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Surfaces, Volume 7, Issue 2 (June 2024) – 15 articles

Cover Story (view full-size image): Waste seashell (scallop shell)-based adsorbent was prepared via mechanochemical reaction with sodium oxalate using ball milling. The oxalate-modified seashell-based adsorbents (OS) were prepared by varying the molar ratio of calcium and oxalate to 0.5, 1, and 2. Sodium oxalate was used as the aqueous solution in ball milling. Lead ion adsorption was conducted with the prepared adsorbent. The adsorption behavior of lead ions was investigated in terms of adsorption kinetics and adsorption equilibrium. The time course of the amount of Pb adsorbed agreed well with Langmuir rate equation. The adsorption equilibrium relationship of OS adsorbent and Pb agreed well with the Langmuir adsorption isotherm. Increasing with the molar ratio, the saturated amount of Pb adsorbed increased slightly from 5.45 × 10−3 to 6.23 × 10−3 mol/g. View this paper
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14 pages, 1724 KiB  
Article
Interactions between Cetyltrimethylammonium Bromide Modified Cellulose Nanocrystals and Surfaces: An Ellipsometric Study
by Xiaoyu Gong, Md Farhad Ismail and Yaman Boluk
Surfaces 2024, 7(2), 428-441; https://doi.org/10.3390/surfaces7020027 - 19 Jun 2024
Viewed by 261
Abstract
The tailoring of the surface properties of cellulose nanocrystals (CNCs) to meet various requirements in environmental, food, and material areas has always been of great interest. In this study, the surface chemistry of CNCs was noncovalently modified by cetyltrimethylammonium bromide (CTAB), followed by [...] Read more.
The tailoring of the surface properties of cellulose nanocrystals (CNCs) to meet various requirements in environmental, food, and material areas has always been of great interest. In this study, the surface chemistry of CNCs was noncovalently modified by cetyltrimethylammonium bromide (CTAB), followed by characterizations and an investigation into its application as a coating material for interfacial interaction over various substrates. Due to the CTAB modification, the surface charge of the CNCs was neutralized, resulting in an increased size of each nanocrystal at the aqueous status and the aggregated microfibers when dried up. The CTAB modification not only decreased the crystallinity of the samples from 48.57% to 9.12%, but also reasonably hydrophobized the CNCs and decreased their total surface energy. Finally, the adsorption behavior of the CNCs and CTAB-CNCs over nonionic, anionic, and cationic polymers was investigated by ellipsometry. Based on the thickness of the CNC and CTAB-CNC layers over 2-Hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), and polyethyleneimine (PEI), we proposed that the adsorption behavior was overall influenced by electrostatic interaction, hydrogen bonding, and van der Waals forces, and the thickness of the adsorbed layers could be impacted by both the surface charge and the size of the crystals. Full article
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14 pages, 1264 KiB  
Article
General Method for Predicting Interface Bonding at Various Oxide–Metal Interfaces
by Michiko Yoshitake
Surfaces 2024, 7(2), 414-427; https://doi.org/10.3390/surfaces7020026 - 3 Jun 2024
Viewed by 380
Abstract
Interface termination bonding between metal oxide and metals is discussed from the viewpoint of thermodynamics. The method of interface termination prediction proposed by the authors for Al2O3–metal and ZnO–metal interfaces is extended to a general interface between metal-oxide and [...] Read more.
