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This study reports the biosorption of nickel using powdered fallen coffee leaves. BET, SEM, FTIR, and XRD characterize the biosorbents. We go over the findings from thermodynamic, kinetic, and equilibrium biosorption experiments. Here are some of the factors that were studied: agitation duration (t), biosorbent size, pH of the aqueous solution (ranging from 1 to 8), initial nickel concentration (C0), pH (ranging from 5 to 150), temperature (ranging from 283 to 323), and so on. Coffee leaf powder is best when the pH is 4. This biosorbent pair works best when dosed at 18 g/L for nickel biosorption. Nitrogen absorption is 4.219 mg/g when coffee leaf powder is used. For nickel biosorption, CCD has optimized four parameters. The data on nickel biosorption are tightly matched to the biosorbent model of pseudo-second-order. The negative sign of the free energy change (ΔG) for coffee leaf powder (-1546 J/mol) reflects both the practicality and spontaneous nature of the biosorbent-material. Powdered coffee leaves are predicted to undergo enthalpy changes of 62.99 J/mol K and entropy changes of 51.08 J/mol K. When the value of ΔS is positive, it indicates that the randomness is increasing, and when the value of enthalpy change is positive, it indicates that the process is endothermic.

Biosorption of lead onto Fallen Coffee Plant leaves (FCPL) powder from an aqueous solution was studied in the present study. The characterization of FCPL powder was done by FTIR, XRD, SEM and BET. The equilibrium agitation time for lead biosorption is 60 min. The optimum pH and dosage values are 5.2 and 20 g/L respectively. In the range of variables studied, percentage biosorption is increased from 75.1 to 95.5 %. The maximum uptake capacity of 3.664 mg/g is obtained at 303 K. In the present investigation the equilibrium data was well explained by Langmuir, Redlich-Peterson with a correlation coefficient of 0.99, and followed by Temkin and Freundlich isotherms. The kinetic studies reveal that the biosorption system obeyed the pseudo second order kinetic model by considering the correlation coefficient value as 0.99. From the values of ∆S, ∆H and ∆G it is observed that the biosorption of lead onto Fallen coffee plant leaves(FCPL) powder was irreversible, endothermic and spontaneous.