pH Values Research Articles

In Operando X-ray Spectroscopic and DFT Studies Revealing Improved H2 Evolution by the Synergistic Ni-Co Electron Effect in the Alkaline Condition.

The different electrolyte conditions, e.g., pH value, for driving efficient HER and OER are one of the major issues hindering the aim for electrocatalytic water splitting in a high efficiency. In this regard, seeking durable and active HER electrocatalysts to align the alkaline conditions of the OER is a promising solution. However, the success in this strategy will depend on a fundamental understanding about the HER mechanism at the atomic scale. In this work, we have provided thorough understanding for the electrochemical HER mechanisms in KOH over Ni- and Co-based hollow pyrite microspheres by in operando X-ray spectroscopies and DFT calculations, including NiS2, CoS2, and Ni0.5Co0.5S2. We discovered that the Ni sites in hollow NiS2 microspheres were very stable and inert, while the Co sites in hollow CoS2 microspheres underwent reduction and generated Co metallic crystal domains under HER. The generation of Co metallic sites would further deactivate H2 evolution due to the large hydrogen desorption free energy (-1.73 eV). In contrast, the neighboring Ni and Co sites in hollow Ni0.5Co0.5S2 microspheres exhibited the electronic interaction to elevate the reactivity of Ni and facilitate the stability of Co without structure or surface degradation. The energy barrier in H2O adsorption/dissociation was only 0.73 eV, followed by 0.06 eV for hydrogen desorption over the Ni0.5Co0.5S2 surface, revealing Ni0.5Co0.5S2 as a HER electrocatalyst with higher durability and activity than NiS2 and CoS2 in the alkaline medium due to the synergy of neighboring Ni and Co sites. We believe that the findings in our work offer a guidance toward future catalyst design.

Separation of Iron from ZnSO4 solution by oxygen pressure-enhanced hydrothermal precipitation

ABSTRACT This study presented a method for removing iron (Fe) from zinc (Zn) sulfate solution utilising an oxygen (O2) pressure-enhanced goethite process. The study investigated the effects of O2 pressure, reaction temperature (T), pH value, and reaction time (t) on the Fe removal process. The results indicated that the oxidation rate increased with increasing T and O2 pressure. The goethite obtained at an O2 partial pressure of 0.2 MPa exhibited higher Fe content and a distinct acicular morphology, containing 55.7% Fe, 5.4% Zn, and 1.9% Sulphur (S). The increase in temperature from 90°C to 110°C accelerated the Fe hydrothermal precipitation, enhancing the Fe content in the goethite from 55.7% to 57.1%. The goethite products with 56.4% Fe content exhibited 95.0% crystallinity at a pH of 3.2, with a tendency for particle aggregation at lower crystallinity levels. The goethite precipitation occurred within the pH range of 2.2−3.5. Furthermore, as the reaction time increased, the hydrothermal precipitation particles increased in size and exhibited higher Fe content. The proposed method modified the O2 mass transfer process, increasing its solubility to enhance the Fe2+ oxidation rate, facilitating the controlled acicular α-FeOOH production with excellent crystallization performance.

Optimizing the synthesis of ZnFe2O4 through chemical and physical methods: effects of the synthesis route on the phase purity, inversion, and magnetic properties of spinel zinc ferrite

In this work, ZnFe2O4 ferrites were prepared by chemical (coprecipitation) and ceramic (ball-milling) methods. The effects of the synthesis route on the phase purity, crystallinity, particle size distribution, and magnetic properties were investigated to identify the most appropriate conditions for the synthesis of high-quality ferrites. The samples were examined by x-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and Mössbauer spectroscopy. The XRD patterns revealed that a high-purity spinel phase was obtained by coprecipitation at pH ≥ 7 by calcining the pristine powder at T ≥ 900 °C, whereas a single spinel phase was obtained at T ≥ 700 °C in the ball-milling method. The crystallite size of the spinel phase exhibited general increasing trends with the increase of the pH value under the same heat-treatment conditions and with the increase of the calcination temperature. Additionally, the mean physical particle size exhibited an increasing trend with the increase of the calcination temperature. The VSM measurements revealed a noticeable degree of inversion in the spinel ferrites prepared by coprecipitation (exhibiting the highest degree at pH = 10) and an insignificant degree of inversion in the spinel ferrites prepared by the ceramic method. However, calcining the powder exhibiting the highest degree of inversion (prepared by coprecipitation at pH = 10) at 1100 °C resulted in ordering the zinc ions at tetrahedral sites of the spinel structure. Mössbauer spectra for representative zinc ferrite samples prepared by the two methods revealed a major central doublet (with a small magnetic sextet corresponding to the α-Fe2O3 phase in the sample at pH = 7). The hyperfine parameters of the doublet observed in the Mössbauer spectra of the samples, and the corresponding magnetization behavior revealed a higher degree of ionic disorder in the spinel ferrite prepared by coprecipitation.

