In this work, the adsorptive removal of methylene blue and methyl orange by UiO-66-NO₂ nanoparticles was studied. The influence of pH on the adsorption capacity was assessed. The kinetics of the adsorption process were investigated and compared with pseudo-first-order, pseudo-second-order, Elovich, and intraparticle models. The kinetics of the adsorption fits moderately with the pseudo-first-order, but perfectly fits with pseudo-second-order models, and has a very good fit with the Elovich and intraparticle models. The adsorption isotherms were measured and compared with the Langmuir and Freundlich models. The adsorption capacity of methyl orange (MO) on UiO-66-NO₂ nanoparticles (142.9 mg/g) was over three times higher than that of methylene blue (MB) on the nanoparticles (41.7 mg/g). The discrepancy between these capacities was attributed to the presence of the -NO₂ functional group, which caused a strong negative mesomeric effect in the metal-organic framework structure.

中文翻译：

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UiO-66-NO2纳米颗粒对亚甲基蓝和甲基橙的吸附研究

在这项工作中，研究了UiO-66-NO ₂纳米颗粒对亚甲蓝和甲基橙的吸附去除。评估了 pH 值对吸附容量的影响。研究了吸附过程的动力学，并与伪一级、伪二级、Elovich 和粒子内模型进行了比较。吸附动力学与拟一级模型适度拟合，但与拟二级模型完全吻合，与 Elovich 和粒子内模型有很好的拟合。测量吸附等温线并与 Langmuir 和 Freundlich 模型进行比较。甲基橙(MO)对UiO-66-NO ₂的吸附能力纳米颗粒 (142.9 mg/g) 比纳米颗粒上的亚甲蓝 (MB) (41.7 mg/g) 高出三倍以上。这些容量之间的差异归因于-NO ₂官能团的存在，其在金属-有机骨架结构中引起强烈的负介晶效应。