Wet Chemistry Research Articles

The study of the anti-icing performance of superhydrophobic silica-nanostructured metal substrates

Superhydrophobic surfaces have proven effective in mitigating ice formation on substrates. This study aimed to experimentally investigate the effects of the surface structure of selected metal substrates on the anti-icing performance. Superhydrophobic surfaces were fabricated on aluminum, copper, stainless steel, and titanium substrates using a spray coating technique with superhydrophobic tridecafluorooctyl triethoxy silane (FAS)-functionalized colloidal silica nanoparticles. The surface wettability, surface morphology, and chemical analysis of the coated surfaces were reported. The results demonstrated successful deposition of silica nanoparticles on all substrates, significantly improving the anti-icing property of the coated surfaces. When compared with uncoated surfaces, the droplet icing times of the coated aluminum plate (C-Al), of the coated copper plate (C-Cu), of the coated stainless steel plate (C-SS), and of the coated titanium plate (C-Ti) significantly enhanced by 751%, 795%, 830% and 1320%, respectively. Also, a heat transfer model was also developed to explain the anti-icing phenomenon.

Scalable Synthesis of Selenide Solid-State Electrolytes for Sodium-Ion Batteries.

Solid-state sodium-ion batteries employing superionic solid-state electrolytes (SSEs) offer low manufacturing costs and improved safety and are considered to be a promising alternative to current Li-ion batteries. Solid-state electrolytes must have high chemical/electrochemical stability and superior ionic conductivity. In this work, we employed precursor and solvent engineering to design scalable and cost-efficient solution routes to produce air-stable sodium selenoantimonate (Na3SbSe4). First, a simple metathesis route is demonstrated for the production of the Sb2Se3 precursor that is subsequently used to form ternary Na3SbSe4 through two different routes: alcohol-mediated redox and alkahest amine-thiol approaches. In the former, the electrolyte was successfully synthesized in EtOH by using a similar redox solution coupled with Sb2Se3, Se, and NaOH as a basic reagent. In the alkahest approach, an amine-thiol solvent mixture is utilized for the dissolution of elemental Se and Na and further reaction with the binary precursor to obtain Na3SbSe4. Both routes produced electrolytes with room temperature ionic conductivity (∼0.2 mS cm-1) on par with reported performance from other conventional thermo-mechanical routes. These novel solution-phase approaches showcase the diversity and application of wet chemistry in producing selenide-based electrolytes for all-solid-state sodium batteries.

Comparison of Cu1.3Mn1.7O4 spinels doped with Ni or Fe and synthesized via wet chemistry and solid-state reaction methods, designed as potential coating materials for metallic interconnects

Comparison of Cu1.3Mn1.7O4 spinels doped with Ni or Fe and synthesized via wet chemistry and solid-state reaction methods, designed as potential coating materials for metallic interconnects

Synchrony of Nitrogen Wet Deposition Inputs and Watershed Nitrogen Outputs Using Information Theory

AbstractNitrogen (N) wet deposition chemistry impacts watershed biogeochemical cycling. The timescale and magnitude of (a)synchrony between wet deposition N inputs and watershed N outputs remains unresolved. We quantify deposition‐river N (a)synchrony with transfer entropy (TE), an information theory metric enabling quantification of lag‐dependent feedbacks in a hydrologic system by calculating directional information flow between variables. Synchrony is defined as a significant amount of TE‐calculated reduction in uncertainty of river N from wet deposition N after conditioning for antecedent river N conditions. Using long‐term timeseries of wet deposition and river DON, NO3−, and NH4+ concentrations from the Lamprey River watershed, New Hampshire (USA), we constrain the role of wet deposition N to watershed biogeochemistry. Wet deposition N contributed information to river N at timescales greater than quick‐flow runoff generation, indicating that river N losses are a lagged non‐linear function of hydro‐biogeochemical forcings. River DON received the most information from all three wet deposition N solutes while wet deposition DON and NH4+ contributed the most information to all three river N solutes. Information theoretic algorithms facilitated data‐driven inferences on the hydro‐biogeochemical processes influencing the fate of N wet deposition. For example, signals of mineralization and assimilation at a timescale of 12 to 21‐weeks lag display greater synchrony than nitrification, and we find that N assimilation is a positive lagged function of increasing N wet deposition. Although wet deposition N is not the main driver of river N, it contributes a significant amount of information resolvable at time scales of transport and transformations.

