Chitosan (CS) was modified by aspartic acid (ASP) by esterification in concentrated sulfuric acid solution to form ASP-modified chitosan.Then,Fe3O4 was coated with precipitation method to synthesize ASP-modified magnetic chitosan (ASP-CS-Fe3O4).The removal rate of Cd2+ can reach 76%.The product was characterized by SEM,IR and XRD,which indicated that ASP-CS-Fe3O4 was synthesized.The optimal adsorption parameters of Cd2+ were determined by adsorption experiments.It was found through the study of adsorption kinetics that the adsorption mechanism of ASP-CS-Fe3O4 was second-order kinetics.Through the study of adsorption isotherms,it is found that the interaction between ASP-CS-Fe3O4 and Cd2+ metal ions may be a single-layer adsorption process consistent with Langmuir isotherm model.
[1] Zhang H F,Dang Q F,Liu C S,et al.Uptake of Pb(Ⅱ) and Cd(Ⅱ) on chitosan microsphere surface successively grafted by methyl acrylate and diethylenetriamine[J].ACS Applied Materials & Interfaces,2017,12(9):11144-11155.
[2] Li Z,Wang L,Meng J,et al.Zeolite-supported nanoscale zero-valent iron:new findings on simultaneous adsorption of Cd(Ⅱ),Pb(Ⅱ),and As(Ⅲ) in aqueous solution and soil[J].Journal of Hazardous Materials,2018,344:1-11.
[3] Tang W W,Zeng G M,Gong J L,et al.Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials:a review[J].Science of the Total Environment,2014,468-469:1014-1027.
[4] 徐莹,吕欣,刘炳杰,等.壳聚糖负载纳米Fe2O3树脂脱除鱼露中的亚硝酸盐[J].中国渔业质量与标准,2015(4):48-54.
[5] Yu X,Tong S,Ge M,et al.Adsorption of heavy metal ions from aqueous solution by carboxylated cellulose nanocrystals[J].Environmental Science:Nano,2013,25:933-943.
[6] Wang X,Liu H,Chen D,et al.Multifunctional Fe3O4@P(St/MAA)@chitosan@Au core/shell nanoparticles for dual imaging and photothermal therapy[J].ACS Applied Materials & Interfaces,2013,5(11):4966-4971.
[7] Wu Z,Xu E,Chughtai M F J,et al.Highly sensitive fluorescence sensing of zearalenone using a novel aptasensor based on upconverting nanoparticles[J].Food Chemistry,2017,230:673-680.
[8] Qiu J,Qiu T.Fabrication and microwave absorption properties of magnetite nanoparticle-carbon nanotube-hollow carbon fiber composites[J].Carbon,2015,81:20-28.
[9] Sharma R K,Puri A,Monga Y,et al.Acetoacetanilide-functionalized Fe3O4 nanoparticles for selective and cyclic removal of Pb2+ ions from different charged wastewaters[J].Journal of Materials Chemistry A,2014,2(32):12888-12898.
[10] Zhao F,Repo E,Sillanpää M,et al.Green synthesis of magnetic EDTA-and/or DTPA-cross-linked chitosan adsorbents for highly efficient removal of metals[J].Industrial & Engineering Chemistry Research,2015,54:1271-1281.
