Preparation Of Modified Cellulose And Its Adsorption Properties For Hg (?) In Water

With the development of modern industry,environmental pollution is becoming more and more serious.Among them,a large number of heavy metal ions,such as Hg²⁺,Pb²⁺,Cd²⁺,Cr³⁺,Ni²⁺,etc.,exist in the sewage discharged by factories and mining enterprises,which pose a serious threat to people's health,and have become a serious problem faced by industrialized cities in the world.It is urgent to study the treatment methods of heavy metal pollution.Modified cellulose is one of the most effective methods to treat heavy metal pollution.The core of this method is the preparation of modified cellulose.Three kinds of heavy metal ion adsorbents were prepared with hemlock sawdust as raw materials,cysteine,2-mercaptopropionic acid and 2-aminophthalic acid as modifiers.They are cysteine modified cellulose adsorbent for hemlock sawdust?cell-Cys?,2-mercaptopropionic acid modified cellulose adsorbent for hemlock sawdust?cell-MPA?and 2-amino terephthalic acid modified cellulose adsorbent for hemlock sawdust?cell-ATA?,respectively.The adsorption of Hg?II?by three Modified Cellulose Adsorbents for hemlock sawdust was studied.In this experiment,mercury sulfate was dissolved in sulfuric acid to prepare simulated industrial wastewater.The concentration of mercury ion before and after adsorption was measured by cold atomic fluorescence spectrometer.The effects of adsorption conditions on the adsorption performance were investigated by changing the temperature,pH value and the amount of adsorbent used in the adsorption experiment.Finally,the Quasi-First-Order and quasi-second-order kinetic models of adsorption kinetics fitting and the two isothermal adsorption models of Langmuir and Freundlich fitting of isothermal adsorption curve were studied,and the maximum adsorption capacity of the three adsorbents was calculated through the formula.The conclusions are as follows:Cysteine modified cellulose adsorbent has a wide range of Ph application.The dynamic adsorption conforms to the quasi-second-order kinetic model.The equilibrium adsorption time is short,and the adsorption equilibrium can be reached within 30 minutes.The optimum dosage is 1g/L.The adsorption isotherm conforms to Langmuir model and the maximum adsorption capacity is 104mg/g.The pH value of 2-mercaptopropionic acid modified cellulose adsorbent has a wide range of application,and has little effect on its adsorption efficiency.The dynamic adsorption conforms to the quasi-second-order kinetic model.The equilibrium adsorption time is short,and the adsorption equilibrium can be reached within 30 minutes.The adsorption isotherm conforms to Langmuir model,and the maximum adsorption capacity of Hg2+on cellulose adsorbent modified by2-mercaptopropionic acid is 66.22 mg/g.The pH value of 2-aminotropephthalic acid modified cellulose adsorbent has a wide range of application,and has little effect on its adsorption effect.The dynamic adsorption conforms to the pseudo-second-order kinetic model.The equilibrium adsorption time is short,and the adsorption equilibrium can be reached in 45 minutes.The adsorption isotherm conforms to Langmuir model,and the maximum adsorption capacity of Hg2+on 2-aminotropic acid modified cellulose adsorbent is 88.49 mg/g.In this study,the adsorption of simulated heavy metal wastewater by cellulose-based modified adsorbents was studied systematically,which provided a theoretical basis for future work.