Abstract

In this study, the removal of methyl violet by natural clays was investigated. Rhassoul-clay, A-clay, E-clay, R-clay, and Y-clay were sampled from different sites in Morocco. Their surface properties were investigated by XRD, XRF, and SEM, as well as zeta potential measurements. Furthermore, the hexamine cobalt and BET methods were employed to estimate the CEC and SSA, respectively. In addition, parameters such as pH, time, temperature, and initial concentration were investigated to evaluate their effect on adsorption. Adsorption kinetics were thoroughly investigated by several mathematic models. The pseudo-second-order model and intraparticle diffusion were found to be the most suitable to describe adsorption. The increase in pH was found to promote the adsorption capacity of methyl violet, except in the case of Rhassoul-clay, which exhibited a non-significant pH dependence. Furthermore, the Langmuir, Freundlich, Harkin–Jura, Halsey, and Temkin models were employed to investigate the adsorption mechanism. The adsorption of methyl violet obeyed the Langmuir model at high concentration, and Temkin model at low concentration. The maximal monolayer adsorption capacity decreased in the order of Rhassoul-clay > A-clay > E-clay > R-clay > Y-clay. Thermodynamic studies indicated that the increase in temperature improved the adsorption capacity of basic dye on A-clay and Rhassoul-clay and that adsorption processes were endothermic.

摘要

在这项研究中，研究了天然粘土对甲基紫的去除作用。Rhassoul 粘土、A 粘土、E 粘土、R 粘土和 Y 粘土是从摩洛哥的不同地点取样的。通过 XRD、XRF 和 SEM 以及 zeta 电位测量来研究它们的表面性质。此外，六胺钴和 BET 方法分别用于估计 CEC 和 SSA。此外，还研究了 pH、时间、温度和初始浓度等参数，以评估它们对吸附的影响。通过几个数学模型彻底研究了吸附动力学。发现伪二级模型和颗粒内扩散最适合描述吸附。发现 pH 值的增加会促进甲基紫的吸附能力，但在 Rhassoul-clay 的情况下，表现出不显着的 pH 依赖性。此外，采用 Langmuir、Freundlich、Harkin-Jura、Halsey 和 Temkin 模型来研究吸附机制。甲基紫的吸附在高浓度时服从Langmuir模型，在低浓度时服从Temkin模型。最大单层吸附量按Rhassoul-clay > A-clay > E-clay > R-clay > Y-clay的顺序降低。热力学研究表明，温度的升高提高了碱性染料在 A 粘土和 Rhassoul 粘土上的吸附能力，并且吸附过程是吸热的。甲基紫的吸附在高浓度时服从Langmuir模型，在低浓度时服从Temkin模型。最大单层吸附量按Rhassoul-clay > A-clay > E-clay > R-clay > Y-clay的顺序降低。热力学研究表明，温度的升高提高了碱性染料在 A 粘土和 Rhassoul 粘土上的吸附能力，并且吸附过程是吸热的。甲基紫的吸附在高浓度时服从Langmuir模型，在低浓度时服从Temkin模型。最大单层吸附量按Rhassoul-clay > A-clay > E-clay > R-clay > Y-clay的顺序降低。热力学研究表明，温度的升高提高了碱性染料在 A 粘土和 Rhassoul 粘土上的吸附能力，并且吸附过程是吸热的。