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首页> 外文期刊>Environmental Science & Technology >Influence of Calcite and Dissolved Calcium on Uranium(VI) Sorption to a Hanford Subsurface Sediment
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Influence of Calcite and Dissolved Calcium on Uranium(VI) Sorption to a Hanford Subsurface Sediment

机译:方解石和钙的溶解对汉福德地下沉积物中铀吸附的影响

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摘要

The influence of calcite and dissolved calcium on U(VI) adsorption was investigated using a calcite-containing sandy silt/clay sediment from the U.S.Department of Energy Hanford site.U(VI) adsorption to sediment,treated sediment,and sediment size fractions was studied in solutions that both had and had not been preequilibrated with calcite,at initial [U(VI)]=10~(-7)-10~(-5) mol/L and final pH=6.0-10.0.Kinetic and reversibility studies (pH 8.4) showed rapid sorption (30 min),with reasonable reversibility in the 3-day reaction time.Sorption from solutions equilibrated with calcite showed maximum U(VI) adsorption at pH 8.4+-0.1.In contrast,calcium-free systems showed the greatest adsorption at pH 6.0-7.2.At pH > 8.4,U(VI) adsorption was identical from calcium-free and calcium-containing solutions.For calcite-presaturated systems,both speciation calculations and laser-induced fluorescence spectroscopic analyses indicated that aqueous U(VI) was increasingly dominated by Ca_2U0_2(C0_3)_3~0(aq) at pH < 8.4 and thatformation of Ca_2UO_2(CO_3)_3~0(aq) is what suppresses U(VI) adsorption.Above pH 8.4,aqueous U(VI) speciation was dominated by UO_2(CO_3)_3~(4-) in all solutions.Finally,results also showed that U(VI) adsorption was additive in regard to size fraction but not in regard to mineral mass:Carbonate minerals may have blocked U(VI) access to surfaces of higher sorption affinity.
机译:利用能源汉福德大学美国分部含方解石的粉砂/粘土沉积物研究了方解石和溶解钙对U(VI)吸附的影响.U(VI)对沉积物,处理过的沉积物和沉积物大小分数的吸附为在[U(VI)] = 10〜(-7)-10〜(-5)mol / L和最终pH = 6.0-10.0的条件下,用方解石预先平衡的溶液进行了研究。动力学和可逆性研究(pH 8.4)显示快速吸附(30分钟),在3天的反应时间内具有可逆性。从方解石平衡的溶液中吸附表明,在pH 8.4 + -0.1时U(VI)的吸附最大。系统在pH 6.0-7.2时显示出最大的吸附。在pH> 8.4时,无钙和含钙溶液中的U(VI)吸附是相同的。对于方解石预饱和系统,形态计算和激光诱导荧光光谱分析均显示U(VI)水溶液越来越被Ca_2U0_2(C0_3)_3〜0(a q)在pH <8.4且Ca_2UO_2(CO_3)_3〜0(aq)的形成抑制了U(VI)的吸附。在pH 8.4以上时,U(VI)的形态以UO_2(CO_3)_3〜(4-最后,结果还表明,U(VI)吸附在尺寸分数方面是累加的,但在矿物质质量方面却不是:碳酸盐矿物可能阻止U(VI)进入具有更高吸附亲和力的表面。

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  • 来源
    《Environmental Science & Technology》 |2005年第20期|p.7949-7955|共7页
  • 作者单位

    Department of Geography and Environmental Engineering,Johns Hopkins University,313 Ames Hall,3400 North Charles Street,Baltimore,Maryland 21218,and Environmental Dynamics and Simulations,Pacific Northwest National Laboratory,Richland,Washington 99352;

    Department of Geography and Environmental Engineering,Johns Hopkins University,313 Ames Hall,3400 North Charles Street,Baltimore,Maryland 21218,and Environmental Dynamics and Simulations,Pacific Northwest National Laboratory,Richland,Washington 99352;

    Department of Geography and Environmental Engineering,Johns Hopkins University,313 Ames Hall,3400 North Charles Street,Baltimore,Maryland 21218,and Environmental Dynamics and Simulations,Pacific Northwest National Laboratory,Richland,Washington 99352;

    Department of Geography and Environmental Engineering,Johns Hopkins University,313 Ames Hall,3400 North Charles Street,Baltimore,Maryland 21218,and Environmental Dynamics and Simulations,Pacific Northwest National Laboratory,Richland,Washington 99352;

    Department of Geography and Environmental Engineering,Johns Hopkins University,313 Ames Hall,3400 North Charles Street,Baltimore,Maryland 21218,and Environmental Dynamics and Simulations,Pacific Northwest National Laboratory,Richland,Washington 99352;

    Department of Geography and Environmental Engineering,Johns Hopkins University,313 Ames Hall,3400 North Charles Street,Baltimore,Maryland 21218,and Environmental Dynamics and Simulations,Pacific Northwest National Laboratory,Richland,Washington 99352;

    Department of Geography and Environmental Engineering,Johns Hopkins University,313 Ames Hall,3400 North Charles Street,Baltimore,Maryland 21218,and Environmental Dynamics and Simulations,Pacific Northwest National Laboratory,Richland,Washington 99352;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境化学;
  • 关键词

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