Synthesis Of Magnetic Xanthan Acidified Chitosan And Its Effect On Removing Sb(?)

Antimony,as a heavy metal element,has attracted much attention due to its chronic toxicity and potential carcinogenic risk.The toxicity of Sb???was 10 times higher than that of Sb???,but the mobility and solubility of Sb???were higher than that of Sb???.Antimony and its compounds can enter human body through respiratory tract,digestive tract and skin contact.All antimony and its compounds are toxic to human body.Antimony and its compounds are easy to combine with the sulfhydryl group in human body or animal body,interfere with the activity of enzymes in the body,destroy the ionic balance in the cell,thus cause the metabolism disorder of the organism,produce the damage to the organism organization,organ and system.Acute poisoning is clinically characterized by vomiting,abdominal pain,diarrhea,hematuria,hepatomegaly,spasm,and arrhythmia,while chronic poisoning is characterized by changes in pulmonary function,chronic bronchitis,emphysema,early tuberculosis,pleural adhesions,and pneumoconiosis.And the cardiovascular system and the kidneys can also be damaged,especially the nervous system.Therefore,antimony and its compounds are listed as priority pollutants in many countries.In this study,a core-shell structured magnetic xanthogenated chitosan heavy metal chelating agent?FSiCS?was successfully prepared by ultrasonic assisted synthesis.During this process of preparation,the chitosan,carbon disulfide and Fe₃O₄ were used as raw materials and glutaraldehyde was used as cross-linking agent.The removal rate of Sb???in aqueous solution was measured to evaluate the performance of FSiCS.When the amount of CS₂ was 3.0 mL,the concentration of NaOH was 9.0%,the reaction time was 60+60 min,the ultrasonic power was 160 W,the amount of glutaraldehyde was 150?L,and the reaction temperature was 50?,the prepared FSiCS had the best performance.The samples were characterized by Fourier transform infrared spectroscopy?FTIR?,scanning electron microscopy and energy dispersive spectroscopy?SEM-EDS?,thermogravimetry-differential thermal analysis?TG-DSC?,vibrating sample magnetometer?VSM?,X ray diffraction?XRD?and X-ray photoelectron spectroscopy?XPS?.The results of FTIR indicated that there were some sulfur-containing groups and chemical bonds in FSiCS,such as-SH,N-C=S,C=S and C-S.The SEM-EDS showed that the particle size of FSiCS was between 100 nm and 250 nm,and the FSiCS was spherical or polygonal.The FSiCS had a coordination and ion exchange with Sb???during the coagulation process.TG-DSC showed that the mass fraction of xanthogenated chitosan in FSiCS was about 44.92%,and the mass fraction of Fe₃O₄@SiO₂ was about 48.32%.VSM showed that FSiCS had excellent magnetic response and superparamagnetism,which achieved a rapid magnetic separation.The XRD analysis indicated that FSiCS still had the crystal characteristics of magnetic Fe₃O₄ particles.During the coagulation process,S atoms on FSiCS didn't reduce Sb???to elemental Sb,but bind to Sb???with coordination bonds.The results of XPS indicated that the Sb existed as Sb???and Sb???in FSiCS,Sb???was oxidized to Sb???.The S atom coordination played a dominant role,accompanied by the effect of Na⁺ion exchange.FSiCS was better than Fe₃O₄ and Fe₃O₄SiO₂ on the removal of Sb???.The strong acidic condition of pH 1.0².0 was beneficial to remove Sb???by FSiCS.When the pH was 2.0,the removal effect was optimal.The Sb???removal rate increased with the increasing dosage,and the Sb???in the solution could be completely removed under the appropriate dosage.The Coexisting anions Cl^-,NO₃^-,PO₄^3-,SO₄^2-,F^-and coexisting cations Ca²⁺,Mg²⁺,Al³⁺,NH₄⁺,Ba²⁺have no obvious adverse effect on the removal of Sb???.SiO₃^2-and K⁺showed a strong adverse effect on Sb???removal when ionic strength was more than 10.0 mM,especially SiO₃^2-.Appropriate parameter of coagulation was beneficial to improve the removal effect of FSiCS on Sb???.Besides,after the FSiCS was used,desorbed and regenerated by NaOH solution for 5 times,and the removal rate of Sb???was more than60.0%,which indicated that FSiCS exhibited a good regenerative coagulation performance.In general,Sb???in solution can be removed effectively by FSiCS,and FSiCS has great potential in the treatment of Sb???water pollution.