磁性片状nZVI-Fe_(3)O_(4)对Zn(Ⅱ)和Pb(Ⅱ)去除机理研究

Study on the removal mechanism of Zn(II)and Pb(II)by magnetic flake nZVI-Fe_(3)O_(4)

针对日益严重的水体重金属污染问题,本实验采用歧化反应制备具有裂隙结构的新型磁性片状纳米零价铁-四氧化三铁(nZVI-Fe_(3)O_(4)),通过多种表征手段对材料的物理化学性质和结构进行了表征,并研究pH、温度、重金属离子溶液初始浓度对nZVI-Fe_(3)O_(4)去除Zn(Ⅱ)和Pb(Ⅱ)效率的影响。实验结果显示,nZVI-Fe_(3)O_(4)对Pb(Ⅱ)和Zn(Ⅱ)的去除在60 min左右达到平衡状态。在p H值为6、温度为25℃、投加量为1 g/L的条件下,nZVI-Fe_(3)O_(4)可在5~30 min内将10 mg/L模拟废水中Zn(Ⅱ)和Pb(Ⅱ)降至痕量级别。随着溶液p H值降低,n ZVI-Fe_(3)O_(4)对Pb(Ⅱ)的吸附效率下降。研究结果表明,nZVI-Fe_(3)O_(4)的去除过程符合Langmuir模型,是一种化学吸附过程。Zn(Ⅱ)的最大吸附量为13.52 mg/g,Pb(Ⅱ)的最大吸附量为26.50 mg/g。热力学研究表明,去除过程是自发吸附的。nZVI-Fe_(3)O_(4)主要通过吸附-共沉淀的方式富集Zn(Ⅱ)和Pb(Ⅱ)。nZVI-Fe_(3)O_(4)可以通过外加磁场进行回收,在废水处理中去除Pb(Ⅱ)和Zn(Ⅱ)方面,具有良好应用前景。

In response to the increasingly serious problem of heavy metal pollution in water bodies,engineering magnetic nanoparticles are widely used in wastewater treatment and remediation.In order to reduce the environmental pollution during the material preparation process,it is of great significance to improve its practicality in environmental protection technology.In this experiment,a new type of magnetic flake zero valent iron ferric oxide(nZVI-Fe_(3)O_(4))with fissure structure was prepared by disproportionation.The physicochemical properties and structure of the material were characterized by multiple characterization techniques.The effects of pH,temperature,and the initial concentration of heavy metal ion solution on the removal efficiency of Zn(II)and Pb(II)by nZVI-Fe_(3)O_(4)were studied.The experimental results showed that the removal of Pb(II)and Zn(II)by nZVI-Fe_(3)O_(4)reached an equilibrium state in about 60 min.Under the conditions of a solution pH of 6,temperature of 25℃,and a dosage of 1 g/L of nZVI-Fe_(3)O_(4),nZVI-Fe_(3)O_(4)can reduce Zn(II)and Pb(II)in 10 mg/L simulated wastewater to trace levels within 5~30 minutes.As the pH value of the solution decreased,the adsorption efficiency of nZVI-Fe_(3)O_(4)on Pb(II)decreased.The research results indicated that the removal process of nZVI-Fe_(3)O_(4)followed the Langmuir model,indicating that it was a chemical adsorption process,and the maximum adsorption capacity of Zn(II)was 13.52 mg/g,while the maximum adsorption capacity of Pb(II)was 26.50 mg/g.Thermodynamic studies had shown that the removal process was spontaneous adsorption.The research results showed that nZVI-Fe_(3)O_(4)mainly enriched Zn(II)and Pb(II)through adsorption co-precipitation.nZVI-Fe_(3)O_(4)can be recovered through an external magnetic field,and experiments had shown that nZVI-Fe_(3)O_(4)had good application prospects in removing Pb(II)and Zn(II)in wastewater treatment.