Abstract The kinetic and equilibrium parameters of the quantitative adsorption for Indigo Carmine (IC) removed by commercial activated carbon (AC) were studied by UV–visible absorption spectroscopy. AC with a high specific surface area (1250.320 m2/g) was characterized by the Brunauer–Emmett–Teller (BET) method and point of zero charge (pzc). The effect of the initial dye concentration (10–60 mg/L), contact time (0–90 min), pH (1−12), agitation speed (0–600 rpm), adsorbent dose (1–10 g/L) and temperature (298–323 K) were determined to find the optimal conditions for a maximum adsorption. The adsorption mechanism of Indigo Carmine onto AC was studied using the first pseudo order, second pseudo order and Elovich kinetics models. The adsorptions kinetic were found to follow a pseudo second order kinetic model with a determination coefficient (R2) of 0.999. To get an idea on the adsorption mechanism, we applied the Webber-Morris diffusion model. The equilibrium adsorption data for Indigo Carmine on AC were analyzed by the Langmuir, Freundlich, Elovich, Dubinin and Temkin models. The results indicate that the Langmuir model provides the best correlation at 25 °C (qmax = 79.49 mg/g) and Dubinin at 40 °C (qmax = 298.34 mg/g). The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters such as free energy (ΔG° = −0.071 to −1.050 kJ/mol), enthalpy (ΔH° = 28.11 kJ/mol), entropy (ΔS° = 0.093 kJ/mol·K) and activation energy (Ea) of 51.06 kJ/mol of adsorption. The negative ΔG° and positive ΔH° values indicate that the overall adsorption is spontaneous and endothermic.

中文翻译：

---

活性炭吸附水溶液中靛蓝胭脂红的热力学和动力学研究

摘要 通过紫外-可见吸收光谱研究了商业活性炭（AC）去除靛蓝胭脂红（IC）的定量吸附动力学和平衡参数。具有高比表面积 (1250.320 m2/g) 的 AC 由 Brunauer-Emmett-Teller (BET) 方法和零电荷点 (pzc) 表征。初始染料浓度 (10–60 mg/L)、接触时间 (0–90 min)、pH (1–12)、搅拌速度 (0–600 rpm)、吸附剂剂量 (1–10 g/L) 的影响) 和温度 (298–323 K) 被确定以找到最大吸附的最佳条件。使用一级伪级、二级伪级和 Elovich 动力学模型研究了靛蓝胭脂红在活性炭上的吸附机制。发现吸附动力学遵循准二级动力学模型，其决定系数 (R2) 为 0.999。为了了解吸附机制，我们应用了 Webber-Morris 扩散模型。靛蓝胭脂红在活性炭上的平衡吸附数据通过 Langmuir、Freundlich、Elovich、Dubinin 和 Temkin 模型进行分析。结果表明朗缪尔模型在 25 °C (qmax = 79.49 mg/g) 和 Dubinin 在 40 °C (qmax = 298.34 mg/g) 下提供了最佳相关性。不同温度下的吸附等温线已用于测定热力学参数，例如自由能 (ΔG° = -0.071 至 -1.050 kJ/mol)、焓 (ΔH° = 28.11 kJ/mol)、熵 (ΔS° = 0.093 kJ/mol·K)和吸附活化能(Ea)为51.06 kJ/mol。