Aromatic Content Research Articles

Machine learning-based modeling of malachite green adsorption on hydrochar derived from hydrothermal fulvification of wheat straw

This study investigated the efficiency of hydrochar derived from hydrothermal fulvification of wheat straw in adsorbing malachite green (MG) dye. The characterizations of the hydrochar samples were determined using various analytical techniques like SEM, EDX, FTIR, X-ray spectroscopy, BET surface area analysis, ICP-OES for the determination of inorganic elements, elemental analysis through ultimate analysis, and HPLC for the content of sugars, organic acids, and aromatics. Adsorption experiments demonstrated that hydrochar exhibited superior removal efficiency compared to feedstock. The removal efficiency of 91 % was obtained when a hydrochar dosage of 2 g L−1 was used for 20 mg L−1 of dye concentration in a period of 90 min. The results showed that the study data followed the Freundlich isotherms as well as the pseudo-second order kinetic model. Moreover, the determined activation energy of 7.9 kJ mol−1 indicated that the MG adsorption was a physical and endothermic process that increased at elevated temperatures. The study also employed an artificial neural network (ANN), a machine learning approach that achieved remarkable R2 (0.98 and 0.99) for training and validation dataset, indicating high accuracy in simulating MG adsorption by hydrochar. The model's sensitivity analysis demonstrated that the adsorbent dosage exerted the most substantial influence on the adsorption process, with MG concentration, pH, and time following in decreasing order of impact.

Use of vegetable oils as an alternate to naphthenic oil for extension of emulsion styrene butadiene rubber

Various petroleum based mineral oils like Distillate Aromatic Extract (DAE), Treated Distillate Aromatic Extract (TDAE), Residual Aromatic Extract (RAE) and Naphthenic oils are used for extension of emulsion polymerized Styrene Butadiene Rubber (E-SBR). Vegetable oils are alternate to these petroleum oil from sustainability point of view as vegetable oils have no Polycyclic Aromatic (PCA) content. They improve abrasion resistance leads to less rubber particulates spread in the environment and reduce rolling resistance leads to lower fuel consumption. However, introduction of few vegetable oils leads to slow down the cure reaction due to high unsaturation to saturation ratio. Presence of high fatty acid content in vegetable oils help in better rubber-filler interaction. In the present research, vegetable origin oils as such without any modification (Decas, Palmolein, Groundnut, Soybean, Mustard and Coconut) extended Styrene Butadiene Rubber (OE-SBR) were characterized in standard American Society for Testing and Materials (ASTM) compound recipe for various processing, different vulcanizate and other performance properties. Curative’s dosages were adjusted in the recipe of vegetable oil extended SBR’s to achieve the 300% modulus value like naphthenic oil. Vegetable oil extended Emulsion Styrene Butadiene Rubber (E-SBR) grades (Prepared with Palmolein and Coconut oils) were showing comparable rheometric and stress-strain properties, high reinforcement index (around 5%), better rubber-filler interaction parameter (around 12%), better abrasion resistance (around 23%) and comparable tanδ value @0°, 30° and 60°C as compared to naphthenic oil extended SBR based compound.

Synthesis of sustainable curcumin based photo-crosslinkable benzoxazines: Thermal, hydrophobic and anti-corrosion properties

Bifunctional polybenzoxazines have been developed using sustainable bio-phenol curcumin, paraformaldehyde with varying nature of monofunctional amines through Mannich condensation. The molecular structure of synthesized benzoxazines were confirmed by ATR-FTIR, 1HNMR and 13CNMR and high-resolution mass spectroscopic (HRMS) analyses. DSC thermograms were used to ascertain the curing behaviour of curcumin-based monomers. Thermal curing of Cu-api occurs at 192 °C and that of Cu-aa undergoes dual curing at 177 °C and 209 °C due to its inherent molecular structure. The thermal stability of synthesized polybenzoxazines was studied using TGA, Cu-a exhibits higher char yield of 63% due to higher aromatic content than that of other polybenzoxazines. The occurrence of dimerization (2π+2π cycloaddition) of curcumin based benzoxazines proceeds through conjugation present in the main chain of curcumin when exposed to UV irradiation, and was monitored through UV–visible spectroscopy. All the synthesized benzoxazine monomers were excited within the wavelength of UV range with occurrence of photoluminescence behaviour in visible region ranges between 448 nm and 530 nm. The value of band gap calculated for the curcumin-based monomers ranged from 3.55 to 3.77 eV. The explicit character of curcumin based benzoxazines can be exploited in the field of optical applications. The hydrophobic behaviour of polybenzoxazines was also studied and the highest water interface angle value of 146° was observed for poly(Cu-tfma) due to the presence of fluorine groups. Furthermore, the Cu-tfma coated cotton fabric was tested for its durability and the results indicated that these materials coated cotton fabrics are better suitable for sustainable high performance hydrophobic applications. The anti-corrosion studies indicated that the poly(Cu-api) coated on mild steel exhibits greater resistance towards corrosion amongst the other polybenzoxazines which can be potentially employed as coating in marine environments.