Dynamic Electrostatic Interfacial Engineering for Block Copolymer Microparticles with Reversible Structures.

Responsive nanoparticle surfactants (NPSs) can dynamically and reversibly modulate the interfacial interactions between incompatible components, which are essential in the interfacial catalysis, corrosion, and self-assembly of block copolymers (BCPs). However, NPSs with stimuli-responsive behavior often involve tedious chemical synthesis and surface modifications. Herein, we propose a strategy to in situ construct a kind of dynamic and reversible NPSs by the interfacial electrostatic interaction between the negatively charged nanoparticles (NPs) and the positively charged homopolymers. The NPSs assembled at the oil/water interface reduce the interfacial tension and direct the confined assembly of BCP. Meanwhile, the dynamic NPSs can be disassembled by increasing the pH value or introducing competitive electrostatic attractions, which can dynamically and reversibly change the interfacial properties as well as the alignment of polymer chains, enabling BCP microparticles with reversibly switchable lamellar and cylindrical structures. Furthermore, by the introduction of aggregation-induced emission luminogens as tails to the NPSs, the reversible transformation of BCP microparticles can be visualized by fluorescence emission, which is dependent on the nanostructures of microparticles. This work establishes a concept for dynamically manipulating interfacial interactions and reversibly switching BCP microparticles without time-consuming NPS synthesis, showing promising applications in the fabrication of smart materials with switchable structures and properties.

Hydrothermally Produced Activated Carbon Impregnated with ZnO for the Adsorptive Removal of Toxic Pharmaceutical Contaminants from Aqueous Solution

This research explores the adsorption (AD) of diclofenac sodium (DS) onto a Hydrothermally produced activated carbon impregnated with ZnO (HTC-AC/ZnO) surface, considering various factors such as initial concentration (IC), adsorbent dose, contact time, and pH. The characterization of HTC-AC/ZnO was performed using X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and nitrogen physisorption spectroscopy (BET). Tests were conducted with different adsorbent doses (0.5–4 g/L) at 303 K and various initial diclofenac concentrations (ranging from 50 mg/L to 250 mg/L) to observe their effects. Additionally, pH values were altered from 2 to 12 to study their influence on AD. Kinetic studies, thermodynamic studies, and AD isotherm models were examined. The Temkin isotherm model (TIM) was found to be the most accurate for DS-AD on HTC-AC/ZnO. For DS-AD on HTC-AC/ZnO, pseudo-first-order models (PFOM), intraparticle diffusion model (IPDM), and pseudo-second-order models (PSOM) were applied, with a correlation coefficient of 0.945, indicating a good fit for PFOM. The kinetics suggested rapid adsorption. Notably, the HTC-AC/ZnO composite exhibited consistent AD characteristics across four consecutive cycles, with a removal efficiency exceeding 99.38%. This suggests that HTC-AC/ZnO is an appropriate and economically viable adsorbent for the elimination of DS from water-based solutions. The investigation provides compelling evidence that HTC-AC/ZnO is a viable adsorbent for the effective elimination of DS from water sources.

