Abstract In this study, Ca/Fe layered double hydroxide (LDH) with good accessible chemically active sites and with intercalate anions of citrate was prepared, and then 3-aminopropyl triethoxysilane as a silane coupling agent was used to modify the LDH surface. Then, in order to improve the thermal stability and removal efficiency toward bivalent Pb2+, polymer matrix nanocomposites (PMNCs) were fabricated by in situ polymerization of aniline in the presence of modified LDH. The as-synthesized PMNCs were characterized by XRD, FT-IR, TGA, TEM, and FE-SEM. Morphological studies revealed that modified LDH were dispersed homogeneously in polymer matrix without any aggregation. Finally, polyaniline (PANI) and synthesized PMNCs were used as adsorbents to removal of Pb2+ from aqueous solution. The effective parameters affecting metal adsorption including contact time, pH and initial concentration were studied and optimized. Also, the sorption kinetics and isotherm of these sorbents were investigated. The results revealed that the kinetic adsorption could be designated by a pseudo- first order model for the removal of Pb2+. Comparing the results of Langmuir and Freundlich equations showed that NC10 % with more adsorption capacity (qmax) and adsorption constant (Kl) were more suitable adsorbent than NC5 % and PANI for removal Pb2+. The results of R2 values show that the Langmuir model showed the best fit on the lead absorption data by PANI and the synthesized PMNCs.

中文翻译：

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表面改性层状双氢氧化物/聚苯胺纳米复合材料：合成、表征和 Pb2+ 去除

摘要 本研究制备了具有良好化学活性位点和嵌入柠檬酸根阴离子的Ca/Fe层状双氢氧化物（LDH），然后使用3-氨基丙基三乙氧基硅烷作为硅烷偶联剂对LDH表面进行改性。然后，为了提高对二价 Pb2+ 的热稳定性和去除效率，在改性 LDH 存在下通过苯胺的原位聚合制备聚合物基质纳米复合材料（PMNCs）。通过 XRD、FT-IR、TGA、TEM 和 FE-SEM 对合成的 PMNC 进行表征。形态学研究表明，改性 LDH 均匀分散在聚合物基质中，没有任何聚集。最后，聚苯胺 (PANI) 和合成的 PMNCs 用作吸附剂从水溶液中去除 Pb2+。研究并优化了影响金属吸附的有效参数，包括接触时间、pH值和初始浓度。此外，还研究了这些吸附剂的吸附动力学和等温线。结果表明，动力学吸附可以由用于去除 Pb2+ 的伪一级模型指定。比较 Langmuir 和 Freundlich 方程的结果表明，具有更高吸附容量 (qmax) 和吸附常数 (Kl) 的 NC10% 是比 NC5% 和 PANI 更适合去除 Pb2+ 的吸附剂。R2 值的结果表明，Langmuir 模型对 PANI 和合成 PMNC 的铅吸收数据显示出最佳拟合。结果表明，动力学吸附可以由用于去除 Pb2+ 的伪一级模型指定。比较 Langmuir 和 Freundlich 方程的结果表明，具有更高吸附容量 (qmax) 和吸附常数 (Kl) 的 NC10% 是比 NC5% 和 PANI 更适合去除 Pb2+ 的吸附剂。R2 值的结果表明，Langmuir 模型对 PANI 和合成 PMNC 的铅吸收数据显示出最佳拟合。结果表明，动力学吸附可以由用于去除 Pb2+ 的伪一级模型指定。比较 Langmuir 和 Freundlich 方程的结果表明，具有更高吸附容量 (qmax) 和吸附常数 (Kl) 的 NC10% 是比 NC5% 和 PANI 更适合去除 Pb2+ 的吸附剂。R2 值的结果表明，Langmuir 模型对 PANI 和合成 PMNC 的铅吸收数据显示出最佳拟合。