...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Environmental Science & Technology >Effect of natural organic substances on the surface and adsorptive properties of environmental black carbon (char): Attenuation of surface activity by humic and fulvic acids
【24h】

Effect of natural organic substances on the surface and adsorptive properties of environmental black carbon (char): Attenuation of surface activity by humic and fulvic acids

机译：天然有机物对环境黑碳（炭）的表面和吸附性能的影响：腐殖酸和黄腐酸对表面活性的减弱

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Black carbon (BC) plays a potentially important role in the availability of pollutants in soils and sediments. Recent evidence points to the possible attenuation of the high surface activity of raw BC by natural substances. We studied the effects of soil humic (HA) and fulvic (FA) acids on the surface properties and affinity for organic compounds of synthesized wood charcoal. Char powder suspended in a solution of HA or FA was loaded with organic matter via adsorption, evaporation of the water, or coflocculation with Al3+. These treatments were chosen to simulate initial and more advanced stages of environmental exposure. Coevaporation dramatically reduced the N-2 Brunauer-Emmett-Teller total surface area of the char, but only moderately the CO2 cumulative surface area up to 1.4 nm. Organic compound adsorption was suppressed in proportion to molecular size, benzene < naphthalene < phenanthrene and 1,2,4-trichlorobenzene, phenanthrene, for humics in the adsorbed and coflocculated states, respectively. Humic substances also increased the linearity of the isotherms. The model we propose assumes that humic substances are restricted to the external surface where they act as pore blocking agents or competitive adsorbates, depending on the temperature and adsorbate size. Nitrogen is blocked from the internal pore space due to stiffness at 77 K of humic strands extending into pore throats, giving an artificially low surface area. Together with previous results, this finding indicates that N-2 may not detect BC microporosity in geosorbents. At higher temperatures (CO2, 273 K; organics, 293 K), humic strands are more flexible, allowing access to interior pores. The counterintuitive molecular size dependence of adsorption suppression by humics is due to a molecular sieving effect in pores in which the adsorption space available to the organic compound is more and more restricted to external sites.
机译：黑碳（BC）在土壤和沉积物中污染物的可利用性中可能发挥重要作用。最近的证据表明天然物质可能会降低粗制BC的高表面活性。我们研究了腐殖酸（HA）和富里酸（FA）对表面活性和对合成木炭有机化合物亲和力的影响。通过吸附，水蒸发或与Al3 +共絮凝，将悬浮在HA或FA溶液中的炭粉装入有机物。选择这些处理方法是为了模拟环境暴露的初始阶段和更高级阶段。共蒸发显着减少了焦炭的N-2 Brunauer-Emmett-Teller炭的总表面积，但仅适度地将CO2累积表面积提高至1.4 nm。对于腐殖质在吸附状态和共絮凝状态下，有机化合物的吸附均与分子大小成比例，分别为苯<萘<菲和1,2,4-三氯苯，菲。腐殖质也增加了等温线的线性。我们提出的模型假设腐殖质被限制在外表面，在该表面上，它们充当孔阻塞剂或竞争性吸附物，具体取决于温度和吸附物的大小。由于腐殖质链在77 K处延伸进入孔喉时的刚度，使得氮气无法进入内部孔隙空间，从而人为地降低了表面积。与以前的结果一起，该发现表明N-2可能无法检测出地质吸附剂中的BC微孔。在较高温度下（CO2，273 K；有机物，293 K），腐殖质股更柔韧，可以进入内部毛孔。腐殖质抑制吸附的分子大小依赖性与直觉相反，这是由于孔中的分子筛作用所致，其中有机化合物可利用的吸附空间越来越局限于外部位置。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号