Utilization of residual zinc–iron-layered double hydroxide after methyl orange management as a new sorbent for wastewater treatment

Abstract

In recent years, enormous attention has been attracted to layered double hydroxides (LDHs) due to their tunable chemical composition and physical properties. In this recent work, Zn–Fe LDH with nitrate as the interlayer anions was prepared via the co-precipitation technique. The production of Zn–Fe LDH was emphasized by different analyses like Fourier-transform infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), zeta potential, field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), partial size, and surface analysis. Then, it was investigated for the remediation of wastewater from anionic methyl orange (MO) under various adsorption parameters (contact time, adsorbent mass, solution pH, and dye initial concentration). The high adsorption capacity of MO (508.2 mg) had been successfully achieved by Zn–Fe LDH from wastewater within 150 min. It was also known that the pH 7 is optimum value for maximum adsorption, which was the most influencing factor. The adsorption kinetic was governed by pseudo-first (PFO) and -second (PSO) models. The equilibrium adsorption data were obeyed to Langmuir model. Additionally, recyclability was tested up to three cycles of recuperate material after dye adsorption. Lastly, the wasted adsorbent has been tested for the management of another (cationic) dye, methylene blue. The adsorption mechanism was emphasized by FTIR analysis and batch adsorption experiments. The developed LDH could be a strong candidate for traditional adsorbents used in wastewater.