茶叶提取液制备纳米零价铁及处理含铅废水的研究

Preparation of Nano-zero-valent iron from tea extract and its use for lead-containing wastewater treatment

通过正交试验方法,选用婺源绿茶、宜春大毛山绿茶、福建铁观音茶3种茶叶提取液制备纳米铁(FeNPs),得出制备纳米铁的最佳工艺条件为:酒精体积浓度为50%,大毛山绿茶(碎成粉末状)与FeCl_3的质量比为2∶1,磁力搅拌时间为45 min。采用XRD、TEM和FT-IR等对大毛山绿茶提取液制备的纳米零价铁(MT-FeNPs)进行了表征。研究表明MT-FeNPs的粒径在50～100 nm。考察了溶液的pH值、MT-FeNPs投加浓度、初始Pb^(2+)质量浓度及反应时间对Pb^(2+)去除效果的影响。结果表明:当pH值为7、初始Pb^(2+)质量浓度为40 mg/L、MT-FeNPs投加量为45mg/L、反应时间为60 min时,去除率达88. 5%。进一步反应动力学的研究表明,反应符合一级动力学反应模型,方程式为ln(C/C_0)=-0. 03157t-3. 86565。

Iron-based nanoparticles(FeNPs)were synthesized using three kinds of tea extract(Wuyuan green tea,Yichun Damao Mountain green tea(MT),Fujian Tie Guanyin tea)by orthogonal experiments,the optimum conditions for preparing FeNPs is:alcohol volume concentration is 50%,the mass ratio of MT(crumbled into powder)and FeCl 3 is 2:1,magnetic stirring time is 45 min.Their morphology,structure and size were pictured by XRD,SEM and FTIR.The FeNP is made up of mostly spherical particles with diameters ranging from 50 to100 nm.The pH value of the solution,MT-FeNPs dosage concentration,initial Pb^2+concentration and reaction time affecting the Pb^2+removal efficiency are investigated.The results showed that degradation rate of Pb^2+is 88.5%when pH is 7,initial Pb^2+concentration is 40 mg/L,the MT-FeNPs dosage is 45mg/L and the reaction time is 60 min.Further study of reaction kinetics showed that the reaction was in accord with the first order kinetic model and the reaction equation was ln(C/C 0)=-0.03157t-3.86565.