Effects of low pH on nitrate reduction by iron powder

被引:277
作者
Huang, YH [1 ]
Zhang, TC [1 ]
机构
[1] Univ Nebraska, Dept Civil Engn, Omaha, NE 68182 USA
关键词
pH; zerovalent iron; nitrate; iron oxides; kinetics;
D O I
10.1016/j.watres.2004.03.015
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The effect of low pH (2-4.5) on nitrate reduction in an iron/nitrate/water system was investigated through batch experiments conducted in a pH-stat. The results showed that nitrate could be rapidly reduced to ammonium at pH 24.5. A black coating, consisted of both Fe(II) and Fe(III), was formed on the surface of iron grains as an iron corrosion product. X-ray diffractometry indicated that the black coating was poorly crystalline, and its spectrum could not be matched with commonly known iron oxides/hydroxides/oxide hydroxides or green rust I/II. The black coating does not inhibit the reactivity of Fe-0 (at least at pH < 3). The black coating was unstable and evolved with time into other oxides under certain conditions. A kinetic model incorporating the effects of pH on nitrate reduction and Langrymuir adsorption of nitrate was proposed, and the parameters were estimated by nonlinear curve fitting. Based on this model, the two major effects of pH on the kinetics of nitrate reduction are that: (a) H+ ions directly participate in the redox reaction of nitrate reduction following first-order kinetics; and (b) H+ ions affect the nitrate adsorption onto reactive sites. (C) 2004 Elsevier Ltd. All rights reserved.
引用
收藏
页码:2631 / 2642
页数:12
相关论文
共 18 条
[1]   Reduction of nitro aromatic compounds by zero-valent iron metal [J].
Agrawal, A ;
Tratnyek, PG .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1996, 30 (01) :153-160
[2]   Kinetics of nitrate, nitrite, and Cr(VI) reduction by iron metal [J].
Alowitz, MJ ;
Scherer, MM .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 2002, 36 (03) :299-306
[3]   CHEMICAL REDUCTION OF NITRATE BY FERROUS IRON [J].
BURESH, RJ ;
MORAGHAN, JT .
JOURNAL OF ENVIRONMENTAL QUALITY, 1976, 5 (03) :320-325
[4]   The reduction of alkali nitrates by hydrous ferrous oxide [J].
Carsley, SH .
JOURNAL OF PHYSICAL CHEMISTRY, 1930, 34 (01) :178-187
[5]   Reduction of nitrate to ammonia by zero-valent iron [J].
Cheng, IF ;
Muftikian, R ;
Fernando, Q ;
Korte, N .
CHEMOSPHERE, 1997, 35 (11) :2689-2695
[6]  
Cornell R.M., 1996, The Iron Oxide: Structure, Properties, Reactions, Occurance and Uses
[7]   ENHANCED DEGRADATION OF HALOGENATED ALIPHATICS BY ZERO-VALENT IRON [J].
GILLHAM, RW ;
OHANNESIN, SF .
GROUND WATER, 1994, 32 (06) :958-967
[8]   Nitrate reduction by metallic iron [J].
Huang, CP ;
Wang, HW ;
Chiu, PC .
WATER RESEARCH, 1998, 32 (08) :2257-2264
[9]   Effects of oxide coating and selected cations on nitrate reduction by iron metal [J].
Huang, YH ;
Zhang, TC ;
Shea, PJ ;
Comfort, SD .
JOURNAL OF ENVIRONMENTAL QUALITY, 2003, 32 (04) :1306-1315
[10]   Kinetics of nitrate reduction by iron at near neutral pH [J].
Huang, YH ;
Zhang, TC .
JOURNAL OF ENVIRONMENTAL ENGINEERING, 2002, 128 (07) :604-611