Varying pH Values Research Articles

Fractionation of stable boron isotopes in alfisols: Application of a novel tool for tracing boron behavior in two soil profiles

Available boron (AB) and total boron (TB) in soil have distinct isotopic values, which are mainly influenced by the pH, organic matter and clay minerals, and can be used to explore the chemical behaviors of boron (B) in adsorption, weathering and eluviation processes. The B isotopic compositions of AB and TB in brown soil (slightly acidic) and cinnamon soil (neutral to slightly alkaline) profiles were investigated by multicollector inductively coupled plasma mass spectrometry. Variations in pH value and organic matter in the two soils directly affected the adsorption of B isotopes (dissolved 11B(OH)3 or 10B(OH)4-) in the aqueous solution, as shown by AB having an average negative δ11B value of −1‰ and a great range of −10.83‰ to +8.32‰ in the cinnamon soil. Furthermore, the long-term effects of adsorption and transportation processes were evidenced by the large range of δ11BTB values (-24.22‰ to +21.07‰) in the two soils. The topsoil layers with more organic matter and higher δ11B values indicated that B isotope fractionation occurred as a result of the input of rainfall, recycling of plant litter and the adsorption of organic matter and clay minerals. The lower δ11B values, the higher B contents and the element ratios in the underlying layers resulted from the weathering of different minerals and the adsorption of AB in the leaching process. This finding is supported by the relationship between AB and the clay/silt ratio, with more negative δ11B values being associated with finer clay particles via the adsorption of 10B(OH)4- in a weakly alkaline soil solution. The δ11B values in soils may be a useful tool for distinguishing geochemical cycling and processes and characterizing long-term processes that are difficult to assess.

Genetic diversity in a core collection of Iranian sour cherry.

The exploitation of plant genetic resources is an important and rapid strategy to release commercial cultivars. In this study, 234 sour cherry genotypes were collected from various locations of Iran and phenotypically assessed according to IPGRI and UPOV descriptors. The genotypes were grafted onto Mahaleb rootstock and were planted in Horticultural Science Research Institute (HSRI) core collection in Karaj, Iran. In this study, 22 different characteristics were measured in the sour cherry genotypes. The results showed that fruit and stone weights varied from 1.65 (G410) to 5.47 g (G125) and 0.13 (G428) to 0.59 g (G149), respectively. The fruit size index comprised average fruit length, width, and diameter, which varied from 10.57 to 19.13. The stalk length was less than 50 mm in 90.6% of the studied genotypes. Twelve of the 234 studied genotypes did not exhibit any symptoms of bacterial canker disease. Principle component analysis (PCA) and cluster analysis classified the studied genotypes into four main groups. Spearman's correlation analysis revealed that fruit size, stone shape, stone size, stalk thickness and weight, and fruit appearance correlated positively with stone and fruit weights. In contrast, fruit juice, fruit skin, and flesh color correlated negatively with the stone and fruit weights. The range of TSS varied between 12.66 (G251) and 26 (G427). Variations in pH value were between 3.66 (G236) and 5.63 (G352). In conclusion, a high level of genetic diversity was observed among the Iranian sour cherry genotypes. This diversity can be considered valuable and applicable for future breeding programs.

Unusual redox stability of pentavalent uranium with hetero-bifunctional phosphonocarboxylate: insight into aqueous speciation.

The +5 state is an unusual oxidation state of uranium due to its instability in the aqueous phase. As a result, gaining information about its aqueous speciation is extremely difficult. The present work is an attempt in that direction and it provides insight into the existence of a new pentavalent species in the presence of hetero-bifunctional phosphonocarboxylate (PC) chelators, other than the carbonate ion, in the aqueous medium. The aqueous chemistry of pentavalent uranium species with three environmentally relevant PCs was probed using electrochemical and DFT methods to understand the redox energy and kinetics of conversion of the U(VI)/U(V) couple, stability, structure, stoichiometry, binding modes, etc. Interestingly, pentavalent uranium complexes with PCs are quite persistent over a wide range of pH starting from acidic to alkaline conditions. The PC chelators block the cation-cation interaction (CCI) of U(V) through strong hetero-bidentate chelation and intermolecular hydrogen bonding (IMHB) interactions which stabilize the pentavalent metal ion against disproportionation. For uranyl species in the presence of PCs, acting as chelators, CV plots were obtained at varying pH values from 2 to 8. The obtained results indicate an irreversible single redox peak involving U(VI) to U(V) conversion and association of a coupled chemical reaction with the electron transfer step. ESI-MS studies were performed to understand the speciation effect on the U(VI)/U(V) redox couple with varying pH. Speciation modelling of U(V) with the PC ligands was carried out, which indicated that the U(V) is redox stable in nearly 47% of the pH region in the presence of the PCs as compared to the carboxylate-based chelators. The free energy and reduction potential of the U(V) complexes and the reduction free energy and disproportionation free energy for the U(VI)/U(V) couple were determined by DFT computations in the presence of the PCs. In situ spectroelectrochemical spectra were recorded to provide evidence for the existence of U(V) species with PCs in the aqueous medium and to acquire its absorption spectra. The present study is highly significant for understanding the coordination chemistry of pentavalent uranium species, accurate modelling of uranium, and isolation of U(V).

