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首页> 外文期刊>Environmental Science & Technology >Cation Exchange Properties of Hydrothermally Treated Coal Fly Ash
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Cation Exchange Properties of Hydrothermally Treated Coal Fly Ash

机译：水热处理粉煤灰的阳离子交换特性

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摘要

Two samples of fly ash were treated for 2—48 h in 3.5 M NaOH at 100℃. Powder XRD patterns of resulting products were obtained, and their CEC was determined. Zeolite P and/or hydroxysodalite formed during the treatment from the glassy part of fly ash, while quartz gradually dissolved and mullite remained stable. Approximately 50% of fly ash could be converted to zeolites with the CEC of resulting products reaching 2.5—3 mequiv/g. Concentrations of extractable B, Mo, and Se in fly ash considerably decreased upon treatment. Adsorption isotherms of lead on treated fly ash suggested that at low initial lead concentrations and at pH lowerthan 6 precipitation of lead compounds is not likely. A desorption experiment indicated incomplete reversibility at higher concentrations, suggesting that part of the adsorption may not have been cation exchange related. Treated fly ash displayed high selectivity for Pb~(2+) > Sr~(2+) > Cu~(2+) > Cd~(2+) > Zn~(2+) > Cs~+ in competition with Na~+, especially at low concentrations of these cations, and was effective in removing Pb and Zn from industrial wastewaters. It was not selective for Ni~(2+) and UO_2~(2+). In a column test, 160 bed vols of NH_4~+-contaminated fish-pond water was filtered through treated fly ash until NH_4~+ breakthrough occurred.
机译：将两个粉煤灰样品在3.5 M NaOH中于100℃处理2-48小时。获得所得产物的粉末XRD图，并确定其CEC。在处理过程中，粉煤灰的玻璃状部分形成了沸石P和/或羟基苏打石，而石英逐渐溶解，莫来石保持稳定。大约50％的粉煤灰可以转化为沸石，最终产品的CEC达到2.5-3 mequiv / g。处理后，粉煤灰中可提取的B，Mo和Se的浓度大大降低。处理过的粉煤灰上的铅吸附等温线表明，在低初始铅浓度和pH值低于6的情况下，铅化合物不可能沉淀。脱附实验表明在较高浓度下可逆性不完全，表明部分吸附可能与阳离子交换无关。处理后的粉煤灰与Na〜竞争，对Pb〜（2+）> Sr〜（2+）> Cu〜（2+）> Cd〜（2+）> Zn〜（2+）> Cs〜+具有很高的选择性。 +，尤其是在这些阳离子的低浓度下，对从工业废水中去除铅和锌有效。 Ni〜（2+）和UO_2〜（2+）没有选择性。在柱测试中，将160床体积的NH_4〜+污染的鱼塘水通过处理过的粉煤灰过滤，直到出现NH_4〜+突破为止。

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  • 来源
    《Environmental Science & Technology》 |1995年第7期|p.1748-1753|共6页
  • 作者

    ARIEH SINGER; VADIM BERKGAUT;

  • 作者单位

    Seagram Centre for Soil and Water Science, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel;

  • 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;
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