Comparing the predictive ability of Sentinel-2 multispectral imagery and a proximal hyperspectral sensor for the estimation of pasture nutritive characteristics in an intensive rotational grazing system

Using remote sensing to estimate the nutritive characteristics of pasture in livestock systems is a rapidly developing area that has the potential to improve pasture management and utilisation and in turn improve livestock productivity. The Copernicus Sentinel-2 paired satellites have shown promise in predicting pasture nutritive characteristics and have a pixel size small enough to be able to identify intra-paddock nutrient variation in rotational dairy grazing systems where paddock sizes are small. This study sought to develop nutrient prediction models using a dataset of nine Sentinel-2A and -2B satellite images, by linking imagery to perennial ryegrass dairy pasture samples cut within known pixels of the images in the days directly after each cloud-free overpass. Just before destructive pasture sampling, a handheld, proximal, hyperspectral sensor was used to gather spectral signatures (400–2500 nm) from areas to be sampled. Pasture samples (n = 200) were analysed using wet chemistry techniques for seven nutritive characteristics. The dry matter concentration of the samples was also measured, creating eight variates to be modelled in total. The Sentinel-2 data from within the selected pixels was extracted and used to create input features for Random Forest prediction models. Input features included the raw multispectral bands, common vegetation indices, and independent variables ‘season’ and ‘month’. Predictive models were also developed from the hyperspectral sensor data using Partial Least Squares Regression. For both modelling types, variable selection was used to reduce model inputs to only those sensitive to each nutrient. Results comparing the final models in an independent validation test showed similar predictive performance of the Sentinel-2 satellite and the proximal hyperspectral sensor for all variates of interest, shown by mean absolute errors that were not significantly different. In each case, the dry matter concentration was the best predicted variable (Lin’s concordance correlation coefficient (LCCC) > 0.90) with excellent potential to be quantified by Sentinel-2 satellites. Crude protein, metabolisable energy, neutral detergent fibre, non-fibre carbohydrate, and water-soluble carbohydrate concentrations were also predicted with good to moderate accuracy by both sensors (LCCC between 0.50 and 0.80). These models would be sufficiently accurate for making qualitative predictions (e.g., grouping into high to low categories). Ash and acid detergent fibre concentrations were poorly predicted (LCCC < 0.50) and these models would not be recommended for further use. It was concluded that multispectral data from Sentinel-2 has great potential to estimate pasture nutrient concentrations for intensively grazed pastures such as those used in dairy systems in temperate regions.

Effect of natural Sirisha bark filler on mechanical and wettability analysis of polymer composites

Today's focus is on biodegradable materials. Natural materials are cost-effective, environmentally benign, and machinable; thus, researchers are investing in them. Synthetic materials are non-renewable and expensive to process. Sirisha trees are prevalent in tropical and subtropical climates. Sirisha bark is treated as bio-waste. In this study, it was examined as a polymer composite filler. After bark filler reinforcement, the material's tensile modulus and impact strength increased to the strong interfacial bond of the bark filler with the PP matrix. The decreased tensile strength with the Sirisha bark filler may be due to agglomeration at a high population of filler in the matrix. As seen in the scanning electron microscope (SEM), Sirisha bark strongly bonded with the polymer matrix, improving interfacial adhesion. Natural filler reinforcement lowered the polymer composites' hydrophobicity depicted in the wettability test.

Osteogenic and antibacterial properties of TiN-Ag coated Ti-6Al-4V bioimplants with polished and laser textured surface topography

