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The impact of solution stoichiometry, upon formation of BaSO4 crystals in 0.02 M NaCl suspensions, on the development of particle size was investigated using dynamic light scattering (DLS). Measurements were performed on a set of suspensions prepared with predefined initial supersaturation, based on the quotient of the constituent ion activity product {Ba2+}{SO42-} over the solubility product Ksp (Ωbarite = {Ba2+}{SO42-}/Ksp = 100, 500, or 1000-11,000 in steps of 1000), and ion activity solution stoichiometries (raq = {Ba2+}:{SO42-} = 0.01, 0.1, 1, 10 and 100), at circumneutral pH of 5.5-6.0, and ambient temperature and pressure. DLS showed that for batch experiments, crystal formation with varying raq was best investigated at an initial Ωbarite of 1000 and using the forward detection angle. At this Ωbarite and set of raq, the average apparent hydrodynamic particle size of the largest population present in all suspensions increased from ∼200 to ∼700 nm within 10-15 min and was independently confirmed by transmission electron microscopy (TEM) imaging. Additional DLS measurements conducted at the same conditions in flow confirmed that the BaSO4 formation kinetics were very fast for our specifically chosen conditions. The DLS flow measurements, monitoring the first minute of BaSO4 formation, showed strong signs of aggregation of prenucleation clusters forming particles with a size in the range of 200-300 nm for every raq. The estimated initial bulk growth rates from batch DLS results show that BaSO4 crystals formed fastest at near-stoichiometric conditions and more slowly at nonstoichiometric conditions. Moreover, at extreme SO4-limiting conditions, barite formation was slower compared to Ba-limiting conditions. Our results show that DLS can be used to investigate nucleation and growth at carefully selected experimental and analytical conditions. The combined DLS and TEM results imply that BaSO4 formation is influenced by solution stoichiometry and may aid to optimize antiscalant efficiency and regulate BaSO4 (scale) formation processes.

Finding simple, easily controlled, and flexible synthetic routes for the preparation of ternary and hybrid nanostructured semiconductors is always highly desirable, especially to fulfill the requirements for mass production to enable application to many fields such as optoelectronics, thermoelectricity, and catalysis. Moreover, understanding the underlying reaction mechanisms is equally important, offering a starting point for its extrapolation from one system to another. In this work, we developed a new and more straightforward colloidal synthetic way to form hybrid Au-Ag2X (X = S, Se) nanoparticles under mild conditions through the reaction of Au and Ag2X nanostructured precursors in solution. At the solid-solid interface between metallic domains and the binary chalcogenide domains, a small fraction of a ternary AuAg3X2phase was observed to have grown as a consequence of a solid-state electrochemical reaction, as confirmed by computational studies. Thus, the formation of stable ternary phases drives the selective hetero-attachment of Au and Ag2X nanoparticles in solution, consolidates the interface between their domains, and stabilizes the whole hybrid Au-Ag2X systems.

The role of Cu:Co composition in bi-metallic Cu-Co/ZnAl₂O₄ catalysts on higher alcohol synthesis (HAS) was investigated at H₂:CO = 4. The addition of Cu strongly facilitated Co reduction upon catalyst activation and suppressed coke deposition during HAS. Formation of predominantly hydrocarbons and higher alcohols was observed on the bi-metallic catalysts. Co/ZnAl₂O₄ produced mainly CH₄ and Cu/ZnAl₂O₄ mainly CH₃OH, while at Cu:Co = 0.6 the best ethanol selectivity of 4.5 % was reached. The microstructure of the spent catalysts confirmed a close interaction of Cu and Co. in press

Inexpensive protic ionic liquids, synthesized from di- or triamines and excess sulfuric acid, were used as solvents and catalysts for the Beckmann rearrangement. The use of ionic liquids in place of oleum or sulfuric acid allowed the base neutralization step, which is required in the conventional Beckmann rearrangement, to be entirely avoided, thereby dramatically improving the atom economy. Using a biphasic water/organic solvent extraction system, it was possible to recover and reuse the ionic liquid. The proposed method was found applicable for the synthesis of a range of primary and secondary amides.

Often lab-scale adsorptive breakthrough experiments are conducted in an isothermal manner, whereas industrial-scale adsorption processes are near-adiabatic. In this work, a polyurethane (PUR) insulating column was manufactured to mimic large-scale non-isothermal behavior via laboratory-scale breakthrough tests. Breakthrough tests with a CO2/N2 gas mixture on zeolite 13X (∼5 g) were performed. A bed temperature increase of 62 °C and long cooling times were observed. When compared to a regular steel column, showing a temperature rise of only 12 °C, the column efficiency was approximately 20% lower due to adiabatic effects. The heat evacuated from the adsorbent bed via the column exhaust was used as a measure for the degree of adiabaticity. Up to 46% of the theoretical heat of adsorption could be detected at the PUR column exhaust compared to 4% at the steel column exhaust. The important difference between isothermal, non-isothermal and adiabatic limit behavior was demonstrated through breakthrough experiments and simulations.

Bipolar membrane electrodialysis (BPMED) could allow for the complete electrification of direct air capture (DAC) technologies. In this work, we have modeled and optimized two DAC processes based on different electrodialysis cell designs. The technical assessment has been complemented by a detailed economic analysis, showing the advantages but also the current shortcomings of this technology and pathways for advancement. A minimum energy demand of 24 MJ kgCO2-1has been estimated for the base-case scenario, a result comparable to what has been reported for other liquid-scrubbing DAC technologies. Several solutions to further abate power consumption have been reviewed, with the most promising case providing a 29% reduction. Membrane cost and performance are currently the main limiting factors. In a scenario where cheaper membranes with better performance are assumed to be available, total costs below $250 tonCO2-1may be feasible, making BPMED a viable fully electrified alternative to other technologies requiring natural gas.

Fast and accurate computational approaches to predicting reactivity in sulfa-Michael additions are required for high-throughput screening in toxicology (e.g., predicting excess aquatic toxicity and skin sensitization), chemical synthesis, covalent drug design (e.g., targeting cysteine), and data set generation for machine learning. The kinetic glutathione chemoassay is a time-consuming in chemico method used to extract kinetic data in the form of log(kGSH) for organic electrophiles. In this work, we use density functional theory to compare the use of transition states (TSs) and enolate intermediate structures following C–S bond formation in the prediction of log(kGSH) for a diverse group of 1,4 Michael acceptors. Despite the widespread use of transition state calculations in the literature to predict sulfa-Michael reactivity, we observe that intermediate structures show much better performance for the prediction of log(kGSH), are faster to calculate, and easier to obtain than TSs. Furthermore, we show how linear combinations of atomic charges from the isolated Michael acceptors can further improve predictions, even when using inexpensive semiempirical quantum chemistry methods. Our models can be used widely in the chemical sciences (e.g., in the prediction of toxicity relevant to the environment and human health, synthesis planning, and the design of cysteine-targeting covalent inhibitors), and represent a low-cost, sustainable approach to reactivity assessment.

