Since 2,4,6-trimercapto-s-triazine (TMT) possesses advantages of multiple adsorption sites and strong binding ability with heavy metals, in this study, layered double hydroxides modified by TMT are prepared (LDHs-TMT) for removing Cu(II)/Pb(II) from contaminated soil. The characterization of structure indicated TMT is intercalated between LDHs layers, and affects growth of crystal structure. The data of kinetics fits pseudo-second-order and intraparticle diffusion models. The isotherms is conformed to Langmuir model, and the adsorption capacity reaches 102.8 mg/g for Cu(II) and 105.8 mg/g for Pb(II). For adsorption mechanism, when concentration of Cu(II)/Pb(II) is low, Cu(II)/Pb(II) is preferentially immobilized by interlayered TMT molecule. As concentration increases, since adsorption sites on TMT are fully occupied, Cu(II)/Pb(II) grab the hydroxy of LDHs and form hydroxide precipitation. The effects of pH, coexistence ions, column leaching and leaching experiments are conducted. The results indicate LDHs-TMT have high adsorption stability and possesses appreciable interception for heavy metal migration.

中文翻译：

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2,4,6-三巯基均三嗪改性镁铝层状双氢氧化物可有效去除土壤中的重金属


由于2,4,6-三巯基均三嗪（TMT）具有多吸附位点和与重金属结合能力强的优点，本研究制备了TMT修饰的层状双氢氧化物（LDHs-TMT）用于去除Cu（ II)/来自受污染土壤的 Pb(II)。结构表征表明TMT插层在LDHs层之间，影响晶体结构的生长。动力学数据符合伪二阶和颗粒内扩散模型。等温线符合Langmuir模型，对Cu(II)的吸附容量达到102.8 mg/g，对Pb(II)的吸附容量达到105.8 mg/g。对于吸附机制，当Cu(II)/Pb(II)浓度较低时，Cu(II)/Pb(II)优先被层间TMT分子固定。随着浓度的增加，由于TMT上的吸附位点被完全占据，Cu(II)/Pb(II)会抓住LDHs的羟基并形成氢氧化物沉淀。进行了pH、共存离子、柱浸和浸出实验的影响。结果表明LDHs-TMT具有较高的吸附稳定性，并且对重金属迁移具有明显的拦截作用。