Abstract

This work evaluated the potential reuse of solid effluents from a Moringa oleifera infusion production company as adsorbents for the removal of nickel from aqueous media. To enhance adsorption performance, the material was chemically modified through an alkaline pretreatment, followed by carboxymethylation or acetylation. The obtained products were characterised by Fourier Transform Infrared spectroscopy to confirm the incorporation of functional groups. The adsorption capacity of the materials was determined, revealing that the moderate improvement observed for the carboxymethylated sample does not justify its low synthesis yield and the increased process complexity. Therefore, only the raw material, the alkaline-pretreated sample, and the acetylated adsorbent were selected for detailed evaluation. Kinetic and equilibrium experiments, as well as packed-column tests, demonstrated that moringa residues exhibit promising performance for the removal of nickel ions. Overall, the results highlight moringa-based materials as low-cost, sustainable adsorbents for wastewater treatment.