New Low-cost Agricultural Biosorbent from Algerian Melon “Cucumis melo” Peels for Remediation of Water Ni (II) Pollution

This research aimed to contribute to the pollution remediation by investing an agricultural food residue developed from Algerian melon (Cucumis melo) fruit peels into novel efficient low-cost biosorbent (AML). Ni(II) metal was selected for the batch biosorption by the AML solid, from aqua system. The impact of different parameters was performed including shaking time, biomass dosage, pH, temperature, and Ni(II) concentration. Interestingly, the biosorption process achieved equilibrium within only 180 min. The kinetic obeyed the pseudo-second order model with high correlation coefficient (0.999). The intraparticle diffusion approach gave R² equals to 0.829 and 0.75. The Ni(II) uptake was strongly dependent on the dosage increment, attaining 88.8% at 2.5 g L^-1, and on pH ranged from 2 to 7. The Langmuir model provided the best fit to the isotherm experimental data with a maximum biosorption capacity achieving 11.11 mgg^-1 at 30°C. The biosorption level was reduced to 4.85 mgg^-1 at 50°C. The negative values of ΔG (-8.25, -12.64, and -14.40 kJmol^-1, at 303, 318, and 323 K respectively) proved the feasibility and spontaneity of the Ni(II) biosorption. The positive values of ΔH and ΔS (85.32 kJmol^-1 and 0.31 kJmol^-1K^-1, respectively) confirmed the endothermic nature of the biosorption process and the randomness increase at the biomass-liquid interface. The AML biosorbent characterization (FTIR, SEM-EDX, CHN(S), TGA-DTG, LTNA, and XPS) confirmed the presence and role of several oxygen-containing groups and mesopores, as well as the ion exchange mechanism supposed mainly occurring between light metals of the AML biomass and the target ions. The current findings highlighted the melon biomass as interesting alternative for the removal of hazardous pollutants.