Abstract

A novel magnetic adsorbent Fe₃O₄/Ni/Ni_xB nanocomposite was synthesised and used for the removal of Pb(II) from water. The nanocomposite effectively absorbs Pb(II), and because the adsorbent is magnetic, it is easily separated from the solution. In addition, carob and grape seeds, which are sustainable materials, are also used for the removal of Pb(II) for the first time in the literature. Characterisation of the adsorbents was performed using scanning electron microscopy combined with energy dispersive X-Ray spectroscopy (SEM−EDX). The effect of pH on the adsorption efficiency of Pb(II) was investigated. The optimum adsorbent doses were determined as 2.0 g/L for the Fe₃O₄/Ni/Ni_xB nanocomposite and 4.0 g/L for the carob and the grape seeds. Three commonly used isotherm models: Langmuir, Freundlich and Dubinin–Radushkevich were applied to the experimental data. The batch adsorption equilibrium data of the three adsorbents fitted well to Langmuir isotherms. The maximum capacities for the adsorption of Pb(II) were determined to be 119.0, 25.3 and 24.4 mg/g for the Fe₃O₄/Ni/Ni_xB nanocomposite, the carob and the grape seeds, respectively. The dimensionless separation factor (R_L) values calculated from the Langmuir isotherm were varied from 0.08 to 1 for three adsorbents. These results demonstrate that the adsorption of Pb(II) on all the adsorbents is favourable. The pseudo-first order, the pseudo-second order and the Weber−Morris intraparticle diffusion kinetic models were used for the identification of the adsorption kinetics of Pb(II) and the correlations of adsorbed Pb(II) with time. The kinetic data is well described with the pseudo-second order kinetic model for all the adsorbents, which indicates that chemisorption plays a dominant role. The adsorption study using a column was successfully applied to real tap water and waste water samples. Also a spiked study (1, 10, 100 mg/L Pb(II)) was also conducted on water samples. As a result, Fe₃O₄/Ni/Ni_xB nanocomposite, the carob and the grape seeds are efficient adsorbents for the removal of Pb(II) from the water samples.

中文翻译：

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使用（Fe 3 O 4 / Ni / Ni x B）磁性纳米复合材料，角豆树（Ceratonia siliqua）或葡萄籽（Vitis vinifera）从水中去除Pb（II）

摘要

合成了新型的磁性吸附剂Fe ₃ O ₄ / Ni / Ni _x B纳米复合材料，并将其用于去除水中的Pb（II）。纳米复合材料有效吸收Pb（II），并且由于吸附剂是磁性的，因此很容易从溶液中分离出来。另外，角豆树和葡萄籽是可持续的材料，在文献中也首次用于去除Pb（II）。吸附剂的表征使用扫描电子显微镜结合能量色散X射线光谱法（SEM-EDX）进行。研究了pH对Pb（II）吸附效率的影响。Fe ₃ O ₄ / Ni / Ni _x的最佳吸附剂剂量确定为2.0 g / LB纳米复合材料，角豆和葡萄籽的含量为4.0 g / L。三种常用的等温线模型：Langmuir，Freundlich和Dubinin–Radushkevich用于实验数据。三种吸附剂的批量吸附平衡数据非常适合Langmuir等温线。Fe ₃ O ₄ / Ni / Ni _x B纳米复合材料，角豆树和葡萄籽的最大吸附能力分别为119.0、25.3和24.4 mg / g 。无量纲分离系数（R _L对于三种吸附剂，根据Langmuir等温线计算的值从0.08变为1。这些结果表明，Pb（II）在所有吸附剂上的吸附都是有利的。拟一阶，拟二阶和韦伯-莫里斯粒子内扩散动力学模型用于鉴定Pb（II）的吸附动力学以及所吸附Pb（II）与时间的相关性。用所有吸附剂的拟二级动力学模型很好地描述了动力学数据，这表明化学吸附起着主导作用。使用色谱柱的吸附研究已成功应用于实际自来水和废水样品。还对水样品进行了加标研究（1、10、100 mg / L Pb（II））。结果，Fe ₃ O ₄ / Ni / Ni_x B纳米复合材料，角豆树和葡萄籽是从水样中去除Pb（II）的有效吸附剂。