Sequestering Divalent Nickel Ions from Aqueous Solution Using Activated Carbon of Citrus limetta Peel: Isothermic and Kinetic Studies

The biochar (activated carbon) derived from Citrus limetta peel waste biomaterial, was tested for the removal of nickel (II) ions from aqueous solution. Batch experiments were conducted with nickel concentration, pH, and dosage to estimate the nickel ions sequestration from aqueous solution. Among the models employed, Langmuir Isotherm fit well with the adsorption data. The kinetic data analysed with Lagergren and Ho Models fit well with pseudo first-order. Maximum removal (99.8%) of Ni(II) was observed at pH 7, with 0.05 g adsorbent dosage of Ni(II) solution 100 mg L-1. The characterization of biochar carried out by using a scanning electron microscope (SEM), energy-dispersive x-ray spectrometer (EDX), and Fourier transform infrared spectrometer (FT-IR) revealed interaction with Ni(II) ions and the formation of isolated aggregates on the biosorbent surface. The results indicate that Citrus limetta peel biochar can effectively be used for the removal of nickel ions from aqueous solution.