Microfibrillated cellulose (MFC) has potential to be used as clean label texture modifier in foods due to its structural and mechanical properties. These properties deteriorate upon drying of MFC dispersions due to aggregation of the microfibrils. In this study dried MFC particles were prepared by spray-drying MFC dispersions in a surplus of maltodextrin to prevent hornification. The aim of this study was to evaluate the effect of MFC particle concentration and MFC:maltodextrin ratio of dried MFC powders on rheological, tribological and sensory texture properties of liquid foods. Scanning Electron Microscopy demonstrated that after spray-drying, MFC powders with polydisperse particle size distribution were obtained (1–30 μm). Upon suspension of spray-dried MFC powder in water, maltodextrin dissolved in the aqueous continuous phase whereas spherical MFC networks retained their shape and co-existed in a mixture with individual fibrils. Spray-dried MFC powders were added to skimmed milk and tomato soup at different concentrations. With increasing concentration of dried MFC particles, shear viscosity, consistency index K, storage and loss modulus of skimmed milks and tomato soups increased whereas flow index n decreased. Addition of spray-dried MFC particles to milks and soups significantly (p < 0.05) increased sensory thickness and creaminess. Milks displayed similar tribological properties irrespective of MFC particle concentration, which was presumably caused by exclusion of the MFC network from the tribological gap. Rheological properties, thickness and creaminess increased more effectively upon addition of low MFC:maltodextrin particles compared to particles with high MFC:maltodextrin ratio. We conclude that spray-dried microfibrillated cellulose particles can be used as thickener or fat replacer in liquid foods. Microfibrillated cellulose (MFC) has potential to be used as clean label texture modifier in foods due to its structural and mechanical properties. These properties deteriorate upon drying of MFC dispersions due to aggregation of the microfibrils. In this study dried MFC particles were prepared by spray-drying MFC dispersions in a surplus of maltodextrin to prevent hornification. The aim of this study was to evaluate the effect of MFC particle concentration and MFC:maltodextrin ratio of dried MFC powders on rheological, tribological and sensory texture properties of liquid foods. Scanning Electron Microscopy demonstrated that after spray-drying, MFC powders with polydisperse particle size distribution were obtained (1–30 μm). Upon suspension of spray-dried MFC powder in water, maltodextrin dissolved in the aqueous continuous phase whereas spherical MFC networks retained their shape and co-existed in a mixture with individual fibrils. Spray-dried MFC powders were added to skimmed milk and tomato soup at different concentrations. With increasing concentration of dried MFC particles, shear viscosity, consistency index K, storage and loss modulus of skimmed milks and tomato soups increased whereas flow index n decreased. Addition of spray-dried MFC particles to milks and soups significantly (p < 0.05) increased sensory thickness and creaminess. Milks displayed similar tribological properties irrespective of MFC particle concentration, which was presumably caused by exclusion of the MFC network from the tribological gap. Rheological properties, thickness and creaminess increased more effectively upon addition of low MFC:maltodextrin particles compared to particles with high MFC:maltodextrin ratio. We conclude that spray-dried microfibrillated cellulose particles can be used as thickener or fat replacer in liquid foods.

Effect of bisulfite (HSO3-) on the stress corrosion cracking (SCC) behavior of 7050-T7451 aluminum alloy in the thin electrolyte layer environment in the presence of Cl- is investigated. Addition of HSO3- inhibits the corrosion initiation but promotes the corrosion propagation and hydrogen uptake. With a quantitative calculation, the HSO3- is demonstrated to significantly facilitate the synergistic effect between stress, corrosion, and hydrogen during the in-situ tensile test, resulting in the change of the SCC controlling step from corrosion-induced hydrogen to mechanical-electrochemical-hydrogen interactions. The buffer effect of HSO3- plays a dominant role in the HSO3--induced acceleration of the SCC degradation.

The effect of hot stamping on the corrosion properties of boron-manganese 22MnB5 steel coated with hot-dip aluminum-silicon was evaluated under severe conditions by a continuous salt spray test (SST). The corrosion mechanism changed from localized to generalized, as cathodic precipitates were not present after hot stamping. Intrinsic defects in press-hardened steel samples were the reason for severe damage in both metallic coating and steel substrate under SST conditions. The red rust formed at the top surface, characterized as different iron-based compounds, is due to both the iron diffusion from the steel substrate toward the surface and the corrosion of the steel substrate.

Microfibrillated cellulose (MFC) is obtained by high-shear treatment of cellulose. MFC is suitable for use as clean-label, low-calorie thickener in semi-solid foods such as mayonnaises due to its high water holding capacity. The aim of this study was to determine the effect of type and concentration of thickener on rheological, tribological and sensory properties of low-fat mayonnaises. Low-fat mayonnaises were prepared with four types of thickeners (MFC, chemically modified starch, native waxy corn starch, xanthan gum) at three concentrations. Higher biopolymer concentrations resulted in increased shear viscosities, G′ and G″, yield stress and enhanced lubrication (i.e. lower friction coefficients). Mayonnaises with modified starch and xanthan gum generally had higher shear viscosity and yield stress compared to mayonnaises with comparable concentrations of MFC and waxy corn starch. MFC-thickened mayonnaises had highest G’, G” and boundary friction coefficients. Sensory properties of mayonnaises were determined using the Rate-All-That-Apply (RATA) method (n = 80). Addition of xanthan gum induced high sliminess and pulpiness, and low melting, creaminess and smoothness. Sensory properties of mayonnaises with MFC were generally similar to those with modified and waxy corn starch, despite differences in appearance (increased yellowness and slightly lower glossiness). Multiple Factor Analysis revealed that more shear-thinning mayonnaises were perceived as slimy. Boundary friction was negatively correlated with stickiness, while friction at the start of the hydrodynamic regime was positively correlated with melting sensations. We conclude that microfibrillated cellulose can be used as a thickener in low-fat mayonnaise as an alternative to commercially used chemically modified starch without considerably affecting its sensory texture properties.

The use of microwave heating for the thermal regeneration of a porous carbon adsorbent in adsorptive carbon capture was evaluated. In this Microwave Swing Adsorption (MSA) process, a multimode microwave oven has been used to accelerate the desorption of CO2 after the adsorption of a CO2 / N2 (15/85 v/v) mixture. Starting from a commercial activated carbon (AC) material (MSP-20X), sorbent extrudates were prepared and loaded in a Teflon column. The heating of the sorbent bed inside the microwave (MW) cavity was characterised at different locations. Although the adsorption bed is not heated uniformly due to hot spots in the multimode MW cavity, flowing a purge gas reduces the non-uniform heating during the regeneration step. This study also reports that MSA regeneration achieves extremely fast total desorption (in 56 to 79 s), the quickest regeneration reported up to date in MSA, and very rapid desorption rates allowing swift adsorption–desorption cycles. This fast desorption is associated with the extremely high heating rates achieved (100 to 400 °C/min). We show that the desorption rate is faster when using higher powers at practically identical MW energy inputs. Complete CO2 desorption can be achieved at slightly longer durations when using 2-step MW heating. When comparing the MSA results with a reference TSA process, MSA outperforms TSA, due to the higher heating rates achieved by MSA. During eleven adsorption–desorption cycles, it is evidenced that the MSA process can regenerate the adsorption bed at a high reproducibility. The microporosity of the material remained intact during the MSA, revealing that localised heating and the high heating rates are not damaging the sorbent material.

Understanding electrochemical sub-processes occurring at solid oxide cells (SOCs) components, mainly air electrodes, is of high importance since they play a key role in improving the performance of SOC devices and their durability. Among various performance analysis methods, electrochemical impedance spectroscopy (EIS) is the most used one in studies. However, analyzing and interpreting EIS data have always been considered as a challenge given the fact that the information provided by the common approach of complex non-linear least square (CNLS) method is limited. Viewed in this sight, the distribution of relaxation time (DRT) approach has gained considerable attention in recent years as a potential approach to analyze EIS measurement results. This study aims at reviewing recent publications that used the DRT method to deconvolute the EIS data and at pathing the way to use DRT methodology and incorporate its results. Studies are focused on six categories of commonly used air electrodes, namely LSCF-based, LSM-based, lanthanide nickelates-based, BSCF-based, and double perovskite-based electrodes, and less-common-used ones.