PH-Responsive textile with anthocyanin-laden hydrogel yarns: a colorimetric and feasibility study

Abstract Responsive materials can transform their visual appearance in reaction to environmental stimuli. One example of such responsiveness involves the use of plant-based anthocyanins as pH-mediated allochroic pigments. Despite the increasing interest and applications of this pigment, its applications in urban contexts are very limited. By using pH-mediated colour change as a phenomenon to trial a colourimetric quantitative framework, this study seeks to bridge smart material design with colour science approaches to enable future scale-up applications. The colour values of anthocyanins immobilised in sodium alginate-based hydrogel discs and yarns were measured in response to varying pH values. The colourimetric measurements in CIELAB colour space provided a device for setting independent colour values that demonstrated a clear pattern across the pH range of 1–12. The colour difference (ΔE00) of mean colour values was perceivably different across the pH scale, with a minimum value of 2.7. Key variables of the process have been summarised, and their relationships have been discussed. Finally, a proof-of-concept small-scale textile prototype encompassing anthocyanin-laden hydrogel yarns was developed. The findings of this study contribute towards the integration of non-destructive means of colour measurement as a quantitative tool for biochemical process evaluation.

A functional Pickering emulsion coating based on octadecenylsuccinic anhydride modified γ-cyclodextrin metal-organic frameworks for food preservation

In the rapidly advancing field of colloid and interface chemistry, food-grade nanoparticles are garnering increased attention for their potential applications in food preservation and innovative material development. Pickering emulsions, stabilized by solid particles, are especially noteworthy for their versatile applicability, spanning from food preservation to innovative material engineering. However, crafting a reliable, application-specific Pickering emulsion that amalgamates both stability and functionality poses a substantial challenge. In this research, we present an in-depth analysis of octadecenylsuccinic anhydride (ODSA) modified γ-cyclodextrin metal-organic frameworks (OCMs) stabilized ODSA Pickering emulsions, probing their stability across varying pH values and ionic strengths, and evaluating their groundbreaking applications, notably in paper coating and enhancing food shelf life. Our results unequivocally indicate a pronounced improvement in paper water resistance and fruit preservation after treatment with the OCMs-ODSA emulsion, heralding a novel methodology in these areas. Additionally, our studies illuminate the intrinsic antimicrobial attributes of OCMs, accentuating their cardinal role in augmenting the emulsion's preservation capabilities and heralding potential widespread applications in microbial mitigation, decay deterrence, and beyond.

As an Application of Sustainability: Utilizing Processed Rice Husk to Remove Cadmium Ions Cd (II) From Aqueous Phase by Adsorption

This study goals to reduce the importance of expensive commercial activated carbon while removing heavy metals from wastewater using cheap, locally available materials (rice husk). To accomplish this goal, a variety of pH values were tested, and it was found that batch studies at pH 5 had the best Cadmium ion removal effectiveness. 180 minutes was determined to be the ideal contact time for the process, and it was discovered that as contact time increased, adsorption effectiveness increased. 180 rpm is the recommended shaking speed, given studies on how agitation speed influences batch adsorption. The effectiveness of the rice husks capacity to eradicate Cadmium Cd (II) from aqueous solutions and absorb it, has assessed. The study revealed that Cd had a 98% effectiveness of removal. The recommended adsorbent's maximum Cd adsorption capability in a batch system was found to be 7.38 mg/g. Three models— Freundlich, Temkin, and Langmuir—were fitted to various equilibrium isothermal experiments. For this system, the experimental best fit was provided by the Freundlich isotherm model, with an value of 0.97. The equilibrium isotherms were discovered to be of a favorable type. When the correlation coefficient (R2) values of each curve for the four models are compared, it appears that the Elovich model best captures the kinetics of the Cadmium ions adsorption onto rice husk. Were the values (Elovich> pseudo-second order> intra-particle diffusion> Pseudo-First Order). According to the research, rice husk may be useful for filtering out wastewater from contaminants and impurities. So, It is a good alternative for expensive activated carbon.

