Abstract In this study, hazelnut shell and walnut shell which are the agricultural wastes existent abundantly in many countries were pyrolyzed at different temperatures in the temperature range of 400–700 °C in order to optimize the physicochemical properties of biochars. The biochars with large surface area were used to removal of lead (Pb2+) ions, one of the most important heavy metal pollutant, from aqueous solutions. The characterization of raw biomass and also biochars produced by pyrolysis were performed using FT-IR, BET, SEM, partial and elemental analysis techniques. In order to determine the adsorption characteristics of both biochars, batch adsorption experiments were carried out under different experimental conditions. The optimum conditions were determined by investigating the effect of adsorption parameters (initial heavy metal concentration, temperature, adsorbent amount, pH, contact time and mixing speed) for efficient removal of Pb2+ ions from aqueous solution. The experimental results were investigated in terms of Langmuir, Freundlich and Temkin isotherm models. Together with the calculated thermodynamic parameters, the adsorption mechanism was tried to be explained. In order to determine the kinetic model of the adsorption process, the experimental data were applied to pseudo first-order, pseudo second-order and intra-particle diffusion model, and the model constants were investigated.

中文翻译：

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从废弃木质纤维素生物质中生产和表征碳基吸附剂：它们在去除重金属方面的有效性

摘要 在本研究中，为了优化生物炭的理化性质，在 400-700 °C 的温度范围内对许多国家大量存在的农业废弃物榛子壳和核桃壳进行了热解。具有大表面积的生物炭用于去除水溶液中最重要的重金属污染物之一的铅 (Pb2+) 离子。使用 FT-IR、BET、SEM、部分和元素分析技术对原始生物质和热解产生的生物炭进行表征。为了确定两种生物炭的吸附特性，在不同的实验条件下进行了批量吸附实验。通过研究吸附参数（初始重金属浓度、温度、吸附量、pH、接触时间和混合速度）对有效去除水溶液中Pb2+离子的影响，确定了最佳条件。根据 Langmuir、Freundlich 和 Temkin 等温线模型研究了实验结果。结合计算的热力学参数，试图解释吸附机制。为了确定吸附过程的动力学模型，将实验数据应用于拟一级、拟二级和颗粒内扩散模型，并研究了模型常数。根据 Langmuir、Freundlich 和 Temkin 等温线模型研究了实验结果。结合计算的热力学参数，试图解释吸附机制。为了确定吸附过程的动力学模型，将实验数据应用于拟一级、拟二级和颗粒内扩散模型，并研究了模型常数。根据 Langmuir、Freundlich 和 Temkin 等温线模型研究了实验结果。结合计算的热力学参数，试图解释吸附机制。为了确定吸附过程的动力学模型，将实验数据应用于拟一级、拟二级和颗粒内扩散模型，并研究了模型常数。