Interface termination bonding between metal oxide and metals is discussed from the viewpoint of thermodynamics. The method of interface termination prediction proposed by the authors for Al2O3–metal and ZnO–metal interfaces is extended to a general interface between metal-oxide and metals. The extension of the prediction method to the interface between metal oxides and elemental semiconductors is also discussed. Information on interface bonding was extracted by carefully examining the experimental results and first-principles calculations in the references. The extracted information on interface bonding from references is compared with the results obtained via the proposed prediction method. It is demonstrated that interface termination bonding can be predicted by extending the method to oxide–metal interfaces in general, when there is no interface reaction such as the reduction of oxide, oxidation of metal, or mixed oxide formation. The method uses only basic quantities of pure elements and the formation enthalpy of oxides. Therefore, it can be applied to most of the metals (including elemental semiconductors) in the periodic table and metal oxides with one stable valence. The method is implemented as a software, “InterChemBond”, and can be used free of charge. Full article
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10 pages, 3091 KiB  
Article
Adsorption of Gadolinium Bisphthalocyanine on Atomically Flat Surfaces: Comparison of Graphene and Hexagonal Boron Nitride from DFT Calculations
by Vladimir A. Basiuk and Elena V. Basiuk
Surfaces 2024, 7(2), 404-413; https://doi.org/10.3390/surfaces7020025 - 1 Jun 2024
Viewed by 329
Abstract
We studied the noncovalent interactions of gadolinium bisphthalocyanine (GdPc2) with cluster models for graphene and hexagonal boron nitride (hBN) of variable size by using the PBE functional of the generalized gradient approximation in conjunction with Grimme’s dispersion correction and [...] Read more.
We studied the noncovalent interactions of gadolinium bisphthalocyanine (GdPc2) with cluster models for graphene and hexagonal boron nitride (hBN) of variable size by using the PBE functional of the generalized gradient approximation in conjunction with Grimme’s dispersion correction and a DND double numerical basis set (that is, PBE-D2/DND). We found that in terms of the bonding strength, changes in the Gd-N bond lengths, the charge and spin of the Gd central ion, and the spin of the GdPc2 molecule, the behaviors of the graphene- and hBN-based model systems are rather similar. As expected, when increasing the size of the graphene and hBN cluster models, the strength of the interaction with GdPc2 increases, in which the bonding with the hBN models is usually stronger by a few kcal/mol. One of the main questions addressed in the present work was whether a change in the antiferromagnetic spin alignment to a ferromagnetic one, which is typical for GdPc2, is (at least theoretically) possible, as it has been observed previously for a number of graphene models when a smaller basis set DN was employed. We found that the use of a larger DND basis set dramatically reduces the occurrence of ferromagnetic adsorption complexes but does not exclude this possibility completely. Full article
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24 pages, 4711 KiB  
Review
The Use of Plant Extracts as Green Corrosion Inhibitors: A Review
by Milad Sheydaei
Surfaces 2024, 7(2), 380-403; https://doi.org/10.3390/surfaces7020024 - 1 Jun 2024
Cited by 1 | Viewed by 608
Abstract
The corrosion of metals is very important, both economically and environmentally, and is a serious concern. Since the past decades, traditional (chemical) corrosion inhibitors to prevent corrosion have been and are still being used. Although these inhibitors can be said to be a [...] Read more.
The corrosion of metals is very important, both economically and environmentally, and is a serious concern. Since the past decades, traditional (chemical) corrosion inhibitors to prevent corrosion have been and are still being used. Although these inhibitors can be said to be a good choice among other protection techniques because of their good efficiency, the toxicity of many of them causes environmental problems, and, due to the change in the laws on the use of chemicals, many of them are no longer allowed. Hence, during the past years, research on green corrosion inhibitors (GCIs) increased and very favorable results were obtained, and now they are very popular. It can be said that biodegradability and easy preparation are their most important factors. Meanwhile, the use of plants, especially their extracts, has been studied a lot. Plant extracts contain compounds that have anti-corrosion properties. In this review, the use of plants as GCIs is investigated, focusing on recent advances in their use. Also, the phenomenon of corrosion, corrosion protection (including coatings, nanoparticles, and chemical inhibitors), and other GCIs are briefly reviewed. Full article
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11 pages, 8664 KiB  
Article
Optical Characteristics of Directly Deposited Gold Nanoparticle Films
by Jordi Sancho Parramon, Tilen Švarc, Peter Majerič, Žiga Jelen and Rebeka Rudolf
Surfaces 2024, 7(2), 369-379; https://doi.org/10.3390/surfaces7020023 - 27 May 2024
Viewed by 401
Abstract
The manuscript presents the optical properties of directly deposited films of gold nanoparticles (AuNPs) prepared by the Ultrasonic Spray Pyrolysis (USP) technology. Four samples were produced, with AuNP deposition times on the glass substrate of 15 min, 30 min, 1 h and 4 [...] Read more.