Response of N, P & K Uptake Pattern under the Different Integrated Nutrient Management Practices on Potato, Solanum tuberosum L., Crop

The experiment was carried out in a Randomized Block Design treatments 8 viz. T1 Control,T2 FYM @ 30 t/ha) + biofertilizer (PSB), T3 poultry manure @ 5 t/ha + biofertilizer (PSB),T4 vermicompost @ 7.5 t/ha + biofertilizer (PSB), T5 FYM @ 10 t/ha + poultry manure @ 1.7 t/ha +vermicompost 2.7 t/ha + biofertilizer (PSB), T6 67% RDF through inorganic sources + 33% RDF through organic sources i.e. FYM + biofertilizer (PSB), T7 33% RDF through inorganic sources + 67% RDF through organic sources i.e. FYM + biofertilizer (PSB) and T8 Farmer practices (through organic). All the treatment combinations were replicated three times. The soil of the experiment field was silty loam in texture and medium in fertility status with the pH values 8.1, organic carbon 0.31%. The available nitrogen, phosphorus and potassium were 140.0, 15.2, and 240 kg ha-1 respectively.

Gluten migration from biodegradable food contact materials poses a risk to celiac disease patients

AbstractDue to the ban of certain single-use plastics in the European Union, food contact materials (FCM) from biobased and/or biodegradable polymers are increasingly being used. Some FCM are made from wheat or rye and therefore contain gluten, which is a food allergen and known to cause celiac disease. Legislation currently does not require allergen labelling on FCM and there is only some first information that gluten from FCM can migrate into gluten-free foods. Our aim was to analyze the extent of gluten migration from six different FCM into a variety of liquid and solid foods to assess the risk of exposure for wheat allergy and celiac disease patients. We show that the extent of gluten migration depended on the properties of the material, the liquid or solid food it comes into contact with and contact time. There was no clear effect of temperature or pH value. Of the six FCM studied, wheat bran-based plates had the highest potential to release gluten with concentrations of up to 203.0 mg/L of gluten in deionized water after 30 min. To protect patients, it is important to raise awareness of the risk of gluten migration from such FCM and help patients identify and avoid gluten-containing FCM. Further, legislation needs to be adapted urgently to include mandatory labelling of allergens on these biodegradable FCM.

Plant-derived bioactive compounds for the inhibition of biofilm formation: a comprehensive review.

Biofilm formation is a widespread phenomenon that impacts different fields, including the food industry, agriculture, health care and the environment. Accordingly, there is a serious need for new methods of managing the problem of biofilm formation. Natural products have historically been a rich source of varied compounds with a wide variety of biological functions, including antibiofilm agents. In this review, we critically highlight and discuss the recent progress in understanding the antibiofilm effects of several bioactive compounds isolated from different plants, and in elucidating the underlying mechanisms of action and the factors influencing their adhesion. The literature shows that bioactive compounds have promising antibiofilm potential against both Gram-negative and Gram-positive bacterial and fungal strains, via several mechanisms of action, such as suppressing the formation of the polymer matrix, limiting O2 consumption, inhibiting microbial DNA replication, decreasing hydrophobicity of cell surfaces and blocking the quorum sensing network. This antibiofilm activity is influenced by several environmental factors, such as nutritional cues, pH values, O2 availability and temperature. This review demonstrates that several bioactive compounds could mitigate the problem of biofilm production. However, toxicological assessment and pharmacokinetic investigations of these molecules are strongly required to validate their safety.

Heterologous expression and characterization of mutant cellulase from indigenous strain of Aspergillus niger.

The purpose of current research work was to investigate the effect of mutagenesis on endoglucanase B activity of indigenous strain of Aspergillus niger and its heterologous expression studies in the pET28a+ vector. The physical and chemical mutagens were employed to incorporate mutations in A. niger. For determination of mutations, mRNA was isolated followed by cDNA synthesis and cellulase gene was amplified, purified and sequenced both from native and mutant A. niger. On comparison of gene sequences, it was observed that 5 nucleotide base pairs have been replaced in the mutant cellulase. The mutant recombinant enzyme showed 4.5 times higher activity (428.5 µmol/mL/min) as compared to activity of native enzyme (94 µmol/mL/min). The mutant gene was further investigated using Phyre2 and I-Tesser tools which exhibited 71% structural homology with Endoglucanase B of Thermoascus aurantiacus. The root mean square deviation (RMSD), root mean square fluctuation (RMSF), solvent accessible surface area (SASA), radius of gyration (Rg) and hydrogen bonds analysis were carried at 35°C and 50°C to explore the integrity of structure of recombinant mutant endoglucanase B which corresponded to its optimal temperature. Hydrogen bonds analysis showed more stability of recombinant mutant endoglucanase B as compared to native enzyme. Both native and mutant endoglucanase B genes were expressed in pET 28a+ and purified with nickel affinity chromatography. Theoretical masses determined through ExPaSy Protparam were found 38.7 and 38.5 kDa for native and mutant enzymes, respectively. The optimal pH and temperature values for the mutant were 5.0 and 50°C while for native these were found 4.0 and 35°C, respectively. On reacting with carboxy methyl cellulose (CMC) as substrate, the mutant enzyme exhibited less Km (0.452 mg/mL) and more Vmax (50.25 µmol/ml/min) as compared to native having 0.534 mg/mL as Km and 38.76 µmol/ml/min as Vmax. Among metal ions, Mg2+ showed maximum inducing effect (200%) on cellulase activity at 50 mM concentration followed by Ca2+ (140%) at 100 mM concentration. Hence, expression of a recombinant mutant cellulase from A. niger significantly enhanced its cellulytic potential which could be employed for further industrial applications at pilot scale.

