Research

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16 pages, 4208 KiB

Open AccessArticle

Chitosan Gel Hydroxypropyl Methylcellulose Membranes: A Novel Approach for the Remediation of Cadmium in Aqueous Solutions and Soils

by Guanyu Cai, Jing Sun, Fei Kang, Qilin Lv, Jin Liu, Jie Wang, Zideng Gao and Xueqin Ren

Coatings 2024, 14(4), 421; https://doi.org/10.3390/coatings14040421 - 31 Mar 2024

Viewed by 662

Abstract

Cadmium (Cd²⁺) pollution in soil and water bodies is a significant environmental concern, necessitating effective remediation strategies. Traditional methods often fall short in efficiency, cost-effectiveness, and environmental sustainability. This study develops and evaluates the effectiveness of chitosan–gelatin–hydroxypropyl methylcellulose (CS-GEL-HPMC) membranes for [...] Read more.

Cadmium (Cd²⁺) pollution in soil and water bodies is a significant environmental concern, necessitating effective remediation strategies. Traditional methods often fall short in efficiency, cost-effectiveness, and environmental sustainability. This study develops and evaluates the effectiveness of chitosan–gelatin–hydroxypropyl methylcellulose (CS-GEL-HPMC) membranes for Cd²⁺ removal from polluted environments. CS-GEL-HPMC membranes were synthesized with varying HPMC concentrations. Their structural and morphological characteristics were analyzed using UV–visible absorption spectroscopy and FT-IR. The membranes’ stability across different pH levels and their morphological traits were assessed. The adsorption efficiency for Cd²⁺ ions was evaluated in both aqueous solutions and soil environments under varying conditions of pH, initial ion concentration, and contact time. The CS-GEL-HPMC membranes demonstrated significant structural integrity and stability, especially at higher HPMC concentrations. UV–visible and FT-IR analyses confirmed the successful integration of HPMC into the CS-GEL matrix. In aqueous solutions, the membranes exhibited efficient Cd²⁺ adsorption, with the best performance observed for the CS30-GEL30-HPMC40 membrane. The adsorption capacity was influenced by contact time, initial Cd²⁺ concentration, and pH. In soil treatments, the membranes effectively reduced Cd²⁺ concentrations, with higher membrane dosages yielding better results. The incorporation of additives like (hydroxyapatite) HAP, fly ash (FA), and cement further enhanced the remediation efficiency. In summary, CS-GEL-HPMC membranes, particularly when combined with additives, emerge as a promising, sustainable solution for Cd²⁺ remediation in both soil and water bodies. This study highlights the potential of biopolymer-based composites in environmental clean-up efforts, offering a novel approach that is both effective and eco-friendly. Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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17 pages, 9629 KiB

Open AccessArticle

Accident-Tolerant Barriers for Fuel Road Cladding of CANDU Nuclear Reactor

by Diana Diniasi, Manuela Fulger, Bogdan Butoi, Paul Pavel Dinca and Florentina Golgovici

Coatings 2023, 13(10), 1739; https://doi.org/10.3390/coatings13101739 - 07 Oct 2023

Viewed by 866

Abstract

The nuclear industry is focusing some efforts on increasing the operational safety of current nuclear reactors and improving the safety of future types of reactors. In this context, the paper is focused on testing and evaluating the corrosion behavior of a thin chromium [...] Read more.

The nuclear industry is focusing some efforts on increasing the operational safety of current nuclear reactors and improving the safety of future types of reactors. In this context, the paper is focused on testing and evaluating the corrosion behavior of a thin chromium coating, deposited by Electron Beam Physical Vapor Deposition on Zy-4. After autoclaving under primary circuit conditions, the Cr-coated Zy-4 samples were characterized by gravimetric analysis, optical microscopy, SEM with EDX, and XRD. The investigation of the corrosion behavior was carried out by applying three electrochemical methods: potentiodynamic measurements, EIS, and OCP variation. A plateau appears on the weight gain evolution, and the oxidation kinetics generate a cubic oxidation law, both of which indicate a stabilization of the corrosion. By optical microscopy, it was observed a relatively uniform distribution of hydrides along the samples, in the horizontal direction. By SEM investigations it was observed that after the autoclaving period, the coatings with thickness from 2 to 3 µm are still adherent and maintain integrity. The XRD diffractograms showed a high degree of crystallinity with the intensity of chromium peaks higher than the intensity of zirconium peaks. Electrochemical results indicate better corrosion behavior after 3024 h of autoclaving. Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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11 pages, 3606 KiB