Polyanhydride Microcapsules Exhibiting a Sharp pH Transition at Physiological Conditions for Instantaneous Triggered Release.

Stimulus-responsive microcapsules pose an opportunity to achieve controlled release of the entire load instantaneously upon exposure to an external stimulus. Core-shell microcapsules based on the polyanhydride poly(bis(2-carboxyphenyl)adipate) as a shell were formulated in this work to encapsulate the model active substance pyrene and enable a pH-controlled triggered release. A remarkably narrow triggering pH interval was found where a change in pH from 6.4 to 6.9 allowed for release of the entire core content within seconds. The degradation kinetics of the shell were measured by both spectrophotometric detection of degradation products and mass changes by quartz crystal microbalance with dissipation monitoring and were found to correlate excellently with diffusion coefficients fitted to release measurements at varying pH values. The microcapsules presented in this work allow for an almost instantaneous triggered release even under mild conditions, thanks to the designed core-shell morphology.

Temporal changes of exposure to water on physic-chemical, stability, and transport characteristics of pyrogenic carbon colloids

Understanding the effect of the aging process on the properties of pyrogenic carbon (PyC) is critical for predicting and evaluating its transport and fate. Water exposure is a common application scenario of PyC entering aquatic systems or flooded paddy fields, which might significantly affect the aging process. However, only some studies focused on the changes in PyC properties by water exposure treatment. In this study, the effect of water exposure on the mobility of PyC was investigated. Fresh PyC, PyC with 1.5 years and 3.5 years of water exposure were selected and named as CK, 1.5WA, and 3.5WA, respectively. Our results revealed that CK had the lowest intensity of surface functional groups (-OH, CO, and C–O–C) and the intensity of 3.5WA was higher than that of 1.5WA. There was no significant change in dissolved organic matter (DOM) content between fresh and aged PyC colloids. However, UV absorbance and its parameters (E2/E3, E4/E6, and SR) exhibited a comparable tendency to the abundance of functional groups (-OH, CO, and C–O–C). The fresh and aged PyC colloids showed high stability in Na+ and Ca2+ solutions at varying pH values (A/A0 > 85%), which was also observed in groundwater. The mobility of fresh and aged PyC colloids differed in Na+ (21.74%–57.19%), Ca2+ (14.30%–40.12%) solutions and groundwater (28.50%–44.24%), but exhibited similar order (3.5WA > 1.5WA > CK). The mechanism of the effect of water exposure on the property and mobility of PyC colloids was explored. This study provides the fundamental information to estimate PyC fate and transport after long-term water exposure.

Synthesis and Application of MnO-Fe2O3 Nanocomposites for the Removal of 137Cs and 60Co Radionuclides from Artificial Radioactive Aqueous Waste

For innovative application in wastewater treatment techniques, MnO-Fe2O3 nanocomposites were successfully synthesized using the sol–gel auto-combustion method at different temperatures for the adsorption of 137Cs and 60Co radionuclides from aqueous solution. The characterization of these nanocomposites was carried out through FT-IR, SEM-EDX, and X-ray diffraction. These nanocomposites were employed as adsorbent materials for the removal of 137Cs and 60Co radionuclides from simulated radioactive waste solutions. The study involved a series of experiments aiming to demonstrate the MnO-Fe2O3 nanoparticles’ exceptional adsorption potential concerning 137Cs and 60Co. Additionally, the investigation delved into how variations in temperature, dose amount, contact time, and pH value influence the adsorption dynamics. Due to their high specific surface area, the synthesized MnO-Fe2O3 nanoparticles had high adsorption capacity of more than 60% and 90% for 137Cs and 60Co, respectively. By investigation of kinetics and adsorption isotherms, pseudo-second-order reaction and the Langmuir model turned out to fit well for the adsorption of 137Cs and 60Co onto the MnO-Fe2O3 nanocomposites. Moreover, a thermodynamic analysis revealed that the adsorption process was spontaneous for both target metals and the adsorption of 60Co was endothermic, whereas the adsorption of 137Cs was exothermic.

