Preparation And Application Of Carboxymethyl Cellulose Coated Magnetic Nanoparticle Composites

Nowadays,heavy metal elements are widely present in various electronic devices,and diffuse into the environment through various channels.After enrichment through the food chain,they finally enter the human body.The accumulation of heavy metals in the human body can induce various diseases.Therefore,the development of environmentally friendly,efficient,and low-cost technology to remove heavy metal ions in waste liquid,such as copper and lead,has important practical significance.The core-shell structured magnetic composite material consists of a magnetic core and a functional shell,which can be used to separate heavy metal ion and recycle from waste liquid with simple operation,low cost and considered difficult to treat.In this study,aqueous solutions containing heavy metals Cu²⁺and Pb²⁺ions respectively are used as a model waste liquid,where the adsorption process of copper and lead ions in solution by paramagnetic Fe₃O₄ microspheres and carboxymethyl cellulose coated magnetite composite material(Fe₃O₄@CMC)is systematically investigated.And the adsorption performance evaluation and mechanism analysis for the two adsorbents Fe₃O₄ and Fe₃O₄@CMC has been carefully made under different conditions.The main research objectives and conclusions are as follows:1.Magnetic Fe₃O₄ microspheres were synthesized by solvent-thermal method,and their surface morphology,crystalline structure,chemical properties and composition properties were characterized by means of scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier infrared spectroscopy(FT-IR),thermogravimetric analysis(TGA)and Zeta potential analysis.At the same time,the isothermal adsorption kinetics of the heavy metal ions onto Fe₃O₄ microspheres was also studied.The adsorption results show that the adsorption process of copper and lead ions to bare Fe₃O₄ microspheres is more conform to the quasi-second-order kinetic model and the Langmuir isothermal adsorption model.At p H 5.0,and 25?,the saturated adsorption capacity(Q_max)of Cu²⁺to Fe₃O₄ adsorbent is 11.01 mg/g.At p H 6.0 and 25?,the saturated adsorption capacity(Q_max)of Pb²⁺is 32.30mg/g.2.Fe₃O₄@CMC magnetic composite microspheres with Fe₃O₄ as the core and CMC as the shell were synthesized by ultrasonic-assisted adsorption and used to adsorb and remove copper and lead ions in aqueous solution.The initial concentration,p H,adsorption time and temperature during the adsorption process for copper and lead ions were investigated.The adsorption results show that the adsorption process of Cu²⁺and Pb²⁺to Fe₃O₄@CMC microspheres is significantly affected by the initial concentration of metal ions and the p H value of the solution.The kinetic and thermodynamic behavior of the adsorption process conforms to the quasi-second-order kinetic model and the Langmuir isothermal adsorption model.At 25?,the maximum adsorption capacity of Fe₃O₄@CMC to Cu²⁺and Pb²⁺reaches to 40.3 mg/g and 151.2 mg/g,respectively,which is 3.66 and 4.68 times higher than that of the adsorption capacity of the pure Fe₃O₄microspheres,and the confirms that adsorption performance has been significantly improved.Attracting by external magnetic field,the composite microspheres as adsorbent can realize the rapid and efficient separation,recovery and reuse from waste liquid.