Performance enhancement of zero valent iron based systems using depassivators: Optimization and kinetic mechanisms

被引:43
作者
Ansaf, Karim Vayalunkal Karottu [1 ]
Ambika, Selvaraj [1 ]
Nambi, Indumathi Manivannan [1 ]
机构
[1] Indian Inst Technol, Dept Civil Engn, Environm & Water Resources Div, Madras, Tamil Nadu, India
关键词
Zero valent iron; Depassivation; PRB's life span; Pitting dissolution and hydrogen ion embrittlement; Hexavalent chromium reduction; PERMEABLE REACTIVE BARRIERS; LONG-TERM PERFORMANCE; ZEROVALENT IRON; WASTE-WATER; ELECTROCHEMICAL DEPASSIVATION; CONTAMINATED WATER; GRANULAR IRON; HEAVY-METALS; SCRAP IRON; REMOVAL;
D O I
10.1016/j.watres.2016.06.064
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The long-term ability of Zero-Valent Iron (ZVI) in contaminant removal relies on the effectiveness of iron to serve as electron donor, which makes it a versatile remediation material. However, the formation of oxide and hydroxide layers results in passive layer on ZVI surface during contaminant removal hinders its reactivity. The focus of this research was to evaluate the performance of corrosive agents such as acetic acid (HAc), aluminium sulphate (Alum) and potassium chloride (KCI) as depassivators to overcome passivation for sustainability and longevity. Batch experiments using seven combinations of the above chemicals were conducted to optimize the dosage of depassivators based on passive layer removal. The influence of depassivators in catalytic activity of ZVI in removing Cr6+ was evaluated. The passive layer on ZVI particles was characterized using Scanning Electron Microscopy (SEM) and confirmed by Energy Dispersive X-ray spectroscopy (EDAX) analysis. The major mechanisms in passive layer removal was found to be H+ ion embrittlement followed by uniform depassivation when [HAc] was used and pitting corrosion when [Alum] and [KCl]were used. All the seven sets of chemicals enabled depassivation, but considering the criteria of maximum depassivation, catalytic activity and long term reactivity the depassivation treatments were effective in order as [HAc-Alum] > [HAc-Alum-KCl] > [HAc] > [Alum] > [HAc-KCl] > [KCl] > [Alum-KCl]. The kinetic rate of ZVI using [HAc-Alum] and [Alum] was relatively unchanged over the pH range of 4-10, made it suitable for ex-situ remediation. This insignificant influence of initial pH in catalytic activity of ZVI along with the improvement in longevity and sustainability makes it suitable for effective water treatment applications. The present work has successfully demonstrated that chemical depassivation can restore considerable reactivity of ZVI in the existing permeable reactive barriers. (C) 2016 Elsevier Ltd. All rights reserved.
引用
收藏
页码:436 / 444
页数:9
相关论文
共 65 条
[1]  
Ambika S, 2016, J ENV MANAG IN PRESS
[2]   Low temperature synthesis of highly stable and reusable CMC-Fe2+(-nZVI) catalyst for the elimination of organic pollutants [J].
Ambika, Selvaraj ;
Nambi, Indumathi Manivannan ;
Senthilnathan, Jaganathan .
CHEMICAL ENGINEERING JOURNAL, 2016, 289 :544-553
[3]  
[Anonymous], STAND METH WAT WAST
[4]  
[Anonymous], AGU FALL M
[5]  
[Anonymous], P 6 INT C ENV SCI TE
[6]   Remediation of alachlor and atrazine contaminated water with zero-valent iron nanoparticles [J].
Bezbaruah, Achintya N. ;
Thompson, Jay M. ;
Chisholm, Bret J. .
JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES, 2009, 44 (06) :518-524
[7]   In-situ remediation of Cr(VI)-contaminated groundwater using permeable reactive walls: Laboratory studies [J].
Blowes, DW ;
Ptacek, CJ ;
Jambor, JL .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1997, 31 (12) :3348-3357
[8]   KINETICS OF THE DISSOLUTION OF COPPER IN IRON(III) CHLORIDE SOLUTIONS [J].
BRYCE, C ;
BERK, D .
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 1995, 34 (04) :1412-1418
[9]   Remediation of DDTs contaminated soil in a novel Fenton-like system with zero-valent iron [J].
Cao, Menghua ;
Wang, Lingling ;
Wang, Li ;
Chen, Jing ;
Lu, Xiaohua .
CHEMOSPHERE, 2013, 90 (08) :2303-2308
[10]   Effects of pH on dechlorination of trichloroethylene by zero-valent iron [J].
Chen, JL ;
Al-Abed, SR ;
Ryan, JA ;
Li, ZB .
JOURNAL OF HAZARDOUS MATERIALS, 2001, 83 (03) :243-254