Pine sawdust, to which sulfuric acid was applied (APSD), was utilized as an inexpensive adsorbent to perform the batch adsorptive removal from a synthetic dye solution of Maxilon Red GRL (MR GRL). The activated adsorbent was characterized by the points of zero charge, FTIR, N 2 adsorption-desorption, SEM, and SEM-EDX analyses. According to the removal results, the highest efficiency of the dye adsorption was reached at 180min. MR GRL removal of 99.35% was achieved using APSD under the optimum conditions (pH=5.7–6.0, temperature=298 K, dye concentration= 250mg/L, and adsorbent dosage=8 g/L). The Langmuir isotherm represents the best explanation model for the experimental data, which has the highest adsorption capacity of 312.5mg/g at 318 K. The compatibility of adsorption with the Langmuir isotherm showed that adsorption was reversible and physical. The other results obtained confirmed this situation. The kinetic research demonstrated that the sorption process was realized in accordance with the pseudo-second-order kinetic model. The thermodynamic parameters revealed that the MR GRL adsorption occurred spontaneously and was exothermic. The findings of the present research confirm that acid-activated pine sawdust may be utilized to remove MR GRL dye from aqueous solutions as a low-cost and efficient adsorbent.

中文翻译：

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通过使用活性松木屑吸附 Maxilon Red GRL 染料从水溶液中高效去除

使用硫酸 (APSD) 的松木屑作为廉价的吸附剂，从 Maxilon Red GRL (MR GRL) 的合成染料溶液中进行批量吸附去除。活化的吸附剂的特征在于零电荷点、FTIR、N 2 吸附-解吸、SEM和SEM-EDX分析。根据去除结果，染料吸附的最高效率在 180min 时达到。在最佳条件下（pH=5.7-6.0，温度=298K，染料浓度=250mg/L，吸附剂用量=8g/L），使用APSD实现了99.35%的MR GRL去除率。Langmuir 等温线代表了实验数据的最佳解释模型，其在 318 K 下的吸附容量最高，为 312.5mg/g。吸附与 Langmuir 等温线的相容性表明吸附是可逆的和物理的。获得的其他结果证实了这种情况。动力学研究表明吸附过程符合准二级动力学模型。热力学参数表明 MR GRL 吸附是自发发生的并且是放热的。本研究的结果证实，酸活化的松木屑可用于从水溶液中去除 MR GRL 染料，作为一种低成本且高效的吸附剂。