Chondroitin sulfate (CS) and hyaluronic acid (HA) methacrylate (MA) hydrogels are under investigation for biomedical applications. Here, the hydrolytic (in)stability of the MA esters in these polysaccharides and hydrogels is investigated. Hydrogels made with glycidyl methacrylate-derivatized CS (CSGMA) or methacrylic anhydride (CSMA) degraded after 2-25 days in a cross-linking density-dependent manner (pH 7.4, 37 °C). HA methacrylate (HAMA) hydrogels were stable over 50 days under the same conditions. CS(G)MA hydrogel degradation rates increased with pH, due to hydroxide-driven ester hydrolysis. Desulfated chondroitin MA hydrogels also degrade, indicating that sulfate groups are not responsible for CS(G)MA's hydrolytic sensitivity (pH 7.0-8.0, 37 °C). This sensitivity is likely because CS(G)MA's N-acetyl-galactosamines do not form hydrogen bonds with adjacent glucuronic acid oxygens, whereas HAMA's N-acetyl-glucosamines do. This bond absence allows CS(G)MA higher chain flexibility and hydration and could increase ester hydrolysis sensitivity in CS(G)MA networks. This report helps in biodegradable hydrogel development based on endogenous polysaccharides for clinical applications.

Green pathways for nonisocyanate polyurethane (NIPU) production have attracted increasing levels of interest. The reaction between 5-membered cyclic carbonate and polyamines is one of the most promising pathways to produce NIPU polymers. Though promising, major technical hurdles such as slow polymerization rate and poor performance hinder the commercialization of NIPU. In this paper, we screened several commercially available triglyceride oil feedstocks for NIPU products, focusing on polymerization kinetics and product performance for industrial application. The impact of carbonated group density on polymerization rate and mechanical strength was determined. We have demonstrated a remarkably higher reactivity of carbonated oil derived from feedstocks with polyunsaturated fatty acid (PUFA). The NIPU derived from such feedstocks also showed improved performance for industrial application. Unlike traditional polyurethane foam production that uses isocyanate and water to generate CO2 as a blowing reagent, there is no gas formation in NIPU polymerization. We have demonstrated a practical and cost-effective approach to produce NIPU foam material using bicarbonate as a blowing reagent. Furthermore, we conducted the first-ever technoeconomic analysis (TEA), revealing that profitable commercial NIPU production can be achieved when operating at sufficient production capacities.

Funding Information: This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (BR) - CNPq [PQ-2/2018: 313831/2018-1], Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro - FAPERJ [JCNE 2018: E-26/203.023/2018; Apoio às Universidades Estaduais: E-26/010.101141/2018; Projetos Temáticos: SEI-260003/001198/2020; PD10 2020: E-26/290.125/2020 post-doctoral Scholarship], and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) [Finance Code 001]. The authors would like to acknowledge NANOFAB/UERJ for the SEM measurements, LCM/CAIPE-UFF for the Raman analyses, G2E-UFF for the RDE electrode, LACES-UFRJ for the thermogravimetric analysis, Multiuser Laboratory of Pontal at the Federal University of Uberlândia for the ASAP analyses (FINEP/2013 INFR13 01.13.0371.00), and LCS/LNNano-CNPEM for the use of AFM in its open facilities. Funding Information: This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (BR) – CNPq [PQ-2/2018: 313831/2018-1], Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro – FAPERJ [JCNE 2018: E-26/203.023/2018; Apoio às Universidades Estaduais: E-26/010.101141/2018; Projetos Temáticos: SEI-260003/001198/2020; PD10 2020: E-26/290.125/2020 post-doctoral Scholarship], and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) [Finance Code 001]. The authors would like to acknowledge NANOFAB/UERJ for the SEM measurements, LCM/CAIPE-UFF for the Raman analyses, G2E-UFF for the RDE electrode, LACES-UFRJ for the thermogravimetric analysis, Multiuser Laboratory of Pontal at the Federal University of Uberlândia for the ASAP analyses (FINEP/2013 INFR13 01.13.0371.00), and LCS/LNNano-CNPEM for the use of AFM in its open facilities. Publisher Copyright: © 2022 The Royal Society of Chemistry. This work reports the application of Mn-doped Co3O4 oxides in the electrocatalytic oxygen evolution reaction (OER). The materials were characterized by structural, morphological, and electrochemical techniques. The oxides with higher Co : Mn molar ratio presented a lower electron transfer resistance, and consequently the most promising OER activities. Pure Co3O4 shows an overpotential at j = 10 mA cm−2 of 761, 490, and 240 mV, at pH 1, 7, and 14, respectively, and a high TOF of 1.01 × 10−1 s−1 at pH 14. Tafel slopes around 120 mV dec−1 at acidic pH and around 60 mV dec−1 at alkaline pH indicate different OER mechanisms. High stability for Co3O4 was achieved for up to 15 h in all pHs, and no change in the structure and morphology after the electrocatalysis was observed. The reported excellent OER activity of the Mn-Co oxides in a wide pH range is important to broaden the practical applicability in different electrolyte solutions. publishersversion published

The economic, environmental, and energetic performance of direct air capture (DAC) processes based on solid sorbents depends significantly on ambient air conditions and the availability of renewable resources. High ambient temperature or low humidity leads to higher energy consumption and lower CO2 productivity; lack of renewable resources may make the direct air capture process not viable. With this work, we investigated how the performance of sorbent-based direct air capture plants varies when changing ambient conditions and how the system should be optimally designed and operated to match the time-dependent variations. To this end, we formulated a new modeling framework, where thermodynamic modeling of adsorption processes is bridged to mixed integer linear optimization via a portable linear model of DAC. The process is based on a vacuum-temperature swing cycle, whose performance was obtained with a rate-based thermodynamic model at varying ambient conditions for an exemplary sorbent representative of different amine-functionalized materials. The optimal design and operation were investigated for (i) a stand-alone DAC system installed at three different geographical locations and (ii) a DAC system embedded in a multi-energy hub aimed at supplying the DAC energy demand from renewable resources. We found that DAC performance is optimal when the process can adjust the operating variables according to the weather profile and when CO2 can be produced flexibly over time, for example, by adopting a buffer storage tank. Other operation strategies are suboptimal but might require less sophisticated control systems. Moreover, the results suggest that capturing costs are significantly smaller in cold and humid conditions. This conclusion holds for both the stand-alone and the integrated DAC systems. However, for the latter, cold and humid conditions are favorable only when abundant renewable energy is available and can be supplied at low costs, for example, via wind farms. These conclusions remain true over a wide range of technical and cost assumptions.

Iron deficiency leading to anemia is one of the most severe and important nutritional deficiencies in the world today. To combat this deficiency, the fortification of food products with iron is a natural way to increase the global iron uptake. Here, we report a novel strategy for iron encapsulation in NaCl crystals via microscopic inclusions containing dissolved iron salt. The liquid inclusions embedded in the crystal insulate the reactive iron salts from their environment while assuring that iron is in a soluble and bioavailable form. While the size distribution of inclusions remains independent of the evaporation conditions, their density increases during crystallization at lower relative humidity. Using Raman confocal microspectroscopy, we have been able to analyze the morphology, length/thickness ratio, of inclusions and show that inclusions evolve toward a plate-like structure with the increase in size. By growing a pure NaCl shell around the iron-containing NaCl crystals, the stability of the composite crystals can be even further enhanced. The role of halite crystals as a carrier for iron fortification opens the way for the delivery of other types of micronutrients by including them in table salt.