Algae pyrolysis in alkaline molten salt: Products transformation

Algae pyrolysis in alkaline molten salt is a promising technology for hydrogen production, but the pyrolysis products transformation has not clearly been described up-to-date. Moreover, the complex bio-oil especially heavy bio-oil fraction directly influences the products transformation pathways, while limiting the hydrogen production yield and application. Both the light and heavy bio-oil fractions are investigated in detail and the effect of alkaline molten salt on products transformation is obtained. Molten salt promotes the cyclization and aromatization of linear alkenes, thereby increasing aromatic compound content and hydrogen production. The decarbonation of Na2CO3 and the deoxygenation of NaOH lead to the methane release, in turn reducing hydrogen production. The heavy compounds tend to polymerize at higher temperatures into compounds with higher molecular weights and unsaturation, while generating hydrogen. As the temperature rises, char reacts with molten salt to form hydrogen and disappears at 650 °C, while aromatics in light compounds condense into heavy compounds, which then grow to form soot-like at 600 °C, accompanying hydrogen release. Based on the relationship between products transformation, hydrogen release and alkaline molten salt effect, strategies to improve the hydrogen yield and purity of AMSP process are proposed.

Drivers and impacts of decreasing concentrations of atmospheric volatile organic compounds (VOCs) in Beijing during 2016–2020

China has implemented various policies and measures for controlling air pollutants. However, our knowledge of the long-term trends in ambient volatile organic compounds (VOCs) after the implementation of these action plans in China remains limited. To address this, we conducted a five-year analysis (2016–2020) of VOC compositions and concentrations in Beijing. The annual VOC concentration decreased from 44.0 ± 28.8 to 26.2 ± 16.4 ppbv, with alkanes being the most prevalent group. The annual average concentrations of alkenes, alkynes, and aromatics have experienced a significant decrease of over 50 %. Seasonal variations indicated higher VOC concentrations in winter and autumn, with more significant reductions observed in winter and autumn. The impact of meteorological conditions caused variations in VOC reductions during the Chinese Spring Festival. Satellite-based measurements of formaldehyde (HCHO) columns confirmed the reduction of VOC emissions during the Coronavirus (COVID-19) lockdown. The normalized annual average VOC concentration decreased by 2.9ppbv yr−1 from 2016 to 2020, and emission reduction contributed to 58.8 % of VOC reduction from 2016 to 2020 after meteorological normalization, indicating the effectiveness of implemented control measures. Based on receptor model, vehicle emissions and industrial sources were identified as the largest contributors to VOC concentrations. Vehicle emissions, liquefied petroleum gas/natural gas (LPG/NG) use, and coal combustion were major drivers of VOC reduction. Potential source region analysis revealed that air masses transported from northwestern and southern regions significantly contributed to VOC concentrations in Beijing. The range of source regions shrunk in both northwestern and southern regions with the reduction in VOC concentrations. The annual variations of ozone formation potential indicated a significant decrease in VOC reactivities through emission control. These results could provide insights into future emission control and coordinated efforts to improve PM2.5 and ozone levels in China.

