Synergistic photocatalytic-adsorption removal effect of NiFe2O4-Zn-Al mixed metal oxide composite under visible-light irradiation

[Display omitted] •NiFe2O4-MMO nanostructure was obtained from calcination NiFe2O4-ZnAl LDH composite prepared by hydrothermal method.•h+ and O2− were crucial for the photocatalytic degradation of Acid red 14 azo dye.•The feasible Z-scheme photocatalytic mechanism was proposed and verified.•The NiFe2O4-MMO could suppressing the recombination of electron-hole pairs and promotes the charge transfer process. Today, the photocatalytic process in visible light has become one of the most attractive water treatment fields. We prepared a NiFe2O4-MMO composite with Zn-Al LDH and NiFe2O4 that have good photocatalytic properties in visible light. Structural studies on the samples were performed by X-ray diffraction pattern (XRD) analysis and scanning electron microscopy (FE-SEM). Also, diffusion reflection spectroscopy (DRS) analysis was used to evaluate the optical properties of the samples. In this study, the mechanisms of adsorption and photocatalytic processes were investigated. The kinetics of adsorption and photocatalytic processes was also evaluated. The rate of the photocatalytic process is higher than the rate of the adsorption process, so the surface of the photocatalyst is not saturated. As a result, the adsorption process increases the efficiency of the photocatalytic process, which indicates the synergistic effect of adsorption-photocatalytic to improve the process of removal of organic pollutants from contaminated water.