Abstract Lemongrass leaf activated carbon (LLAC) was prepared using physicochemical process for MB dye removal from aqueous systems. The adsorbent was characterized by SEM and FTIR techniques respectively. Batch adsorption studies were investigated using four operational parameters: initial dye concentration (25 mg/L-500 mg/L), contact time (0 hr to 24 hr), temperatures (30°C - 60°C) and pH (2-12). The surface chemistry analysis shows that upon the interaction of MB dye with the adsorbent, the bands are significantly altered after MB dye adsorption e.g, band at 2125 cm−1, 1650.09–1514 cm−1, 1386.98–1 273.05 cm−1, 1088.60 cm−1, etc disappeared upon the interaction of the LLAC with the MB dye. Whereas, the surface morphology shows that the activation process with the NaOH has contributed to the widening and formation of pores on the LLAC surface which is required for efficient MB dye uptake. MB dye adsorption is strongly dependent on initial dye concentrations while the percentage MB dye removal by LLAC increases with increasing solution pH until it reached the optimum at pH 12 with maximum percentage removal of 64.36 %. The equilibrium data were fitted into eight different isotherms. Koble-Corrigan model best fitted the adsorption data with a maximum sorption capacity of 342.9 mg/g and R2 = 0.999. The pseudo-first-order kinetic model best explained MB dye adsorption onto LLAC. Thermodynamic parameters (such as ∆G0, ∆H0, and ∆S0) were also determined. The sorption process for MB dye removal was endothermic; the reaction mechanism follows the physisorption process.

中文翻译：

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柠檬草叶对亚甲蓝染料去除的吸附潜力

摘要 采用物理化学方法制备柠檬草叶活性炭 (LLAC)，用于去除水性体系中的 MB 染料。吸附剂分别通过SEM和FTIR技术表征。使用四个操作参数研究批量吸附研究：初始染料浓度 (25 mg/L-500 mg/L)、接触时间（0 小时至 24 小时）、温度 (30°C - 60°C) 和 pH (2- 12)。表面化学分析表明，MB 染料与吸附剂相互作用后，MB 染料吸附后谱带发生显着变化，例如，谱带在 2125 cm-1、1650.09-1514 cm-1、1386.98-1 273.05 cm-1、1088.60 cm-1 等在 LLAC 与 MB 染料相互作用后消失。然而，表面形态表明，NaOH 的活化过程有助于 LLAC 表面上孔的扩大和形成，这是有效吸收 MB 染料所必需的。MB 染料吸附强烈依赖于初始染料浓度，而 LLAC 去除 MB 染料的百分比随着溶液 pH 值的增加而增加，直到达到最佳 pH 值 12，最大去除百分比为 64.36%。平衡数据被拟合成八个不同的等温线。Koble-Corrigan 模型最适合吸附数据，最大吸附容量为 342.9 mg/g，R2 = 0.999。准一级动力学模型最好地解释了 MB 染料在 LLAC 上的吸附。还确定了热力学参数（例如 ∆G0、∆H0 和 ∆S0）。MB 染料去除的吸附过程是吸热的；