Study of aromatic extraction from light cycle oil from the viewpoint of industrial applications

Light cycle oil (LCO) is a significant products of fluid catalytic cracking (FCC) process in refineries. Increasing the output of high-value chemicals from LCO is an important step towards achieving ‘dual carbon’ targets. Separating aromatic and non-aromatic components in LCO is crucial to producing valuable products. Extraction is a promising process for separating these components based on the principle of “polar similarity and solubility”. From the perspective of industrial applications, this study explores the development and application of novel functionalized extractants to produce valuable products. Ionic liquids (ILs) with alkyl-substituted imidazoles [CnMIM]+ and alkyl-substituted pyridines [CnMPy]+ as cations and tetrafluoroborate [BF4]− and hexafluorophosphate [PF6]− as anions were used. The effects of extraction temperature, IL-oil ratio, number of extraction stages, and reusability were systematically investigated. In addition, the basic physical properties data of ILs and residues in oil were studied in detail. The suitability of ionic liquids for industrial applications was evaluated based on their solubility with hydrocarbons, physical and chemical properties, selectivity for aromatics, and residues in oil. Following a thorough examination of the performance of ionic liquids for the extraction of aromatics from LCO, [C6MIM][PF6] was identified as the most suitable extractant. A multi-stage countercurrent extraction process was established and the conditions systematically studied. The results demonstrate that the aromatic content of the extracted oil is greater than 95 wt%, which can be utilized for producing BTX products. Meanwhile, the aromatic content of the raffinate oil is less than 10 wt%, which can function as a clean diesel blending component or as steam cracking feedstocks. This study has successfully promoted the industrial application of functionalized ionic liquids for the LCO dearomatization process and provided an essential reference for developing new functionalized extraction solvents.

Organo-mineral associations and size-fractionated colloidal organic carbon dynamics in a redox-controlled wetland

The formation of organo-mineral associations serves as a crucial mechanism for stabilizing soil organic matter, particularly for determining the fate of soil organic carbon (OC) in redox dynamic wetlands characterized by high C content. Despite its importance, few studies have assessed the retention, transformation, and transport of colloids (1–1000 nm) and colloidal OC (COC) in those environments. This leaves a crucial knowledge gap concerning the quantities of colloids and COC and their molecular compositions, especially considering the significant role of metabolically active depressional wetlands that may play as biogeochemical hotspots for C cycling. To address this gap, we conducted a study in a Delmarva Bay depressional wetland located in Blackbird State Forest, Delaware, USA. We established a transect encompassing upland (U), transition (T), and wetland (W) zones based on seasonal hydrologic conditions. We installed piezometers at 50 cm, 100 cm, and 200 cm depths within each zone and collected pore-water samples from 11/2017 to 05/2019. We then fractionated these samples into dissolved (<2.3 nm), natural nanoparticle (NNP, 2.3–100 nm), fine colloid (100–450 nm), and particulate (450–1000 nm) fractions via sequential centrifugation and ultrafiltration, and quantified their concentration and molecular composition. We observed variations in the concentration and molecular composition of soil COC both vertically at different soil depths and horizontally along a redox gradient from the U-T-W transect. The sum of the NNP and fine colloid fractions accounted for 47±20% of the operationally defined “dissolved” (<450 nm) fraction. Isotope ratio mass spectrometry and X-ray photoelectron spectroscopy analyses further revealed that the NNP fraction is more enriched in heavier δ13C isotope and oxidized carbonyl/carboxyl C functional groups (C=O, p<0.05) with significantly higher surficial atomic percentages of C (p<0.01), N (p<0.01), and Mg:Al ratios (p<0.05), and lower atomic percentages of Al (p<0.01) and Si (p<0.01) compared to the larger particles. The formation of cation bridges and/or hydrogen bonds between carboxylic OC and phyllosilicate minerals likely dominated the mineral-OC association in the NNP fraction. The higher surface C enrichment in the particulate fraction compared to the NNP fraction suggests a patchy distribution of more plant-derived OC through organo-organic interactions in the larger fractions. Along the transect, Zone U exhibited significant enrichment of heavier δ13C isotope and lower SUVA values than the Zones T and W indicating inefficient decomposition and dissociation of SOM from minerals due to the reductive dissolution of Fe and Al oxides under anoxic conditions. Furthermore, an increase in low molecular weight microbial metabolites with reduced aromatic OC content was observed at deeper depths in Zones U and T. Our study provides new insights into the concentration and molecular composition of size-fractionated COC, highlighting the need to separately consider the NNP and fine colloid fractions from the operationally defined “dissolved” phase. This is crucial for assessing the biogeochemical cycling of OC in redox-active wetlands, a pressing need amidst the growing concerns about the impacts of climate change.

