Preparation And Adsorption Properties Of Magnetic Metal Nanocomposites

In this study,three kinds of magnetic metal nanocomposites have been prepared,and determined using various analysis techniques such as X-ray diffraction?XRD?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,and etc.In addition,the excellent adsorption performance and recycling ability of the composites were demonstrated by adsorption experiments.?1?A novel hollow Ni/C composite nanosphere was fabricated using calcination methods,and used for the removal of Pb²⁺,Cd²⁺,Hg²⁺from water media.The crystalline form,morphology,magnetic properties and specific surface of the composites were characterized by XRD,IR,SEM,TEM,magnetometer and specific surface analysis techniques.Langmuir and Freundlich models were used to fit the adsorption isotherms.The results were in accordance with pseudo-second-order kinetics and Freundlich adsorption isotherms.The as-prepared hollow Ni/C composite nanosphere exhibited high affinity to Pb²⁺.Nanoscale hollow spheres provide a large number of active sites for ions adsorption and favorable channel for ions transportation,which make it successfully to reach the adsorption equilibrium in 15 min,and the maximum adsorption efficiency for Pb²⁺is 93.4%.Competitive adsorption experiments of three ions were carried out.The adsorptive capacity of materials for three metal ions can be expressed as Pb²⁺>Hg²⁺>Cd²⁺.Furthermore,the hollow Ni/C composite nanosphere can be regenerated simply by external magnetic field and acid-washing.?2?Mesoporous Co/CoO/SiO₂ nanospheres were fabricated by heat treatment of the silica and cobalt acetate at a temperature of 600?.The crystalline form,morphology,magnetic properties and specific surface of the composites were characterized by XRD,IR,SEM,TEM,magnetometer and specific surface analysis techniques.In addition,the adsorption performance of Co/CoO/SiO₂ nanospheres to heavy metal ions were also evaluated under different conditions?adsorption time,adsorbent amount,pH?.The results showed that the adsorption efficiency of the adsorbent for Pb²⁺was the highest,reaching 93.4%.Competitive adsorption experiments,the adsorption capacity of mesoporous Co/CoO/SiO₂nanospheres for three metal ions can be analyzed as Pb²⁺>Hg²⁺>Cd²⁺.?3?Ni-CNT composites were synthesized by heat treatment at 900?using Dicyandiamide?C₂H₄N₄?and nickel nitrate as raw materials,and confirmed using various analysis techniques such as X-ray diffraction?XRD?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,and infrared spectrometer?FTIR?.Besides,the effects of adsorption time,adsorbent dose and pH on the adsorption of Congo red were also investigated.The results show that Ni-CNT composites have the highest adsorption efficiency,97.8%in this study,when the adsorption time reached 20 min,the adsorbent dosage reached1.0 g L^-1,and the pH value was about 8.Through cyclic experiments,it was found that the adsorption efficiency remained stable after five cycles.Furthermore,the adsorbent was easy to separate from the solution by the help of external magnetic field.