Original Paper
Insights into Glyphosate Adsorption in Aqueous Solutions Using Zn-Al Layered Double Oxide
- Emanoel Hottes, Glauco Favilla Bauerfeldt, Clarissa Oliveira da Silva, Rosane Nora Castro, Marcelo Hawrylak Herbst
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- Published online by Cambridge University Press:
- 22 January 2024, pp. 497-512
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Contamination of surface and groundwater with glyphosate, used widely on crops to control weeds, can cause severe environmental damage. Processes for glyphosate removal from water bodies have been developed, but few are effective and all are expensive. This objective of the present study was to investigate the use of a layered double oxide as a potentially effective and inexpensive material to remove glyphosate from water. Equilibrium, kinetics, and adsorption mechanisms were evaluated, in addition to the effects of competing anions and temperature on glyphosate adsorption. Up to 95% of glyphosate was removed from a synthetic solution in 50 min by Zn2Al-LDO (layered double oxide in Zn/Al ratio of 2:1) at pH 10. The adsorption isotherms were type L and the Langmuir model best fitted the experimental data, with a qmax value of 191.96 μg mg–1 at 25°C. The XRD pattern did not support the hypothesis of intercalation of glyphosate anions, whereas Fourier-transform infrared and solid-state 13C and 31P magic angle spinning nuclear magnetic resonance confirmed the adsorption of glyphosate anions on the Zn2Al-LDO surface, through carboxylate and phosphonate moiety interactions with end-on and side-on modes. The degree of removal of glyphosate increased with increasing temperature and decreased with increasing concentration of competing anions, with carbonate anions having the most prominent effect on the inhibition of glyphosate adsorption. The adsorption kinetics fitted a pseudo-first order law. Moreover, the intraparticle diffusion model suggested that the adsorption process depends on the formation and thickness of the film at the solution/solid interface.
From Coupling Second-Order Stresses to Understanding and Predicting the Structural Response of a Dioctahedral Smectite
- Chadha Mejri, Walid Oueslati, Abdesslem Ben Haj Amara
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- Published online by Cambridge University Press:
- 22 January 2024, pp. 513-538
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The employment of clay minerals in the transport of water, nutrients, and contaminants depends on a few factors, including permeability, hydration behavior, ion-exchange efficiency, and more. With the application of external stress, it is still difficult to understand how clay particles swell and collapse, how water is retained, how hydration heterogeneities are formed within crystallites, and how interlamellar space is organized. The present work studied the link between geochemical, thermal, kinetic constraints (established at the laboratory scale), and intrinsic clay features by exchanging Na-rich montmorillonite (SWy2) with Ni2+, Mg2+, or Zn2+ cations. By comparing the experimental 00l reflections with the calculated reflections obtained from the structural models, quantitative X-ray diffraction (XRD) analysis has enabled the building of a theoretical profile describing the layer stacking mode (LSM) and allowed the description of interlayer space (IS) configuration along the c* axis. Regardless of the type of the exchangeable cations (EC), XRD modeling revealed that all samples exhibited interstratified hydration behavior within the crystallite size, which probably indicates partial or incomplete saturation of the IS. This theoretical result was defined by the appearance of two hydration states (1W and 2W), which were unrelated to the strain strength creating a higher degree of structural heterogeneity. Using the theoretical decomposition of the observed XRD patterns, the identification of all distinct layer populations and their stacking mode was achieved. The segregated LSM are, therefore, obviously superior as a function of stress strength.
Influence of pH on the Hydrothermal Synthesis of Al-Substituted Smectites (Saponite, Beidellite, and Nontronite)
- I. Criouet, J. C. Viennet, F. Baron, E. Balan, A. Buch, L. Delbes, M. Guillaumet, L. Remusat, S. Bernard
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- Published online by Cambridge University Press:
- 22 January 2024, pp. 539-558
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Smectitic clay minerals are unique indicators of paleoenvironmental conditions and exhibit a unique reactivity in the mineral world. Smectites may exhibit tetrahedral substitutions (Al3+, and sometimes Fe3+, can substitute for Si4+ in tetrahedral sites), resulting in a layer-charge increase, thereby impacting their properties (e.g. swelling and sorption capacities, catalytic properties, expandable abilities). The objective of the present study was to determine the influence of pH conditions on the hydrothermal production of smectite end-members exhibiting tetrahedral Al substitutions (saponite, beidellite, and nontronite), using X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) methods. The results of a series of syntheses conducted at various pH values allowed discussion of the crystallization pathways of these smectites from a mechanistic point of view. Altogether, the present study provided easily reproducible protocols for the hydrothermal production of pure saponite, nontronite, or beidellite (i.e. with no other mineral). The successful synthesis of pure saponite was achieved by exposing the starting gels to 230°C for 4 days in solutions at pH ranging from 5.5 to 14. The successful synthesis of pure beidellite was achieved by exposing the starting gels to 230°C for 9 days in a solution at pH 12. The successful synthesis of pure nontronite was achieved by exposing the starting gels to 150°C for 2.5 days in a solution at pH 12.5. Although extrapolating experimental results to natural settings remains difficult, the results of the present study may be of great help to constrain better the geochemical conditions existing or having existed on extraterrestrial planetary bodies.