2020.00835.CEEIND 2021.01432.CEECIND RC2-2019-007 It is proven that fluorinated gases (F-gases) have a vast impact on climate change due to their high global warming potential. Hence, it is imperative to search for new molecules to replace them in current applications, as well as technologies to capture, recover, and recycle F-gases to avoid their emissions to the atmosphere. One of the attractive technologies for this purpose is to absorb them in fluorinated ionic liquids (FILs), given their solubilization power. However, the complexity of FILs and the time-consuming experimental methodologies to fully characterize them hinder their prompt usage in this urgent field. In this work, the soft-Statistical Associating Fluid Theory (soft-SAFT) Equation of State is used as a tool to investigate the solubility of six different F-gases (R-32, R-125, R-134a, R-14, R-116, R-218) in five FILs ([C2C1Im][C4F9SO3], [C2C1Im][C4F9CO2], [C2C1py][C4F9SO3], [C2(C6F13)C1Im][N(CF3SO2)2], and [C2(C6F13)C1Im][N(C2F5SO2)2]). The robustness of the soft-SAFT approach allowed the establishment of new FIL models in a simple and fast way, and the calculation of F-gases solubility in them, in excellent agreement with existing experimental data. Once the models were assessed, a systematic study was performed regarding the structural features of FILs favoring their performance to absorb F-gases by using the soft-SAFT approach as a screening tool. It has been obtained that the solubility is favored by the presence of a perfluoroalkyl chain in the imidazolium cation, together with a bulkier anion. In all cases, [C2(C6F13)C1Im][N(C2F5SO2)2] shows a superior solubility of F-gases than the [C2(C6F13)C1Im][N(CF3SO2)2], also indicating that the addition of one carbon to the two anionic symmetric fluorinated chains contributes to the gas-philicity of the FILs. This work proves the relevance of using the soft-SAFT framework to obtain insights into the behavior of such complex systems and key trends, even when experimental data are scarce, as a step forward in assessing systems for separating and recovering F-gases. publishersversion published

Adsorbent monoliths are gaining increasing interest in gas phase separation processes, but have rarely been studied for liquid phase separations. In this work, we investigate an activated carbon monolith for the recovery of biobutanol from model liquid mixtures as well as compare the obtained column dynamics with the adsorption of biobutanol from gas mixtures. Single solute adsorption isotherms of acetone, n-butanol and ethanol revealed the carbon’s larger affinity for n-butanol (0.11 g/g adsorbed at 2 wt%), while dynamic separations on a fixed-bed of crushed monolith granules proved its capability to effectively separate an aqueous mixture of these three fermentation products. In contrast, liquid phase breakthrough experiments of n-butanol on the monolith column were marked by almost instantaneous detection of adsorbate at the outlet (< 5 min.) and broad tailing of the concentration curve. Measures to improve inlet flow distribution or increasing temperature to enhance mass transfer were unsuccessful. In contrast, using the same inlet flow distributors, a sharp breakthrough profile could be obtained in vapor phase, while the gas contact time (17 s) was much lower than in liquid phase (1300 s). A comparison of characteristic mass transfer times of the adsorption process highlighted the important role of the external film resistance in liquid compared to vapor phase adsorption.

Phosvitins is a key egg yolk protein and can often be found in food emulsions. It is highly phosphorylated and hence phosvitins contain a large number of negatively charged amino acid groups, for pH > pI. Due to the presence of these phophoserines, phosvitins bind to positively charged multivalent ions. Its amphipolar structure makes phosvitin also an efficient emulsion stabilizer. The ion binding and emulsifying abilities of phosvitins are influenced by environmental conditions such as pH and ionic strength. Various physicochemical properties of phosvitins such as size and charge under various conditions, and how they self-assemble via multivalent ions are not well-understood. To gain more insight into these physical characteristics, we performed high brilliance synchrotron small angle X-ray scattering (SAXS) on phosvitin solutions. The structure factor S(q) obtained from the SAXS profiles showed that the double layer interactions between charged phosvitin assemblies are strongly affected by pH and ionic strength of the buffer. The effects of multivalent ions (Mg2+, Fe3+) on the size and structure of phosvitin were also investigated. Our results revealed that the aggregation of phosvitin mediated by metal ions is induced by electrostatic attraction and only occurs beyond a threshold cation concentration, where phosvitin loses long-range electrostatic double layer repulsions. These findings help understanding the effects of metal ions and pH on phosvitin in more complex environments such as food emulsions.

While methane-powered vehicles produce fewer greenhouse gas emissions in comparison to conventional fuel vehicles, there is a significant amount of methane slip in their exhaust that needs to be treated. This study investigates non-thermal plasma (NTP) assisted catalytic methane oxidation as an alternative method for the low temperature methane slip abatement applicable to the exhaust of biogas methane-powered vehicles. It is concluded that high CH4 conversion and CO2 selectivity can be obtained using NTP-catalysis at low temperature with Pd/Al2O3 found to be the most promising candidate among all catalysts tested. In addition, it was found that CH4 conversion efficiency was dependent on the feed gas components and gas hourly space velocity as well as how the activation energy is introduced. For example, a combination of plasma and external heat supply provides advantages in terms of CH4 conversion along with lower plasma energy consumption. The presence of N2 and O2 in the feed gas during NTP-catalytic methane oxidation results in unfavourable NOX formation which linearly increases with CH4 conversion. These results conclude that the most suitable aftertreatment option involves the combination of an oxidation catalyst with plasma to target the hydrocarbon and CH4 oxidation, followed by an ammonia-SCR system to convert the NOX formed in plasma assisted zone.

Funding Information: This work was supported by the Associate Laboratory Institute for Health and Bioeconomy – i4HB (project LA/P/0140/2020) which are financed by national funds from FCT/MCTES. FCT/MCTES is also acknowledged for supporting the National Portuguese NMR Network (ROTEIRO/0031/2013–PINFRA/22161/2016, cofinanced by FEDER through COMPETE 2020, POCI, PORL, and FCT through PIDDAC). A. C. acknowledges financing from Fundação Calouste Gulbenkian, grant no. 219201, and from the Angolan Embassy in Lisbon, Portugal, INAGBE grant. Dr. Ramesh Pandian is acknowledged for the initial acquisition and processing of single crystal X-ray data. Publisher Copyright: © 2023 The Author(s) The kinetics and thermodynamics of the pH-dependent multistate of species generated by the trans-chalcone of n-pyridinebenzopyrylium (n = 2′, 3′) were studied by UV–vis spectroscopy, 1H NMR and HPLC-MS, and the results compared with those reported for n = 4′. Due to the slow kinetics of the multistate species interconversion, the conjugation of these techniques has shown to be a powerful tool to investigate the behaviour of these systems. The species involved in the multistate are mutatis mutandis the same observed in anthocyanins and related compounds except for the flavylium cation, which was not observed in these systems even in very acidic medium. The rates of the interconversion of the multistate species upon pH stimuli are much slower than in anthocyanins. The compound bearing the pyridine nitrogen in position 2′ gives two novel products absorbing in the visible. Formation of the new products is particularly efficient from the thermal evolution of the photochemical products obtained upon light irradiation of the protonated trans-chalcone in a mixture of methanol:acidic water (1:1). This confirms the unique capacity of the substituents in position 2′ in giving intramolecular reactions involving the benzopyrylium core. Crystal structures for the three pyridine chalcone compounds (n = 2′, 3′, 4′) were obtained and the respective structures discussed. publishersversion published

projects LA/P/0037/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3N. This work was also supported by ERC-CoG-2014. The authors would also like to thank João Lopes for his contribution with the home-made mechanical abrasion setup. Publisher Copyright: © 2023 The Author(s) The search of sustainable gadgets, such as the portable electronics and wearables, have sparked the need for more sustainable and environment friendly constituent elements (e.g., electrode materials, separators, and green electrolytes) and low-cost scalable fabrication techniques. Herein, a facile and scalable blow spinning technique is proposed for the synthesis of a cellulose-based separator for flexible energy storage devices. A cellulose acetate and polystyrene (CA:PS) based composite separator is synthesized for the first time for flexible supercapacitors by exploiting the blow spinning technique. Different combinations of CA:PS were synthesized, and electrochemical performances of the devices were evaluated. A sweat simulation solution is used as green electrolyte for the development of symmetrical carbon yarn-based supercapacitors. The influence on the device performances of pristine carbon yarn, activated carbon yarns and PEDOT functionalized carbon yarns, electrodes were compared. Specific capacitances of 2.8 Fg−1 and 33 Fg−1 were obtained for pristine carbon and PEDOT functionalized carbon fibers respectively. The fabricated devices exploiting the composite separator exhibited good washing stability up to 30 cycles and capacitance retention of 95% up to 1000 charge/discharge cycles. publishersversion published

