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Vermiculite
About: Vermiculite is a research topic. Over the lifetime, 2320 publications have been published within this topic receiving 37142 citations.
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98 citations
TL;DR: In this paper, the role of different 2:1 clay mineral populations in soil K absorption and release was investigated using an X-ray pattern decomposition program to quantify peak area modifications induced by K addition and K removal through plant action.
98 citations
TL;DR: In this paper, the authors investigated the effect of pH and contact time on the adsorption process of cadmium removal from aqueous solutions and found that the optimum pH for adsorbing was 6.6.
Abstract: The present study involves an investigation of a low-cost adsorbent, vermiculite for the removal of cadmium from aqueous solutions. The effects of pH and contact time on the adsorption process were examined. The optimum pH for adsorption was found to be 6. Residual cadmium concentration reached equilibrium in four hours and the rate of cadmium adsorption by vermiculite was rapid in the first hour of the reaction time. Ho's pseudo second order model best described the reaction rate. Batch adsorption experiments conducted at room temperature (22±1°C) showed that the adsorption pattern followed the Freundlich isotherm model. The maximum removal of cadmium obtained from batch studies was 96%. Thomas model was used to describe the adsorption data from column studies. Overall, the results showed that vermiculite could be considered as a potential adsorbent for cadmium removal from aqueous solutions.
96 citations
TL;DR: In this article, a low-cost adsorbent was produced from clay mineral of vermiculite using chemical modification, which achieved an improvement in methylene blue removal compared to that of unmodified samples.
Abstract: A novel low-cost adsorbent was produced from clay mineral of vermiculite using chemical modification. The vermiculite was modified with polyamide through in-situ interfacial polymerization. Adsorption performance of the modified adsorbent was investigated for methylene blue removal from aqueous solution. The influence of various operational parameters of the adsorption process was studied through kinetics, thermodynamics, and equilibrium. Noticeable enhancement in methylene blue removal was achieved for modified vermiculite compared to that of un-modified samples. The obtained equilibrium results were fitted to Langmuir, Freundlich, Temkin, Dubinin – Radushkevich, and Sips, where Langmuir model was best followed. Maximum removal uptake was found to be 76.42 mg/g, whereas maximum removal efficiency of 99% was achieved. Pseudo-second order kinetic model was best followed for the experimental kinetics. The modified vermiculite was characterized by scanning electron microscope coupled with energy dispersive spectrometer (SEM/EDS), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Brunauer–Emmett–Teller (BET). The characterization outcome revealed that polymer chain was successfully attached to the vermiculite surface. The thermodynamic investigations showed that negative values of the free energy ΔG were reported, and the negativity was found to increase with increasing the temperature, which implies that the adsorption is spontaneous, energetic and favorable. Moreover, a positive value of enthalpy ΔH (10.98 KJ/mole) was reported, which indicated that the nature of adsorption is endothermic.
96 citations
TL;DR: Differential scanning calorimetry and dynamic mechanical analysis revealed that the nanoclay interacts with the polyurethane hard segments.
Abstract: Natural vermiculite was modified by cation exchange with long-chain quaternary alkylammonium salts and then dispersed in polyether-based polyols with different structures and ethylene oxide/propylene oxide ratios. The dispersions were evaluated by X-ray scattering and rheology. In all polyol dispersions tested, polyols were intercalated into the vermiculite interlayers. Also, significant shear thinning behavior was observed. A large interlayer spacing of ∼90 A was achieved in one polyol suitable for polyurethane elastomer synthesis. In polyurethane made with this polyol, clay platelets were extensively intercalated or exfoliated. The composites showed a >270% increase in tensile modulus, >60% increase in tensile strength, and a 30% reduction in N2 permeability with a loading of 5.3 wt % clay in polyurethane. Differential scanning calorimetry and dynamic mechanical analysis revealed that the nanoclay interacts with the polyurethane hard segments.
95 citations