In this study, polished and laser textured Ti6Al4V alloy bioimplant samples were coated with TiN and Ag using PVD technique and evaluated for the synergistic effects of osseointegration and antibacterial behaviour. The surface roughness parameters, surface wettability, XPS, XRD and SEM analysis of the modified surface were carried out. The level of osseointegration of the coated samples was evaluated through in-vitro osteoblast cell adhesion and fluorescent microscopy. The antibacterial property was evaluated through the degree of bacterial adhesion using S.aureus strain. The osseointegration and antibacterial properties are correlated with the physio-chemical characteristics of the coated samples. The results show that the negative skewness value for the case of textured surface is also associated with increased surface roughness in comparison with polished surface. TiN-Ag coated textured samples are hydrophilic in nature due to the increased surface roughness and the presence of metallic oxides with hydrophilic properties at the surface. Both the coated samples have exhibited improved cell adhesion and proliferation with the TiN-Ag coated textured samples showing slightly higher osteointegration together with preferential alignment of cells due to the phenomenon of contact guidance. With regard to antibacterial behaviour also, both the TiN-Ag coated polished and TiN-Ag coated textured samples demonstrated improved performance than its un-coated counterparts. The study revealed that TiN-Ag PVD coating on polished and laser textured Ti6Al4V implant samples is favourable for better osseointegration and antibacterial behaviour of the implants. Also, the laser textured-TiN-Ag PVD coated samples are superior over TiN-Ag coated polished samples with regard to their osseointegration and antibacterial performance.

Low temperature preparation of diopside nanoparticles: in-vitro bioactivity and drug loading evaluation

Bioactive diopside (CaMgSi2O6) nanoparticles have recently gained potential usefulness as bone replacement materials and nano vehicles for delivering therapeutics. The structural characteristics of this ceramic have found to be a key factor in bone bonding ability. To attain the desired product for 100% clinical success, it is important to realize the relationship between structure and biological activity. Synthesis of these nanoparticles via the solid-state method has been regarded as a low-cost and easy process in large-scale, but time consuming reactions and high temperature (≈ 1400 °C) are required. On the other side, the wet chemistry can overcome these drawbacks, whereas the presence of byproducts in the final powder has limited this method in large-scale production. The present document has represented a simple, fast and one-pot sol–gel approach for the synthesis of highly pure diopside nano-powders (< 20 nm) by using not-expensive precursors. Calcination of the obtained powder has been conducted at various temperatures (700, 1000 and 1200 °C). The physicochemical and microstructural properties of the products have been characterized by XRD, FTIR, FESEM and TEM. Moreover, the impact of the crystallinity on the bioactivity, drug loading capacity and drug release behavior of the synthesized nanoparticles have been investigated here for the first time. The in-vitro bioactivity results of the prepared diopside samples in a simulated body fluid (SBF) at 37 °C revealed the higher capability of the sintered sample to deposit calcium phosphate, compared with the amorphous one. High quantity of gentamicin (around 10 µg) could attach to the surface of 1 miligram of the sintered diopside during the early stages of contact (3 h), suggesting the potential use of diopside as a new class of nano-vehicles for antibiotics. The release behavior indicated a sustained release of gentamicin (80%) after 24 h. In conclusion, diopside nanoparticles can be a promising candidate as a drug-vehicle for bone filling, implant coating or bone cement applications.

Porous carbon nanosheets derived from two-dimensional Fe-MOF for simultaneous voltammetric sensing of dopamine and uric acid

It is of great significance for electrochemical sensors to simultaneously detect dopamine (DA) and uric acid (UA) related to biological metabolism. In this work, two-dimensional (2D) porous carbon nanosheets (CNS) was prepared as electrocatalysts to improve the sensitivity, the selectivity, and the detection limit of the simultaneous detection. First, 2D amorphous iron-metal organic frameworks (Fe-MOF) was synthesized with Fe3+ and terephthalic acid via a facile wet chemistry method at room temperature. And then, CNS was prepared by pyrolysis and pickling of Fe-MOF. CNS had large specific surface area, good electrical conductivity and lots of carbon defects. The response currents of the CNS modified electrode was larger than those of the control electrodes in the simultaneous determination. The simultaneous determination was measured via differential pulse voltammetry to reduce the effect of capacitive currents on quantitative analysis. The CNS modified electrodes showed high sensitivity and low detection limit for the simultaneous detection of DA and UA. The modified electrodes have been successfully used to detect DA and UA in normal human serum.

Towards a clean environment: To what extent can trees serve as phytoremediators for chemically polluted soils?

