Arsenic removal by goethite and jarosite in acidic conditions and its environmental implications
Arsenic removal by goethite and jarosite in acidic conditions and its environmental implications
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DOI：
10.1016/j.jhazmat.2009.06.097
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发表时间：
2009-11-15
影响因子：
13.6
通讯作者：
Gimenez, Javier
中科院分区：
文献类型：
--
作者：
Asta, Maria P.;Cama, Jordi;Gimenez, Javier
施韦特曼石（Fe 8 O 8（OH）（5.5）（SO 4）（1.25））、黄钾铁矾（KFe 3（SO 4）（2）（OH）（6））和针铁矿（FeOOH）控制着受酸性矿山废水（AMD）影响地区砷的自然衰减。进行批实验以检查合成针铁矿和合成黄钾铁矾在高酸性pH（1.5-2.5）、两种离子强度（0.02-0.15 mol dm（-3），NaCl）和硫酸盐浓度在5 × 10（-3）至2.8 × 10（-1）mol dm（-3）范围内的吸附能力。在没有其他阴离子竞争的情况下，黄钾铁矾对As（V）的去除效果优于针铁矿。黄钾铁矾和针铁矿的最大吸附容量分别为1.2 × 10 ~（-4）和7.0 × 10 ~（-6）mol·m ~（-2）。在相似的实验条件下。砷吸附在针铁矿上的变化作为溶液中的平衡砷浓度的函数符合非竞争性Langmuir等温线。在钾黄钾铁矾的情况下，吸附数据不能拟合的Langmuir或Freundlich等温线，因为硫酸根-砷酸根阴离子交换可能是吸附机制。离子强度和pH值对针铁矿和黄钾铁矾的吸附容量的影响不大，在小的pH值范围内研究。硫酸盐是AMD天然系统中的主要阴离子，其存在对砷去除具有负面影响，因为硫酸盐与砷酸盐竞争表面吸附位点。此外，在pH值为2-3的施氏黄钾铁矾或针铁矿的转化砷的动员提出了针铁矿和K-黄钾铁矾的吸附容量是相当低的施氏报道。(C)2009 Elsevier B. V.保留所有权利。
Schwertmannite (Fe8O8(OH)(5.5)(SO4)(1.25)), jarosite (KFe3(SO4)(2)(OH)(6)) and goethite (FeOOH) control natural attenuation of arsenic in acid mine drainage (AMD) impacted areas. Batch experiments were conducted to examine the sorption capacity of synthetic goethite and synthetic jarosite at highly acidic pH (1.5-2.5), at two ionic strengths (0.02-0.15 mol dm(-3), NaCl) and at sulphate concentrations in the range of 5 x 10(-3) to 2.8 x 10(-1) mol dm(-3). In the absence of competitive effects of other anions, K-jarosite presents better removal efficiency than goethite for As(V). The maximum sorption capacity is estimated to be 1.2 x 10(-4) and 7.0 x 10(-6) mol m(-2) for jarosite and goethite. respectively, under similar experimental conditions. The variation of arsenic sorbed on goethite as a function of the equilibrium arsenic concentration in solution fits a non-competitive Langmuir isotherm. In the case of K-jarosite, sorption data could not fit a Langmuir or Freundlich isotherm since sulphate-arsenate anion exchange is probably the sorption mechanism. Ionic strength and pH have little effect on the sorption capacity of goethite and jarosite in the small range of pH studied. The presence of sulphate, which is the main anion in AMD natural systems, has a negative effect on arsenic removal since sulphate competes with arsenate for surface sorption sites. Moreover, mobilization of arsenic in the transformation of schwertmannite to jarosite or goethite at pH 2-3 is proposed since the sorption capacities of goethite and K-jarosite are considerably lower than those reported for schwertmannite. (C) 2009 Elsevier B.V. All rights reserved.