This study investigates the potential use of activated carbon, prepared from pomegranate peels, as an adsorbent activated using H3PO4 and its ability to remove crystal violet from an aqueous solution. The adsorbent was characterized by the Brunauer–Emmett–Teller method (specific surface area: 51.0674 m2 g−1) and point of zero charge (pHPZC = 5.2). However, some examined factors were found to have significant impacts on the adsorption capacity of activated carbon derived from pomegranate peels such as the initial dye concentration (5–15 mg L−1), solution pH (2–14), adsorbent dose (1–8 g L−1), agitation speed (100–700 r/min), and temperature (298–338 K). The best adsorption capacity was found at pH 11 with an adsorbent dose of 1 g L−1, an agitation speed at 400 r/min, and a contact time of 45 min. The adsorption mechanism of crystal violet onto activated carbon derived from pomegranate peels was studied using the pseudo-first-order, pseudo-second-order, Elovich, and Webber–Morris diffusion models. The adsorption kinetics were found to rather follow a pseudo-second order kinetic model with a determination coefficient (R2) of 0.999. The equilibrium adsorption data for crystal violet adsorbed onto activated carbon derived from pomegranate peels were analyzed by the Langmuir, Freundlich, Elovich, and Temkin models. The results indicate that the Langmuir model provides the best correlation with qmax capacities of 23.26 and 76.92 mg g−1 at 27°C and 32°C, respectively. The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters like the free energy, enthalpy, and entropy to predict the nature of adsorption process. The negative values ΔG0 (−5.221 to −1.571 kJ mol−1) and ΔH0 (−86.141 kJ mol−1) indicate that the overall adsorption is spontaneous and exothermic with a physisorption process. The adsorbent derived from pomegranate peels was found to be very effective and suitable for the removal of reactive dyes from aqueous solutions, due to its availability, low-cost preparation, and good adsorption capacity.

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石榴皮活性炭吸附结晶紫的传质过程：动力学和热力学研究

本研究调查了从石榴皮制备的活性炭作为使用 H3PO4 活化的吸附剂的潜在用途及其从水溶液中去除结晶紫的能力。吸附剂通过 Brunauer-Emmett-Teller 方法（比表面积：51.0674 m2 g-1）和零电荷点（pHPZC = 5.2）表征。然而，一些研究因素被发现对源自石榴皮的活性炭的吸附能力有显着影响，例如初始染料浓度（5-15 mg L-1）、溶液 pH 值（2-14）、吸附剂剂量（1 –8 g L-1)、搅拌速度 (100–700 r/min) 和温度 (298–338 K)。在 pH 11、吸附剂量为 1 g L-1、搅拌速度为 400 r/min 和接触时间为 45 min 时发现最佳吸附能力。使用准一级、准二级、Elovich 和 Webber-Morris 扩散模型研究结晶紫在石榴皮活性炭上的吸附机制。发现吸附动力学更符合准二级动力学模型，其决定系数 (R2) 为 0.999。通过 Langmuir、Freundlich、Elovich 和 Temkin 模型分析了吸附在源自石榴皮的活性炭上的结晶紫的平衡吸附数据。结果表明，Langmuir 模型在 27°C 和 32°C 下分别提供了与 23.26 和 76.92 mg g-1 的 qmax 容量的最佳相关性。不同温度下的吸附等温线已用于测定热力学参数，如自由能、焓、和熵来预测吸附过程的性质。负值 ΔG0 (-5.221 to -1.571 kJ mol-1) 和 ΔH0 (-86.141 kJ mol-1) 表明整体吸附是自发和放热的物理吸附过程。来自石榴皮的吸附剂被发现非常有效，适用于从水溶液中去除活性染料，因为它的可用性、低成本制备和良好的吸附能力。