Bioremediation of anthraquinone dye using bimetallic Ni-Zn nanohybrid synthesized from <i>Ficus exasperate</i> leaf extract

Abstract

This study investigated the synthesis of bimetallic core-shape Ni-Zn nanoparticles using Ficus exasperate leaf extract. The incorporated bimetallic Ni-Zn nanoparticles were applied for the removal of anthraquinone dye from an aqueous solution using various adsorption parameters such as adsorbate concentration, contact time, pH, temperature, and adsorbent dosage. The presence of biomolecule compounds in the aqueous extract of Ficus exasperata was confirmed by a UV-visible spectrophotometer (UV) and Fourier Transform Infrared (FT-IR) Spectrometer. A High-Resolution Transmission Electron Spectrometer revealed a spherical shape whose diameter ranged between 10.67- 30.73 nm with an average particle size of 17.42 nm. The maximum adsorption capacity for Langmuir isotherm (qm) was found to be 50.08 mg/g with R2 of 0.9994 proving the adsorption isotherm best fit for Langmuir adsorption isotherm. The Pseudo second-order kinetic model best fitted the adsorption process. The results of Gibbs free energy (ΔG°) and enthalpy change (ΔH°) of the adsorption of anthraquinone dye are − 81.48 J/mol/K and −26 kJ/mol indicating a spontaneous and exothermic reaction. The regeneration of the green synthesized Ni-Zn nanoparticles up to the fifth removal cycle at 48.08 mg/g revealed excellent results for the removal of anthraquinone dye from an aqueous solution. The obtained results showed that green synthesized core-shape Ni-Zn nanoparticles are excellent and eco-friendly biomaterials for the removal of anthraquinone dye from an aqueous solution.