Role of an antagonistic bacterium, Bacillus subtilis PE7, in growth promotion of netted melon (Cucumis melo L. var. reticulatus Naud.).

The aim of this study was to determine the plant growth-promoting effect of Bacillus subtilis PE7 on growth of melon plants. B. subtilis PE7 isolated from kimchi was identified based on colonial and microscopic morphology along with analyses of 16S rRNA and pycA gene sequences. Strain PE7 showed different levels of inhibition on phytopathogens and was able to grow at variable temperatures and pH values. Strain PE7 had the ability to produce siderophores, indole-3-acetic acid (IAA), ammonia, exopolysaccharides, and 1-aminocyclopropane-1-carboxylic acid deaminase, as well as solubilize insoluble phosphate and zinc. The IAA secretion of strain PE7 showed a concentration-dependent pattern based on the concentration of l-tryptophan supplemented in the fertilizer-based culture medium. The LC-MS analysis indicates the presence of IAA in the culture filtrate of strain PE7. Treatment of the B. subtilis PE7 culture containing different metabolites, mainly IAA, significantly promoted melon growth in terms of higher growth parameters and greater plant nutrient contents compared to treatments with the culture without IAA, fertilizer, and water. The cells of B. subtilis PE7 attached to and firmly colonized the roots of the bacterized melon plants. Based on our results, B. subtilis PE7 can be utilized as a potential microbial fertilizer to substitute chemical fertilizers in sustainable agriculture.

How applied reclamation treatments and vegetation type affect on soil fauna in a novel ecosystem developed on a spoil heap of carboniferous rocks

The restoration of soil fauna on a spoil heap is a strong indicator of successful reclamation. The studies were conducted on two types of materials: bare rock (BR) and BR with topsoil (TS) which were applied during coal spoil reclamation and three vegetation types. Four variants investigated included natural forest succession on BR (Succession_BR) and TS (Succession_TS), afforestation (Reclamation_TS) and afforestation with Robinia pseudoacacia (Robinia_TS). Soil pH, soil organic carbon (SOC) and total nitrogen (TN) content, and soil texture were measured in 0–10 cm layers. Earthworms were collected using hand sorting method, and enchytraeids were collected using wet extraction with the heating method.The investigated soil had varying pH values from 5.3 in a BR to 7.2 in Robinia_TS. The highest content of SOC and TN were in Successinon_BR, and the lowest was in Succession_TS. Enchytraeids density was in the following increasing order: 275, 2982, 3001 and 4548 ind m−2 for Succession_BR, Robinia_TS, Succession_TS and Reclamation_TS, respectively. Earthworm density ranged from 0 ind. m−2 in the Succession_BR through 116 ind m−2 and 120 ind m−2 in Reclamation_TS and Succession_TS, respectively up to 162 ind m−2 in the Robinia_TS.The reclamation treatment was a major driver for soil fauna development while vegetation type was of secondary importance. Investigated soil fauna was positively related to pH value and clay content. The most stimulating variant for the development of earthworms and enchytraeids was the application of reclamation with various tree species and the planting of Robinia pseudoacacia on the topsoil.

The inhibitory effect of berberine chloride hydrate on Streptococcus mutans biofilm formation at different pH values.

Streptococcus mutans (S. mutans) is one of the major cariogenic bacteria of dental caries owing to its ability to adhere to tooth surfaces and biofilm formation. Berberine chloride hydrate (BH), a quaternary ammonium salt alkaloid, has diverse pharmacological efforts against microorganisms. However, the effect of BH on S. mutans biofilm has not been reported. Considering that berberine is a quaternary ammonium salt alkaloid, which needs to adapt to a large variation in pH values and the acid resistance of S. mutans, we employed three groups including pH 5 (acidic), pH 8 (alkaline), and unprocessed group (neutral) to examine the antibiofilm activities of BH against S. mutans during different pH values. In this study, we found BH effectively suppresses S. mutans biofilm formation as well as its cariogenic virulence including acid production and EPS synthesis significantly, and the inhibitory effort was reduced under acidic condition whereas elevated under alkaline condition. In addition, we preliminarily explored the influence of pH values on the structural stability and biosafety of BHas well as the underlying mechanism of inhibition of S. mutans biofilm formation with BH. Our study showed BH could maintain a good structural stability and low toxicity to erythrocytes at different pH values. And BH could downregulate the expression of srtA, spaP, and gbpC, which play critical roles in the adhesion process, promoting bacterial colonization and biofilm formation. Furthermore, comX and ldh expression levels were downregulated in BH-treated group, which might explain its inhibitory effect on acid production.IMPORTANCEDental caries is a common chronic detrimental disease, which could cause a series of oral problem including oral pain, difficulties in eating, and so on. Recently, many natural products have been considered as fundamental sources of therapeutic drugs to prevent caries. Berberine as a plant extract showed good antibiofilm abilities against microorganism. Our study focuses on its antibiofilm abilities against S. mutans, which was defined as major cariogenic bacterium and explored the role of pH values and possible underlying mechanisms in the inhibitory effect of BH on S. mutans biofilm formation. This study demonstrated a promising prospect for BH as an adjuvant drug in the prevention and management of dental caries.

