Wild carob (WC), an abundant and unused lignocellulosic waste in Algeria, has been used as an inexpensive biosorbent for the elimination of methylene blue (MB) from the aqueous solution and as a precursor for the preparation of a new activated carbon by chemical activation with ZnCl₂ (ACWC). The adsorbent materials were characterized by N₂ physisorption, SEM/EDX, FTIR spectroscopy and isoelectric point (pHpzc) measurements. The adsorption performance of WC and ACWC was estimated for MB at different adsorption variables, such as solution pH (2–11), MB initial concentrations (25–200 mg L⁻¹), time (0–1500 min), adsorbent dose (0.25–2.00 g L⁻¹), temperature (10–40 °C) and NaCl concentration (0.0–0.5 M). The obtained results indicate that WC has an acidic surface due to the presence of carboxyl and phenol groups that play an important role in the fixation of cationic dye molecules, obtaining a maximum monolayer adsorption capacity of 84 mg g⁻¹ at natural pH (7.5) and 40 °C. However, this adsorption performance was much higher in the case of the ACWC sample (218 mg g⁻¹). From the equilibrium data, the Freundlich, Langmuir, Sips and Redlich–Peterson isotherms parameters of both samples were calculated and compared. For WC, the experimental data fitted well with Redlich–Peterson, Langmuir and Sips isotherm models, while in the case of ACWC they were best represented by the Redlich–Peterson and Sips isotherms. The adsorption kinetics data were found to follow the pseudo-second-order model for WC and the pseudo-first-order model for ACWC. The thermodynamic parameters suggest that, for both materials, the process was endothermic and spontaneous in the range of temperatures studied.

野生角豆树（WC）是阿尔及利亚大量未使用的木质纤维素废料，已被用作廉价的生物吸附剂，用于从水溶液中消除亚甲基蓝（MB），并用作通过化学活化制备新的活性炭的前体用ZnCl ₂（ACWC）。通过N ₂物理吸附，SEM / EDX，FTIR光谱和等电点（pHpzc）测量来表征吸附材料。在不同的吸附变量（例如溶液pH（2-11），MB初始浓度（25-200 mg L ^-1），时间（0-1500分钟），吸附剂剂量（MB）下，估计了WC和ACWC对MB的吸附性能。0.25–2.00克L ^-1），温度（10–40°C）和NaCl浓度（0.0–0.5 M）。所得结果表明，由于羧基和酚基的存在对阳离子染料分子的固定起着重要作用，因此WC具有酸性表面，在自然pH（7.5）下的最大单层吸附能力为84 mg g ^-1和40°C。但是，对于ACWC样品（218 mg g ^-1），这种吸附性能要高得多。）。根据平衡数据，计算并比较了两个样品的Freundlich，Langmuir，Sips和Redlich-Peterson等温线参数。对于WC，实验数据与Redlich-Peterson，Langmuir和Sips等温线模型非常吻合，而在ACWC的情况下，它们最好由Redlich-Peterson和Sips等温线表示。发现吸附动力学数据遵循WC的伪二级模型和ACWC的伪一级模型。热力学参数表明，对于两种材料，在所研究的温度范围内，该过程都是吸热的且自发的。