茶叶制备绿色纳米铁及其对废水中铬、铅的去除

发布时间：2018-03-07 19:03

  本文选题：茶叶　切入点：纳米铁　出处：《南华大学》2015年硕士论文　论文类型：学位论文

【摘要】：纳米铁的制备技术迅速发展,方法多种多样。生物法制备纳米铁因其具备原材料来源广,反应条件温和,产物不易团聚,以及有毒副产物少等特点,成为了学者们争相研究的方向。目前关于生物合成纳米铁的研究还刚起步,因此,合理选择生物质、深入分析其起作用的成分、探讨其反应机理、优化纳米颗粒形态和尺寸提高产率是纳米铁解决重金属污染应用的发展方向。本文利用黑茶还原制备出绿色纳米铁(BT-Fe NPs),通过UV-Vis、SEM、EDX、FTIR、XRD等方法对BT-Fe NPs进行表征。再将此颗粒负载在凹凸棒(ATP)上进行改性,合成新型纳米颗粒——绿色纳米铁/凹凸棒(BT-Fe NPs/ATP)。并检测其去除废水中铬(Ⅵ)、铅(Ⅱ)的效率,考察了不同因素对去除效率的影响,通过表征分析探究了BT-Fe NPs去除重金属的机理。实验结果如下:(1)合成的BT-Fe NPs为无定形的球形颗粒,粒径100~200nm左右,纳米颗粒中的铁主要以磁赤铁矿(γ-Fe2O3),磁铁矿(Fe3O4)和铁氢氧化物形式存在,颗粒表面包裹C-N,C-O,-OH等有机基团。(2)在25℃,p H=4.0,Cr(Ⅵ)初始浓度20mg/L,反应时间90min条件下,BT-Fe NPs对Cr(Ⅵ)去除率达到96.3%。由于包裹了黑茶提取液中的有机成分,BT-Fe NPs的抗氧化性优于化学法制备的Na BH4-Fe NPs。在室温下,Pb(Ⅱ)的初始浓度为10mg/L,在p H值为7,BT-Fe NPs/ATP投加量为0.1g,反应时间为90min时,Pb(Ⅱ)的去除率可达99.8%。(3)改性后,BT-Fe NPs/ATP保持了ATP的层链状结构特征,具有较大的比表面积,椭球形的绿色纳米铁颗粒分散负载在平行的ATP晶束上,粒径约为200~500nm,团聚现象明显减少。(4)去除铬、铅过程中起主要作用的基团是C-N基团和Fe-O键,茶叶中的有机基团将重金属离子吸附在纳米颗粒表面,Fe-O键进而对其还原,说明了绿色纳米铁去除铬、铅的过程是一个吸附和还原共同作用的复杂物理化学过程。
[Abstract]:The rapid development of the nano iron preparation technology, a variety of methods. The biological preparation of nano iron because it has a wide source of raw materials, mild reaction conditions, the product is not easy to agglomerate and less toxic by-products, become the scholars to research. Current research on the biological synthesis of nano iron has just started therefore, a reasonable choice of biomass, in-depth analysis of its functional components, explore the reaction mechanism, optimize the size and morphology of nanoparticles to improve the yield of nano iron is to solve the development direction of the application of heavy metal pollution. The reduction of black tea prepared green nano iron (BT-Fe NPs) by UV-Vis, SEM, EDX, FTIR, XRD. The methods used to characterize BT-Fe NPs. Then the particle supported on Attapulgite (ATP) was modified to synthesis of new nano particles - Green nano Fe / attapulgite (BT-Fe NPs/ATP). And the inspection of the removal of chromium (VI), 閾，

本文编号：1580565