The autoxidation of triglyceride (or triacylglycerol, TAG) is a poorly understood complex system. It is known from mass spectrometry measurements that, although initiated by a single molecule, this system involves an abundance of intermediate species and a complex network of reactions. For this reason, the attribution of the mass peaks to exact molecular structures is difficult without additional information about the system. We provide such information using a graph theory-based algorithm. Our algorithm performs an automatic discovery of the chemical reaction network that is responsible for the complexity of the mass spectra in drying oils. This knowledge is then applied to match experimentally measured mass spectra with computationally predicted molecular graphs. We demonstrate this methodology on the autoxidation of triolein as measured by electrospray ionization-mass spectrometry (ESI-MS). Our protocol can be readily applied to investigate other oils and their mixtures.

Nanoporous solids, including microporous, mesoporous and hierarchically structured porous materials, are of scientific and technological interest because of their high surface-to-volume ratio and ability to impose shape- and size-selectivity on molecules diffusing through them. Enormous efforts have been put in the mechanistic understanding of diffusion–reaction relationships of nanoporous solids, with the ultimate goal of developing materials with improved catalytic performance. Single-molecule localization microscopy can be used to explore the pore space via the trajectories of individual molecules. This ensemble-free perspective directly reveals heterogeneities in diffusion and diffusion-related reactivity of individual molecules, which would have been obscured in bulk measurements. In this article, we review developments in the spatial and temporal characterization of nanoporous solids using single-molecule localization microscopy. We illustrate various aspects of this approach, and showcase how it can be used to follow molecular diffusion and reaction behaviors in nanoporous solids.

The recently developed family of 3D halide perovskites with general formula (A)1-x(en)x(M)1-0.7x(I)3-0.4x (A = MA, FA; M = Pb2+, Sn2+ en = ethylenediammonium), often referred to as "hollow"perovskites, exhibits exceptional air stability and crystallizes in the high symmetry α phase at room temperature. These properties are counterintuitive, considering that these structures include the large divalent en cation charge-compensated by vacancies of Pb cations and I anions. Moreover, the understanding of their transport behavior is incomplete. To provide new insights into the ionic and electronic transport properties of these "hollow"perovskites, we performed DC polarization experiments and ab initio calculations on the {en}MAPbI3 material. We observe large variations of ionic and electronic conductivities with en concentration, which can be explained by charge and site arguments in conjunction with trapping effects. The latter is reflected by the increase of the activation energies for iodide ion transport with higher en content that we observe from both experimental and computational results. The connection between these transport phenomena and the stability of "hollow"perovskite materials and devices is discussed.

In the present study, the coked catalysts derived from catalytic reforming of the pyrolysis volatiles of polyethylene (PE), lignin (LG) and their mixture were developed as low-cost and environmentally-friendly carbon materials-containing composites to remove heavy metal ions from aqueous solution. The composites were thoroughly characterized by SEM, TEM, XRD, TGA and FT-IR and then their adsorption capability towards Pb(ii) was investigated. It is found that curved cone-shape carbon nanotubes (CNTs) with abundant structural defects and O-containing surface functional groups, such as C-O, CO and -OH, can be obtained from the catalytic reforming of the mixture of PE and LG. The CNT-containing catalyst composite presents a superior adsorption capability towards Pb(ii) when it is employed in Pb(ii) removal. Adsorption isotherm and adsorption kinetics studies show that the adsorption process can be well simulated by the Langmuir isotherm and pseudo-second-order model, demonstrating that the adsorption is subjected to a homogeneous and chemical process. The calculated maximum adsorption capacity is as high as 146.08 mg g-1, which is much higher than most of the adsorbents reported. Moreover, thermodynamic analysis reveals that the adsorption is spontaneous and endothermic. Accordingly, the used catalyst from the catalytic reforming can be developed as a low-cost and highly-efficient adsorbent.

This study presents a novel combination of microwave irradiation and structured zeolite/SiC foam catalyst to improve the methanol-to-hydrocarbons (MTH) process as well as its environmental sustainability. Accordingly, ZSM-5/SiC foam was studied under microwave irradiation at various reaction temperatures (400–550 °C) and space velocities (8 and 12 h−1) and compared to conventional ZSM-5 pellets. ZSM-5/SiC foam promoted higher selectivity towards C1−C5 hydrocarbons (∼95%) and particularly propylene (∼40% at 400 °C and 8 h−1) compared to ZSM-5 pellets (∼40% and 6–9%, respectively) due to the enhanced mass and heat transfers. The microwave-assisted MTH process with both the structured catalyst and pellets was also assessed on the environmental sustainability via life cycle assessment in comparison with the conventionally-heat process with the structured catalyst. The results showed that the microwave-based process with the structured catalyst could reduce the environmental impacts of propylene production by 22–30% compared to the conventionally-heated process with the same catalyst.

Colloid transport through a porous medium changes geometrical and hydraulic properties of the pore space. The impact of this effect depends on the colloid types and pore space surface properties which determine the likelihood of pore clogging. Colloid attachment and subsequent detachment are key factors in pore clogging. In this study, the impact of four major fluid and colloids properties on the pore surface and hydraulic conductivity alteration during colloids transport were evaluated using machine learning. These four parameters include solution ionic strength, zeta potential, colloid size and fluid flow velocity. A combined lattice Boltzmann-smoothed profile method was used to simulate accurately coupled mechanisms governing colloid transport to evaluate the impact of the four parameters on the resulting pore space properties after colloid transport. The result of several simulations revealed significant changes of pore surface coverage by the attached colloids, and conductivity, void fraction and coordination number of colloid agglomerates created during transport of individual colloids. Since the simulation of the impact of combination of all possible sets of four parameters is very time consuming, an Artificial Neural Network (ANN) was used as a prognostic method to use the results of several simulations to predict the behavior for a wide range of pore, colloidal and fluid properties. Reported results from a set of 162 simulation case studies for different possible combination of solution ionic strength, zeta potentials, colloid size and flow velocity were selected as input parameters for the machine learning. Four output parameters, namely, pore surface coverage, conductivity, void fraction and coordination number of the colloidal particles were selected. To lower the prediction error value, which is targeted to be lower than 10%, networks were trained 50 times using a MATLAB code, and in each training, after at most 10 epochs, networks were trained. A maximum relative error value of 8.95% was obtained, which is very well within the range of training quality criteria. The results show that the ANN can profoundly predict the simulation outcomes for a wide range of ionic strength (IS) and can be directly used to obtain the value of dependent variables through simple calculations using network weights and transfer functions.

