Adsorption of Cu (II), Ni (II), and Zn (II) from water on recyclable modified coconut biochar: Kinetics and isotherm studies

The present research assessed adsorptive ability of potassium permanganate modified biochar derived from coconut shell aimed at removing copper, nickel and zinc ions present in wastewater under competitive as well as non-competitive scenarios. The findings indicate that the modified biochar had much higher removal efficiencies for Ni, Zn and Cu in non-competitive settings, with removal rates of 85.25%, 71.15%, and 99.5%, respectively. However, in competitive settings, Zn and Ni adsorption efficiencies declined significantly, with values of 45.4% and 32.3%, demonstrating the competitive character of metal ion interactions. Cu(II) exhibited outstanding adsorption capability, maintaining roughly 92.6% efficiency even in mixed settings, indicating a preferential binding process. The adsorption kinetic results were consistent with the Pseudo second order kinetic model, while the Langmuir model accurately represented the equilibrium adsorption process with maximum adsorption capacities of 63.694 mg/g(Ni(II)), 72.463 mg/g(Zn(II)), and 90.090 mg/g(Cu(II)). After three cycles, the analysis of the regeneration experiment showed that KMnO 4 -modified has outstanding Cu(II), Zn(II), and Ni(II) adsorption capacity, offering KMnO 4 -modified biochar as a workable way to remediate heavy metal-contaminated wastewater.