Abstract:
Rapid urban and industrial growth globally, notably in the textile and pharmaceutical sectors, leads to substantial water pollution due to the discharge of pollutants containing many harmful dyes. Researchers around the world are collaboratively working on devising efficient treatment methodologies. The use of clay and mineral-based adsorption processes is widespread due to their cost-effective operational approach. In contemporary times, double perovskite has emerged as a novel material that has captured the interest of researchers owing to its unique properties. Various studies have reported that engineering perovskites enhance the adsorption properties of the material. In this work, Sr2MnNiO6 and LaSrMnNiO6 double perovskite were synthesized using the sol-gel method, to remove carcinogenic dye trypan blue from the aqueous solution by adsorption. The crystal structures, morphology, elemental composition, and surface area of the synthesized nanoparticles were characterized using X-ray Diffraction (XRD), Field emission Scanning electron microscope (FESEM), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), and BET surface area analysis, respectively. In addition, the surface charge was also characterized by determining the point of zero charge (pzc). XRD reveals the formation of the hexagonal and monoclinic structures of Sr2MnNiO6 and LaSrMnNiO6. The average crystallite size of 27.84 nm for Sr2MnNiO6 and 17.01 nm for LaSrMnNiO6 were determined employing the Debye Scherrer equation. In addition, the FESEM image revealed the formation of a porous structure for both of the materials, while the particle size of LaSrMnNiO6 is smaller than the Sr2MnNiO6. The calculated surface area from BET analysis found 4.02 m2/g and 9.10 m2/g for Sr2MnNiO6, and LaSrMnNiO6, respectively. The effects of various operational parameters, such as pH, stirring speed, contact time, temperature, and initial dye concentration, were investigated to explore the optimum adsorption capability. Isotherm modeling revealed the favorability of both Langmuir and Freundlich models, where Langmuir was the best fitted for both Sr2MnNiO6 and LaSrMnNiO6. The pseudo-second-order kinetic model was found to be well-studied in describing the adsorption process with an adsorption capacity of 1035 mg/g and 855 mg/g for Sr2MnNiO6 and LaSrMnNiO6 respectively. Finally, by revealing the effective adsorbent towards Trypan blue adsorption, this work supports SDG6 i. e. clean water and sanitation for all.