A low cost activated carbon was prepared from hazelnut shells by chemical activation with sodium hydroxide at 600 °C in a N₂ atmosphere and then combined with magnetic NiFe₂O₄ nanoparticles by hydrothermal and co-precipitation methods. Samples were characterized by FESEM, TEM, XRD, FT-IR, nitrogen adsorption and magnetic measurements. Results indicated that the NiFe₂O₄ nanoparticles synthesized by the hydrothermal method had a higher saturation magnetization and smaller average particle size than those produced by the co-precipitation method. The specific surface area and total pore volume of the activated carbon decreased from 314 to 288 m²/g and 0.3639 to 0.3338 cm³/g, respectively by forming a hybrid with the magnetic NiFe₂O₄ nanoparticles synthesized by the hydrothermal method. NiFe₂O₄ nanoparticles were mainly distributed on the surface, although a few were inside the pores of the activated carbon. Their sizes were the same as those of the original ones. The saturation magnetization of the hybrids was lower than those of the original NiFe₂O₄ nanoparticles due to the existence of the activated carbon. They showed superparamagnetic behavior at room temperature and were easily separated from solutions by an external magnet.

通过在N ₂气氛中在600°C下用氢氧化钠进行化学活化，从榛子壳中制备低成本的活性炭，然后通过水热和共沉淀法将其与磁性NiFe ₂ O ₄纳米粒子混合。通过FESEM，TEM，XRD，FT-IR，氮吸附和磁测量对样品进行表征。结果表明，与共沉淀法相比，水热法合成的NiFe ₂ O ₄纳米粒子具有更高的饱和磁化强度和更小的平均粒径。活性炭的比表面积和总孔体积从314降至288 m ² / g，从0.3639降至0.3338 cm ³分别通过与通过水热法合成的磁性NiFe ₂ O ₄纳米粒子形成杂化物来实现。NiFe ₂ O ₄纳米颗粒主要分布在表面上，尽管少数在活性炭的孔内。它们的大小与原始大小相同。由于存在活性炭，杂化物的饱和磁化强度低于原始的NiFe ₂ O ₄纳米粒子。它们在室温下表现出超顺磁性能，并易于通过外部磁体与溶液分离。