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Chemical modification of coal fly ash for the retention of low levels of lead from aqueous solutions

机译：粉煤灰的化学改性，可保留水溶液中低含量的铅

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摘要

A chemically-modified coal fly ash was prepared by immobilization of mercaptoethanol or mercaptoace-tic acid to develop a low-cost and effective solid phase retention system for low levels of lead from aqueous solutions. The organically-functionalized coal fly ash-based retention system experienced high thermal and chemical stability. The batch extraction procedure was used to explore the equilibrium, kinetic and thermodynamic characteristics of the retention of lead by the functionalized sorbent at various temperatures. Several equilibrium models were compared to evaluate the lead retention process with a better fitting using the Langmuir model. Kinetic studies were also carried out to fit the experimental data. The pseudo-second-order and Elovich models provided the highest coefficients of determination, but the function Z and the McLintock method confirmed better applicability of the Elovichian model. Lead was retained up to about 45 μg g~(-1) at pH 5.0, with similar results for the two ligands, mercaptoethanol and mercaptoacetic acid. Thermodynamic studies provided negative free energy changes, indicating spontaneity of the retention process. Positive values for both enthalpy and entropy indicated an endo-thermic retention with high affinity lead-sorbent.
机译：通过固定巯基乙醇或巯基乙酸制备化学改性的粉煤灰，以开发出一种低成本，有效的固相保留系统，用于从水溶液中分离出少量铅。有机功能化的粉煤灰基固位系统具有很高的热稳定性和化学稳定性。分批萃取程序用于探索在各种温度下官能化吸附剂对铅的保留的平衡，动力学和热力学特性。使用Langmuir模型比较了几个平衡模型，以更好地拟合来评估铅保留过程。还进行了动力学研究，以适应实验数据。伪二阶模型和Elovich模型提供了最高的确定系数，但是函数Z和McLintock方法证实了Elovichian模型的更好适用性。铅在pH 5.0时保留至约45μgg（-1），对于两个配体巯基乙醇和巯基乙酸具有相似的结果。热力学研究提供了负的自由能变化，表明保留过程的自发性。焓和熵都为正值表示具有高亲和力铅吸附剂的内热保留。

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  • 来源
    《Fuel》 |2012年第2012期|p.135-144|共10页
  • 作者

    M.I. Munoz; A.J. Aller;

  • 作者单位

    Department of Applied Chemistry and Physics, Area of Analytical Chemistry, Faculty of Biological and Environmental Sciences, University of Leon, E-24071 Leon, Spain;

    Department of Applied Chemistry and Physics, Area of Analytical Chemistry, Faculty of Biological and Environmental Sciences, University of Leon, E-24071 Leon, Spain;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    chemical modification; coal fly ash; lead; retention equilibrium; kinetic studies;

    机译：化学修饰粉煤灰铅;保留平衡动力学研究;

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