The manuscript presents the optical properties of directly deposited films of gold nanoparticles (AuNPs) prepared by the Ultrasonic Spray Pyrolysis (USP) technology. Four samples were produced, with AuNP deposition times on the glass substrate of 15 min, 30 min, 1 h and 4 h. The morphological characterisation of the deposited films showed that the size of the first deposited AuNPs was between 10 and 30 nm, while, with a longer duration of the deposition process, larger clusters of AuNPs grew by coalescence and aggregation. The prepared layers were characterised optically with Ultraviolet–visible spectroscopy (UV–vis) and ellipsometry. The ellipsometric measurements showed an increasingly denser and thicker effective thickness of the AuNP layers. The extinction spectra displayed a clear local surface plasmonic resonance (LSPR) signature (peak 520–540 nm), indicating the presence of isolated particles in all the samples. For all AuNP layers, the imaginary part of the parallel and perpendicular components of the anisotropic dielectric function was dominated by a central peak at around 2.2 eV, corresponding to the LSPR of isolated particles, and a high-energy shoulder due to Au interband transitions. It was shown that, as the density of particles increased, the extinction cross-section grew over the whole spectral range where measurements are taken. Thus, the response can be explained with an enhanced electromagnetic response between the AuNPs that can be connected to the increase in particle density, but also by the formation of clusters and irregular structures. Full article
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11 pages, 1309 KiB  
Article
Formation of Organic Monolayers on KF-Etched Si Surfaces
by Tiexin Li, Zane Datson and Nadim Darwish
Surfaces 2024, 7(2), 358-368; https://doi.org/10.3390/surfaces7020022 - 10 May 2024
Viewed by 598
Abstract
Silicon is the most commonly used material in the microelectronics industry, due to its inherent advantages of high natural abundance, low cost, and high purity, coupled with the chemical and electrical stability at the interface with its oxide. For molecular electronics applications, oxide-free [...] Read more.
Silicon is the most commonly used material in the microelectronics industry, due to its inherent advantages of high natural abundance, low cost, and high purity, coupled with the chemical and electrical stability at the interface with its oxide. For molecular electronics applications, oxide-free Si surfaces are widely used because of the relative ease of removing the oxide (SiOx) by chemical means, yielding a surface which forms strong covalent bonds with a wide range of chemical functional groups; another advantage is that these surfaces remain oxide-free in the absence of oxidising agents. Standard procedures require the use of either HF, NH4F, or a mixture of both as the etching solution; however, these two chemicals are highly corrosive and toxic, posing a significant risk to the experimentalist. Here, we report that for silicon wafers etched by using potassium fluoride, a less toxic chemical, the resulting surface is free of oxides and can be functionalized by self-assembled monolayers of 1,8-nonadiyne. To demonstrate this, Si/SiOx wafers were etched by using either KF or NH4F, followed by hydrosilylation with 1,8-nonadiyne and a click reaction of the terminal alkyne with azidomethylferrocene. The surface coverages and electron transfer kinetics of the ferrocene-terminated KF-etched surfaces are comparable to those formed by acidic fluoride etching procedures. This is the first study comparing the differences between surfaces functionalized by self-assembled monolayers of 1,8-nonadiyne which were etched by KF and NH4F. KF could be used as a replacement chemical for etching silicon wafers when a less corrosive and toxic chemical is required. Full article
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18 pages, 3802 KiB  
Article
Evaluation of the Feasibility of the Prediction of the Surface Morphologiesof AWJ-Milled Pockets by Statistical Methods Based on Multiple Roughness Indicators
by Nikolaos E. Karkalos, Muthuramalingam Thangaraj and Panagiotis Karmiris-Obratański
Surfaces 2024, 7(2), 340-357; https://doi.org/10.3390/surfaces7020021 - 10 May 2024
Viewed by 716
Abstract
Improvement of the surface quality of machined parts is essential in order to avoid excessive and costly post-processing. Although non-conventional processes can efficiently carry out the machining of difficult-to-cut materials with high productivity, they may also, for various reasons, be related to increased [...] Read more.