Ni/ZnO@ZSM-5 Reaction Adsorption Desulfurization Catalyst for Octane Number Improvement

Reaction adsorption desulfurization technology is one of the main means of gasoline desulfurization. In this work, ZnO nanoparticles were prepared by pyrolytic oxidation using ZIF-8 as precursor. ZnO spheres with particle size of 5 nm can be formed after the pyrolysis of Zif-8. Ni/ZnO5nm prepared by equal volume impregnation method can achieve 99.2% desulfurization rate at 390°C, which has more excellent desulfurization performance compared to Ni/ZnO100nm. Ni/ZnO@ZSM-5 was synthesized by in-situ growth-pyrolysis oxidation-equal volume impregnation method. In the reaction adsorption desulfurization process of FCC gasoline, the desulfurization rate reached 99.5%, and the aromatic content in the product increased by 10.7 percentage points, showing excellent octane number improvement. This work provides new ideas for the synthesis of ZnO nanoparticles as well as novel reactive adsorbent desulfurizers, and promotes the development of S-Zorb process.

Is there a role for aromatic plants in blue tit (Cyanistes caeruleus) nests? Results from a correlational and an experimental study

The utility of fresh green material in avian nests is still not fully understood. Potential explanations include the effects of plants’ volatile compounds on parasite reduction (nest protection hypothesis) or direct beneficial effects on nestling condition (drug hypothesis). We used correlative data collected during 2020 and 2021 in a Mediterranean population of blue tits (Cyanistes caeruleus) as well as experimental data (aromatic nest content manipulation) to assess the effects of aromatic plant use on nestling physiological condition and survival, nest-dwelling ectoparasitic pressure and its relationship with breeding parameters. We found that aromatic plants were disproportionally used in relation to their abundance in the environment and that their use was positively related to egg mass (but only in 2020). Blowflies and facultative parasitic mites were more frequent in nests with aromatics compared to nests without aromatics, but obligatory parasitic mites were less abundant in nests with aromatics. However, no effects of aromatic plants were observed on nestling haemoglobin levels nor erythrocyte sedimentation rate or other physiological health metrics, but the heterophil to lymphocyte ratio was higher in nests with the highest quantity of aromatics. The artificial addition of mint reduced the flea abundance, but 7-day old nestlings showed significantly lower colour saturation and brightness in the mouth flange. Nestling survival to fledging was not related to aromatic plant use. Therefore, our results partially support a beneficial effect of aromatic plants in blue tit nests because some ectoparasite groups were reduced. Immediate effects on nestling physiology or survival could not be established.Significance statementSome avian species place fresh aromatic plant material in their nests, and several non-mutually exclusive hypotheses have been proposed to explain its potential functions. In this study, we use both correlational and experimental data from a blue tit population to test two hypotheses, namely the ‘nest protection hypothesis’ and the ‘drug hypothesis’. The first one proposes that aromatic plants have direct repellent effects against ectoparasites, while the latter poses that these plant components benefit nestling condition through the stimulation of some components of the immune system. Our results suggest that some ectoparasites, such as fleas and obligatory parasitic mites, were less abundant in nests where aromatic plants were artificially or naturally added, respectively, but no relationships were detected with nestling physiology or survival, which could be partially explained by our small sample size. Our study partially supports a beneficial effect of aromatic plants in avian nests.

Seasonal Monitoring of Water Quality Parameters and Pesticides at the Altınapa Reservoir Watershed