Three stepwise pH progressions in stratum corneum for homeostatic maintenance of the skin

The stratum corneum is the outermost skin layer with a vital role in skin barrier function. It is comprised of dead keratinocytes (corneocytes) and is known to maintain its thickness by shedding cells, although, the precise mechanisms that safeguard stratum corneum maturation and homeostasis remain unclear. Previous ex vivo studies have suggested a neutral-to-acidic pH gradient in the stratum corneum. Here, we use intravital pH imaging at single-corneocyte resolution to demonstrate that corneocytes actually undergo differentiation to develop three distinct zones in the stratum corneum, each with a distinct pH value. We identified a moderately acidic lower, an acidic middle, and a pH-neutral upper layer in the stratum corneum, with tight junctions playing a key role in their development. The upper pH neutral zone can adjust its pH according to the external environment and has a neutral pH under steady-state conditions owing to the influence of skin microbiota. The middle acidic pH zone provides a defensive barrier against pathogens. With mathematical modeling, we demonstrate the controlled protease activation of kallikrein-related peptidases on the stratum corneum surface that results in proper corneocyte shedding in desquamation. This work adds crucial information to our understanding of how stratum corneum homeostasis is maintained.

Hydrogeochemical and GIS Analysis of Groundwater Quality for Drinking and Irrigation Purposes in Kuzhithuraiyar Sub-Basin, Kanniyakumari District, Tamil Nadu, India

A hydrogeochemical analysis was conducted to find the suitability of the groundwater for drinking and irrigation purposes in the Kuzhithuraiyar sub-basin, Kanniyakumari district, Tamil Nadu, India. 48 groundwater samples were collected from the different locations of the study area during both the pre- and postmonsoon periods. This study assesses the groundwater quality for drinking and irrigation purposes based on the analytical results, water quality index, Wilcox plot, and irrigation parameters such as electrical conductance, Kelly’s ratio, sodium absorption ratio values, magnesium hazards, bicarbonate, and the residual sodium carbonate index. The pH values ranged from 8.5 to 6.5, suggesting generally acceptable conditions. TDS concentrations range from 24 to 1277 mg/L, whereas EC values range from 37.50 to 1996 μS/cm. It is observed from the collected samples that the pre-monsoon water samples TDS’ values were exceeded the recommended TDS limits than postmonsoon samples. Water quality indices indicate that 50% of premonsoon samples and 48% of postmonsoon samples are suitable for drinking. In total, 10% of samples are admissible to a doubtful category before and after the monsoon, 6% are good to permissible during the monsoon, and 84% are good to permissible. Kelly’s ratio shows that 56% and 48% of samples collected during the post- and premonsoon are suitable for irrigation, respectively, whereas the remaining samples are not. Due to magnesium hazards, 40% and 44% of pre- and postmonsoon samples are not suitable for irrigation. Overall, the postmonsoon samples exceeded the permissible TDS limit (1000 mg/L) by 10% and the premonsoon samples by 6. 13% of samples obtained after the monsoon and 19% collected before the monsoon have a potential salinity greater than three, indicating that these samples are unacceptable. The sustaining water quality and mitigating possible hazards in the Kuzhithuraiyar sub-basin require continuous monitoring and focused measures.