The study investigated the potential of five common tree species in West Africa to bioaccumulate heavy metals in their various plant components over the course of different growth phases and at varying contamination levels (control, double the permissible level and triple the permissible limit). Heavy metals in plant tissues were extracted and analyzed using standard wet chemistry procedures. The results showed metal concentrations in tree tissues to positively and significantly correlate with contamination level, growth stage, and plant component. Metal mobility and availability in the tree tissues were in descending order of Mn >Zn>Cu=Pb>Cd. We found heavy metals to be principally accumulated in the stem tissues following a metal exclusion theory, independent of tree species. Tree roots demonstrated a significant accumulation of heavy metals second only to the stem. The results revealed that heavy metal mobility and bioavailability in plant tissue was tree-specific, growth stage-dependent, and metal-specific; showing that trees have a preferential affinity to accumulate a specific metal or pollutant. The study established Shorea roxborghi to be a mono-accumulator of manganese while Tectona grandis and Terminalia ivorensis were multi-accumulators of metals such as Mn, Cu, Zn and Pb. The interactive effects of contamination levels and tree species showed Tectona grandis and Terminalia ivorensis grown in chemically polluted soils at triple the permissible level to have the highest heavy metal uptake with the highest phytoextraction potential. We conclude that all the tree species considered in this study could potentially be effective phytoremediators of chemically polluted soils through their ability in phytoextraction of metals such as lead, zinc, copper, and manganese as well as through phytostabilization of cadmium in contaminated soils.

Profile and nano-scale distribution of soil organic carbon for upland and paddy soils from an alluvial plain in South China

Understanding the heterogeneous distribution of soil organic carbon (C) (SOC) in different soil environments is essential for predicting SOC preservation. However, SOC distribution differs in profile scales and molecular levels in various farmland soils, making it challenging to elucidate the environmental behaviors of SOC. In the present study, upland and paddy soil samples were both collected at different depths (0–100 cm) from an alluvial plain in the Pearl River Delta of South China. Wet chemistry experiments coupled with 13C-nuclear magnetic resonance (NMR) and spherical aberration correction scanning transmission electron microscopy (Cs-STEM) were used to determine the vertical distribution, chemical composition, and nano-scale sequestration mechanisms of SOC in upland and paddy soils. SOC content for upland soil, which was highest at the depth of 0–20 cm (6.98 ± 0.34 g·kg−1), decreased with increasing soil depth, while that of paddy soil had the highest content at a depth of 80–100 cm (86.66 ± 5.26 g·kg−1). Statistical analysis revealed that mineral-associated organic C (MAOC) in the upland soil and particulate organic C (POC) in the paddy soil were the major C fractions that were related to SOC content. Further analysis of NMR spectra showed that the molecular composition of upland SOC differs vertically, while the molecular composition and proportion of organic C in paddy soil varied with soil depth. Cs-STEM results revealed that the relative percentage of carboxyl C decreased from 0 to 20 cm (42.1%) to 80–100 cm (28.8%) with an increase in aromatic C from 7.7 to 27.2% for the upland soil, while the four C species showed similar abundance for paddy soil at different depths, consistent with the NMR results. Overall, the upland SOC was not as easily mineralized as that of paddy soil due to a lower percentage of easily oxidized carbon, higher percentage of MAOC, and higher decomposition degree. The results of this study would enrich our quantitative understanding of the profile distribution and chemical diversity of SOC from macro to micro scales in the alluvial plain from South China, and provide insights into C preservation in natural soils.

Weed control and weed biomass influenced first cutting forage accumulation and nutritive value of spring‐seeded alfalfa

AbstractWeeds can influence the economics of alfalfa (Medicago sativa L.) production by reducing forage yield and nutritive value or by contaminating hay. Field studies were conducted in Idaho in 2021 and 2022 to evaluate the effect of weed control treatments on alfalfa forage accumulation, weed biomass, and nutritive value. In addition, the relationship between the proportion of individual weed species biomass and alfalfa nutritive value was assessed. These studies included eight different herbicide and herbicide combination treatments, including the untreated check. Treatments were comprised of preemergence, early postemergence (after 80% alfalfa emergence), and postemergence (third trifoliate alfalfa) herbicide applications. Data collection included weed control efficacy, weed and alfalfa biomass, and alfalfa nutritive value. Additional samples were collected and combined in these alfalfa to weed biomass proportions (percentage by weight): 0/100, 20/80, 40/60, 60/40, 80/20, and 100/0, for wet chemistry analysis of forage nutritive value to evaluate the relationship between the proportion of individual weed species biomass and alfalfa nutritive value. The acetochlor‐only treatment provided less than 50% weed control, while the EPTC (S‐ethyl‐N,N‐dipropylthiocarbamate)‐only treatment provided 54%–81% weed control. The control provided by acetochlor and EPTC was less than that provided by treatments containing imazamox and imazamox plus bromoxynil. Weed biomass in forage (23%–55% of total biomass) due to poor or no weed control reduced crude protein, increased fiber concentrations, and reduced the relative feed value. The relationship between the proportion of individual weed species biomass and alfalfa nutritive value was linear for all weed species evaluated.