Open AccessEditor’s ChoiceArticle

Influence of Surface Roughness on Nanocrystalline Diamond Films Deposited by Distributed Antenna Array Microwave System on TA6V Substrates

by Azadeh Valinattaj Omran, Chaimaa Mahi, Romain Vayron, Céline Falentin-Daudré and Fabien Bénédic

Coatings 2023, 13(7), 1300; https://doi.org/10.3390/coatings13071300 - 24 Jul 2023

Viewed by 1074

Abstract

In this study, the characteristics of nanocrystalline diamond films synthesized at low surface temperature on Ti-6Al-4V (TA6V) substrates using a distributed antenna array microwave reactor aiming at biomedical applications were investigated. The surface roughness of the TA6V substrates is varied by scratching with [...] Read more.

In this study, the characteristics of nanocrystalline diamond films synthesized at low surface temperature on Ti-6Al-4V (TA6V) substrates using a distributed antenna array microwave reactor aiming at biomedical applications were investigated. The surface roughness of the TA6V substrates is varied by scratching with emery paper of 1200, 2400, 4000 polishing grit. Nanocrystalline diamond (NCD) coatings with morphology, purity, and microstructure comparable to those obtained on silicon substrates usually employed in the same reactor and growth conditions are successfully achieved whatever the polishing protocol. However, the latter has a significant effect on the roughness parameters and hardness of the NCD films. The use of the finest polishing grit thus permits us to enhance the hardness value, which can be related to the work-hardening phenomenon arising from the polishing process. Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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23 pages, 5911 KiB

Open AccessEditor’s ChoiceArticle

Hybrid Materials Based on ZnO Nanoparticles and Organo-Modified Silica Coatings as Eco-Friendly Anticorrosive Protection for Metallic Historic Artifacts

by Mihaela Ioan, Dan Florin Anghel, Mihai Anastasescu, Ioana Catalina Gifu, Elvira Alexandrescu, Roxana Ioana Matei, Cristian Petcu, Ioana Stanculescu, Georgiana Alexandra Sanda, Daniela Bala and Ludmila Otilia Cinteza

Coatings 2023, 13(7), 1193; https://doi.org/10.3390/coatings13071193 - 03 Jul 2023

Viewed by 2363

Abstract

Cultural heritage metallic artifacts are often subjected to environmental factors that promote degradation through corrosion processes. Anticorrosion protection is needed both for the long-term preservation of outdoor monuments and the short-term conservation of archaeological artifacts. In this work, functional nanocoatings based on ZnO [...] Read more.

Cultural heritage metallic artifacts are often subjected to environmental factors that promote degradation through corrosion processes. Anticorrosion protection is needed both for the long-term preservation of outdoor monuments and the short-term conservation of archaeological artifacts. In this work, functional nanocoatings based on ZnO nanoparticles (NPs) in a silica matrix are prepared as a replacement for a commercial Incralac lacquer. Facile sol–gel synthesis is employed for obtaining silica filmogenic materials, using tetraethoxysilane (TEOS) and 3-glycidyloxypropyl trimethoxysilane (GPTMS). Silica-based nanocomposite coatings, with and without ZnO NPs and benzotriazole (BTA) as anticorrosion agents, applied on copper coupons by brushing are characterized by using VIS and FTIR spectroscopy, SEM and AFM and compared to Incralac lacquer as reference materials. The optical and morphological properties of the proposed silica coatings are similar to the Incralac specimens. The protective effect against corrosion is investigated on the copper coupons as model metallic objects subjected to a corrosion test by using potentiodynamic polarization in a 3.5% NaCl solution at ambient temperature. The influence of the presence of BTA and ZnO NPs in both silica and Incralac coatings is studied, and the variations in the anticorrosive, morphological and optical properties with the concentration of ZnO NPs are evidenced. The presence of moderate concentrations of ZnO in both nanomaterials leads to changes in the color parameters slightly above the limit accepted in the field of cultural heritage (ΔE* 5.09 and 6.13), while a high ZnO concentration of 3% leads to higher values (ΔE* > 10). Regarding the anticorrosive effect, the silica-based coatings with ZnO and BTA present similar efficiencies to that of the Incralac reference material (corrosion rates in the range of 0.044–0.067 mm/year for silica coatings compared to 0.055 mm/year for Incralac). Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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14 pages, 4667 KiB