Improvement of the surface quality of machined parts is essential in order to avoid excessive and costly post-processing. Although non-conventional processes can efficiently carry out the machining of difficult-to-cut materials with high productivity, they may also, for various reasons, be related to increased surface roughness. In order to optimize the surface quality of generated surfaces in a reliable way, surface profiles obtained during these processes must be adequately modeled. However, given that most studies have focused on Ra or Rz indicators or are based on the assumption of a normal distribution for the profile heights, relevant models cannot accurately represent the surface characteristics that exist in a real machined surface with a high degree of accuracy. Thus, in the present study, a new modeling approach based on the use of a statistical probability distribution for the surface profile height is proposed. After six different distributions were evaluated on the basis of a three-stage procedure involving different roughness indicators pertaining to the abrasive waterjet (AWJ) milling of pockets, it was found that, although it is not possible to model the nominal values of every roughness parameter simultaneously, in several cases, it is possible to approximate the values of critical indicators such as Ra, Rz, Rsk, Rku and Rp/Rv ratio by Weibull distribution with a sufficient degree of accuracy. Full article
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44 pages, 10192 KiB  
Review
Metal–Perovskite Interfacial Engineering to Boost Activity in Heterogeneous Catalysis
by Christoph Malleier and Simon Penner
Surfaces 2024, 7(2), 296-339; https://doi.org/10.3390/surfaces7020020 - 6 May 2024
Viewed by 729
Abstract
In this review, we have assessed the possibility of metal–perovskite interfacial engineering to enhance the catalytic activity and selectivity in a range of heterogeneous catalytic reactions. We embarked on a literature screening of different perovskite material classes and reactions to show the versatility [...] Read more.
In this review, we have assessed the possibility of metal–perovskite interfacial engineering to enhance the catalytic activity and selectivity in a range of heterogeneous catalytic reactions. We embarked on a literature screening of different perovskite material classes and reactions to show the versatility of the perovskite structures to induce the formation of such hetero-interfaces and the widespread nature of the phenomenon in catalytic research. There is almost no limitation on the chemical composition of the used perovskites and the nature of the catalyzed reaction, be it under reduction or oxidation conditions. We attempted to classify the perovskite materials, discuss the different strategies leading to the hetero-interfaces, and detail the synergistic action of the components of the respective interfaces. We also provide a critical assessment of the large body of data that is available in terms of a knowledge-based approach to the comparison of differently prepared interfaces with varying interfacial extent to gain a deeper understanding of the bi-functional operation of the interfaces and the urgent necessity to study and characterize such interfaces under realistic operation conditions. Full article
(This article belongs to the Special Issue In Situ and Operando Catalyst Characterization)
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13 pages, 5376 KiB  
Article
Fluorine Free Surface Modification of Microfibrillated Cellulose-Clay Composite Films: Effect of Hydrophobicity on Gas Barrier Performance
by Mohammed Arif Poothanari and Yves Leterrier
Surfaces 2024, 7(2), 283-295; https://doi.org/10.3390/surfaces7020019 - 1 May 2024
Viewed by 1008
Abstract
Diffusion barrier composite films based on microfibrillated cellulose (MFC) and clay were developed with attention paid to the influence of thermal annealing and a fluorine-free surface silylation on their microstructure, water contact angle (WCA), mechanical properties, oxygen transmission rate (OTR), and water vapor [...] Read more.