Quantitative relationship between soil pH and electrical conductivity values and cadmium phytoavailability for Chinese cabbage under simulated conditions

Pot experiments were conducted to investigate the impacts of continuous addition of different concentrations of calcium chloride (CaCl2) and/or low-molecular-weight organic acids (LMWOAs) on soil pH, electrical conductivity (EC), and cadmium (Cd) transformation. These factors subsequently affected Cd phytoavailability in a system consisting of Cd-contaminated soil and Chinese cabbage (Brassica chinensis L.). The results indicate that CaCl2 addition had a greater impact on reducing soil pH value, increasing soil EC value, and enhancing Cd phytoaccumulation in Chinese cabbage compared to LMWOAs. When soil pH dropped by 0.3 unit and the soil EC increased by 500 µS cm−1, the Cd concentration in the Chinese cabbage shoots was 3 times higher than that in the control group. Throughout two planting terms of Chinese cabbage, the addition of CaCl2 (1.6–3.2 g kg−1) and LMWOAs (≤ 1.0 g kg−1) led to phytoextracted Cd concentration exceeding exchangeable Cd concentration in soil samples before the pot experiment. Regarding phytoextracted Cd, desorption from carbonate-bound Cd contributes more than desorption from bound to organic matter Cd and adsorption to Fe/Mn oxide Cd. This study underscores the influence of soil pH and EC value variations and Cd transformation on Cd phytoavailability. Special attention should be given to leafy vegetables grown in Cd-contaminated soil, as the phytoavailable Cd concentration reaches approximately 2.0 µg kg−1, which may lead to Cd levels surpassing acceptable limits for Chinese cabbage.

The shape-dependent inhibitory effect of rhein/silver nanocomposites on porcine reproductive and respiratory syndrome virus

Traditional Chinese medicines (TCMs)/nanopreparations as viral antagonists exhibited a structure–function correlation, i.e., the differences in surface area/volume ratio caused by the variations in shape and size could result in different biochemical properties and biological activities, suggesting an important impact of morphology and structure on the antiviral activity of TCM-based nanoparticles. However, few studies paid attention to this aspect. Here, the effect of TCM-based nanoparticles with different morphologies on their antiviral activity was explored by synthesizing rhein/silver nanocomposites (Rhe@AgNPs) with spherical (S-Rhe/Ag) and linear (L-Rhe/Ag) morphologies, using rhein (an active TCM ingredient) as a reducing agent and taking its self-assembly advantage. Using porcine reproductive and respiratory syndrome virus (PRRSV) as a model virus, the inhibitory effects of S-Rhe/Ag and L-Rhe/Ag on PRRSV were compared. Results showed that the product morphology could be regulated by varying pH values, and both S- and L-Rhe/Ag exhibited good dispersion and stability, but with a smaller size for L-Rhe/Ag. Antiviral experiments revealed that Rhe@AgNPs could effectively inhibit PRRSV infection, but the antiviral effect was morphology-dependent. Compared with L-Rhe/Ag, S-Rhe/Ag could more effectively inactivate PRRSV in vitro and antagonize its adsorption, invasion, replication, and release stages. Mechanistic studies indicated that Rhe@AgNPs could reduce the production of reactive oxygen species (ROS) induced by PRRSV infection, and S-Rhe/Ag also had stronger ROS inhibitory effect. This work confirmed the inhibitory effect of Rhe@AgNPs with different morphologies on PRRSV and provided useful information for treating PRRSV infection with metal nanoparticles synthesized from TCM ingredients.Graphical abstract

