Mg(OH)2 Supported Nanoscale Zero Valent Iron Enhancing the Removal of Pb(Ⅱ) from Aqueous Solution

摘要

In the past two decades,nanoscale zerovalent iron(nZVI) has received much attention because of its large specific surface area,high reaction activity,and strong reductive power.Studies show that nZVI appears to be effective in removing various pollutants,such as chlorinated organic compounds,nitroaromatic compounds,dyes,and heavy metal ions.Nevertheless,nZVI particles tend to aggregate due to the high surface energy and magnetic force,leading to sharp deterioration of activity,durability,and efficiency,which would greatly hinder the large scale application of nZVI.On the other hand,nanoscale magnesium hydroxide (Mg(OH)2)has aroused extensive attention because of low-cost and environmental friendliness.Researches indicate that Mg(OH)2exhibits a promising prospect in acid wastewater treatment,heavy metal deprivation,and decoloration of printing and dyeing wastewater.The authors' previous researches reveal that the morphology of Mg(OH)2 can be easily controlled and modified to obtain a self-supported flowerlike structure with large specific surface area,which can potentially provide an ideal carrier fomZVI particles.In this talk,we will introduce our recent work,aiming to develop a novel composite by loading nZVI onto Mg(OH)2 (nZVI@Mg(OH)2),for testing its performance in wastewater treatment[1].With Pb(Ⅱ) as an example,results show that the agglomeration of nZVI particles was eliminated,and a superb capacity for Pb(Ⅱ) uptake was achieved (1986.6 mg/g),much higher than the weighted sum value (1246 mg/g) of its component,indicating the existence of a synergy between nZVI and Mg(OH)2.Further mechanism analyses attested that Mg(OH)2 played acrucial role by releasing OH-which can enhance the reduction of Pb(Ⅱ).