Altınapa Reservoir is a reservoir located on the Meram Stream in the Konya Province in Türkiye that supplies drinking water. The Altınapa Reservoir feeds the Konya Drinking Water Treatment Plant with 37.8 million m3 of water annually and the treated water is delivered by the drinking water network. The aim of this study was to determine the effect of agricultural activities and settlements on water quality in the Altınapa Reservoir Watershed. In the study, major water quality parameters (pH, electrical conductivity, total organic carbon, total nitrogen, nitrite, nitrate, phosphorus, phosphate, and total suspended solids) and pesticides were monitored at four stations (K1, K2, K3, K4) on the sub-streams feeding reservoir. Major water quality parameters were monitored at monthly intervals for 12 months between June 2020 and May 2021, and pesticides were monitored seasonally at 4 seasons (Fall 2019, Winter 2020, Summer 2020, and Spring 2021). A correlation matrix was used to assess the connections between nine indicators of water quality. The annual average conductivity and pH values of the samples taken from four different stations of the Meram Stream were 432 µS/cm and 8.04, respectively. The highest value for total nitrogen was 10.73 mg/L and it was 0.87 mg/L for nitrate. Annual average total organic carbon values were determined as 1.35, 1.69, 1.51, and 1.46 mg/L at K1, K2, K3, and K4 stations, respectively. Specific UV absorbance indicated that organic matters of water are mostly hydrophilic and have low aromatic content. In seasonal pesticide monitoring, 71 different compounds were detected in water samples. The compounds whose concentrations exceeded Turkish Environmental Quality Standards were identified as DDD-op, DDE-p.p', diflufenican, and imidacloprid. Pesticides constitute most of the micropollutants detected in water samples. The highest positive correlation among water quality parameters was obtained between conductivity and nitrate (0.81) and total nitrogen (0.88).

Development and Performance Evaluation of an Asphalt Regenerant Derived from Waste Engine Oil Residue.

This study assessed the fundamental physical properties and chemical composition of three specific waste engine oil residue (WEORs) asphalt regenerants. Through dynamic shear rheometer and rolling thin-film oven tests, the performance of aged asphalt was evaluated using three key indicators. Thin-layer chromatography investigations probed the WEOR-induced changes in the aging asphalt components, leading to the creation of two novel asphalt regenerants, WEOR-H and WEOR-G. WEOR-G was developed from WEOR-1, liquid rubber, ultraviolet absorber, light shielding agent, and antioxidant, while WEOR-H was formulated from WEOR-2, aromatic oil, and liquid rubber. The study employed differential scanning calorimetry and conventional laboratory tests to analyze the road performance attributes of Ingevity J type regenerant (J), WEOR-G, and WEOR-H. The results indicated that WEORs increase the saturate and aromatic content in asphalt and partially replenish the missing lightweight components of aged asphalt, moderately improving the three key indicators, though the regenerative effect is restricted. Achieving a full restoration of component proportions within aged asphalt to their initial levels proved unattainable, and direct application of any of the three WEORs as asphalt regenerants is impractical. WEOR-H and WEOR-G demonstrated potential in enhancing aged asphalt binder road performance, outpacing three other WEORs. At a 14% dosage, WEOR-G and WEOR-H could increase the 10 °C ductility to 23.5 and 21.4 cm, respectively, effectively counterbalancing the insufficient ability of WEOR-1 and WEOR-2 to restore the low-temperature performance of aged asphalt. Among the regenerants, WEOR-G, possessing superior regenerative effects, the lowest glass transition temperature, and optimal low-temperature deformation resistance, emerged as the most efficacious. This inquiry furnishes vital data support for future applications of WEOR-G asphalt regenerant.

Metabolic and Molecular Rearrangements of Sauvignon Blanc (Vitis vinifera L.) Berries in Response to Foliar Applications of Specific Dry Yeast.

Dry yeast extracts (DYE) are applied to vineyards to improve aromatic and secondary metabolic compound content and wine quality; however, systematic information on the underpinning molecular mechanisms is lacking. This work aimed to unravel, through a systematic approach, the metabolic and molecular responses of Sauvignon Blanc berries to DYE treatments. To accomplish this, DYE spraying was performed in a commercial vineyard for two consecutive years. Berries were sampled at several time points after the treatment, and grapes were analyzed for sugars, acidity, free and bound aroma precursors, amino acids, and targeted and untargeted RNA-Seq transcriptional profiles. The results obtained indicated that the DYE treatment did not interfere with the technological ripening parameters of sugars and acidity. Some aroma precursors, including cys-3MH and GSH-3MH, responsible for the typical aromatic nuances of Sauvignon Blanc, were stimulated by the treatment during both vintages. The levels of amino acids and the global RNA-seq transcriptional profiles indicated that DYE spraying upregulated ROS homeostatic and thermotolerance genes, as well as ethylene and jasmonic acid biosynthetic genes, and activated abiotic and biotic stress responses. Overall, the data suggested that the DYE reduced berry oxidative stress through the regulation of specific subsets of metabolic and hormonal pathways.

