Preparation and photocatalytic properties of Zr–BiOI/GO composites.

Azo dyes are difficult to degrade, dark in color and toxic in the aqueous environment, which will harm the ecological environment and human health if left untreated. Photocatalytic technology has a wide range of applications in the treatment of printing and dyeing wastewater; in the present study, nano Zr–BiOI/GO photocatalytic composites were prepared by a hydrolysis method using Bi(NO 3) 3 –5H 2 O and ZrOCl–8H 2 O as precursors and GO as carriers. The structure and properties of the samples were characterized by combining test methods such as XRD, FESEM, TEM, XPS, and UV–vis. Congo red (CR) was used as the target pollutant to assess the photocatalytic performance of the prepared materials. The results showed that the specific surface area of 10 % Zr–BiOI/GO increased from 21.98 m2/g to 152.79 m2/g, and the average particle size decreased from 21.61 nm to 17.75 nm compared with that of BiOI. Compared with BiOI, the light-absorption threshold of 10 % Zr–BiOI/GO was increased from 640.6 to 726.4 nm, and the forbidden bandwidth was decreased from 1.94 eV to 1.71 eV. In addition, the nanocomposites exhibited excellent stability and removal of organic dyes and could be used as a potential photocatalyst for water remediation under visible light. The removal of CR by 10 % Zr–BiOI/GO composite was 95.42 % at 120 min. The photocatalytic degradation process of Zr–BiOI/GO conformed to the first-order kinetic model, and the correlation coefficient of the kinetic curve of 10 % Zr–BiOI/GO was 0.9465 and the reaction rate constant was the greatest at 0.0221 min−1. Superoxide radicals [·O 2 −] play a major role in photocatalytic activity. The results indicate that nanocomposites are a promising candidate for photocatalytic degradation of water pollutants. In this paper, Zr–BiOI/GO photocatalytic composites were prepared by a simple hydrolysis method, which possessed higher specific surface area and narrower forbidden bandwidth than pure BiOI, and could remove up to 95.42 % of Congo red (CR) solution under visible light, in addition to the high stability and recycling rate of Zr–BiOI/GO. [Display omitted] • The pore structures of Zr–BiOI/GO photocatalytic materials prepared by hydrolysis method were well developed. • The maximum removal of Congo red by mesoporous Zr–BiOI/GO photocatalytic material was 96.84 %. • Paradigm of Zr–BiOI/GO resource recovery and wastewater treatment was provided. • Long-term experiments were conducted with excellent stability. [ABSTRACT FROM AUTHOR]