Antibacterial finishing of textile materials using modified bentonite
- Ljiljana Topalić-Trivunović, Aleksandar Savić, Rada Petrović, Darko Bodroža, Dragana Grujić, Miodrag Mitrić, Zoran Obrenović, Dragana Gajić, Mugdin Imamović
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- Published online by Cambridge University Press:
- 22 January 2024, pp. 559-576
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Direct application of heavy metals as antibacterial agents can cause skin irritations and discoloration of the tissue and it can result in short-term applicability. One of the ways to solve these problems is to immobilize these agents on bentonite. Treatment of textile materials with such activated bentonite for use in various branches of industry has attracted the attention of many researchers in recent years. The objective of the present study was to develop a potential use of Cu- and Zn-modified bentonites as antibacterial finishing agents for two textile materials, non-woven textile (NT) and knitted fabric (PL). The bentonite samples were characterized using ED-XRF (energy dispersive X-ray fluorescence spectrometry), XRPD (X-ray powder diffraction), SEM (scanning electron microscopy), FTIR (Fourier-transform infrared spectroscopy), and BET (N2 adsorption-desorption) analyses. SiO2 and Al2O3 oxides were the main components of all bentonite samples indicated by ED-XRF analysis, while the XRPD analysis confirmed that the natural bentonite (NB) consisted of montmorillonite (Mnt) as the dominant mineral (peaks at 6.94, 19.94, 35.09, and 54.09°2θ) and small amounts of quartz and calcite. A reduction in the basal plane spacing, d001, of Mnt occurred in Cu/Zn-B1, Cu/Zn-B3, and CuB, while in Cu/Zn-B2 and ZnB the basal spacing increased. Also, the size and form of particles and porosity changed, which was confirmed by the BET analysis. Modified bentonite samples experienced a reduction in the specific surface area and total pore volume, as well as movement of the middle mesopore diameter toward the larger diameters. The Zn-modified bentonite demonstrated a greater antibacterial effect on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus than Cu- and Na-modified bentonite samples with a MIC (minimum inhibitory concentration) of 0.94 mg/mL, while among Cu/Zn bentonite samples, Cu/Zn-B2 had the strongest antibacterial effect (MIC 0.47 mg/mL). Cu/Zn-B2 was integrated on NT and PL using a screen printing method and showed good antibacterial activity. The printed NT showed better activity than printed PL, and increasing the concentration of applied Cu/Zn-B2 also increased the antibacterial properties.
Determination of Sulfide Consumption by Fe-bearing Components of Bentonites
- Jebril Hadi, Jean-Marc Greneche, Paul Wersin, Petri Koho, Barbara Pastina
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- Published online by Cambridge University Press:
- 22 January 2024, pp. 577-599
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Geologic repositories for spent nuclear fuel use bentonite as a buffer to protect the metallic containers confining the radioactive material. Sulfate-reducing bacteria, which may be present in groundwater, at the bentonite–host rock interface or eventually within the bentonite may produce sulfide, representing a potential threat for the metallic canisters, particularly copper. Bentonites can act as potential sulfide scavengers. Little is yet known, however, regarding the underlying mechanisms, the maximum extent of sulfide consumption, and the potential impacts on bentonite structure under repository conditions. In the current study, concentrated (4–150 mM) sulfide solutions were reacted in batch experiments with six natural Fe-bearing bentonites, with various purified Fe-bearing components of bentonite (a series of purified montmorillonites and three iron (oxyhydr)oxides), and with one synthetic mixture, for up to 1.5 months at pH values ranging from 7 to 13. The solutions were analyzed by colorimetry to determine sulfide and polysulfide concentrations and the solids were analyzed by 57Fe Mössbauer spectrometry to determine iron speciation. Important sulfide consumption coupled with a reduction of structural Fe in the clay samples was observed. Not all clay structural Fe was reactive toward sulfide; the proportion of active structural Fe depended on the clay structure and pH. In the presence of excess sulfide in solution regarding Fe in the solid sample, the clay structural Fe was found to be the main reactant while the reaction with iron (oxyhydr)oxides was largely inhibited. Three bentonite groups were distinguished, based on the sulfide oxidation capacity of their main clayey component.