Diffusion barrier composite films based on microfibrillated cellulose (MFC) and clay were developed with attention paid to the influence of thermal annealing and a fluorine-free surface silylation on their microstructure, water contact angle (WCA), mechanical properties, oxygen transmission rate (OTR), and water vapor transmission rate (WVTR). The OTR of MFC at 23 °C increased from 1.2 to 25.3 cm3/m2/day/bar as relative humidity increased from 50% to 80%. Annealing increased the film’s crystallinity, surface roughness, and hydrophobicity, while decreasing its OTR by 20% at 80%RH. The addition of clay led to a 30% decrease of OTR at 80%RH due to partial exfoliation and to a 50% decrease when combined with annealing. Silylation increased the hydrophobicity of surface of the film and its combination with clay and annealing led to a WCA of 146.5°. The combination of clay, annealing, and silylation considerably reduced the OTR at 80%RH to a value of 8 cm3/m2/day/bar, and the WVTR at 23 °C and 50%RH from 49 g/m2/day for MFC to 22 g/m2/day. The reduction of OTR and WVTR was found to correlate with the increase in surface hydrophobicity of the film, which was attributed to the reduced access of water molecules within the MFC network. Full article
(This article belongs to the Collection Featured Articles for Surfaces)
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18 pages, 3475 KiB  
Review
Microcalorimetry Techniques for Studying Interactions at Solid–Liquid Interface: A Review
by Heshu Hu, Jiazhong Wu and Minghui Zhang
Surfaces 2024, 7(2), 265-282; https://doi.org/10.3390/surfaces7020018 - 23 Apr 2024
Viewed by 1020
Abstract
Solid–liquid interfacial phenomena play an essential role in our everyday lives and are often regarded as the outcome of interactions at the solid–liquid interface. However, the intricately intrinsic mechanism underlying interfacial interactions renders in situ simulations and direct measurements challenging. As an effective [...] Read more.
Solid–liquid interfacial phenomena play an essential role in our everyday lives and are often regarded as the outcome of interactions at the solid–liquid interface. However, the intricately intrinsic mechanism underlying interfacial interactions renders in situ simulations and direct measurements challenging. As an effective analytic method for studying solid–liquid interfacial interactions, microcalorimetry can provide the most basic thermodynamic information (including changes in enthalpy, entropy, and Gibbs free energy during solid–liquid binding/separation processes), which is extremely crucial for understanding interaction directionality and limitation. This review is dedicated to highlighting the pivotal role of microcalorimetry in studying solid–liquid immersion and adsorption processes. Specifically, we provide an overview of the commonly employed microcalorimetric methods, including differential scanning calorimetry (DSC), isothermal titration calorimetry (ITC), and immersion microcalorimetry (IM), and delve into the influence factors of enthalpy change, and finally discuss the specific applications of microcalorimetry in studying various solid–liquid binding processes. There remains a vast expanse of thermodynamic information regarding solid–liquid interactions that await exploration via calorimetry. Full article
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14 pages, 1950 KiB  
Article
Surface and Aggregation Properties of Rhamnolipids in Water–Bioethanol Mixtures: A Step toward Green Formulation Design
by Rodolfo Esposito, Francesco Taddeo, Vincenzo Russo, Irene Russo Krauss and Gerardino D’Errico
Surfaces 2024, 7(2), 251-264; https://doi.org/10.3390/surfaces7020017 - 7 Apr 2024
Viewed by 1031
Abstract
Water–ethanol mixtures are largely exploited for many different applications, from industrial processes to pharmaceutical formulations. Surfactants are often added to tune their interfacial properties. Sustainability concerns require redesigning such blends to minimize their environmental impact. A successful approach is to replace synthetic oil-based [...] Read more.
