Magnetic nanoparticle (Fe3O4) impregnated onto tea waste for the removal of nickel(II) from aqueous solution

The removal of Ni(II) from aqueous solution by magnetic nanoparticles prepared and impregnated onto tea waste (Fe3O4-TW) from agriculture biomass was investigated. Magnetic nanoparticles (Fe3O4) were prepared by chemical precipitation of a Fe2+ and Fe3+ salts from aqueous solution by ammonia solution. These magnetic nanoparticles of the adsorbent Fe3O4 were characterized by surface area (BET), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infrared Spectroscopy (FT-IR). The effects of various parameters, such as contact time, pH, concentration, adsorbent dosage and temperature were studied. The kinetics followed is first order in nature, and the value of rate constant was found to be 1.90 × 10−2 min−1 at 100 mg L−1 and 303 K. Removal efficiency decreases from 99 to 87% by increasing the concentration of Ni(II) in solution from 50 to 100 mg L−1. It was found that the adsorption of Ni(II) increases by increasing temperature from 303 to 323 K and the process is endothermic in nature. The adsorption isotherm data were fitted to Langmuir and Freundlich equation, and the Langmuir adsorption capacity, Q°, was found to be (38.3) mg g−1. The results also revealed that nanoparticle impregnated onto tea waste from agriculture biomass, can be an attractive option for metal removal from industrial effluent.