Raw and Organically Modified Clays and Their Various Application

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Clays and Engineered Mineral Materials".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 4625

Special Issue Editors


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Guest Editor
Institute of Inorganic Chemistry, Slovak Academy of Sciences, 845 36 Bratislava, Slovakia
Interests: clays, organoclays; soil and water treatment; FTIR spectroscopy; adsorbents of pollutants; clay–polymer nanocomposites

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Co-Guest Editor
Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, New Haven, CT 06511, USA
Interests: clay minerals; clay-polymer nanocomposites; soil organic carbon; organo-mineral interactions; synchrotron radiation spectroscopy

Special Issue Information

Dear Colleagues,

Research on clay minerals has received considerable attention because of their natural prevalence, low cost, reactivity, nonhazardous nature in handling, etc. Clay minerals have been widely investigated for their significance in various geological, industrial, and environmental settings. Further, a very important part is surface modifications of clay minerals with organic surfactants, which have received attention because they allow the creation of new applications and new materials. Modified clays are used in various applications, such as adsorbents of organic pollutants in air, water, and soil; thixotropic fluids; rheological control agents; and for the preparation of clay–polymer nanocomposites. Several routes can be employed to modify clays and clay minerals, such as adsorption, ion exchange with organic cations, grafting of organic compounds, binding of inorganic and organic anions, pillaring by different types of poly(hydroxo metal) cations, and reaction with acids. This Special Issue aims to help to uncover new advances in unmodified and modified clays and their use in various fields.

Dr. Michal Slaný
Dr. Itamar Shabtai
Guest Editors

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Keywords

  • Clay minerals
  • Organoclays
  • Clay–polymer nanocomposites
  • Environmental mineralogy
  • Mineral geochemistry

Published Papers (2 papers)

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Research

21 pages, 6332 KiB  
Article
Lysozyme–Mineral Clay Systems: Comparison of Interaction for Controlled Release in Feed Application
by Marianna Guagliano, Matteo Dell’Anno, Giovanni Dotelli, Elisabetta Finocchio, Maria Lacalamita, Ernesto Mesto, Serena Reggi, Luciana Rossi, Emanuela Schingaro, Elena Staltari and Cinzia Cristiani
Minerals 2023, 13(5), 660; https://doi.org/10.3390/min13050660 - 10 May 2023
Cited by 1 | Viewed by 1450
Abstract
A synthetic approach to bond lysozyme (LY) to commercial natural carriers, namely clay minerals (bentonite, BN; and sepiolite, SP) and commercial zeolite (Phil 75®, PH), already in use in feed formulation, is proposed. The synthetic route, which implies solid–liquid adsorption, is [...] Read more.
A synthetic approach to bond lysozyme (LY) to commercial natural carriers, namely clay minerals (bentonite, BN; and sepiolite, SP) and commercial zeolite (Phil 75®, PH), already in use in feed formulation, is proposed. The synthetic route, which implies solid–liquid adsorption, is a simple and effective way for preparing hybrid materials characterized by LY loadings up to 37 mgLY/gcarrier. By operating at pH 4.3, initial LY content of 37.5 mgLY/gcarrier, and reaction time of 90 min, hybrid materials with LY loadings of 37, 35, and 12 mgLY/gcarrier for LY-SP, LY-BN, and LY-PH, respectively were obtained. The LY initial concentration and pH, as well as the physico-chemical properties of the carries were found to be the parameters that govern the synthesis of the materials. The driving force for an effective LY adsorption and interaction is the combined Zero Point Charge (ZPC) of the carriers, always negative (in the range between −4 and −170 mV) and the positive ZPC of LY, as well as the carrier morphology, characterized by mesoporosity (pore dimensions in the range of 5–12 nm). However, it is the interaction of charges of opposite sign that mainly affects LY loadings and bond strength. Based on SEM-EDX analysis, LY molecules are quite homogeneously spread onto the carriers’ surface. TG-DTG analyses showed that the LY–carrier interaction in the hybrid materials is stronger than that in a simple mechanical mixture of the components. Specifically, in the hybrid materials, the phenomenon at 300 °C, associated to LY decomposition, is broadened and slightly shifted towards higher temperatures (320–350 °C), whereas in a mechanical mixture of the same composition, it occurs at temperatures closer to those of free LY, as if there were no or very weak interactions. At pH 3, a very little LY release, 0.03 and 0.01 mgLY/gcarrier, was found for LY-BN and LY-PH, respectively. The latter became larger at pH 7, 0.06 mgLY/gcarrier for both BN and PH carriers, suggesting that BN and PH are better modulators of LY release. The paper provides insights for the study and the development of new optimized feed formulations for the targeted delivery of natural compounds with antimicrobial activity, alternatives to antibiotics, and vaccinal antigens. Full article
(This article belongs to the Special Issue Raw and Organically Modified Clays and Their Various Application)
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17 pages, 5133 KiB  
Article
Simple and Rapid Synthesis of Organically Modified Natural Acid Clay for the Adsorption of Anionic and Cationic Dyes
by Tomohiro Iwasaki
Minerals 2023, 13(1), 41; https://doi.org/10.3390/min13010041 - 27 Dec 2022
Cited by 5 | Viewed by 2421
Abstract
A simple method for organically modifying a natural acid clay (Japanese acid clay) rapidly with alkylamine has been developed. Japanese acid clay mainly consists of acidic montmorillonite and was successfully modified with decylamine in water at room temperature for a short time period [...] Read more.
A simple method for organically modifying a natural acid clay (Japanese acid clay) rapidly with alkylamine has been developed. Japanese acid clay mainly consists of acidic montmorillonite and was successfully modified with decylamine in water at room temperature for a short time period (10 min) using an ultrasonic bath without any pretreatments. The structure of the modified clay changed from exterior surface modification to intercalation with an increase in the decylamine content. The equilibrium adsorption capacity for the anionic dye methyl orange (MO) increased with increasing decylamine content. The adsorption kinetics and isotherm were well described by the pseudo-second-order and Langmuir models, respectively. Better MO adsorption was obtained under the conditions of high dosage, low pH value, and low temperature. The adsorbent was also found to have good adsorption for not only MO but also other anionic dyes (Congo red and eosin Y) and cationic dyes (methylene blue, crystal violet, and rhodamine B). In particular, the decylamine-intercalated clay adsorbent exhibited a high level of adsorption capacity for Congo red and crystal violet. The results demonstrate that the synthesis process can provide a simple and cost-effective organoclay as an adsorbent with high performance for the removal of anionic and cationic dyes. Full article
(This article belongs to the Special Issue Raw and Organically Modified Clays and Their Various Application)
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