Comparative Evaluation of Unpeeled Cassava (Manihot esculenta) and Tacca (Tacca involucrata) Tuber Flours as Substrates for Bioethanol Production

The ever-increasing demand for alternatives to fossil fuel due to its negative impacts on the environment and high prices have resulted in the search for feedstock for bioethanol production. Cassava is one of the major staple foods that is processed into various preservative forms in Nigeria, while tacca is a plant growing in the wild and is eaten by a few people during scarcity of food. Unpeeled cassava and tacca tubers were processed into flour. The flour was hydrolyzed using Aspergillus niger and Saccharomyces cerevisiae, separately. The bioethanol potentials of tuber flours were evaluated using a single-step process. Hydrolysis of 10g of cassava tuber flour separately by Aspergillus niger and Saccharomyces cerevisiae produced (g/100mL) 0.720 and 0.765 of sugar, respectively, while hydrolysis of 10g of tacca tuber flour separately by Aspergillus niger and Saccharomyces cerevisiae produced (g/100mL) 0.392 and 0.367 of sugar respectively. Evaluation of the effect of time during hydrolysis of cassava tuber flour for 24h by Aspergillus niger and Saccharomyces cerevisiae separately produced (g/100mL) 1.44 and 0.737 of sugar, while hydrolysis of tacca tuber flour for 24h produced (g/100mL) 0.768 and 0.493 of sugar. Evaluation of the effect of varying pH values during hydrolysis of the tuber flours revealed that pH 5.6 produced the highest concentration of sugar (0.240g/100mL) and (0.803g/100mL) when Aspergillus niger and Saccharomyces cerevisiae were separately used to hydrolyze cassava tuber flour. When Aspergillus niger and Saccharomyces cerevisiae were separately used to hydrolyze tacca tuber flour at pH 5.6, 0.626g and 0.436g of sugar was produced. Fermentation of cassava tuber flour by mixed culture of Aspergillus niger and Saccharomyces cerevisiae for 48h produced 3.851%(w/v) bioethanol at 24h of fermentation, while fermentation of tacca tuber flour by mixed culture of Aspergillus niger and Saccharomyces cerevisiae produced 3.236% (w/v) bioethanol at 48h. Cassava tuber flour produced a higher concentration of bioethanol than tacca tuber flour. These results have shown that tacca tuber is a potential feedstock for bioethanol production, hence exploitation of nonfood materials such as tacca tuber for bioprocesses can reduce the over _dependence on cassava tuber.

Coal slime as a good modifier for the restoration of copper tailings with improved soil properties and microbial function.

In recent years, the solid wastes from the coal industry have been widely used as soil amendments. Nevertheless, the impact of utilizing coal slime for copper tailing restoration in terms of plant growth, physicochemical characteristics of the tailing soil, and microbial succession remains uncertain.Herein, the coal slime was employed as a modifier into copper tailings. Their effect on the growth and physiological response of Ryegrass, and the soil physicochemical properties as well as the bacterial community structure were investigated. The results indicated that after a 30-day of restoration, the addition of coal slime at a ratio of 40% enhanced plant growth, with a 21.69% rise in chlorophyll content, and a 62.44% increase in peroxidase activity. The addition of 40% coal slime also increased the content of nutrient elements in copper tailings. Following a 20-day period of restoration, the concentrations of available copper and available zinc in the modified tailings decreased by 39.6% and 48.51%, respectively, with 40% of coal slime added. In the meantime, there was an observed augmentation in the species diversity of the bacterial community in the modified tailings. The alterations in both community structure and function were primarily influenced by variations in pH value, available nitrogen, phosphorus, potassium, and available copper. The addition of 40% coal slime makes the physicochemical properties and microbial community evolution of copper tailings reach a balance point. The utilization of coal slime has the potential to enhance the physicochemical characteristics of tailings and promote the proliferation of microbial communities, hence facilitating the soil evolution of two distinct solid waste materials. Consequently, the application of coal slime in the restoration of heavy metal tailings is a viable approach, offering both cost-effectiveness and efficacy as an enhancer.