Copper oxide-anchored ZnO nanoflakes for the enhanced photocatalytic degradation performance and mechanistic investigations

An efficient CuO anchored ZnO nanoflakes were synthesized through facile wet chemistry method and the catalysts were well characterized using various sophisticated instruments. CuO nanoparticle incorporation was found to have a direct linear relationship with light absorbance. The degradation ability of the ZnO/CuO p-n junction was studied on the degradation of methyl orange. Under UV–Vis light illumination, the photocatalytic removal efficacy of methyl orange over CuO/ZnO p-n junction is up to 89%, which is greater than that of barecatalysts. The maximized photocatalytic degradation performance might be ascribed to the augmented visible light harvesting capacity and reduced the rate of photogenerated electron-hole pair recombination. The efficient photoinduced electron and hole pair charge separation upon excitation is aided by the effective formation of p-n junctions between ZnO and CuO. Based on the findings, a plausible photocatalytic mechanism for the as-synthesized CuO anchored ZnO nanoflake was proposed.

Rapid evaluation of organic and pyritic δ34S values in immature sedimentary rocks using a Rock-Eval 7S® coupled to MC-ICPMS

Sulfur isotopic values (δ34S) in sedimentary organic matter and pyrite provide essential information about the global S cycle. The measurement of δ34S values is commonly used to reconstruct paleo-environmental conditions of sediment deposition. In petroleum geochemistry, δ34S values are used to trace relationships between disparate elements of petroleum systems. However, the determination of organic and pyrite δ34S values requires a tedious and time-consuming (weeks) stepwise procedure. Here we used the latest version of the Rock-Eval® 7S analyzer, which can quantify different S-fractions in sedimentary rocks. We have coupled the Rock-Eval® pyrolysis cycle with a multi-collector inductively coupled plasma mass spectrometer (RE/MC-ICPMS). The analysis requires a small sample size (5 to 90 mg), and minimum sample preparation of acid treatment to avoid the carbonate effect on the pyrolyzed pyrite-S. The RE/MC-ICPMS system allows for measuring the pyrolysable organic-S and pyrite-S and directly determining δ34S values from a decarbonated rock. The new method was applied to a set of immature sedimentary rocks of various paleoenvironmental origins and geographic locations. The rapid analysis by the RE/MC-ICPMS, which takes only 20 min per sample, achieved an average precision of 0.5‰, for peaks above 5 nanomole of S. Accuracy was determined relative to a common wet chemistry method followed by an offline EA-IRMS analysis and reached an agreement of <1‰.

Synthesis, characterization, and density functional theory calculation studies of a novel Rb-based lead halide perovskite material

Inorganic lead halide perovskites have appeared as favorable and novel materials for their effective use in photovoltaics. The synthesis route of such materials via the simple wet chemistry technique renders these inorganic halide perovskites the ideal property for light-harvesting materials. Despite these novel properties, the inherently unstable nature under increased heat and ambient moisture conditions is still a conjecture that needs to be addressed. This work shows the wet chemistry method as a synthesis route of the novel RbPbCl3 perovskite using four different solvents for photovoltaic applications. Interestingly, the synthesized perovskite was stable in only one solvent with a band gap of 2.6 eV, whereas the material degraded in the other three. The DFT calculations performed post-geometric optimization revealed well-defined electronic bandgap and optical properties, nearly imitating the experimental data of our synthesized perovskite. The copious properties such as electronic, optical, and formation energy revealed that the perovskite possesses huge charge screening ability, a low recombination rate of electron-hole pairs, board absorption spectrum, and high stability. Henceforth, establishes its suitability for photovoltaic devices. The close fit of the experimental results with our theoretical trend demonstrates the importance of developing a computational strategy to screen for new perovskite materials for photovoltaic cells.