Water–ethanol mixtures are largely exploited for many different applications, from industrial processes to pharmaceutical formulations. Surfactants are often added to tune their interfacial properties. Sustainability concerns require redesigning such blends to minimize their environmental impact. A successful approach is to replace synthetic oil-based components with affordable unpurified bio-derived alternatives. In this respect, we have characterized aqueous mixtures of bioethanol, obtained by the fermentation of algae, and rhamnolipids, biosurfactants of microbial origin. The physico-chemical characterization of water–bioethanol binary mixtures in terms of refractive index, density, viscosity, and surface tension indicates that bioethanol behaves like pure ethanol with negligible effects of impurities. Analysis of tensiometric titrations shows that, at bioethanol contents higher than 20–30% bioethanol mass percent, rhamnolipid aggregation is impaired, whereas surface adsorption at the water–air interface remains poorly affected. Overall, bio-derived components can be proposed as a promising alternative to oil-derived chemicals in eco-sustainable formulations. Full article
(This article belongs to the Collection Featured Articles for Surfaces)
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13 pages, 4350 KiB  
Article
Study on the Sound Absorption Properties of Recycled Polyester Nonwovens through Alkaline Treatment and Dimple Processing
by Gyeong Cheol Yu, Jeong Jin Park, Eun Hye Kang, Sun Young Lee, Youl Huh and Seung Goo Lee
Surfaces 2024, 7(2), 238-250; https://doi.org/10.3390/surfaces7020016 - 2 Apr 2024
Viewed by 949
Abstract
This study focused on manufacturing efficient automobile sound-absorbing materials through alkaline treatment and dimple processing of recycled polyethylene terephthalate (rPET) nonwoven fabric. The rPET nonwoven fabric was produced with a sound-absorbing material through compression molding. It was improved through the development of porous [...] Read more.
This study focused on manufacturing efficient automobile sound-absorbing materials through alkaline treatment and dimple processing of recycled polyethylene terephthalate (rPET) nonwoven fabric. The rPET nonwoven fabric was produced with a sound-absorbing material through compression molding. It was improved through the development of porous sound-absorbing materials through alkaline treatment and resonant sound-absorbing materials through dimple processing. As a result of morphological analysis, alkaline treatment showed that pore size and air permeability increased according to temperature and concentration increase conditions. On the other hand, dimple processing caused a decrease in air permeability and a decrease in pores due to yarn fusion, and as the dimple diameter increased, the sound-absorbing coefficient increased in the 5000 Hz band. Finally, it was judged that effective sound absorption performance would be improved through a simple process through alkaline treatment and dimple processing, and thus there would be applicability in various industrial fields. Full article
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13 pages, 4212 KiB  
Article
A Route towards Durable Underwater Stable Superhydrophobic Surfaces: PET-Reinforced Candle Soot Layers
by Xinghua Wu, Zhaokang Han, Yuchao Wang, Yutong Pan and Xiaohua Jie
Surfaces 2024, 7(2), 225-237; https://doi.org/10.3390/surfaces7020015 - 2 Apr 2024
Viewed by 915
Abstract
Superhydrophobic coating is widely used due to its waterproof and self-cleaning properties. Carbon soot (CS) nanoparticles are naturally superhydrophobic and non-toxic which are superior to other superhydrophobic coating. However, the weak binding force of the CS nanoparticle layers hinders their practical application. In [...] Read more.