Failure mechanisms of nitrogen-doped diamond-like carbon films: Exfoliation or localized attack behaviour of films under hydrochemistry evolution

Nitrogen-doped diamond-like carbon (N-DLC) films with different nitrogen content were prepared on the surface of 2024 aluminium alloy using plasma-enhanced chemical vapour deposition technology. The failure mechanisms of the N-DLC films during seawater exposure have been investigated. The results demonstrated that nitrogen doping significantly affected the failure behaviour of the DLC films in seawater. Extensive exfoliation of the DLC film was found without the addition of nitrogen. However, when the nitrogen flow rate is 10 sccm and 15 sccm, significant localized corrosion of the DLC film and the aluminium alloy substrate occurred. The difference in the thermodynamic process of corrosion of the N-DLC films was mainly due to the changes in pH value on the local solution caused by the formation and hydrolysis of NH4+. In the DLC film without nitrogen additive, large oxide particles were formed at the film-substrate interface due to the acidification of the solution. Meanwhile, the internal stress of the DLC film was high under this condition. The film was easily exfoliated and ultimately lost its protective effect on the substrate. The corrosion products could not grow sustainably due to the variable pH value when excess nitrogen was added to the DLC film. No extensive exfoliation of the DLC films with 10 sccm and 15 sccm nitrogen addition has occurred, but obvious corrosion channels were formed in the substrate because of the localized corrosion. The evolution mechanism of oxidation behaviour in the presence of variations in local hydrochemistry is also discussed.

Measuring insoluble calcium content in curds during cheesemaking

A rapid water‐soluble calcium (WSC) extraction was evaluated as an in‐process method to quickly quantify insoluble calcium (ICa) phosphate content during cheesemaking and compare it with existing methods for finished cheese, that is cheese juice and acid–base titration. Although there were some differences in methods when evaluated using string cheese and Mozzarella, results for ICa obtained from the WSC method were consistent with the cheese juice. This WSC method was successful in measuring the ICa in curds during manufacture of Mozzarella made with varying pH values at whey drainage. Meltability of cheese correlated with ICa content at 1 month of storage.

Synthesis of ZnFe2O4 spinel nanoparticles at varying pH values and application in anode material for lithium-ion battery

Spinel materials have attracted increasing attention as anode materials for lithium-ion batteries (LIBs) owing to their unique structures. ZnFe2O4 spinel was synthesized by a co-precipitation method at different pH values — pH 11, pH 12, and pH 13 — followed by annealing in air at 750 °C for 3 h. The pH of the medium significantly influences the properties of ZnFe2O4. At pH 11, ZnFe2O4 particles of sizes 25–70 nm were covered by amorphous layers with thicknesses of approximately 2 nm, whereas higher degrees of crystallinity and larger particle sizes were obtained at higher pH values (12 and 13). Additionally, at pH 12, the Zn:Fe molar ratio in the prepared sample was 1:1.3, which deviated significantly from the nominal formula (1:2). Possibly, owing to the presence of amorphous layers that allow an isotropic volume change during the lithiation/delithiation steps, ZnFe2O4 prepared at pH 11 exhibited the best performance when employed as an anode material in LIBs. Namely, its reversible specific capacity at the 1st and the 160th cycles at 0.1 A g−1 were 0.69 Ah g−1 and 0.72 Ah g−1, respectively. Although ZnFe2O4 prepared at pH 12 gave an initial reversible specific capacity up to 0.89 Ah g−1, its capacity retention after 160 cycles was only 20%. Therefore, adjusting the pH of the coprecipitation step can improve the final lithium storage performance by controlling the degree of crystallinity, particle size, and chemical composition of the anode material ZnFe2O4.

Asymmetric Block Extension of Star-Shaped [PEG-SH]4 - toward Poly(dehydroalanine)-Functionalized PEG Hydrogels for Catch and Release of Charged Guest Molecules.

With the incorporation of polyampholytic segments into soft matter, hydrogels can serve as a reservoir for a variety of charged molecules which can be caught and released upon changes in pH value. Asymmetric block extension of one arm for star-shaped poly(ethylene glycol) [PEG26 -SH]4 using short segments of polyampholytic poly(dehydroalanine) (PDha) is herein demonstrated while maintaining the functional thiol end groups for network formation. For subsequent hydrogel synthesis with up to 10wt.% PDha a straightforward and biocompatible photoinitiated thiol-ene click reaction is exploited. The investigation of the swelling properties of the hydrogel revealed responsive behavior toward ionic strength and variations in pH value. Moreover, the reversible adsorption of the model dyes methylene blue (MB) and acid orange 7 (AO7) is investigated by UV-vis measurements and the procedure can be successfully transferred to the adsorption of the adhesion peptide RGDS resulting in an uptake of 1.5 wt% RGDS with regard to the dry weight of the hydrogel.