Stawiński Wojciech, Freitas Olga, Chmielarz Lucjan, Węgrzyn Agnieszka, Komędera Kamila, Błachowski Artur, Figueiredo Sónia
REQUIMTE, LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal.
Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland.
Chemosphere. 2016 Jun;153:115-29. doi: 10.1016/j.chemosphere.2016.03.004. Epub 2016 Mar 22.
The influence of different acid treatments over vermiculite was evaluated. Equilibrium, kinetic and column studies have been conducted. The results showed that vermiculite first treated with nitric acid and then with citric acid has higher adsorption capacity, presenting maximum adsorption capacities in column experiments: for Astrazon Red (AR), 100.8 ± 0.8 mg g(-1) and 54 ± 1 mg g(-1) for modified and raw material, respectively; for Methylene Blue (MB) 150 ± 4 mg g(-1) and 55 ± 2 mg g(-1) for modified and raw material, respectively. Materials characterization by X-ray diffraction, UV-vis-diffuse reflectance spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, X-ray fluorescence, N2 adsorption and CEC determination, has been performed. The results suggest the existence of exchange of interlayer cations, leaching of metals from vermiculite's sheets and formation of an amorphous phase in the material. Adsorption follows pseudo 2(nd) order model kinetics for both dyestuffs and equilibrium occurs accordingly to Langmuir's model for AR and Freundlich's model for MB. In column systems Yan's model is the best fit. The enhanced properties of acid treated vermiculite offer new perspectives for the use of this adsorbent in wastewater treatment.
评估了不同酸处理对蛭石的影响。进行了平衡、动力学和柱实验研究。结果表明，先经硝酸处理再用柠檬酸处理的蛭石具有更高的吸附容量，在柱实验中呈现出最大吸附容量：对于阿斯特拉宗红（AR），改性蛭石和原料蛭石的最大吸附容量分别为100.8±0.8 mg g(-1)和54±1 mg g(-1)；对于亚甲基蓝（MB），改性蛭石和原料蛭石的最大吸附容量分别为150±4 mg g(-1)和55±2 mg g(-1)。通过X射线衍射、紫外-可见-漫反射光谱、漫反射红外傅里叶变换光谱、X射线荧光、N2吸附和阳离子交换容量测定对材料进行了表征。结果表明材料中存在层间阳离子交换、蛭石片层中金属的浸出以及非晶相的形成。两种染料的吸附均遵循准二级动力学模型，AR的吸附平衡符合朗缪尔模型，MB的吸附平衡符合弗伦德利希模型。在柱系统中，Yan模型拟合效果最佳。酸处理蛭石性能的增强为该吸附剂在废水处理中的应用提供了新的前景。
