The oxidation of pyrite at pH 7 in the presence of reducing and nonreducing Fe(III)-chelators

抗坏血酸 化学 黄铁矿 无机化学 氧化还原 反应速率常数 螯合作用 草酸盐 核化学 动力学 矿物学 食品科学 量子力学 物理
作者
Stefan Peiffer,Irene Stubert
出处
期刊:Geochimica et Cosmochimica Acta [Elsevier BV]
卷期号:63 (19-20): 3171-3182 被引量:46
标识
DOI:10.1016/s0016-7037(99)00224-0
摘要

The oxidation rate of pyrite at pH 7, 25°C and at constant partial pressure of oxygen (0.21 and 0.177 atm) was measured in the presence of the Fe(III)-chelators NTA, oxalate, leucine, EDTA, citrate, IDA and the Fe(III)-reductant ascorbic acid. With the exception of leucine and EDTA, non-reducing Fe(III)-chelators increased the oxidation rate relative to the reference state of formation of the Fe(OH)2+ complex at pH 7. The rate increase was proportional to the logarithm of the conditional stability constant of the ligands for the complexation of Fe3+. No effect on the oxidation rate was observed in the presence of EDTA, which shifted the redox potential of the redox couple Fe2+/Fe3+ to a value below that in the absence of any ligand at pH 7. Ascorbic acid decreased the pyrite oxidation rate by a factor of 5 at ascorbic acid concentrations between 10−4 and 10−2 mol L−1. Comparison of the rate constants for the oxidation of ascorbic acid by surface bound Fe(III) in the absence and presence of pyrite shows that the pyrite surface accelerates this reaction by a factor of 10. The oxidation of both pyrite and ascorbic acid is of fractional order with respect to ascorbic acid (HAsc): rpy=0.55 c(HAsc)−0.35 rHAsc=3.6 c(HAsc)0.59. Both the results from experiments with Fe(III)-chelating ligands and the Fe(III)-reductant, suggest a very efficient interference in the electron cycling between Fe(II) and Fe(III) at the pyrite surface. The interference seems to be mainly related to the reductive side of the iron cycling. It is therefore concluded that the electron transfer between ferric iron and pyritic sulfur limits the pyrite oxidation rate at pH 7.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
罗拉发布了新的文献求助10
刚刚
1秒前
1秒前
鱼e完成签到,获得积分10
3秒前
3秒前
4秒前
4秒前
song发布了新的文献求助10
6秒前
ding应助时尚初之采纳,获得10
6秒前
罗拉完成签到,获得积分10
6秒前
6秒前
7秒前
yun尘世完成签到,获得积分10
8秒前
8秒前
自信南霜完成签到,获得积分10
8秒前
tingting9完成签到,获得积分10
11秒前
11秒前
12秒前
卡布奇诺完成签到,获得积分10
12秒前
13223456发布了新的文献求助10
12秒前
青山落日秋月春风完成签到,获得积分10
14秒前
15秒前
16秒前
16秒前
小马甲应助动听的雅绿采纳,获得30
17秒前
1177发布了新的文献求助10
19秒前
19秒前
喜喵喵完成签到,获得积分10
20秒前
20秒前
20秒前
20秒前
11关注了科研通微信公众号
21秒前
123456完成签到,获得积分10
22秒前
时尚初之发布了新的文献求助10
22秒前
ddd完成签到,获得积分10
23秒前
喜喵喵发布了新的文献求助10
25秒前
无情的函发布了新的文献求助10
25秒前
麦乐迪完成签到 ,获得积分10
26秒前
SYLH应助云横秦岭家何在采纳,获得10
26秒前
bkagyin应助如意枫叶采纳,获得10
27秒前
高分求助中
A new approach to the extrapolation of accelerated life test data 1000
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 500
‘Unruly’ Children: Historical Fieldnotes and Learning Morality in a Taiwan Village (New Departures in Anthropology) 400
Indomethacinのヒトにおける経皮吸収 400
Phylogenetic study of the order Polydesmida (Myriapoda: Diplopoda) 370
基于可调谐半导体激光吸收光谱技术泄漏气体检测系统的研究 350
Robot-supported joining of reinforcement textiles with one-sided sewing heads 320
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3989242
求助须知:如何正确求助?哪些是违规求助? 3531393
关于积分的说明 11253753
捐赠科研通 3270010
什么是DOI,文献DOI怎么找? 1804868
邀请新用户注册赠送积分活动 882084
科研通“疑难数据库(出版商)”最低求助积分说明 809136