El Mahmoudi Soufiane, Elmchaouri Abdellah, El Kaimech Assya, Gil Antonio
INAMAT^2, Departamento de Ciencias, Universidad Pública de Navarra, Campus de Arrosadía, 31006 Pamplona, Spain.
Laboratory of Physical Chemistry & Bioorganic Chemistry, Faculty of Science and Techniques Mohammedia, University Hassan II of Casablanca, Mohammedia 20650, Morocco.
Materials (Basel). 2022 Oct 14;15(20):7169. doi: 10.3390/ma15207169.
The aim of this study is to optimize the adsorption of pentachlorophenol (PCP) using an organo-clay under the response surface methodology. The adsorbent was selected from a montmorillonite exchanged by various cations, such as Fe, Al, Zn, Mg, Na, and modified by bromide cetyltrimethylammonium (CTAB) as surfactant. The obtained organo-montmorillonite was characterized using several techniques, such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and nitrogen adsorption, performed at -196 °C. The results showed an increase in basal space from 1.65 to 1.88 nm and a decrease in the specific surface and pore volume, with an increase in pore diameter, including the presence of characteristic bands of -CH- and -CH- groups at 2926 and 2854 cm in the FTIR spectrum after the modification. The optimization of PCP removal by clay adsorbents is achieved using the response surface methodology (RSM) with a four-factor central composite model, including pH of solution, mass of adsorbent, contact time, and initial concentration. The results proved the validity of the regression model, wherein the adsorption capacity reaches its maximum value of 38 mg/g at a lower adsorbent mass of 20 mg, pH of 6, contact time (t) of 5 h, and initial concentration of 8 mg/L.
本研究的目的是在响应面法的条件下，利用有机黏土优化五氯苯酚（PCP）的吸附。吸附剂选用经多种阳离子（如铁、铝、锌、镁、钠）交换的蒙脱石，并以溴化十六烷基三甲基铵（CTAB）作为表面活性剂进行改性。采用多种技术对所得有机蒙脱石进行表征，如傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、热重分析（TGA）、扫描电子显微镜（SEM）以及在-196°C下进行的氮气吸附。结果表明，改性后基面间距从1.65纳米增加到1.88纳米，比表面积和孔体积减小，孔径增大，同时在FTIR光谱中出现了2926和2854厘米处-CH-和-CH-基团的特征谱带。采用包含溶液pH值、吸附剂质量、接触时间和初始浓度的四因素中心复合模型，通过响应面法（RSM）实现了黏土吸附剂对PCP去除效果的优化。结果证明了回归模型的有效性，即在吸附剂质量为20毫克、pH值为6、接触时间（t）为5小时以及初始浓度为8毫克/升的较低条件下，吸附容量达到最大值38毫克/克。