Incorporation of Th4+ and Sr2+ into Rhabdophane/Monazite by Wet Chemistry: Structure and Phase Stability.

Rhabdophane is an important permeable reactive barrier to enrich radionuclides from groundwater and has been envisaged to host radionuclides in the backend of the nuclear fuel cycle. However, understanding of how An4+ and Sr2+ precipitate into rhabdophane by wet chemistry has not been resolved. In this work, Th4+ and Sr2+ incorporation in the rhabdophane/monazite structure as La1-2xSrxThxPO4·nH2O solid solutions is successfully achieved in the acid solution at 90 °C. Some specific issues such as lattice occupation of Th4+ and Sr2+, precipitation reaction kinetics, and crystal growth affected by starting stoichiometry are discussed in detail, along with investigating the chemical stability of La1-2xSrxThxPO4·nH2O precipitations and associated La1-2xSrxThxPO4 monazite. The results reveal that the excess of Sr2+ appears to be a prevailing factor with a suggested initial Sr: Th ≥ 2 to obtain the stability domain of La1-2xSrxThxPO4·nH2O (x = 0∼ 0.1). A rapid ion removal associated with a nucleation process has been observed within 8 h, and Th4+ can be removed more than 98% after 24 h in 0.01 mol/L solutions. From structural energetics based on density functional theory, the lattice occupation of Th4+ and Sr2+ is energetically favorable in nonhydrated lattice sites of [LaO8], although two-thirds of lattice sites are associated with [LaO8·H2O] hydrated sites. Intriguingly, the crystal transformation from rhabdophane to monazite associated with the transformation from [SrO8] to [SrO9] polyhedra can greatly improve the leaching stability of Sr2+.

Influence of Channel Surface with Ozone Annealing and UV Treatment on the Electrical Characteristics of Top-Gate InGaZnO Thin-Film Transistors.

The effect of the channel interface of top-gate InGaZnO (IGZO) thin film transistors (TFTs) on the electrical properties caused by exposure to various wet chemicals such as deionized water, photoresist (PR), and strippers during the photolithography process was studied. Contrary to the good electrical characteristics of TFTs including a protective layer (PL) to avoid interface damage by wet chemical processes, TFTs without PL showed a conductive behavior with a negative threshold voltage shift, in which the ratio of Ga and Zn on the IGZO top surface reduced due to exposure to a stripper. In addition, the wet process in photolithography increased oxygen vacancy and oxygen impurity on the IGZO surface. The photo-patterning process increased donor-like defects in IGZO due to organic contamination on the IGZO surface by PR, making the TFT characteristics more conductive. The introduction of ozone (O3) annealing after photo-patterning and stripping of IGZO reduced the increased defect states on the surface of IGZO due to the wet process and effectively eliminated organic contamination by PR. In particular, by controlling surface oxygens on top of the IGZO surface excessively generated with O3 annealing using UV irradiation of 185 and 254 nm, IGZO TFTs with excellent current-voltage characteristics and reliability could be realized comparable to IGZO TFTs containing PL.

Antimony immobilization mechanism on schwertmannite: Insights from the microstructure of schwertmannite