Thermodynamic and structural investigation of oily wastewater treatment using peach kernel and walnut shell based activated carbon.

Despite the many articles about activated carbon with different precursors in adsorption process, no in-depth research has been carried out to understand the causes of the difference in surface adsorption characteristics of activated carbon with different precursors and different activation processes. In this work, the ability of two active carbon adsorbents made of walnut shell and peach kernel by two chemical and physical methods (totally 4 different types of activated carbon) in treatment of oily wastewater including diesel, gasoline, used oil or engine lubricant has been compared. The results show that the chemical activated peach carbon active with 97% hardness has provided the highest hardness and physical activated walnut carbon active has obtained the lowest hardness value (87%). It is also found that peach activated carbon has a higher iodine number than walnut activated carbon, and this amount can be increased using chemical methods; Therefore, the highest amount of Iodine Number is related to Peach activated carbon that is made by chemical method (1230 mg/g), and the lowest amount of iodine number is seen in walnut activated carbon that is made by physical method (1020 mg/g). moreover, the pore diameter of physical activated carbon is lower than chemical activated carbon in all cases. So that the pore diameter of chemical activated peach carbon active is equal to 22.08 μm and the measured pore diameter of physical activated peach carbon active is equal to 20.42 μm. These values for walnut are obtained as 22.74 μm and 21.86 μm, respectively. Furthermore, the temperature and pH effects on the adsorption of different synthesized oily wastewater was studied and it was found that a decrease in adsorption can be seen with an increase in temperature or decreasing the pH value, which can be referred to this fact that the process of adsorption is an exothermic process. Finally, to analyze the compatibility of adsorption isotherms with experimental data and to predict the adsorption process, three different isotherms named Langmuir, Temkin, and Freundlich isotherms were applied and their parameters were correlated. The correlation results show that the Langmuir isotherm had the best correlation in all cases compared to the Freundlich and Temkin isotherms, based on the correlation coefficient, and the calculated R2 values which was greater than 0.99 in all the studied cases.

Influence of Anthropogenic Pollution on Soil and Plants of Gosa Dumpsite, Abuja, Nigeria

Despite increased awareness of the causes of environmental pollution, it continues to pose a serious threat to both developed and developing countries worldwide. The Gosa dumpsite in Abuja serves as a receptacle for various waste materials from both high and low-income areas of the metropolis. Surprisingly, peri-urban farmers residing in the vicinity still cultivate edible crops on this polluted land. This study aims to assess the impact of waste dumping at Gosa dumpsite on selected soil properties and the uptake of heavy metals by plants. In order to achieve this objective, soil and plant samples were collected from established 5 x 5 m2 quadrants during the early and late dry as well as rainy seasons of 2019 and 2020. The collected samples underwent analysis using standard methods to determine their physical and chemical properties. Additionally, the study identified the dominant plant species within the dumpsite through standard methods. The findings revealed that the dumpsite soil exhibited characteristics of loamy sand, with the highest pH value of 8.85 ± 0.90 recorded during the dry season of 2020. Other significant soil results included total nitrogen at 1.09 ± 0.64 g kg-1, organic carbon at 9.88 ± 0.10 g kg-1, Cd at 11.93 ± 2.25 mg kg-1, Hg at 2.18 ± 1.08 mg kg-1, and Pb at 54.68 ± 8.68 mg kg-1, all of which were observed during the early rainy season of 2020. During the remaining seasons considered, lower values were obtained. Notably, these values exceeded the permissible levels set by the FAO for soil intended for cultivating edible crops. Furthermore, the plant species Ageratum conyzoides demonstrated the highest uptake of heavy metals, with concentrations of 4.47 ± 1.15 mg kg-1 for Cd, 1.77 ± 1.08 mg kg-1 for Hg, and 19.56 ± 4.83 mg kg-1 for Pb, all recorded during the early dry season of 2020. In conclusion, although the Gosa dumpsite in Abuja may appear fertile enough for cultivation, the study's results highlight that it cannot be deemed suitable for the production of edible crops. The presence of heavy metals and other pollutants in the soil poses a significant risk to crop health and, consequently, to human consumption.