Recovery of Base Oil from Used Oil through Solvent Extraction Followed by Adsorption: A Review

Base oil is the major component of lubricating oil, which is present in its original form and used lubricating oil in a sufficient amount. This review article focuses on the recovery of base oil from used oil through solvent extraction followed by adsorption. Different solvents and various solvent-to-oil ratios are studied. Solvent selection is based on its ability to selectively dissolve the base oil from used oil and to reject the impurities in the solution. The percentage yield and quality of extracted oil usually depend upon the nature of the solvent, solvent-to-oil ratio, and nature of impurities. Various solvents and solvent-to-oil ratios are studied. However, results show that methyl ethyl ketone (MEK) is the best solvent because it gives the maximum sludge removal, is more easily recovered, and also has a low cost. A two-phase system occurs after adequate mixing of solvent and oil. Before solvent addition, oil is dehydrated to remove water present as impurities, and then light hydrocarbons are removed using vacuum distillation. After solvent addition, the extracted phase is separated, leaving behind the sludge phase, which consists of aggregates of impurities. The solvent is evaporated from the extracted phase. The extracted oil is put in contact with a suitable adsorbent to absorb the aromatic contents and heavy metals in it. In the end, additives are added to the recovered oil for the formulation of a new lubricant.

Investigating pyrolysis characteristics of Shengdong coal through Py-GC/MS

Abstract Shengdong coal was single-step and multi-step pyrolyzed by pyrolysis-gas chromatography/mass spectrometry. In the single-step pyrolysis process, Mono-ring aromatics contents reach a maximum value at 800°C, while phenolic contents are significantly reduced, which might be attributed to the dehydroxylation of phenolics. Naphthalene content also reaches a maximum value at 800°C in the single-step pyrolysis process; however, naphthalene was not detected in the multi-step pyrolysis process. So naphthalene might come from the ring-opening of multi-ring aromatics or the cyclization of mono-ring aromatics in the single-step pyrolysis process. Only phenol and o-cresol were detected, but no p-cresol in the multi-step pyrolysis process; however, p-cresol content reaches a maximum value at 800°C, meanwhile, phenol content was decreased and o-cresol was disappeared in the single-step pyrolysis process, which suggests that p-cresol may be derived from isomerization of o-cresol or alkylation of phenol. It provides an idea for strengthening more basic research related to the rapid pyrolysis of coal.

Vegetable oil extended emulsion styrene butadiene rubbers for passenger car radial tire tread application

Currently emulsion polymerized Styrene Butadiene Rubber (E-SBR) is extended with various petroleum based mineral oils like Distillate Aromatic Extract (DAE), Treated Distillate Aromatic Extract (TDAE), Residual Aromatic Extract (RAE) and Naphthenic oils. It is obvious that introduction of vegetable oil should result in almost zero Polycyclic Aromatic Content (PCA) content and therefore, are environmentally friendly, renewable, and sustainable. In the present work, vegetable oil extended Styrene Butadiene Rubber (OE-SBR) were characterized for chemical properties and found that all the properties were meeting the specification requirements of mineral oils extended grades. These rubbers were also evaluated in standard Passenger Car Radial (PCR) tire tread compound recipe for various processing, different vulcanizate and other performance properties. The developed grades with vegetable oils required less mixing energy (around 10% for master batch and 15% for final batch) and shown better flow behavior (around 15% power law index and 20% activation energy reduction), better carbon dispersion (around 20%), high reinforcement index (around 15%), better rubber-filler interaction parameter (around 20%), better abrasion resistance (around 20%) and lower tanδ value @60°C (around 15%) as compared to TDAE oil extended SBR based compound. This may help to improve life of a PCR tire and reduction in fuel consumption of the vehicle.

