不同晶型磁黄铁矿活化PDS降解工业废水中常见的罗丹明B:性能差异和机理
Natural pyrrhotite with different crystal forms activating PDS for the degradation of Rhodamine B prevalent in industrial wastewater:Performance differences and mechanisms
刘仕统 1王军 1刘洋 1杨宝军 1于世超 1洪茂鑫 1邱冠周1
作者信息
- 1. School of Minerals Processing&Bioengineering,Central South University,Changsha 410083,China;Key Laboratory of Biohydrometallurgy of Ministry of Education,Central South University,Changsha 410083,China
- 折叠
摘要
本文研究了天然六方磁黄铁矿(HNP,Fe0.93S)与天然单斜磁黄铁矿(MNP,Fe0.85S)活化过硫酸盐(PDS)降解罗丹明B(RhB)的性能差异及其机理.结果表明,在酸性和弱碱性条件下,MNP/PDS体系的降解效率(pH=4时为97.15%)均高于HNP/PDS体系(pH=4时为86.91%),且两个体系的降解效率均随pH的升高而降低.MNP/PDS体系较高的降解效率与体系中较高的溶解铁浓度和MNP表面较强的反应性有关,且后者是主要因素,即降解反应主要发生在磁黄铁矿的表面及近表面处.MNP较强的表面反应性首先体现在其相对较高的Zeta电位,这使得MNP与PDS之间的静电引力更强,PDS更容易被MNP活化.其次,MNP表面具有更高的腐蚀电流密度,这有利于Fe(II)对PDS的非均相活化以及表面还原性硫物种(如S2-和S22-)作为电子给体将Fe(III)还原为Fe(II)(或Fe3+还原为Fe2+).此外,MNP表面的疏松氧化层在降解过程中容易脱落,进而暴露出新的表面活性位点.
Abstract
In this study,we investigated the difference and mechanism of the degradation of Rhodamine B by hexagonal natural pyrrhotite(HNP,Fe0.93S)and monoclinic natural pyrrhotite(MNP,Fe0.85S)activating peroxydisulfate(PDS).The results show that the degradation efficiency of MNP/PDS system was higher than that of HNP/PDS system under both acidic and weak alkaline conditions,and both decreased with the increase of pH.The better degradation efficiency was related to the higher dissolved iron concentration of MNP/PDS system and the stronger surface reactivity of MNP.Among them,the surface reactivity was recognized as dominant,namely,the degradation reaction mainly occurred on and near the surface of natural pyrrhotite(NP).The strong surface reactivity of MNP was first reflected in the higher Zeta potential,so that the electrostatic attraction between MNP and PDS was greater.This meant that PDS was more easily activated by MNP.Secondly,the MNP possessed higher surface oxidation degree and higher corrosion current density,which contributed to the heterogeneous activation of PDS by Fe(II)and the reduction of Fe(III)to Fe(II)(or Fe3+ to Fe2+)by surface reductive sulfur species(such as S2-and S22-)as electron donors.Moreover,the loose oxide layer on the MNP surface was easy to fall off during the degradation process,and new surface reaction sites are re-exposed.
关键词
天然磁黄铁矿/不同晶型/罗丹明B/过硫酸盐/降解Key words
natural pyrrhotite/different crystal forms/Rhodamine B/peroxydisulfate/degradation引用本文复制引用
基金项目
国家自然科学基金(52274288)
国家自然科学基金(U1932129)
国家自然科学基金(52204303)
国家自然科学基金(51934009)
出版年
2023
NETL
NSTL
万方数据