Arsenic in an alkaline AMD treatment sludge: Characterization and stability under prolonged anoxic conditions

被引:16
作者
Beauchemin, Suzanne [1 ]
Fiset, Jean-Francois [1 ]
Poirier, Glenn [2 ]
Ablett, James [3 ]
机构
[1] Nat Resources Canada, CANMET Min & Mineral Sci Labs, Ottawa, ON K1A 0G1, Canada
[2] Canadian Museum Nat, Earth Sci Res Div, Ottawa, ON K1P 6P4, Canada
[3] Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France
基金
加拿大自然科学与工程研究理事会;
关键词
REDUCTIVE DISSOLUTION; MICROBIAL REDUCTION; IRON HYDROXIDE; CLAY-MINERALS; FERRIHYDRITE; ADSORPTION; OXIDATION; SURFACE; TAILINGS; SORPTION;
D O I
10.1016/j.apgeochem.2010.07.004
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Lime treatment of acid mine drainage (AMD) generates large volumes of neutralization sludge that are often stored under water covers. The sludge consists mainly of calcite, gypsum and a widespread ferrihydrite-like Fe phase with several associated species of metal(loid) contaminants. The long-term stability of metal(loid)s in this chemically ill-defined material remains unknown. In this study, the stability and speciation of As in AMD sludge subjected to prolonged anoxic conditions is determined. The total As concentration in the sludge is 300 mg kg(-1). In the laboratory, three distinct water cover treatments were imposed on the sludge to induce different redox conditions (100%N-2, 100%N-2 + glucose, 95%N-2:5%H-2). These treatments were compared against a control of oxidized, water-saturated sludge. Electron micro-probe (EMP) analysis and spatially resolved synchrotron X-ray fluorescence (SXRF) results indicate that As is dominantly associated with Fe in the sludge. In all treatments and throughout the experiment, measured concentrations of dissolved As were less than 5 mu g L-1. Dissolved Mn concentration in the N-2 + glucose treatment increased significantly compared to other treatments. Manganese and As K-edge X-ray absorption near edge structure spectroscopy (XANES) analyses showed that Mn was the redoxactive element in the solid-phase, while As was stable. Arsenic(V) was still the dominant species in all water-covered sludges after 9 months of anoxic treatments. In contrast, Mn(IV) in the original sludge was partially reduced into Mn(II) in all water-covered sludges. The effect was most pronounced in the N-2 + glucose treatment, suggesting microbial reduction. Micro-scale SXRF and XANES analysis of the treated sludge showed that Mn(II) accumulated in areas already enriched in Fe and As. Overall, the study shows that AMD sludges remain stable under prolonged anoxic conditions. External sources of chemical reductants or soluble C were needed to induce lower redox state in the systems, and even under these imposed treatments, only weakly reducing conditions (Mn threshold) developed. The results suggest that As(V) in AMD sludge will remain stable under prolonged anoxic conditions as long as Mn(IV) is present and organic matter accumulation is negligible. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.
引用
收藏
页码:1487 / 1499
页数:13
相关论文
共 76 条
  • [1] X27A - A new hard X-ray micro-spectroscopy facility at the National Synchrotron Light Source
    Ablett, JM
    Kao, CC
    Reeder, RJ
    Tang, Y
    Lanzirotti, A
    [J]. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 2006, 562 (01) : 487 - 494
  • [2] Allison JerryD., 1991, MINTEQA2PRODEFA2 GEO
  • [3] *AN SERV GROUP, 1996, MICR LEACH DET AS BI
  • [4] ARSENATE ADSORPTION ON AMORPHOUS ALUMINUM HYDROXIDE
    ANDERSON, MA
    FERGUSON, JF
    GAVIS, J
    [J]. JOURNAL OF COLLOID AND INTERFACE SCIENCE, 1976, 54 (03) : 391 - 399
  • [5] SURFACE AND BULK CHARACTERISTICS OF BINARY OXIDE SUSPENSIONS
    ANDERSON, PR
    BENJAMIN, MM
    [J]. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1990, 24 (05) : 692 - 698
  • [6] Effect of pH and anion type on the aging of freshly precipitated iron(III) hydroxide sludges
    Baltpurvins, KA
    Burns, RC
    Lawrance, GA
    Stuart, AD
    [J]. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1996, 30 (03) : 939 - 944
  • [7] In situ characterization of Mn(II) oxidation by spores of the marine Bacillus sp strain SG-1
    Bargar, JR
    Tebo, BM
    Villinski, JE
    [J]. GEOCHIMICA ET COSMOCHIMICA ACTA, 2000, 64 (16) : 2775 - 2778
  • [8] REDOX CHEMISTRY OF SOILS
    BARTLETT, RJ
    JAMES, BR
    [J]. ADVANCES IN AGRONOMY, VOL 50, 1993, 50 : 151 - 208
  • [9] BEAUCHEMIN S, 2007, P C MIN ENV 4 SUDB O
  • [10] BEAUCHEMIN S, 2004, 04013 CANMETMMSL