To enhance the performance of charge-detection mass spectrometry, we investigated the behaviour of macromolecular single ions on their paths towards and within the Orbitrap analyser. Ions with a mass beyond one megadalton reach a plateau of stability and can be successfully trapped for seconds, travelling a path length of multiple kilometres, thereby enabling precise mass analysis with an effective resolution of greater than 100,000 at a mass-to-charge ratio of 35,000. Through monitoring the frequency of individual ions, we show that these high-mass ions, rather than being lost from the trap, can gradually lose residual solvent molecules and, in rare cases, a single elementary charge. We also demonstrate that the frequency drift of single ions due to desolvation and charge stripping can be corrected, which improves the effective ion sampling 23-fold and gives a twofold improvement in mass precision and resolution.

Capacitive deionization (CDI) as an emerging desalination technology attracts increasing attention due to its advantages such as low cost, environmental friendliness, simple operation, and large water recovery. This study presents a systematic, objective, and comprehensive review of CDI research via scientometric analysis. The dataset was collected from Web of Science and analysed by software Biblioshiny, VOSviewer and CiteSpace. After analysing a sum of 2270 documents, we identified the most influential journals, countries, institutions, authors, and publications. We also mapped the networks of co-authorship, co-citation, and keywords co-occurrence. Desalination has the largest number of publications in CDI. China is the country with the largest number of publications, and Egypt has the highest level of international collaboration. The keyword and cluster analyses demonstrate the evolution of CDI electrodes from traditional carbon materials through carbon-based nanomaterials to Faradaic materials and the diversification of CDI cell architectures. The timeline visualization displays five popular research topics, including electrode materials, charge efficiency, water salinity, CDI cell architectures, and selective removal. Moreover, we provided several recommendations for future research. This article will give authors an intuitive understanding of the research status, frontier topics, and emerging trends in CDI.

The use of 1,3-dimethylimidazolium-2-carboxylate as an organocatalyst for the glycolysis of waste PET, poly(ethylene terephthalate), is reported for the first time. Post-consumer PET was completely depolymerised in less than 1 h at 180◦C with up to 60% of bis(2-hydroxyethyl terephthalate) (BHET) was recovered by precipitation after cooling of the reaction mixture. Under comparable conditions the basic ionic liquid, 1,3-dimethylimidazolium acetate, was a significantly less effective catalyst suggesting that catalysis occurs through formation of a nucleophilic N-heterocyclic carbene.

Volatile fatty acids (VFA) produced by fermentation of organic-rich wastewater streams can, after efficient recovery from the dilute fermentation broth, serve as a circular source of carbon and be catalytically upgraded into various valuable platform molecules. Waste-derived VFA, that is, a mixture of acetic, propionic, and butyric acids, can thus be converted into mixed ketones, which in turn are valuable intermediates for light aromatics synthesis. Here, an integrated process is presented for the recovery and in-line catalytic conversion of VFA extracted from a fermentation broth by adsorption on a nonfunctionalized resin adsorbent. Gas-phase ketonization of the VFA was studied with and without co-fed water, which is inevitably coextracted from the broth, over TiO2 anatase catalysts to assess catalyst performance, including stability as a function of time on stream. While VFA conversion over bare TiO2 at 375 °C proceeded at 90% conversion with 100% selectivity to ketones, the presence of water in the feed resulted in an activity drop to 40%. Catalyst stability toward water could be greatly improved by dispersing the titania on a hydrophobic carbon support. The carbon-supported catalyst showed superior performance in the presence of excess water, providing a quantitative yield toward ketones at 400 °C. The approach thus allows coupling of VFA recovery from a fermentation broth with successful catalytic upgrading to mixed ketones, thus providing a novel route for the production of value-added products from waste streams.

peer-reviewed The full text of this article will not be available in ULIR until the embargo expires on the 01/07/2021 Hydrodynamic cavitation (HC) is being increasingly used for a wide range of applications including waste water treatment. No systematic comparison of pollutant degradation performance of different HC devices is available. In this work, for the first time: a basis for comparing performance of HC devices and a systematic comparison of pollutant degradation performance of five different types of HC devices based on linear and swirling flows is presented. 2,4 dichloroaniline (DCA) was selected as a model pollutant in water as it contains multiple functional groups on an aromatic ring. Experiments were performed at two values of pressure drop across HC devices (100 and 200 kPa) at a constant initial concentration (35 ppm), pH (7) and temperature (18 oC) for five types of HC devices namely orifice, venturi, orifice with swirl, venturi with swirl and vortex diode. The pollutant degradation was interpreted by a per-pass degradation factor approach. The study demonstrated that five different types of cavitation devices performed similar to each other when these devices were designed to exhibit similar pressure drop versus flow rate curve. It was conclusively shown that swirl does not supress degradation performance while offering advantages on shielding device walls from collapsing cavities. This is an important and new result which will be useful for selecting and designing cavitation devices. Pollutant degradation data for geometrically similar vortex diodes of two smaller scales showed significantly higher degradation performance. The number of passes required for ~10% degradation for the devices with nominal capacity of 1, 5 and 20 LPM were 15, 100 and 1200 passes respectively. The presented experimental data from these seven devices will be useful for evaluating computational models and hopefully stimulate further development of predictive computational models in this challenging area.

In this work, hot-dip galvanised steel wires were exposed in Belgium and Indonesia for 4.5 years and correlation of corrosion products formed on the exposed wires with their corrosion properties was studied. Corrosion products were identified with local Raman analysis and correlated with corrosion activity based on odd random phase electrochemical impedance spectroscopy and Tafel behaviour. Raman spectroscopy results confirmed that corrosion products formed in both atmospheric conditions differed either in quantity and/or in chemical nature, which indicated that ‘aged in Belgium’ and ‘aged in Indonesia’ wires did not have similar surface compositions. The comparison of the instantaneous corrosion behaviour of pristine and aged wires based on corrosion currents (polarisation curve) and impedance values in 0.1 M NaCl and 0.1 M Na2SO4 declared that aged in Belgium (AIB) and aged in Indonesia (AII) wires exhibited different corrosion behaviour, which confirmed that corrosion products formed in the environments of the exposed wires were dominating their corrosion behaviour.

UIDB/50025/2020 UIDP/50025/2020 UID/CTM/50025/2019 . Silver sulfide (Ag2S) is a low band gap material, which absorbs near-infrared light and is of great importance in areas such as nanotechnology and biomedicine. We report the influence of the starting reagents, synthesis time, and light radiation on the geometry and size of silver sulfide nanoparticles and on the fraction of metallic Ag obtained in a microwave reactor. The X-ray diffraction diffractograms confirmed that Ag2S is the main product if the reaction's precursor contains silver in the oxidation state of +1 and mostly metallic silver (Ag°) when it is +2. Small nanoparticles (∼6 nm) of spherical geometry are present in the transmission electron microscopy images for the synthesis performed with the lamp light ON, while with the light switched OFF, wider and hundreds of nanometers longer particles are observed. This discriminative effect occurs with shorter synthesis time duration (

Single-site catalysts can demonstrate high activity and selectivity in many catalytic reactions. The synthesis of these materials by impregnation from strongly oxidizing aqueous solutions or pH-controlled deposition often leads to low metal loadings or a range of metal species. Here, we demonstrate that simple impregnation of the metal precursors onto activated carbon from a low-boiling-point, low-polarity solvent, such as acetone, results in catalysts with an atomic dispersion of cationic metal species. We show the generality of this method by producing single-site Au, Pd, Ru and Pt catalysts supported on carbon in a facile manner. Single-site Au/C catalysts have previously been validated commercially to produce vinyl chloride, and here we show that this facile synthesis method can produce effective catalysts for acetylene hydrochlorination in the absence of the highly oxidizing acidic solvents previously used. [Figure not available: see fulltext.].

