Abdel Ghafar Hany H, Radwan Emad K, El-Wakeel Shaimaa T
University of Jeddah, College of Science and Arts at Khulais, Department of Chemistry, Jeddah 23218, Saudi Arabia.
Water Pollution Research Department, National Research Centre, 33 El Bohouth Street, Dokki, Giza 12622, Egypt.
ACS Omega. 2020 Mar 20;5(12):6834-6845. doi: 10.1021/acsomega.0c00166. eCollection 2020 Mar 31.
In this study, natural clay (NC) was collected from Saudi Arabia and modified by cocamidopropyl betaine (CAPB) at different conditions (CAPB concentration, reaction time, and reaction temperature). NC and modified clay (CAPB-NC) were characterized using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and N adsorption at 77 K. The adsorption efficiency of NC and CAPB-NC toward Pb and reactive yellow 160 dye (RY160) was evaluated. The adsorption process was optimized in terms of solution initial pH and adsorbent dosage. Finally, the adsorption kinetics and isotherms were studied. The results indicated that NC consists of agglomerated nonporous particles composed of quartz and kaolinite. CAPB modification reduced the specific surface area and introduced new functional groups by adsorbing on the NC surface. The concentration of CAPB affects the adsorption of RY160 tremendously; the optimum concentration was 2 times the cation exchange capacity of NC. The equilibrium adsorption capacity of CAPB-NC toward RY160 was about 6 times that of NC and was similar for Pb. The adsorption process followed the pseudo-second-order kinetics for both adsorptive. RY160 adsorption on CAPB-NC occurs via multilayer formation while Pb adsorption on NC occurs via monolayer formation..
在本研究中，天然粘土（NC）取自沙特阿拉伯，并在不同条件下（椰油酰胺丙基甜菜碱（CAPB）浓度、反应时间和反应温度）用CAPB进行改性。使用X射线衍射、热重分析、傅里叶变换红外光谱、场发射扫描电子显微镜以及77 K下的N吸附对NC和改性粘土（CAPB-NC）进行了表征。评估了NC和CAPB-NC对Pb和活性黄160染料（RY160）的吸附效率。从溶液初始pH值和吸附剂用量方面对吸附过程进行了优化。最后，研究了吸附动力学和等温线。结果表明，NC由由石英和高岭石组成的团聚无孔颗粒构成。CAPB改性降低了比表面积，并通过吸附在NC表面引入了新的官能团。CAPB的浓度对RY160的吸附有极大影响；最佳浓度为NC阳离子交换容量的2倍。CAPB-NC对RY160的平衡吸附容量约为NC的6倍，对Pb的吸附容量与之相似。两种吸附质的吸附过程均遵循准二级动力学。RY160在CAPB-NC上的吸附通过多层形成发生，而Pb在NC上的吸附通过单层形成发生。
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