Green Synthesis of Cobalt Oxide Decorated Chitosan Substrates for Electrochemical Detection of Nitrite and Hydrogen Evolution Reactions

Synthesis of NiCo2O4 supported on Chitosan for potential adsorption of copper ions in water samples

The present work involved the synthesis of nano-spinel oxide, which was subsequently incorporated into chitosan to enhance the adsorption efficiency of Cu(II) from aqueous samples. The chitosan was compared with the modified chitosan (nickel cobaltite@Chitosan) in terms of adsorption performance toward Cu (II) ions. Structural and morphological characterization was investigated using X-ray powder diffraction (XRD), which confirms the crystalline structure; scanning electron microscopy (SEM) to reveal surface morphology, transmission electron microscopy (TEM), to examine the nanoscale dispersion, and thermal analysis, to asses the material stability. Various experimental parameters, including pH and catalyst mass loading, were tuned. The adsorption data were found to be best described by Langmuir isotherm, indicating monolayer adsorption. The reaction order was found to obey pseudo-first-order kinetics, suggesting that physisorption controls the process. The synthesized catalyst had a retention efficiency of 92% across three consecutive cycles, demonstrating its potential as a reusable and efficient adsorbent for Cu(II) removal from water.