摘要
探讨膨润土负载双金属铁钯(B-Fe/Pd)纳米材料催化降解微囊藻毒素-LR(MC-LR)的效果和机理.结果表明,在5mgL-1的MC-LR溶液中加入0.1g的纳米B-Fe/Pd,初始pH为6.86,振荡速度为250rmin-1,温度为298K的条件下,经过180min后对MC-LR的降解效率达96.86%.降解溶液的UV-vis和HPLC结果表明,MC-LR在238nm的特征峰消失.通过SEM-EDS、XRD、FTIR和XPS技术对B-Fe/Pd降解前后的样品进行表征,结果显示,降解后纳米B-Fe/Pd中的Fe形成了Fe的氧化物与氢氧化物.降解过程的动力学拟合结果显示,B-Fe/Pd降解MC-LR符合伪一级动力学,活化能为12.77kJmol-1.根据降解、表征和动力学结果分析其反应机理,推断是MC-LR首先吸附在B-Fe/Pd颗粒表面,接着纳米铁与水反应产生的氢气在Pd的催化作用下产生大量的氢自由基,并与MC-LR发生链式还原反应,使得MC-LR中最具毒性的共轭双键断开而降解.
In this paper, bentonite supported bimetallic Fe/Pd nanoparticles （B-Fe/Pd） was explored to use for degradation of microcystin-LR （MC-LR）. 96.86% of MC-LR was degraded after 180 min with an initial MC-LR concentration of 5 mg L-1 （pH 6.86） using 0.1 g B-Fe/Pd. UV-Vis and HPLC-UV showed that the peak of MC-LR at 238 nm was disappeared after B-Fe/Pd react with MC-LR. SEM-EDS, XRD, FTIR and XPS used for characterization of B-Fe/Pd before and after reaction with MC-LR revealed the formation of iron oxide and iron hydroxides after degradation of MC-LR. The degradation of MC-LC using B-Fe/Pd fitted well the pseudo-first kinetic order model with an activation energy was 12.77 kJ mo1-1. Degradation mechanism of MC-LR was proposed, which was based on firstly MC-LR adsorded in the surface of bentonite and iron nanoparticles-palladium particles, secondly iron nanoparticles reacted with water to produce hydrogen, and the formation of hydrogen radical by the Pd catalysis, finally MC-LR was reduced by hydrogen radical, where the most toxic conjugated double bond of MC-LR was broken by the reduction.
出处
《中国科学：化学》
CAS
CSCD
北大核心
2013年第2期217-225,共9页
SCIENTIA SINICA Chimica
基金
福建师范大学"闽江学者"人才建设项目的资助