Hydrothermal carbon spheres produced from glucose, cyclodextrin, and starch

The production of hydrothermal carbons from glucose, cyclodextrin, and starch was reported at 180 °C and 200 °C for 24 hr, both with and without 2-chloro propionic acid. The yields of hydrothermal carbons varied depending on the feedstock and temperature. At the lowest temperature, glucose gave the highest yield of hydrochar, while at 200 °C, the yields did not differ significantly among the three feedstocks, with the highest yield obtained for cyclodextrin-derived hydrochars. The use of a catalyst not only decreased the yield of hydrothermal carbons but also resulted in an increase in the diameter of hydrochars for all saccharides. When compared to raw saccharides, the O/C and H/C ratios of hydrothermal carbons were significantly lower, suggesting that significant deoxygenation and dehydration occurred after the HTC processing. In the non-catalytic runs, hydrochars for each feedstock showed an increase in aromatic content when the temperature was increased from 180 °C to 200 °C. The size of the carbon spheres was significantly influenced by various factors including the operating conditions, the type of saccharide used, and the pH of the aqueous solutions. The diameters of carbon spheres produced in runs with catalysts were larger when compared to their corresponding hydrothermal carbons from the non-catalyst runs.

Cross-Talk of Cation-π Interactions with Electrostatic and Aromatic Interactions: A Salt-Dependent Trade-off in Biomolecular Condensates.

Biomolecular condensates are essential for cellular functionality, yet the complex interplay among the diverse molecular interactions that mediate their formation remains poorly understood. Here, using coarse-grained molecular dynamics simulations, we address the contribution of cation-π interactions to the stability of condensates formed via liquid-liquid phase separation. We found greater stabilization of up to 80% via cation-π interactions in condensates formed from peptides with higher aromatic residue content or less charge clustering. The contribution of cation-π interactions to droplet stability increases with increasing ionic strength, suggesting a trade-off between cation-π and electrostatic interactions. Cation-π interactions, therefore, can compensate for reduced electrostatic interactions, such as occurs at higher salt concentrations and in sequences with less charged residue content or clustering. Designing condensates with desired biophysical characteristics therefore requires quantification not only of the individual interactions but also cross-talks involving charge-charge, π-π, and cation-π interactions.

Bioactivity profile of dissolved organic matter and its relation to molecular composition

Dissolved organic matter (DOM) occupies a huge and uncharted molecular space. Given its properties, DOM can be presented as a promising biotechnological resource. However, research into bioactivities of DOM is still in early stages. In this study, the biotechnological potential of terrestrial and marine DOM, its molecular composition and their relationships are investigated. Samples were screened for their in vitro antibacterial, antifungal, anticancer and antioxidant activities. Antibacterial activity was detected against Staphylococcusaureus in almost all DOM samples, with freshwater DOM showing the lowest IC50 values. Most samples also inhibited Staphylococcusepidermidis, and four DOM extracts showed up to fourfold higher potency than the reference drug. Antifungal activity was limited to only porewater DOM towards human dermatophyte Trichophytonrubrum. No significant in vitro anticancer activity was observed. Low antioxidant potential was exerted. The molecular characterization by FT-ICR MS allowed a broad compositional overview. Three main distinguished groups have been identified by PCoA analyses. Antibacterial activities are related to high aromaticity content and highly-unsaturated molecular formulae (O-poor). Antifungal effect is correlated with highly-unsaturated molecular formulae (O-rich). Antioxidant activity is positively related to the presence of double bonds and polyphenols. This study evidenced for the first time antibacterial and antifungal activity in DOM with potential applications in cosmeceutical, pharmaceutical and aquaculture industry. The lack of cytotoxicity and the almost unlimited presence of this organic material may open new avenues in future marine bioprospecting efforts.Graphical abstract

Polycyclic aromatic hydrocarbons: Measuring the air quality of three communities in Port Harcourt, Rivers State