Schwertmannite affects the mobility of antimony (Sb) in acid mine drainage, yet the Sb sorption mechanism remains elusive. In this study, the molecular-level mechanism and the driving force of Sb(V) immobilized on schwertmannite were investigated by a combination of wet chemistry, extended X-ray absorption fine structure (EXAFS) analysis, density functional theory (DFT) calculations, and a surface complexation model (SCM). The observed sorption capacity for Sb(V) was as high as 235.63 mg/g. Such remarkable sorption capacity is primarily achieved by the anion exchange reaction and surface complexation reaction of Sb(V) with sulfate and surface/tunnel inner-surface hydroxyl groups, respectively, and the contribution of the anion exchange reaction to Sb(V) immobilization decreases markedly with increasing Sb(V) loading or pH. The loading of Sb(V) appears to be the key parameter controlling its immobilization mechanism on schwertmannite. Low-loaded Sb(V) primarily generates bidentate-mononuclear and bidentate-binuclear surface complexes (adsorption products) and is concurrently partly incorporated into the Fe-O framework of schwertmannite to form a hexadentate-hexanuclear complex (incorporation product). With increasing Sb(V) loading, Sb is primarily adsorbed on the surface and in the tunnel of schwertmannite with the formation of bidentate-mononuclear (dominant) and bidentate-binuclear complexes without incorporation. The inconsistency of the immobilization mechanism is controlled by the amount of released sulfate induced by Sb(V). The substantial system energy reduction caused by the formation of Sb(V) adsorption and incorporation products on the surface and in the tunnel of schwertmannite is the driving force for the stable immobilization of Sb(V) by schwertmannite, and the energy reduction caused by tunnel complexes is far more obvious than that caused by surface complexes. A charge distribution multisite complexation model was established based on bidentate-mononuclear and bidentate-binuclear surface complexes with fitted Log K values of 21.99 ± 0.18 and 12.84 ± 0.92, respectively, which consistently predicted Sb(V) sorption across pH 3.0–9.0 for all involved Sb(V) loadings. In addition, Sb(V) has a strong stabilizing effect on the schwertmannite structure and broadens its pH stability window (pH 3.0–9.0). This study facilitates elucidation of the fate and geochemical cycling of Sb in the mining environment and helps to promote the application of the microstructure of schwertmannite in other studies of microscopic interface chemistry.

Modification of nonwoven polymer materials for increasing of their filtration and antibacterial properties

AbstractPolytetrafluoroethylene (PTFE), octenidine dihydrochloride (OCT), and zinc oxide (ZnO) were used to modify the polypropylene nonwoven material by the methods of “wet chemistry” and low‐energy electron beam deposition (EBD). The influence of nonwoven material modification on the morphology, chemical composition, filtration, and antibacterial properties was established. The modified material has antibacterial activity against the gram‐positive strain Staphylococcus aureus and against gram‐negative strains of Escherichia coli and Klebsiella pneumoniae (suppression of bacterial growth for materials with OCT was 100%, with ZnO—70%). PTFE application to Aquaspun leads to a significant increase in the contact angle (from 141.3° to 152.7°) and air filtration efficiency (from 78.3% to 83.4%), which provides the barrier properties of the material. It was established that the material obtained using low‐energy EBD demonstrated a more pronounced antimicrobial potential against the tested strains of St. aureus.Highlights The influence of polypropylene nonwoven materials surface modification methods is systematically investigated. Low‐energy electron beam deposition increases antibacterial and filtration properties of nonwoven materials. Surface modification methods increase barrier properties of polypropylene nonwoven materials.

Effect of the ZnFe2O4 shell in Fe3O4 on the properties of its nanocomposites with P3HT

The coating of the nanoparticles (Nps), in addition to avoiding their agglomeration and degradation in the different media used, provides them with new properties and, therefore, also to the nanocomposite obtained. In this work, new hybrid nanocomposites based on poly(3-hexylthiophene) with Nps of Fe3O4 or Fe3O4@ZnFe2O4 core@shell are synthesized and characterized. Fe3O4 Nps are obtained by the chemical bath deposition method, while Fe3O4@ZnFe2O4 core@shell Nps are synthesized by wet chemistry by deposition of ZnO on the surface of Fe3O4 Nps. P3HT/Fe3O4 and P3HT/Fe3O4@ZnFe2O4 nanocomposites are obtained by in-situ synthesis of P3HT by the Grignard metathesis method (GRIM) in the presence of different concentrations of the Nps (3HT/Fe3O4 or 3HT/Fe3O4@ZnFe2O4 weight ratio: 1/0.01 and 1/0.02). The incorporation of Fe3O4 and Fe3O4@ZnFe2O4 in the P3HT polymeric matrix is corroborated by FTIR. With the incorporation of both nanoparticles (Fe3O4 and Fe3O4@ZnFe2O4) to P3HT, the roughness increased, and the absorbance was increased depending on the concentration of the particles. The presence of Fe3O4@ZnFe2O4 core@shell Nps in P3HT increases the decomposition temperature, and the photoconductivity. On the other hand, the electrochemical characterization shows an increase in the cycle area when incorporating Fe3O4@ZnFe2O4 in P3HT. The P3HT/Fe3O4@ZnFe2O4 nanocomposites obtained in this work present interesting optoelectronic properties to be applied in different optoelectronic devices.