PROPERTIES OF URBAN SOILS AFTER DECONTAMINATION MEASURES ON THE RADIOACTIVELY CONTAMINATED TERRITORY OF THE CITY OF ELEKTROSTAL

We studied morphological properties, pH, organic carbon content, and specific activity of 137Cs and natural radionuclides (40K, 226Ra, 232Th) in the upper horizons of soils in deactivated and slightly damaged areas of the city. The studies were carried out in the urban ecosystems of the city of Elektrostal (Moscow region) in 2019, i.e. 6 years after local precipitation of 137Cs due to a radiation incident. Morphological features of the upper horizons of urban soils were: brownish-gray color, light-loamy composition, small-lumpy and lumpy structure, inclusions of construction and household waste. In the upper horizons of urbiquasizems and urban soils, a low carbon content (less than 1%) with high coefficients of variation - were detected. In the studied urban soils, a wide range of water pH values was noted: from acidic (4,6-5,5) to highly alkaline (> 8,0) reaction. Correlation analysis showed that in the upper horizons of UR, the content of organic carbon was reduced and alkalinization of the soil environment was observed. The accumulative type of distribution of 137Cs was recorded for soil profiles of polluted urban ecosystems in which decontamination measures were not carried out. The profiles of urban soils that were subjected to decontamination revealed low values of the specific activity of 137Cs in surface bulk layers and maxima in buried contaminated horizons. In the bulk horizons of UR, which include a large amount of crushed stone, there is an increase in the specific activity of 226Ra. Some technogenic horizons UR and TCH, consisting mainly of quartz sand, are characterized by very low values of specific activities 226Ra and 40K. Correlations of chemical and radiation indicators in the profiles of urban soils reflect the different composition and properties of upper horizons formed as a result of excavation and decontamination work.

GAM-7: an organic-inorganic hybrid layered aluminophosphate crystal formed by zeolite transformation.

The interzeolite conversion (IZC) of metallo- and aluminophosphate zeolites was demonstrated using a non-cyclic secondary amine, diisopropylamine, as the organic structure-directing agent (OSDA). The IZC of AlPO4-5 with AFI topology could successfully produce an unknown highly crystalline phase, named GAM-7. In metallo-aluminophosphates (metal-AlPOs), SAPO-5 with a small amount of SiO2 was also interconverted to a single crystal GAM-7, designated as [Si]GAM-7. However, in other metal-AlPOs, the corresponding GAM-7 crystals were formed as either an intermediate or a mixture of plural crystals. Additionally, it was found that GAM-7 could also be obtained by hydrothermal synthesis (HTS), but not synthesized from a silico-aluminophosphate hydrogel, indicating that [Si]GAM-7 can be prepared by only the IZC technique. The obtained GAM-7 crystal was well-characterized to elucidate the framework structure, and this revealed that GAM-7 was a new organic-inorganic hybrid layered aluminophosphate having a terminal POH group in the corrugated layered sheets, and the OSDA molecule between the layers was robustly interacting with an acidic POH site by a hydrogen bond. Furthermore, we have performed the tracking of pH values during the transformation from AlPO4-5 into GAM-7 and have argued a reasonable consideration for the IZC process.

Density Functional Study of Electrocatalytic Carbon Dioxide Reduction in Fourth-Period Transition Metal–Tetrahydroxyquinone Organic Framework

This study investigates the utilisation of organometallic network frameworks composed of fourth-period transition metals and tetrahydroxyquinone (THQ) in electrocatalytic CO2 reduction. Density functional theory (DFT) calculations were employed in analysing binding energies, as well as the stabilities of metal atoms within the THQ frameworks, for transition metal TM-THQs ranging from Y to Cd. The findings demonstrate how metal atoms could be effectively dispersed and held within the THQ frameworks due to sufficiently high binding energies. Most TM-THQ frameworks exhibited favourable selectivity towards CO2 reduction, except for Tc and Ru, which experienced competition from hydrogen evolution reaction (HER) and required solution environments with pH values greater than 5.716 and 8.819, respectively, to exhibit CO2RR selectivity. Notably, the primary product of Y, Ag, and Cd was HCOOH; Mo produced HCHO; Pd yielded CO; and Zr, Nb, Tc, Ru, and Rh predominantly generated CH4. Among the studied frameworks, Zr-THQ displayed values of 1.212 V and 1.043 V, corresponding to the highest limiting potential and overpotential, respectively, while other metal–organic frameworks displayed relatively low ranges of overpotentials from 0.179 V to 0.949 V. Consequently, it is predicted that the TM-THQ framework constructed using a fourth-period transition metal and tetrahydroxyquinone exhibits robust electrocatalytic reduction of CO2 catalytic activity.