There are a good number of major oil-producing companies as well as numerous activities that involve the combustion of organic matter. These activities release enormous quantities of pollutants into the atmosphere and there seems to be a paucity of data that captures the concentration of pollutants in the air as well as their health implications. This study was aimed at determining the levels/concentrations of polycyclic aromatic hydrocarbons in the surrounding air of three communities in Port Harcourt, Rivers State. Rivers State houses two oil refineries, a fertilizer company, and numerous companies. Sampling was conducted using the EGASPIN 2018 sampling procedure. Air samples were collected unto sterilized filter paper from the three communities using a Bosean meter. Sample extraction and analysis were conducted using GC-FID (EPA 8270). The study was conducted over the dry and wet seasons in 2019. Dry season result showed the presence of majorly four low molecular weight polycyclic aromatic hydrocarbons - naphthalene, fluorene, phenanthrene, and anthracene; in Okrika, concentrations of were 2.766±1.429 mg/kg, 0.976±0.491 mg/kg, 0.014±0.007 mg/kg and 0.040±0.023 mg/kg respectively; in Mgbuodohia the concentrations were 0.822±0.668 mg/kg, 1.199±0.626 mg/kg, 0.008±0.004 mg/kg and 0.012±0.009 mg/kg respectively; in Chokocho the concentrations were 0.144±0.097 mg/kg, 1.074±0.738 mg/kg, 0.001±0.000 mg/kg, and 0.142±0.067 mg/kg respectively. Wet season results showed the concentration of naphthalene, fluorene, phenanthrene, and anthracene; in Okrika, the concentration was 0.271±0.034 mg/kg, 0.108±0.019 mg/kg, 0.055±0.009 mg/kg and 0.001±0.000 mg/kg respectively; in Mgbuodohia the concentrations were 0.014±0.002 mg/kg, 0.005±0.004 mg/kg, 0.009±0.002 mg/kg and 0.001±0.000 mg/kg respectively; in Chokocho the concentrations were 0.001±0.000 mg/kg, 0.001±0.000 mg/kg, 0.002±0.001 mg/kg and 0.001±0.000 mg/kg. Against the backdrop of past studies linking the concentration of PAHs to the presence of refineries and other anthropogenic human activities, the Chokocho study location was chosen as a control site. The result agrees with the premise that air around regions where there is relatively less human activity like the combustion of organic matter, tend to have lower concentration of polycyclic aromatic hydrocarbon content. The total concentrations of PAHs in the air during the dry season are 3.809 mg/kg, 2.045 mg/kg, and 1.375 mg/kg in Okrika, Mgbuodohia, and Chokocho respectively, showing Okrika to be the most polluted followed by Mgbuodohia and lastly Chokocho. Source apportionment points to petrogenic, pyrolytic, and other possible sources. The detection of just four out of the sixteen priority PAHs points to the fact that there seems to be more effect on other matrices like soil and water.

Mitigation of hydrocarbon toxicity using bacterial consortium in microcosm environment for agrarian fecundity

Petroleum contamination in the soil has been well emphasized as a toxic and hazardous soil pollution contributing to a significant portion of soil infertility worldwide. In the present study, bacterial consortium CHM1 composed of 5 strains belonging to genera Klebsiella, Pantoea, and Enterobacter was evaluated for hydrocarbon degradation ability in the soil environment, as well as their performance in remediating ecotoxicity and phytotoxicity. Initially, the degradation efficiency (1.98%/day) in the soil environment was evaluated. Scanning Electron Microscopy combined with Energy Dispersive X-ray spectroscopy revealed an increase in nitrogen content by 24.98% and a decrease in carbon content by 22.76% implying an improvement in soil fertility. The Fourier Transform InfraRed spectroscopy and Gas Chromatographic analysis revealed significant depletion of aromatic, cyclic, long aliphatic, and complex acid and ester content of the test soil. Moreover, the quantitative PCR analysis exhibited the non-competitive coexistence of each component of the CHM1 consortium. Different enzymatic assays revealed elevated dehydrogenase and superoxide dismutase activity in the degradation system due to the introduction of CHM1 in the soil microcosm. Vibrio fischeri-assisted ecotoxicity analysis had established the potential of CHM1 to efficiently minimize the ecotoxicity of hydrocarbon contamination. The phytotoxicity analysis was performed using four different plant models viz. Chickpeas (Cicer arientinum), Coriander (Coriandrum sativum), Fenugreek (Trigonella foenum-graecum), and Spinach (Spinacia oleracea) exhibiting CHM1 amendment helped to restore plant germination and growth in hydrocarbon-contaminated soil system efficiently. The promising results from this study indicated the possible application of the bacterial consortium in hydrocarbon-contaminated land management and soil restoration for cultivation or other plantation purposes.