Silva Vanderlane Cavalcanti, Araújo Maria Eduarda Barbosa, Rodrigues Alisson Mendes, Vitorino Maria do Bom Conselho, Cartaxo Juliana Melo, Menezes Romualdo Rodrigues, Neves Gelmires Araújo
Graduate Program in Materials Science and Engineering (PPG-CEMat), Federal University of Campina Grande, Av. Aprígio Veloso-882, Bodocongó, Campina Grande 58429-900, PB, Brazil.
Laboratory of Materials Technology (LTM), Department of Materials Engineering, Federal University of Campina Grande, Av. Aprígio Veloso-882, Bodocongó, Campina Grande 58429-900, PB, Brazil.
Materials (Basel). 2021 Sep 30;14(19):5688. doi: 10.3390/ma14195688.
The effect of heat treatment on the adsorptive capacity of a Brazilian palygorskite to remove the dyes crystal violet (CV) and congo red (CR) was investigated. The natural palygorskite was calcined at different temperatures (300, 500 and 700 °C) for 4 h. Changes in the palygorskite structure were evaluated using X-ray diffraction, X-ray fluorescence, thermogravimetric and differential thermal analysis, N adsorption/desorption and Fourier transform infrared spectroscopy. The adsorption efficiency of CV and CR was investigated through the effect of initial concentration, contact time, temperature, pH and dosage of adsorbent. The calcination increased the adsorption capacity of palygorskite, and the greatest adsorption capacity of CV and CR dyes occurred in the sample calcined at 700 °C (Pal-700T). The natural and calcined samples at 300 and 500 °C followed the Freundlich isothermal model, while the Pal-700T followed the Langmuir isothermal model. Adsorption kinetics results were well described by the Elovich model. Pal-700T showed better adsorption performance at basic pH, with removal greater than 98%, for both dyes. Pal-700T proved to be a great candidate for removing cationic and anionic dyes present in water.
研究了热处理对巴西坡缕缟石去除结晶紫（CV）和刚果红（CR）染料吸附能力的影响。将天然坡缕缟石在不同温度（300、500和700℃）下煅烧4小时。使用X射线衍射、X射线荧光、热重和差示热分析、N吸附/脱附和傅里叶变换红外光谱对坡缕缟石结构的变化进行了评估。通过初始浓度、接触时间、温度、pH值和吸附剂用量的影响研究了CV和CR的吸附效率。煅烧提高了坡缕缟石的吸附能力，CV和CR染料的最大吸附容量出现在700℃煅烧的样品（Pal-700T）中。300和500℃的天然和煅烧样品遵循Freundlich等温模型，而Pal-700T遵循Langmuir等温模型。吸附动力学结果可用Elovich模型很好地描述。Pal-700T在碱性pH值下表现出更好的吸附性能，两种染料的去除率均大于98%。Pal-700T被证明是去除水中阳离子和阴离子染料的理想候选材料。
