Background

The selective removal of Pb(II) ions is meaningful not only to the waste water treatment but also the lead recycling.

Methods

In this study, two kinds of thiazole Schiff base modified mesoporous silica, SBA-NS, SBA-ENS, were prepared by modifying SBA-15 with aminopropyl and [2-aminoethylamino]-propyl groups, respectively, and then followed by Schiff condensation with 2-aldehyde-thiazole. The effects of pH, time, ions concentration, and temperature on the Pb(II) adsorption performance were investigated.

Significant Findings

The kinetics analysis and adsorption isotherms revealed that the overall Pb(II) adsorption process by the two adsorbents was more consistent with the pseudo-second-order kinetic model and Langmuir isotherm model. The thermodynamic parameters showed spontaneous and exothermic Pb(II) adsorption nature onto SBA-NS and SBA-ENS. Compared with amino modified silica precursors, SBA-NS and SBA-ENS exhibited improved adsorption selectivity for Pb(II) in binary metal ion systems with co-existing cations. Besides, the adsorption behavior is not affected by the ionic strength, and the adsorbents can be easily reused without significant loss in of Pb(II) removal efficiency. The density functional theory method demonstrated that the imine N atoms on the two adsorbents played a dominant role during the Pb(II) sorption process.

中文翻译：

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β-噻唑席夫碱改性SBA-15介孔二氧化硅选择性吸附Pb(II)的合成

背景

选择性去除 Pb(II) 离子不仅对废水处理有意义，而且对铅回收也有意义。

方法

本研究通过分别用氨基丙基和[2-氨基乙基氨基]-丙基对SBA-15进行改性，然后与2-醛-噻唑。研究了pH、时间、离子浓度和温度对Pb(II)吸附性能的影响。

重要发现

动力学分析和吸附等温线表明，两种吸附剂对 Pb(II) 的整体吸附过程更符合拟二级动力学模型和 Langmuir 等温线模型。热力学参数表明 Pb(II) 吸附到 SBA-NS 和 SBA-ENS 上的自发和放热性质。与氨基改性二氧化硅前体相比，SBA-NS 和 SBA-ENS 在共存阳离子的二元金属离子系统中对 Pb(II) 表现出更高的吸附选择性。此外，吸附行为不受离子强度的影响，并且吸附剂可以很容易地重复使用，而不会显着降低 Pb(II) 的去除效率。密度泛函理论方法表明，两种吸附剂上的亚胺 N 原子在 Pb(II) 吸附过程中起主导作用。