Open AccessEditor’s ChoiceArticle

Characterization of Two Types of Polylactic Acid Coating Loaded with Gentamicin Sulphate Deposed on AZ31 Alloy

by Manuela Elena Voicu, Daniela Ionita, George-Octavian Buica, Doina Draganescu, Valentina Anuta, Florentina Monica Raduly and Ioana Demetrescu

Coatings 2023, 13(6), 1105; https://doi.org/10.3390/coatings13061105 - 15 Jun 2023

Cited by 1 | Viewed by 1005

Abstract

This paper compares two types of polylactic acid (PLA) coating on AZ31 alloy obtained by dip coating and electrospinning. Both types of coating were loaded with gentamicin sulphate (GS) and the drug-loading efficiency and release were assessed. A higher encapsulation and release efficiency [...] Read more.

This paper compares two types of polylactic acid (PLA) coating on AZ31 alloy obtained by dip coating and electrospinning. Both types of coating were loaded with gentamicin sulphate (GS) and the drug-loading efficiency and release were assessed. A higher encapsulation and release efficiency of GS was seen for dip coating (73% and 49.53%, respectively) compared to nanofiber coating (65% and 12.37%, respectively). Furthermore, the antibacterial effect of the samples with and without GS was assessed using Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, showing that the samples with the drug encapsulated are more resistant to bacteria than the other samples. The electrochemical data reveal a higher stability in the SBF of the surface obtained by dipping than that obtained by electrospinning. The PLA coating shows a porosity of 46% for the sample obtained through dip coating and 32% for nanofibers, which is in accordance with the BET analysis results. Moreover, a higher adhesion strength was obtained for AZ31-PLA-dip (4.99 MPa) than for the AZ31-PLA-nanofibers (1.66 MPa). All samples were structurally, morphologically, and topographically characterized. Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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13 pages, 3344 KiB

Open AccessEditor’s ChoiceArticle

Complex Bioactive Chitosan–Bioglass Coatings on a New Advanced TiTaZrAg Medium–High-Entropy Alloy

by Andrei Bogdan Stoian, Radu Nartita, Georgeta Totea, Daniela Ionita and Cristian Burnei

Coatings 2023, 13(5), 971; https://doi.org/10.3390/coatings13050971 - 22 May 2023

Viewed by 1233

Abstract

High-entropy alloys (HEAs), also known as multicomponent or multi-principal element alloys (MPEAs), differ from traditional alloys, which are usually based only on one principal element, in that they are usually fabricated from five or more elements in large percentages related to each other, [...] Read more.

High-entropy alloys (HEAs), also known as multicomponent or multi-principal element alloys (MPEAs), differ from traditional alloys, which are usually based only on one principal element, in that they are usually fabricated from five or more elements in large percentages related to each other, in the range of 5%–35%. Despite the usually outstanding characteristics of HEAs, based on a properly selected design, many such alloys are coated with advanced composites after their elaboration to further improve their qualities. In this study, 73Ti-20Zr-5Ta-2Ag samples were covered with chitosan and a mixture of chitosan, bioglass, and ZnO particles to improve the materials’ antibacterial properties. A variety of methods, including scanning electron microscopy, atomic force microscopy, and mechanical and electrochemical determinations, has permitted a quantified comparison between the coated and uncoated surfaces of this medium–high-entropy alloy. The materials’ properties were enhanced by the complex coating, giving the alloys not only high antibacterial activity, but also good corrosion protection. Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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13 pages, 4799 KiB

