Department of Chemical Engineering, Federal University of São João del-Rei, MG 443 (Kilometer 7), Ouro Branco, Minas Gerais, 36420-000, Brazil.
Environ Sci Pollut Res Int. 2019 Oct;26(28):28622-28632. doi: 10.1007/s11356-019-04641-0. Epub 2019 Mar 6.
The Rhodamine B adsorption was realized in batch using calcined bentonite clay. The effects of Rhodamine B initial concentration, pH, and temperature were evaluated and the conditions where the adsorption was favored were in 500 mg L, pH 3, and 35 °C. The equilibrium isotherms studied were from Langmuir and Freundlich. The coefficients of determination (R > 0.99) were found to confirm the best fitted to Langmuir isotherm, with a monolayer adsorption capacity (q) of 552.49 mg g. The kinetic data agreed well with the pseudo-second order model (R > 0.99). The in natura and calcined clay were characterized by the techniques of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N physisorption (BET), and scanning electron microscopy (SEM). Thermodynamic parameters including Gibbs free energy (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were calculated to estimate the nature of Rhodamine B adsorption in clay. The results suggested that the adsorption was endothermic and spontaneous, with the enthalpy adsorption increasing with the increase of temperature. Therefore, calcined bentonite can be used as an efficient adsorbent for discoloration of large volume of residual water, presenting low-cost and high adsorptive capacity.
使用煅烧膨润土粘土在批量中实现了罗丹明 B 的吸附。评估了罗丹明 B 初始浓度、pH 值和温度的影响，并确定了吸附有利的条件为 500mg/L、pH 值 3 和 35°C。研究的平衡等温线为朗缪尔和弗伦德利希。发现决定系数（R>0.99）证实最适合朗缪尔等温线，单层吸附容量（q）为 552.49mg/g。动力学数据与准二级模型（R>0.99）吻合良好。天然和煅烧粘土通过 X 射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、N 物理吸附（BET）和扫描电子显微镜（SEM）进行了表征。计算了热力学参数，包括吉布斯自由能（ΔG°）、焓变（ΔH°）和熵变（ΔS°），以估计粘土中罗丹明 B 吸附的性质。结果表明，吸附是吸热和自发的，随着温度的升高，吸附焓增加。因此，煅烧膨润土可作为一种有效吸附剂，用于大量残留水的脱色，具有低成本和高吸附容量的特点。
