Insights into the equilibrium, kinetic and thermodynamics of nickel removal by environmental friendly Lansium domesticum peel biosorbent

• Eco-friendly Lansium domesticum peel waste was used for nickel removal.
• Equilibrium of nickel biosorption was best represented by Langmuir model.
• Kinetic of nickel biosorption followed pseudo-second-order model.
• Nickel biosorption was exothermic, feasible and spontaneous.

Lansium domesticum peel (LDP), a waste material generated from the fruit consumption, was evaluated as a biosorbent for nickel removal from aqueous media. The effects of dosage, contact time, initial pH, initial concentration and temperature on the biosorption process were investigated in batch experiments. Equilibrium data were fitted by the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich models using nonlinear regression method with the best-fit model evaluated based on coefficient of determination (R2) and Chi-square (χ2). The best-fit isotherm was found to be the Langmuir model exhibiting R2 very close to unity (0.997–0.999), smallest χ2 (0.0138–0.0562) and largest biosorption capacity (10.1 mg/g) at 30 °C. Kinetic studies showed that the initial nickel removal was rapid with the equilibrium state established within 30 min. Pseudo-second-order model was the best-fit kinetic model indicating the chemisorption nature of the biosorption process. Further data analysis by the intraparticle diffusion model revealed the involvement of several rate-controlling steps such as boundary layer and intraparticle diffusion. Thermodynamically, the process was exothermic, spontaneous and feasible. Regeneration studies indicated that LDP biosorbent could be regenerated using hydrochloric acid solution with up to 85% efficiency. The present investigation proved that LDP having no economic value can be used as an alternative eco-friendly biosorbent for remediation of nickel contaminated water.