Photocatalytic degradation of Alizarin Red S dye from aqueous media under visible light using ZIF-8/ g-C3N4 nanocomposite

Abstract

Alizarin Red S (ARS) is one of the anionic dyes that is widely used in metal, chemical, printing and dyeing industries. This dye is one of the synthetic and chemical dyes and its discharge into the environment can have very harmful effects. Considering the dangers of water pollutants for the environment and human health, it is very essential to use advanced water purification methods and correct control of industrial processes to reduce and prevent the discharge of such dyes into water. One of these methods is the photocatalytic process. In this research, ZIF-8/C3N4 nanocomposite was synthesized and characterized by FT-IR, XRD, FE-SEM and DRS analyses, then it was used as a photocatalyst in the process of photocatalytic degradation of ARS under sunlight. Four factors of photocatalyst dose, pH, initial concentration of dye and time were selected as effective factors on the process and optimized using central composite design (CCD). The optimization results showed that the highest percentage of dye degradation (90%) was obtained in the photocatalyst dose =11.5 mg, pH=5, initial dye concentration=33 mg L -1 , the volume of H2O2=50 μL, and time=50 min. The kinetics of the ARS dye degradation process was investigated and the results showed that the dye degradation process follows the first-order kinetic model. The application of the ARS dye removal process was also inspected in the wastewater sample of Kavir tire factory in Birjand city, and the percentage of degradation was observed above 92.45% for different concentrations of ARS. Finally, using reusability tests, it was proved that the synthesized nanocomposite has good stability and reusability in the photocatalytic process.