摘要
银纳米颗粒(AgNPs)具有表面等离子体共振效应,对光催化反应具有显著的增强作用,但其合成通常需要额外的有机试剂作为还原剂,并且在无配体条件下AgNPs极易团聚.本工作在模拟太阳光下,利用环境水介质中广泛存在的天然有机质腐殖酸(HA)原位还原银离子(Ag+)形成稳定的AgNPs,对水中典型有机卤代污染物四溴双酚A(TBBPA)具有优异的光催化降解效果.当HA和Ag+浓度分别为1 mg/L和0.2 mmol/L时,AgNPs在1 h内对2 mg/L TBBPA的去除率达74.9%,远高于商用AgNPs的降解效果.通过不同条件的对照实验发现,中性pH更有利于TBBPA的降解,降低了对实际应用中设备和反应条件的需求.同时,通过活性物种的抑制实验发现,光照HA原位还原Ag+生成的AgNPs具有较高的光催化活性,能够通过表面等离子体共振效应同时产生多种活性物种,包括单线态氧(1O2)、羟基自由基(·OH)和超氧阴离子(O2·-),从而强化TBBPA的降解.因此,该工作实现了在温和条件下,通过廉价的HA原位还原生成具有高效光催化活性的AgNPs,在水中有机污染物的降解方面具有潜在的应用前景.
Silver nanoparticles(AgNPs)could enhance the photocatalytic reaction significantly owing to its surface plasmon resonance(SPR)effect.However,AgNPs are usually unstable without the ligands and their preparation process always requires organic chemicals as the reducing agents.In this work,humic acids(HA),widely existent in environmental water samples,were used as both reductant and ligand for in situ synthesizing and stabilizing AgNPs under simulated sunlight.The results of photocatalytic experiments indicate that the as-prepared AgNPs show excellent activity for the degradation of tetrabromobisphenol A(TBBPA),a typical organic halogenated pollutant in water.With AgNPs generated in the mixture of 1 mg/L HA and 2 mmol/L Ag+,74.9%TBBPA was degraded in 1 h.This degradation efficiency is much better than that of commercial AgNPs.Through controlling the reaction conditions,neutral pH was found to be beneficial for the degradation of TBBPA,which would lower the requirements of equipments and reaction conditions in practical applications.By the inhabitation test of active species,singlet oxygen(1O2),hydroxyl radical(·OH)and superoxide anion(O2·-)generated via the SPR effect of the in situ formed AgNPs under illumination,were simultaneously identified to be the active species in the degradation of TBBPA.Therefore,the AgNPs with high photocatalytic activity are in situ synthesized by using cheap HA under mild conditions,exhibiting potential for applications in photocatalytic degradation of organic pollutants in wastewater.
作者
李文杰
虞盛松
陈洁洁
LI Wenjie;YU Shengsong;CHEN Jiejie(Department of Applied Chemistry,University of Science and Technology of China,Hefei 230036,China)
基金
统筹推进世界一流大学和一流学科建设专项资金(YD3530002001)资助
关键词
银纳米颗粒
绿色合成
腐殖酸
四溴双酚A
光催化降解
silver nanoparticles
green synthesis
humic acids
tetrabromobisphenol A
photocatalytic degradation