Open AccessArticle

Mechanical and Anticorrosive Properties of TiNbTa and TiNbTaZr Films on Ti-6Al-4V Alloy

by Yung-I Chen, Yi-Jyun Chen, Cheng-Yi Lai and Li-Chun Chang

Coatings 2022, 12(12), 1985; https://doi.org/10.3390/coatings12121985 - 18 Dec 2022

Cited by 2 | Viewed by 1361

Abstract

In this study, TiNbTa and TiNbTaZr films were utilized as protective coatings on a Ti-6Al-4V alloy to inhibit corrosive attacks from NaCl aqueous solution and simulated body fluid. The structural and mechanical properties of multicomponent TiNbTa(Zr) films were investigated. The corrosion resistance of [...] Read more.

In this study, TiNbTa and TiNbTaZr films were utilized as protective coatings on a Ti-6Al-4V alloy to inhibit corrosive attacks from NaCl aqueous solution and simulated body fluid. The structural and mechanical properties of multicomponent TiNbTa(Zr) films were investigated. The corrosion resistance of the TiNbTa(Zr)-film-modified Ti-6Al-4V alloy was evaluated using potentiodynamic polarization tests in a NaCl aqueous solution. The results indicate that the TiNbTa(Zr) films with high Ti and Zr contents exhibited inferior corrosive resistance related to the films with high Ta and Nb contents. Moreover, the TiNbTa(Zr)-coated Ti-6Al-4V plates were immersed in Ringer’s solution for eight weeks; this solution was widely used as a simulated body fluid. The formation of surficial oxide layers above the TiNbTa(Zr) films was examined using transmission electron microscopy and X-ray photoelectron spectroscopy, which prevented the elution of Al and V from the Ti-6Al-4V alloy. Ti₃₃Nb₁₉Ta₂₁Zr₂₇, Ti₁₅Nb₆₈Ta₈Zr₉, and Ti₈Nb₈Ta₇₉Zr₅ films are suggested as preferential candidates for TiNbTa(Zr)/Ti-6Al-4V assemblies applied as biocompatible materials. Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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Review

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21 pages, 1088 KiB

Open AccessEditor’s ChoiceReview

Present and Future of ZrO₂ Nanostructure as Reservoir for Drug Loading and Release

by Ramona-Daniela Radu (Dușman) and Doina Drăgănescu

Coatings 2023, 13(7), 1273; https://doi.org/10.3390/coatings13071273 - 20 Jul 2023

Cited by 4 | Viewed by 1450

Abstract

Extensive research has been conducted on ZrO₂ nanostructures due to their favorable biocompatibility, low toxicity, and promising prospects in various biomedical applications. They can be used as drug carriers, facilitating the administration of therapeutic substances into the body while enhancing their effectiveness [...] Read more.

Extensive research has been conducted on ZrO₂ nanostructures due to their favorable biocompatibility, low toxicity, and promising prospects in various biomedical applications. They can be used as drug carriers, facilitating the administration of therapeutic substances into the body while enhancing their effectiveness and safety. This is achieved by regulating the timing, location, and rate at which drugs are released within the body. Several factors can influence the effectiveness of drug loading onto ZrO₂ nanostructures, such as the physicochemical characteristics of the drugs, the surface properties of the ZrO₂ nanostructures, and the specific methods used for drug loading. A wide range of drugs may be loaded onto ZrO₂ nanostructures including anti-cancer drugs, antibiotics, anti-inflammatory drugs, antifungal drugs, anti-osteoporotic drugs, etc. The release kinetics of drugs can be influenced by different factors, such as the size and shape of ZrO₂ nanostructures, the pH and temperature of the release medium, and the characteristics and molecular weight of the specific drug being released. While ZrO₂ nanostructures have demonstrated significant potential as drug delivery systems, further research on these structures is essential to optimize drug loading and release strategies. Full article

(This article belongs to the Special Issue New Strategies and Recent Advances in Investigations of Micro- and Nano-Coatings for Technological and Biomedical Applications)

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