The Research On The Modification Of Magnetic Chitosan And Its Adsorption Performance Of Copper Ions

The molecular chain of chitosan contains many amino and hydroxyl groups.It has better adsorption properties to heavy metal ions and can be used as an adsorbent to remove heavy metal ions from wastewater.Chitosan is one of the adsorbent with more abundant.biodegradable,renewable and environmental friendly.But chitosan is easy to dissolve in acidic media and the amino group of chitosan can be protonated.Besides,the lower specific gravity of raw chitosan makes it difficult to separate from aqueous solution and limits its use as an effective adsorbent.The magnetic chitosan has good magnetic and adsorption properties.The hydroxyl?-OH?and amino?-NH2?group on the surface of magnetic chitosan can be easily modified.Moreover,it is easy to regenerate and reuse after adsorption.The functionalization of magnetic chitosan can enhance its adsorption properties and selectivity.In this paper,magnetic chitosan modified with thiosemicarb azide?TSC-Fe₃O₄/CTS?and poly aniline-magnetic chitosan?PAN-Fe₃O₄/CTS?were synthesized.The adsorption of the Cu²⁺ ions was also investigated.?1?The TSC-Fe₃O₄/CTS adsorbent was successfully synthesized with glutaraldehyde as the cross-linker.The products were characterized by scanning electron microscopy?SEM?,Fourier transform infrared spectroscopy?FTIR?and X-ray diffraction?XRD?.The adsorption capacity of Cu???ions adsorbed on was studied by different pH value,adsorption time,the initial concentration of Cu???ions.The adsorption kinetics,adsorption isotherms and adsorption thermodynamic were investigated.?2?PAN-Fe₃O₄/CTS adsorbent was prepared using ammonium persulfate as initiator with magnetic chitosan and aniline as raw materials.The modified product was characterized by Fourier transform infrared spectroscopy?FTIR?.The adsorption capacity of Cu???ions adsorbed on PAN-Fe₃O₄/CTS was studied by different pH value,adsorption time and the initial concentration of Cu???ions.The adsorption kinetics and adsorption isotherms were investigated to study the adsorption process of Cu???ions adsorbed on PAN-Fe₃O₄/CTS.The results showed that:?1?TSC-Fe₃O₄/CTS adsorbent has good adsorption properties and selectivity for Cu²⁺ ions.When the temperature was 25?,the pH value was 6,the adsorption time was 6h and the initial concentration of Cu²⁺ ions was 250mg/L,the adsorption of Cu²⁺ ions by TSC-Fe₃O₄/CTS adsorbent reached adsorption saturation.The adsorption process was better described by the pseudo-second-order model.The sorption equilibrium data was fitted well with the Langmuir isotherm model and the maximum adsorption capacity toward Cu???ions was of 256.62mg/g.?2?PAN-Fe₃O₄/CTS adsorbent has good adsorption properties for Cu²⁺ions.When the temperature was 25?,the pH value was 6,the adsorption time was 2h and the initial concentration of Cu²⁺ ions was 250mg/L,the adsorption of Cu²⁺ ions by PAN-Fe₃O₄/CTS adsorbent reached adsorption saturation.The adsorption process was better described by the pseudo-second-order model.The sorption equilibrium data was fitted well with the Langmuir isotherm model and the maximum adsorption capacity toward Cu???ions was of 112.44mg/g.