Department of Chemical Engineering, Iran University of Science and Technology, Tehran, Iran.
Sci Rep. 2023 Sep 20;13(1):15608. doi: 10.1038/s41598-023-42918-0.
This study aimed to investigate the adsorption mechanism of Pb in wastewater using activated carbon derived from inexpensive materials, specifically avocado, bitter orange, and walnut leaves, through a single-step chemical activation process. The activated carbon was prepared using sulfuric acid as an activator, with a particle size of 1 mm. The pyrolysis reactor (slow-pyrolysis) operated at 600 °C for 90 min with a nitrogen flow rate of 5 L/min. Batch experiments were conducted under various conditions to determine the optimal dosage (1.5 g/L), equilibrium contact time (180 min), and pH (6.5). The study focused on employing cost-effective and highly efficient adsorbents, namely biochar produced from tree leaves, for the adsorption process. The results indicated that the pseudo-second-order kinetic model accurately described the adsorption process, while the Freundlich isotherm model best fit the experimental data. These findings suggest that tree leaves can serve as cost-effective and efficient adsorbents for a wide range of applications. Furthermore, multiple adsorption factors were evaluated in batch mode, including contact duration, pH, adsorbent dosage, concentration of the Pb solution, and temperature. The maximum adsorption capacities for the activated carbon derived from avocado, bitter orange, and walnut leaves were found to be 60.46, 59.42, and 58.48 mg/g, respectively. Thus, this study highlights the effectiveness and economic feasibility of using pyrolysis-derived activated carbon from low-cost materials for the removal of Pb from wastewater.
本研究旨在通过一步化学活化法，利用鳄梨、苦橙和核桃叶等廉价材料制备的活性炭，研究其对废水中 Pb 的吸附机制。采用硫酸作为活化剂，将活性炭的粒径制备为 1mm。在 600°C 下以 5L/min 的氮气流量通过热解反应器（慢速热解）运行 90min。在不同条件下进行批量实验，以确定最佳剂量（1.5g/L）、平衡接触时间（180min）和 pH 值（6.5）。本研究重点采用经济高效的吸附剂，即树叶生物炭进行吸附过程。结果表明，准二级动力学模型准确描述了吸附过程，而 Freundlich 等温线模型则最佳拟合了实验数据。这些结果表明，树叶可以作为一种高效、经济的吸附剂，应用于广泛的领域。此外，在批量模式下评估了多种吸附因素，包括接触时间、pH 值、吸附剂剂量、Pb 溶液浓度和温度。从鳄梨、苦橙和核桃叶中提取的活性炭的最大吸附容量分别为 60.46、59.42 和 58.48mg/g。因此，本研究强调了使用低成本材料热解衍生的活性炭去除废水中 Pb 的有效性和经济可行性。