Superhydrophobic coating is widely used due to its waterproof and self-cleaning properties. Carbon soot (CS) nanoparticles are naturally superhydrophobic and non-toxic which are superior to other superhydrophobic coating. However, the weak binding force of the CS nanoparticle layers hinders their practical application. In this study, micro-nanostructured PET-CS superhydrophobic coatings were prepared by a simple method. The obtained coatings presented durable superhydrophobicity and underwater stability, which are superior to PDMS-CS coatings and CS layers. The coating surfaces demonstrated superhydrophobicity under a water pressure of 13.72 kPa for up to 16 days. The surface could withstand water flush for more than 15 min. The coatings also demonstrated good mechanical stability and maintained superhydrophobicity after an abrasion length of 8 m. The stable long-lasting underwater superhydrophobic surface is of great importance for marine applications. Full article
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17 pages, 6161 KiB  
Article
Preparation of Adsorbent from Mechanochemical Reaction-Based Waste Seashell with Sodium Oxalate and Its Application in Pb Ion Adsorption
by Hideo Maruyama
Surfaces 2024, 7(2), 208-224; https://doi.org/10.3390/surfaces7020014 - 30 Mar 2024
Viewed by 1375
Abstract
Waste seashell (scallop shell)-based adsorbent was prepared via mechanochemical reaction with sodium oxalate using ball milling. The oxalate-modified seashell-based adsorbents (OS) were prepared by varying the molar ratio of calcium and oxalate to 0.5, 1, and 2. Sodium oxalate was used as the [...] Read more.
Waste seashell (scallop shell)-based adsorbent was prepared via mechanochemical reaction with sodium oxalate using ball milling. The oxalate-modified seashell-based adsorbents (OS) were prepared by varying the molar ratio of calcium and oxalate to 0.5, 1, and 2. Sodium oxalate was used as the aqueous solution in ball milling. Lead ion adsorption was conducted with the prepared adsorbent. The adsorption behavior of lead ions was investigated in terms of adsorption kinetics and adsorption equilibrium. The time course of the amount of Pb adsorbed agreed well with Langmuir rate equation. The adsorption equilibrium relationship of OS adsorbent and Pb agreed well with the Langmuir adsorption isotherm. Increasing with the molar ratio, the saturated amount of Pb adsorbed increased slightly from 5.45 × 10−3 to 6.23 × 10−3 mol/g. Under the present experimental conditions, the maximum equilibrium adsorption was 5.93 × 10−3 mol/g, which is greater than that reported in the literature. Full article
(This article belongs to the Collection Featured Articles for Surfaces)
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12 pages, 6263 KiB  
Article
Microstructure and Properties of Thin-Film Submicrostructures Obtained by Rapid Thermal Treatment of Nickel Films on Silicon
by Vasilina Lapitskaya, Ruslan Trukhan, Tatyana Kuznetsova, Jaroslav Solovjov, Sergei Chizhik, Vladimir Pilipenko, Karyna Liutsko, Anastasiya Nasevich and Maksim Douhal
Surfaces 2024, 7(2), 196-207; https://doi.org/10.3390/surfaces7020013 - 27 Mar 2024
Viewed by 1069
Abstract
Nickel films of 40 nm thickness were obtained by means of magnetron sputtering on a single-crystalline silicon substrate. The films were subjected to rapid thermal treatment (RTT) for 7 s until the temperature increased from 200 to 550 °C. By means of the [...] Read more.
Nickel films of 40 nm thickness were obtained by means of magnetron sputtering on a single-crystalline silicon substrate. The films were subjected to rapid thermal treatment (RTT) for 7 s until the temperature increased from 200 to 550 °C. By means of the X-ray diffraction method, the structural-phase composition of nickel films before and after RTT was explored. The atomic force microscopy method due to direct contact with the surface under study, made it possible to accurately define the microstructure, roughness, specific surface energy and grain size of the nickel films before and after RTT, as well as to establish the relationship of these parameters with the phase composition and electrical properties of the films. Surface specific resistance was measured using the four-probe method. Based on XRD results, formation of Ni2Si and NiSi phases in the film was ascertained after RTT at 300 °C. At RTT 350–550 °C, only the NiSi phase was formed in the film. The microstructure and grain size significantly depend on the phase composition of the films. A correlation has been established between specific surface energy and resistivity with the average grain size after RTT at 350–550 °C, which is associated with the formation and constant restructuring of the crystal structure of the NiSi phase. Full article
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