Pyrophyllite clay-derived porous geopolymers for removal of methylene blue from aqueous solutions
Pyrophyllite clay-derived porous geopolymers for removal of methylene blue from aqueous solutions
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DOI：
10.1016/j.matchemphys.2022.127281
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发表时间：
2022-12-31
影响因子：
4.6
通讯作者：
Bakiz, Bahcine
中科院分区：
文献类型：
--
作者：
Ettahiri, Youssef;Bouna, Lahcen;Bakiz, Bahcine
本研究报告的合成和表征的多孔地质聚合物系统的基础上，自然发生的摩洛哥叶蜡石粘土。叶蜡石在地聚合反应中的贡献很小，地聚合物基质的形成是通过偏高岭土的碱活化来保证的。叶蜡石的作用是形成无序和非均质的地质聚合物，促进孔隙的生成。采用X射线衍射（XRD）、29 Si和27 Al魔角旋转核磁共振（MAS NMR）、傅立叶变换红外光谱（FTIR）、差热分析（DTA）和热重分析（TGA）等方法对天然粘土、煅烧后的偏叶蜡石相和制备的地质聚合物样品的结构和形貌进行了表征，通过Brunauer-Emmett-Teller（BET）方法和扫描电子显微镜（SEM）进行的N2吸附/解吸等温线分析。与使用原始叶蜡石粘土相（SBET = 30 m2/g和Vp = 0.05 cm 3/g）测定的那些值相比，从使用煅烧的偏叶蜡石前体（SBET = 86 m2/g和Vp = 0.08 cm 3/g）的产物测量的比表面积（SBET）和孔体积（Vp）都显著增加。水介质中亚甲基蓝（MB）的吸附符合准二级动力学，吸附模型符合Langmuir吸附模型。热力学数据表明，吸附过程是自发的、不可逆的、吸热的，吸附量达到64.10 mg/g。
This study reports the synthesis and characterization of a porous geopolymer systems based a naturally occurring Moroccan pyrophyllite clay. The contribution of pyrophyllite in geopolymerization reaction was very low, the geopolymer matrix formed was assured by alkaline activation of the metakaolin present in the sample. The pyrophyllite role is forming of disordered and heterogeneous geopolymer promote the pore creation. The structure and morphology of the raw natural clay, calcined meta-pyrophyllite phase and prepared geopolymer samples are characterized by several methods namely, X-ray Diffraction (XRD), 29Si and 27Al magic-angle -spinning nuclear magnetic resonance (MAS NMR) analysis, Fourier Transform Infra-Red (FTIR) spectroscopy, Differential Thermal Analysis (DTA) and Thermal Gravimetric Analysis (TGA), N2 adsorption/desorption isotherm analysis by the Brunauer-Emmett-Teller (BET) method and Scanning Electron Microscopy (SEM). The specific surface area (SBET) and pore volume (Vp) measured from products utilizing the calcined meta-pyrophyllite precursor (SBET = 86 m2/g and Vp = 0.08 cm3/g) have both increased markedly compared to those values determined using a raw pyrophyllite clay phase (SBET = 30 m2/g and Vp = 0.05 cm3/g). The methylene blue (MB) molecular adsorption experiment realized in water medium exhibited Pseudo Second Order (PSO) rate kinetics and adopted a Langmuir adsorption model. The thermodynamics data shows that the chemisorption is spontaneous, irreversible, and endothermic, with the quantity of MB molecules retained by the porous geopolymer specimen reaching 64.10 mg/g.