Controlled synthesis of Ni in NiO@C and the influence of its content on the adsorption efficiency of the resulted product

Using Ni(CH ₃ COO) ₂ •4H ₂ O and AR14 (Acid Red 14) as raw materials, the pH of the reaction system was adjusted with NaOH (aq) to ensure the complete deposition of Ni(CH ₃ COO) ₂ •4H ₂ O and AR14 into Ni(OH) ₂ @AR14 which was then calcined at high temperature in a nitrogen atmosphere to obtain the Ni/NiO@C composite product. The morphology and structure of the product were investigated by SEM, XRD, and FT-IR. The results indicate that the product consists of fine particles with an amorphous structure, composed of elemental Ni, NiO, and C. The adsorption performance of the synthesized product was investigated using AR14 as a probe pollutant. The results show that the calcination temperature, annealing temperature, and carbon introduction amount significantly affect the content of elemental Ni in the product, which is a key factor influencing the adsorption efficiency of AR14, with higher Ni content being beneficial for improving the product’s adsorption efficiency. This study also investigated the adsorption efficiency of the synthesized product for other pollutants such as AO7 (Acid Orange 7), Cu ²⁺ , and Pb ²⁺ . The results show that when the AR14 concentration in the reaction system is 0.1 g/L, the calcination temperature is 600°C, and the annealing temperature is 100°C, the synthesized product 600-100-Ni/NiO@0.1C exhibits high adsorption efficiency for the corresponding pollutants. Additionally, this study analyzed the mechanism by which elemental Ni enhances the adsorption efficiency of the synthesized product.