Mixtures of few representative hydrocarbon species are often used in computational studies as surrogates of market petroleum fuels, which contain hundreds of components. While this simplification is imperative for computational costs of reaction kinetics, it introduces unavoidably uncertainties in simulations. Differences between the real and the surrogate fuels regarding mixture formation, oxidation chemistry, and fuel composition contribute to such uncertainties. An evaluation of the underlying concept of a surrogate fuel model in terms of engine performance is thus of high interest. This paper presents an experimental study with a spark-ignition (SI) single-cylinder engine (SCE) to compare the combustion and emission characteristics between a market gasoline fuel and its corresponding four-component surrogate (iso-octane, n-heptane, toluene, ethanol). The measurements cover a wide range of operating points in terms of engine load, speed, air-to-fuel ratio, and operating conditions. Together with standard performance and emission measurements, a non-standard hydrocarbons (HC) analysis has been performed with a fast flame ionization detector and an ion-molecule-reaction mass spectrometer. The comparison reveals very good agreement between the market gasoline and the surrogate fuel regarding combustion and global gaseous emission behaviors, with an average deviation for almost all of the analyzed quantities below 2%. The comparison of CO emissions in stoichiometric operation presents a higher scatter, due to the high sensitivity of the CO emissions on mixture formation and fuel volatility. The different compositions of the two fuels also lead to deviations of speciated-HC emissions, which is confirmed by mass spectrometry. Additionally, the sooting tendency of the surrogate fuel is found to be more than 10 times lower compared to the market gasoline fuel.

This study proposed that hybrid scrap cast iron particles (SIP)-aerobic biodegradation technology could enhance the biodegradability of toxic wastewater. SIP cleaved the azo linkages of Direct Green1 dye to form benzidine, 4-aminophenol, aniline and 1,2,7-triamino-8-hydroxynapthalene-3,6-disulfonic acid. SIP-mediated dye reduction was effective at wide pH range; however, kinetic analysis revealed fastest pseudo-first order dye reduction rate at acidic pH 3 (kd = 0.549 min−1) followed by pH 9 (kd = 0.383 min−1) and pH 7 (kd = 0.318 min−1). The daughter aromatic amines produced were partially adsorbed onto the SIP surface and maximally at neutral pH. The adsorption process followed pseudo-second order adsorption kinetics and Langmuir isotherm. Benzidine was adsorbed more than 4-aminophenol and aniline. BOD5 of the SIP-treated effluent increased from 0.93 to 12 mg/L showing improved biodegradability. The daughter amines were rapidly mineralized in the aerobic bioreactor within 6 h. Cost-effective SIP pre-treatment could accelerate mineralization and detoxification of recalcitrant wastewater. Keywords: Adsorption, Biodegradability, Direct green 1 (DG1), Reduction, Scrap cast iron particles (SIP)

Experiments were performed for the synthesis of meso-substituted tetraphenyl porphyrins in order to obtain growth active points for PAMAM branches and a functionalized periphery with thiazole groups for increasing the metal complexation activity. Characterization by 1H and 13C NMR, mass spectrometry and infrared spectrometry confirmed the produced dendrimeric nanostructures; the chemical reduction of metallic Ag and Cu inside the dendrimer was proved by XPS. Finally, the toxicity of the metal-dendrimer complex was analyzed by means of the bacterial respiration test. Keywords: Porphyrin, PAMAM-dendrimers, Metal complex, Metal species

In order to broaden the temperature range of NO oxidation reaction in flue gas and maintain high oxidation efficiency, various loading amounts of MnOx-CoOx/TiO2 mesoporous catalysts were tested in the catalytic oxidation of NO. It was found that 15%MnOx-CoOx(2 : 1)/TiO2 demonstrated the best adsorption performance to oxygen species and contained more oxygen vacancies, as well as the best surface oxygen mobility, thus exhibiting excellent NO catalytic oxidation activity. O3 (O3/NO < 1) combined with 15%MnOx-CoOx(2 : 1)/TiO2 improved the oxidation efficiency of NO at 50-400 °C, especially below 250 °C. When the temperatures were less than 250 °C, the oxidation efficiencies of NO by O3 over 15%MnOx-CoOx(2 : 1)/TiO2 were 5-13% higher than the calculated theoretical efficiencies. This indicated that there was a synergistic effect between O3 and 15%MnOx-CoOx(2 : 1)/TiO2 below 250 °C. Based on the results of in situ DRIFTS studies, it was deduced that monodentate nitrates were the main intermediates that produced a synergistic effect due to the introduction of O3. In addition, O3 accelerated the transformation between nitrate species, decreased the decomposition temperature of nitrate species, and inhibited the accumulation of nitrate ions, thus improving the oxidation efficiency of NO.

Bio-synthesis approach for gold nanoparticles (AuNPs) has received tremendous attention as an efficient and eco-friendly process. However, kinetic growth and colloidal stability of AuNPs synthesized by this process remained challenging. In this study, Elaeis guineensis (oil palm) kernel (OPK) extract prepared in an ionic liquid (IL)[EMIM][OAc] (1-ethyl-3-methylimidazolium acetate) was employed to control and tune the size and morphology of AuNPs. Synthesized AuNPs were characterized using UV-vis spectrophotometer, dynamic light scattering (DLS) and transmission electron microscopy (TEM) to observe any changes in absorbance, surface charge and particle size, respectively. IL mediated AuNPs were examined for 120 days and found well dispersed and stable at room temperature. UV-vis analysis demonstrated that volume of extract played an important role to control the stability of AuNPs. After 120 days, only 8.86% reduction from maximum absorbance was observed using 2 mL of volume of extract, which was elevated to 47.64% in case of 0.3 mL. TEM analysis was performed periodically after day 1, day 30, day 60, day 90 and day 120 and minor increase in the size was observed. Insignificant change in zeta potential value after 120 days supported enhanced stability of IL mediated AuNPs. Crystalline nature of AuNPs was confirmed by X-ray diffraction (XRD) pattern. The particles size and zeta potential of AuNPs was measured as 8.72 nm and −18.7 mV, respectively. However, the absence of [EMIM][OAc] from OPK extract resulted into larger particles size (9.64 nm), low zeta potential value (−13.9 mV) and enhanced aggregation of particles. Finally, experimental data were used to predict the theoretical and the experimental settling time for AuNPs to evaluate colloidal stability. Keywords: Gold nanoparticles, Elaeis guineensis, Ionic liquids, Particle size, Particle growth, Stability

This study presents essential oil composition of three Melaleuca species namely, Melaleuca bracteata F. Muell, Melaleuca fulgens R. Br. subsp. steedmanii and Melaleuca leucadendron (L.) L. collected from different regions of Pakistan. The chemical composition of essential oils was analyzed by GC-FID and GC–MS. Eugenol methyl ether was identified as a principal component in M. bracteata (82.3%), M. fulgens (87.8%) and M. leucadendron (95.4%) oils. In vitro antibacterial studies were done by agar well diffusion and microdilution method and the tested essential oils exhibited bacteriostatic and bactericidal effects against the tested foodborne pathogens at 4–8 µg/ml. Time kill assay showed significant bactericidal effect of oils for four weeks. The antioxidant potential was assessed by free radical scavenging activity and reducing power assay. The oils showed strong antioxidant activity with approximately 89.0–89.5% inhibition of 2,2-diphenyl-1-picrylhydrazyl radical and ferric reducing power in the range of 1.94 ± 0.007–2.04 ± 0.04% at 100 µg/ml. Keywords: Melaleuca bracteata, M. fulgens, M. leucadendron, Essential oils, Antibacterial activity, Antioxidant potential

