Photocatalytic degradation of methylene blue dye by nanocomposite basedon Mg-Al layered double hydroxides

With the increasing development of industries, water pollution by organic pollutants such asdyes has become a serious environmental crisis [۱]. The purpose of this research is to design andsynthesize an environmentally friendly nanocomposit based on layered double hydroxide (LDH)to enhance the separation of charge carriers and improve the photocatalytic performance for thedecomposition of the cationic dye methylene blue (MB) under visible light irradiation. Compositeprepared via hydrothermal and co-precipitation methods.Various analyses including Fouriertransform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM),transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray(EDX), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), Dynamic LightScattering (DLS) and Zeta Potential and photoluminescence (PL) were conducted to characterizethe synthesized samples. Additionally, various electrochemical studies such as electrochemicalcyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), transient photocurrent(TPC), and linear scanning voltammetry (LSV) were performed to further investigate thesynthesized materials and study the fate of electrons generated under light irradiation. The effectof absorption, amount of catalyst and pH on the photocatalytic efficiency of pollutant degradationwas investigated and the optimal reaction conditions were determined. Through Scavenger tests ,the active agents involved in the photodegradation of MB were identified, and a photocatalyticdegradation mechanism for MB was proposed. The synthetic Mg-Al LDH -based compositeappears to be very promising for use in a variety of commercial domains and industries in thefuture. They can also be employed to photodegrade other organic contaminants.

کلیدواژه ها:

Photocatalyst ، Layered Double Hydroxide ، Methylene Blue