Development of a Nanostructured Film Containing Palygorskite and Dermaseptin 01 Peptide for Biotechnological Applications
- Karla Costa Bezerra Fontenele Oliveira, Emanuel Airton de Oliveira Farias, Paulo Ronaldo Sousa Teixeira, Vitor Schwenck Brandão, Rafael Miguel Sábio, Alyne Rodrigues de Araújo, Peter Eaton, Luiz Carlos Bertolino, Marcelo Porto Bemquerer, Hernane da Silva Barud, José Roberto de Souza de Almeida Leite, Carla Eiras
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- Published online by Cambridge University Press:
- 22 January 2024, pp. 600-615
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Clay minerals are suitable matrices to anchor organic molecules such as antimicrobial peptides (AMPs) so that their bioactivity is maintained, enabling the formation of new materials with potential for new applications in biotechnology. The objective of the present study was to develop a nanostructured film where the properties of palygorskite (Plg) were combined at the molecular level with Dermaseptin 01 (DRS 01), in which the clay mineral also served as a substrate for the immobilization of this peptide. The films were prepared using the Layer-by-Layer (LbL) self-assembly technique. Crude palygorskite without purification (Plg IN) was subjected to physical and chemical procedures to increase its adsorptive properties. The structure, chemical composition, and morphology of Plg were investigated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). LbL films were adsorbed onto ITO (Indium Tin Oxide) and characterized electrochemically by cyclic voltammetry (CV), UV-Visible spectroscopy, and atomic force microscopy (AFM). For the ITO/DRS 01 and ITO/Plg/DRS 01 films, an oxidation process at +0.77 V was observed, confirming that the DRS 01 maintained its electroactive behavior and intrinsic properties. The results also showed that Plg served as excellent support for the immobilization of DRS 01, increasing its concentration and availability in the film form. This work reported immobilizing the DRS 01 peptide with Plg for the first time in an ultrathin film with bioactive properties. Thus, the film developed can be explored for applications such as biosensor devices and antimicrobial coating materials as well as other biotechnological applications.
Raw Materials Used in Traditional Pottery from Northern Morocco: Possible Alternative Material for a Sustainable Future in the Fran Ali Area
- Fatima Hilali, Younes El Kharim, Hasnaa Hilali, Ali Bounab, Hicham El Idrissi, Khalid Draoui, Mustapha El Hadri, Mohamed Ahniche
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- Published online by Cambridge University Press:
- 22 January 2024, pp. 616-636
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The colluvium and saprolite deposits in the Fran Ali area (Oued Laou, northern Morocco) constitute the main source of raw materials used in traditional pottery. These materials are becoming scarce, however, so alternative materials with the same characteristics are needed; this would ensure the sustainability of pottery activities in the area. The objective of the present study was to examine ten representative samples of clayey materials extracted from the Fran Ali area, i.e. the Ikhadimene, Dar Haddoune, Ihadounene, Aqqbat Ajjoua, and Isalahene sites. The geological materials consist mainly of grayish to brownish phyllites, thin layers of yellowish clay, thicker intervals of reddish-yellow soils ranging in depth from 1 to 4 m, and reddish colluvium soils. The physical properties of these materials were determined using semi-wet sieving and Atterberg limit tests, while chemical, mineralogical, and thermal properties were obtained from the methylene blue test (MBT), the calcimetry test, X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), and thermogravimetric and differential thermal (TGA/DTGA) analysis. The results suggest that the soils contain 21–35% clay, 28–34% silt, and 37–52% sand. They are moderately plastic, with methylene blue adsorption capacities ranging from 3 to 7% and minimal CaCO3 carbonate contents (1–4%). Samples are dominated by SiO2 (51–57%), Al2O3 (17–21%), and Fe2O3 (8–10%). Mineralogically, they are composed of illite (19–27%), chlorite (0–22%), kaolinite (5–9%), and quartz (29–32%). Thermal analysis showed a relatively large mass loss of ~10%. The samples are deemed to be moderately plastic. The results indicate that this raw material is acceptable for pottery fabrication, given the small proportion of irregular interlayer content and its average geotechnical properties. In addition, extraction of the colluvium material is not sustainable because of the relative scarcity of the material. Given the mineralogical similarity between the weathered layers (colluvium) and their parent rock (shales), the present results suggest that the latter is a suitable alternative to the former.