In this study, the adsorption equilibrium and diffusivity parameters of p-nitrophenol were estimated for water containing different concentrations of secondary amides. Commercial powdered activated carbon was used as an adsorbent. The external mass transfer coefficient (kf), the surface diffusion coefficient (Ds) and the standard free Gibbs energy were calculated for p-nitrophenol in the presence of different secondary amide concentrations. The analysis established that there are correlations between structural parameters of amides, on the one hand, and diffusion and thermodynamic parameters for p-nitrophenol adsorption process, on the other. It was noticed that voluminous hydrophobic amides decreased the adsorption capacity of p-nitrophenol on activated carbon. On the basis of the results obtained for external mass transfer coefficients, it is assumed that amides cause the reduction of adsorption capacity of p-nitrophenol onto activated carbon by concentrating at the solid/liquid interface. Keywords: Adsorption, Amides, Natural organic matter, P-nitrophenol

Cu and N-doped TiO2 photocatalysts were synthesized from titanium (IV) isopropoxide via a microwave-assisted sol-gel method. The synthesized materials were characterized by X-ray diffraction, UV-vis diffuse reflectance, photoluminescence (PL) spectroscopy, SEM, TEM, FT-IR, Raman spectroscopy, photocurrent measurement technique, and nitrogen adsorption–desorption isotherms. Raman spectra and XRD showed an anatase phase structure. The SEM and TEM images revealed the formation of an almost spheroid mono disperse TiO2 with particle sizes in the range of 9-17 nm. Analysis of N2 isotherm measurements showed that all investigated TiO2 samples have mesoporous structures with high surface areas. The optical absorption edge for the doped TiO2 was significantly shifted to the visible light region. The photocurrent and photocatalytic activity of pure and doped TiO2 were evaluated with the degradation of methyl orange (MO) and methylene blue (MB) solution under both UV and visible light illumination. The doped TiO2 nanoparticles exhibit higher catalytic activity under each of visible light and UV irradiation in contrast to pure TiO2. The photocatalytic activity and photocurrent ability of TiO2 have been enhanced by doping of the titania in the following order: (Cu, N) - codoped TiO2 > N-doped TiO2 > Cu-doped TiO2 > TiO2. COD result for (Cu, N)-codoped TiO2 reveals ∼92% mineralization of the MO dye on six h of visible light irradiation. Keywords: TiO2, Nanoparticles, Doping, COD, Photocatalytic activity

A rapid, simple and highly efficient method for the synthesis of a variety of 2-aryl-benzimidazoles, 2-aryl-benzothiazoles and quinoxalines has been developed using Koser’s reagent [PhI(OH)OTs] as catalyst. The present work highlights the potential of Koser's reagent ([PhI(OH)OTs]) for the synthesis of benzimidazoles, benzothiazoles and quinoxalines, etc. Short reaction time, high yields, importantly low catalyst loading, broad substrate scope and scalability are the salient features of this methodology. Particularly, this method has been employed successfully to synthesize highly structured indole-benzimidazole and quinoxaline-6-carboxamide derivatives as well as biologically important benzimidazole-imidazo[1,2-a]pyridine conjugates in moderate to good yields. These remarkable features make the present methodology a valid contribution to the existing precedents for the synthesis of benzimidazoles, etc. In the MTT assay, benzimidazole-imidazo[1,2-a]pyridine conjugates 3s, 3t and 3v were found to be active on MCF-7 (IC50 values of 5.10 ± 0.10, 8.23 ± 0.02, and 10.75 ± 0.03 µM, respectively) and MDA-MB-231 cell lines (IC50 values of 10.83 ± 0.13, 7.68 ± 0.05, and 7.87 ± 0.24 µM, respectively). Flow-cytometry analysis revealed that the treatment of MCF-7 cells with compound 3s showed moderate effect on the progression of G0/G1 phase of the cell cycle. Keywords: Koser’s reagent, Benzimidazoles, Benzothiazoles, Quinoxalines, Imidazo[1,2-a]pyridine

Many natural products play important roles as antioxidants and represent useful scaffolds for the development of new agents. Particularly, polyphenols in which oxygenated xanthones can be included have proven their efficacy as antioxidants for several applications. To better understand the antioxidant potential of oxygenated xanthones, a library of twenty mono and di-oxygenated xanthones was investigated. The antioxidant properties were evaluated by their 2,2-diphenyl-1-picrylhydrazyl (DPPH) and peroxyl radical scavenging effect as well as their inhibitory effect on the prooxidant enzyme myeloperoxidase (MPO). A quantitative structure-activity relationship (QSAR) model predicted the maximal atomic partial charge (Qmax) as the descriptor being implied in the antioxidant activity of the referred xanthones. From the antioxidant screening, emerged the hit compound, 1,2-dihydroxyxanthone (10), that was further characterized for its chelating properties and its effect on a human keratinocyte cell line. Taken together, the results suggest the possible effectiveness of xanthone derivatives as antioxidants with potential for topical administration. Keywords: Antioxidant activity, Myeloperoxidase, Scavenging effect, Structure-activity relationships, Xanthones

Single crystals of pure and xylenol orange (XO; C31H32N2O13S) dye doped (0.01, 0.05 and 0.1 mol%) ammonium dihydrogen phosphate (ADP; NH4H2PO4) were grown by slow evaporation method with the vision to improve the properties of pure ammonium dihydrogen phosphate crystal. The theoretical morphology of the grown crystals was drawn using Bravais–Friedel–Donnay–Harker (BFDH) law. The selective nature of xylenol orange dye to selectively stain the particular growth sectors of ADP crystal was studied. The structural analysis of as grown crystals was carried out using powder XRD study. The identification of the functional groups present in the ADP material was done using Fourier transform infrared (FTIR) spectroscopy. The linear optical study on pure and dye doped crystals was carried out using UV–vis–NIR spectroscopy. The optical band gap, extinction coefficient, refractive index and optical conductivity were calculated using the transmittance spectra for all the samples. In photoluminescence studies, the blue emission intensity got quenched and an orange emission at 597 nm was seen as a result of XO doping. The thermal stability and decomposition temperature of ADP crystal were found to decrease as an effect of dye doping. The piezoelectric charge coefficient, SHG conversion efficiency, mechanical strength and wettability were also enhanced as a result of XO dye doping. Keywords: Nonlinear optical materials, Dye-doped crystals, Optical properties, Piezoelectricity, Mechanical properties

WOS: 000505076000010, SnO nanoparticles have been successfully synthesized in the presence of Triton-X 100 (TX-100) surfactant via hydrothermal method for the first time, and the photocatalytic activity under UV and visible light irradiation for the degradation of Methylene Blue (MB) and Rhodamine B (RdB) organic textile dyes was investigated. The structural, morphological and chemical characterizations were investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), UV-vis. diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL) analysis. The results reveal that the addition of surfactant, TX-100, in the precursor solutions leads to reduction in crystallite size with significant changes in morphological structure of SnO nanoparticles. The synthesized SnO nanoparticles show excellent photocatalytic activity under UV or visible light irradiation. MB and RdB dyes degraded completely under UV irradiation after 90 and 150 min, respectively. Also, MB and RdB dyes degraded only 150 min later under visible light illumination with a little amount of photocatalyst (0.8 g/L). Hence, this work explores the facile route to synthesizing efficient SnO nanoparticles for degrading organic compound under both UV and visible light irradiations. (C) 2017 Production and hosting by Elsevier B.V. on behalf of King Saud University., Scientific and Technical Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113Z656]; Administrative Units of The Research Projects of Selcuk UniversitySelcuk University [17201006], The authors are grateful for financial support by The Scientific and Technical Research Council of Turkey (Project no: 113Z656) and The Administrative Units of The Research Projects of Selcuk University (Project no: 17201006). This work produced from M. Saribel's M. Sc Thesis.