Separation and characterisation of montmorillonite from a low‐grade natural bentonite: using a non‐destructive method

Abstract

Bentonite clays containing mostly montmorillonite as a nanostructure group of smectite have been used as industrial raw material in many applications. The presence of the other impurities in bentonite clays reduces the value of bentonite. Therefore, the bentonite purification is necessary. In this research, the purification and separation of montmorillonite from a low-grade natural bentonite were considered on the regular and comprehensive plan. For this purpose, a set of methods including dispersion, sodium-activation, sedimentation, sonication and centrifugation were used. In contrast to many methods, there were often complex, expensive and non-effective; this purification method was found to be effective for removing almost all quartz, carbonates and clinoptilolite as the major impurities. In this purification method, the montmorillonite content was increased from 15 to 84% with the separation yield of 80%. The influence of centrifugal force and the type of ultrasonication indicated the most critical parameters in the purification yield, the physical properties and the crystalline structure of the final products. The laser particle size distribution analysis, X-ray diffraction, semi-quantitative analysis and Fourier-transform infrared spectroscopy results showed the decrease of impure phase without any structural changes or damages in clay framework.

Sustainable and Green Synthesis of Iron Nanoparticles Supported on Natural Clays via Palm Waste Extract for Catalytic Oxidation of Crocein Orange G Mono Azoic Dye

“…These changes prove the successful loading and immobilization of NZVI particles on bentonite fibers. The O–H stretching vibrations of Al–OH, Al, and adsorbed H 2 O molecules and O–H bending vibration of the adsorbed water molecule were observed at 3620 and 3695 cm –1 and 3392 and 1632 cm –1 . , The peak at 1427 cm –1 relates to the C–O stretching vibration of carbonate impurity . The peaks at 1166 and 980 cm –1 are assigned to the Si–O stretching vibration of bentonite tetrahedral sheets .…”

“… 70 , 72 The peak at 1427 cm –1 relates to the C–O stretching vibration of carbonate impurity. 73 The peaks at 1166 and 980 cm –1 are assigned to the Si–O stretching vibration of bentonite tetrahedral sheets. 47 Also, the peaks at 447 and 406 cm –1 are assigned to the Si–O–Si bending vibration.…”

High-throughput Design of a Lightweight and Ultra-strong Refractory Eutectic High-Entropy Alloy with Outstanding Irradiation Resistance

“…Phases of the Nb55V25Ta5Si15 REHEA were analyzed via the X'pert highscore plus software [56] . The morphologies of the Nb55V25Ta5Si15 REHEA were observed, using a field emission scanning electron microscope (JEO, JSM-7800F Prime) equipped with the energy dispersive The experimental nanohardness and Young's modulus were determined by analyzing the loaddisplacement (P-h) curves, using the Oliver and Pharr method [57] and calculated by the Nix-Gao model [58] .…”

FeAl12-polyoxocations intercalated nano-bentonite fabrication in concentrated suspension using one-step ultrasonic-microwave irradiation for arsenic removal from alkaline wastewater

“…The NB mainly consisted of montmorillonite as a major phase, but the presence of illite, quartz, and calcite in NB composed the impure phase. Therefore, before the pillaring process to decrease impurities of NB, a set of purification methods such as sedimentation, sonication, centrifugation, and sodium activation according to the method of Barakan and Aghazadeh (2019a) were used. The cation exchange capacity (CEC) of NB and purified natural bentonite (PNB) were determined by using Bower method (Bower et al 1952) in the values of 43 and 113 cmol(+)/kg clay, respectively.…”