract

Photocatalytic removal of toxic textile dyes from wastewater is a challenge because of the relatively low efficiency of photocatalysts. There has been sustained interest in a variety of cheap, hybrid, and efficient nanomaterials for wastewater treatment. In the present work, a novel photocatalyst polyacrylamide/Ni0.02Zn0.98O (PAM/NZP) was synthesized successfully by addition of nanoparticles during polymerization of acrylamide in aqueous medium using ammonium persulfate and N,N′-methylenebis(acrylamide). The material possesses excellent photoactivity and high adsorption capacity.The present investigation describes the applicability of PAM/NZP for removal of malachite green (MG) and rhodamine B (RB) from aqueous solution. The effect of adsorption capacity of cross-linked polyacrylamide on photocatalytic activity of Ni0.02Zn0.98O was also studied. The materials were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, small area electron diffraction, thermal gravimetric analysis, and ultraviolet–visible spectroscopy. The optical band gap was 3.17 eV for NZP and 3.07 eV for PAM/NZP, which is quite lower than that of bare ZnO. The simultaneous adsorption and photocatalysis proved to be a better reaction condition for photodegradation of both the dyes in the presence of PAM/NZP under natural sunlight irradiation. A significant removal efficiency of 99.17% for RB and 96.55% for MG was achieved in 2 h of solar illumination in the presence of the nanocomposite. In addition, the nanocomposite has a high recycling efficiency.