Functionalization of Bentonite and Vermiculite after the Creation of Structural Defects through an Acid Leaching Process

Abstract

The synthesis and use of functionalized materials is growing every year. Thus, this work presents a methodology for the functionalization of bentonite and vermiculite after the acid leaching of the raw materials. Leaching was performed with sulfuric acid (H 2 SO 4 ), and the functionalization was performed with (3-mercaptopropyl)trimethoxysilane (MPTS), which was oxidized after being anchored to the support. Compared to the results in the literature for directly functionalized raw bentonite, the materials had a greater number of anchored propyl sulfonic acid groups, and the greatest number of these groups led to an increase in the acidity of the raw materials. The raw and functionalized bentonite and vermiculite were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), N 2 adsorption and the surface acidity was determined by acid-base titration.

Bentonites Modified with Phosphomolybdic Heteropolyacid (HPMo) for Biowaste to Biofuel Production

“…XRD patterns of natural bentonites (Bent) (Figure 2a,b) showed peaks related to montmorillonite (Mt), Kaolinite (K) and quartz (Q) cristals, an importante fingerprint for compounds that belong to the smectite group [34,44,50,60].…”

“…The derivative curves (Figure 3b–d) provided information on the different steps of the decomposition of the natural and modified clays. At temperatures below to 150 °C there was a weight loss attributed to desorption of water adsorbed on the external surface or coordinated with interchangeable cations between the clay mineral layers [34,41,44,50]. That weight loss can also be attributed to the inclusion of hydrated HPMo in the pores of the supports [41,59].…”

“…The catalytic effects of PAHs in acidic reactions depends on three factors: acidity, heteropolianion structure and the type of reaction. On the other hand, clays may be used as catalyst support [9,13,16,20,25,26,34,41,44], or act as acid catalysts [7,8,38,39], redox catalysts and in removing heavy metals from the environment from modifications [45,46]. Both the modified-bentonite and bentonite are promising supports due to their common fascinating features, such as their inherent acidity, excellent thermal stability, and easily controlled structure and morphology.…”

Effect of Structure and Chemical Activation on the Adsorption Properties of Green Clay Minerals for the Removal of Cationic Dye

“…Indeed, the treatment with minerals acids significantly changed their textural characteristics. This can expand their applications to include environmental protection [14,15], catalytic cracking of petroleum [16], catalyst supports in many chemical processes and detergent in paper industries and textile fabrications [17][18][19]. In fact, the most applications of these clays are bleaching, purification and stabilization of vegetable oils.…”

Efficient Adsorption and Photocatalytic Degradation of Dyes by AgI‐Bi2MoO6/Vermiculite Composite under Visible Light

“…The materials pore size, surface area and pore volume are obtained by N 2 adsorption. Nitrogen adsorption‐desorption isotherms of vermiculite and 5 wt%‐A/B‐V4 composite are presented in Figure a and Figure b, which possessed a type I isotherm corresponding to microporous solids . Besides, the pore size distribution is shown in Figure c, and it can be observed that the pore diameter of vermiculite is mainly 4 nm.…”