Araújo Maria Eduarda Barbosa, Silva Vanderlane Cavalcanti, Fernandes Jucielle Veras, Cartaxo Juliana Melo, Rodrigues Alisson Mendes, Menezes Romualdo Rodrigues, de Araújo Neves Gelmires
Graduate Program in Materials Science and Engineering, Federal University of Campina Grande, Av. Aprígio Veloso - 882, Campina Grande, Paraíba, 58429-900, Brazil.
Laboratory of Materials Technology (LTM), Academic Unit of Materials Engineering, Federal University of Campina Grande (UFCG), Campina Grande, Paraíba, 58429-900, Brazil.
Environ Sci Pollut Res Int. 2022 Dec;29(60):90446-90462. doi: 10.1007/s11356-022-22083-z. Epub 2022 Jul 23.
Waste rock from bentonite mining (WRBM) was evaluated as potential adsorbents for removing crystal violet (CV) and methylene blue (MB) cationic dyes from contaminated water. The waste samples (AM01, AM02, and AM03) were collected from different locations of the bentonite mine and characterized through X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy, N adsorption/desorption, and cation exchange capacity. The adsorption efficiency of CV and MB dyes was investigated through the effect of initial concentration, contact time, pH, the dosage of adsorbent, and temperature. Sample AM02 showed the largest surface area (69.13 m/g) and the best adsorptive performance for both dyes, with removal more significant than 90%. The adsorption of CV and MB in the waste followed the Langmuir isothermal model. Samples AM01 and AM02 followed the pseudo-second-order (PSO) kinetic model, while AM03 better fitted the Elovich kinetic model. The enthalpy (ΔH), entropy (ΔS), and Gibbs energy (ΔG) were evaluated as adsorption parameters. The process of adsorption of CV and MB dyes in the waste was predominantly endothermic and occurred spontaneously. WRBM samples proved to be a promising candidate for removing cationic dyes present in water.
膨润土矿开采废石（WRBM）被评估为从受污染水中去除结晶紫（CV）和亚甲基蓝（MB）阳离子染料的潜在吸附剂。从膨润土矿的不同位置采集了废石样品（AM01、AM02和AM03），并通过X射线衍射、X射线荧光、傅里叶变换红外光谱、氮吸附/脱附和阳离子交换容量对其进行了表征。通过初始浓度、接触时间、pH值、吸附剂用量和温度的影响，研究了CV和MB染料的吸附效率。样品AM02表现出最大的表面积（69.13 m²/g），对两种染料的吸附性能最佳，去除率均超过90%。废石中CV和MB的吸附遵循Langmuir等温模型。样品AM01和AM02遵循准二级（PSO）动力学模型，而AM03更符合Elovich动力学模型。对焓（ΔH）、熵（ΔS）和吉布斯自由能（ΔG）进行了评估，作为吸附参数。废石中CV和MB染料的吸附过程主要是吸热的，且是自发进行的。WRBM样品被证明是去除水中阳离子染料的有前途的候选材料。
