Abstract

In the present work, continuous fixed-bed column and batch studies were undertaken to investigate the efficiency of iron-based metal–organic framework (Fe-BTC) for the removal of methyl orange as a model contaminant from aqueous solutions. The batch experiments were carried out by varying operational parameters such as adsorbent dosage, pH, temperature, and initial contaminant concentration. The results showed that Fe-BTC had a high removal efficiency under a wide pH range. The equilibrium data were best fitted by the Langmuir model with a maximum adsorption capacity of 100.3 mg g⁻¹ at 298 K. In order to assess the industrial feasibility of Fe-BTC, fixed-bed column studies were conducted to obtain breakthrough curves, breakthrough and saturation times, and maximum uptakes at different bed heights. The breakthrough time was 20.0 and 46.2 h at 0.75 and 1.5 cm bed depths, respectively. The bed removal efficiency was 35.2 and 46.7% at 0.75 and 1.5 cm bed depth, respectively. The bed maximum adsorption capacity was 20.2 and 21.6 mg/g at 0.75 and 1.5 cm bed depths, respectively. Moreover, the application of empirical breakthrough curve models showed good agreement with the modified dose response model (R²> 0.99). Also, the analytical solution of the advection–dispersion–adsorption mass transfer equation showed an excellent fit to the experimental breakthrough data (R²> 0.99). Further, the analytical model was utilized to predict the length of the mass transfer zone as a function of the bed depth and to construct a 3D surface plot that can be utilized to predict the breakthrough at different bed depths.

Graphic Abstract

中文翻译：

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铁基金属有机框架去除甲基橙的吸附潜力：分批和固定床色谱柱研究

摘要

在目前的工作中，进行了连续固定床色谱柱和批量研究，以研究铁基金属有机框架（Fe-BTC）去除水溶液中的模型污染物甲基橙的效率。通过改变操作参数如吸附剂剂量，pH，温度和初始污染物浓度进行批量实验。结果表明，Fe-BTC在宽pH范围内具有较高的去除效率。平衡数据最好由Langmuir模型拟合，最大吸附容量为100.3 mg g ^-1为了评估Fe-BTC的工业可行性，进行了固定床柱研究，以获取突破曲线，突破和饱和时间以及在不同床高下的最大吸收量。在0.75和1.5 cm的床深处，穿透时间分别为20.0和46.2 h。在0.75和1.5 cm的床深度下，床的去除效率分别为35.2和46.7％。在0.75和1.5cm床深度下，床的最大吸附容量分别为20.2和21.6mg / g。此外，经验突破曲线模型的应用与修正的剂量反应模型显示出良好的一致性（R ² > 0.99）。同样，对流-扩散-吸附传质方程的解析解也非常适合实验突破数据（R² > 0.99）。此外，利用分析模型来预测传质区的长度与床层深度的函数关系，并构建可用于预测在不同床层深度处的穿透的3D表面图。

图形摘要