Why Bubbles Coalesce Faster than Droplets: The Effects of Interface Mobility and Surface Charge.

Air bubbles in pure water appear to coalesce much faster compared to oil emulsion droplets at the same water solution conditions. The main factors explaining this difference in coalescence times could be interface mobility and/or pH-dependent surface charge at the water interface. To quantify the relative importance of these effects, we use high-speed imaging to monitor the coalescence of free-rising air bubbles with the water-air interface as well as free-falling fluorocarbon-oil emulsion droplets with a water-oil interface. We measure the coalescence times of such bubbles and droplets over a range of different water pH values (3.0, 5.6, 11.0). In the case of bubbles, a very fast coalescence (milliseconds) is observed for the entire pH range in pure water, consistent with the hydrodynamics of fully mobile interfaces. However, when the water-air interface is immobilized by the deposition of a monolayer of arachidic acid, the coalescence is significantly delayed. Furthermore, the coalescence times increase with increasing pH. In the case of fluorocarbon-oil droplets, the coalescence is always much slower (seconds) and consistent with immobile interface coalescence. The fluorocarbon droplet's coalescence time is also pH-dependent, with a complete stabilization (no coalescence) observed at pH 11. In the high electrolyte concentration, a 0.6 M NaCl water solution, bubbles, and droplets have similar coalescence times, which could be related to the bubble interface immobilization at the late stage of the coalescence process. Numerical simulations are used to evaluate the time scale of mobile and immobile interface film drainage.

Preparation and Characterization of Protein-Based Hydrogel: Cottonseed Protein Grafted with 2-Acrylamido-2-Methylpropanesulfonic Acid (AMPS)

Preparation and Characterization of Protein-Based Hydrogel: Cottonseed Protein Grafted with 2-Acrylamido-2-Methylpropanesulfonic Acid (AMPS)

Ecofriendly Controlled-Release Insecticide Carrier: pH-/Temperature-Responsive Rosin-Derived Hydrogels for Avermectin Delivery against Mythimna separata (Walker).

The exploration of environmentally friendly, less toxic, sustained-release insecticide is increasing with the growing demand for food to meet the requirements of the expanding population. As a sustained-release carrier, the unique, environmentally friendly intelligent responsive hydrogel system is an important factor in improving the efficiency of insecticide utilization and accurate release. In this study, we developed a facile approach for incorporating the natural compound rosin (dehydroabietic acid, DA) and zinc ions (Zn2+) into a poly(N-isopropylacrylamide) (PNIPAM) hydrogel network to construct a controlled-release hydrogel carrier (DA-PNIPAM-Zn2+). Then, the model insecticide avermectin (AVM) was encapsulated in the carrier at a drug loading rate of 36.32% to form AVM@DA-PNIPAM-Zn2+. Surprisingly, the smart controlled carrier exhibited environmental responsiveness, strongly enhanced mechanical properties, self-healing ability, hydrophobicity, and photostability to ensure a balance between environmental friendliness and the precision of the drug release. The release experiments showed that the carboxyl and amide groups in the polymer chains alter the intermolecular forces within the hydrogel meshes and ingredient diffusion by changing temperatures (25 and 40 °C) and pH values (5.8, 7.4, and 8.5), leading to different release behaviors. The insecticidal activity of the AVM@DA-PNIPAM-Zn2+ against oriental armyworms was good, with an effective minimum toxicity toward aquatic animals. Therefore, AVM@DA-PNIPAM-Zn2+ is an effective drug delivery system against oriental armyworms. We anticipate that this ecofriendly, sustainable, smart-response carrier may broaden the utilization rosin and its possible applications in the agricultural sector.

Study on the Optimization and Experimental of Fly Ash and Sludge in Ecological Slope Protection Substrate

Study on the Optimization and Experimental of Fly Ash and Sludge in Ecological Slope Protection Substrate