Total Organic Carbon Analysis Research Articles

From the sea to the land: How microbial mats dominated marine and continental environments in the Ediacaran Camaquã Basin, Brazil

Precambrian sedimentary successions exposed worldwide record microbial deposits within both marine and continental strata. The Camaquã Basin records the transition from the Ediacaran to Cambrian periods in strata that comprise marine to lacustrine environments. The Camaquã Basin fossils comprise microbial mats and organic-walled microfossils in very close association. Carbonaceous laminae are common within the siltstone and mudstone layers and represent remarkably well-preserved Ediacaran microbial mats. These mats occurred along shallow marine through deep and shallow lake settings. The excellent preservation of these structures seems to be the product of calm hydrodynamic conditions and floodings. These hydrodynamic undisturbed environments allowed microbial mat growth. Besides, episodic floodings brought clay particles, which deposits guaranteed isolation from organic decomposition of mats. In general, the siltstones and mudstones record microbially induced sedimentary structures (MISS) that are typical from Ediacaran strata, such as wrinkle marks and elephant skin structures. Our research revealed that the occurrence of these structures is not limited to marine settings, as common in records from this period, but also present in lacustrine environments. Field studies were combined with optical and scanning electron microscopy plus energy-dispersive X-ray spectroscopy (SEM-EDS) analyses to demonstrate the vast occurrence of microbial mats along the deposits that registered the Camaquã Basin development. Geochemical data (whole-rock and total organic carbon (TOC) analyses) contribute to improving sedimentological descriptions, bringing light regarding the depositional environment where these microbial communities have developed. The excellent preservation state of organic matter on these marine and lacustrine siliciclastic sequences represents an impressive record in a Proto-Gondwana basin.

Methylene blue degradation using chitosan-Fe2O3 composite and photo-Fenton

This study aims to study the photodegradation process of methylene blue using a synthetic chitosan-Fe2O3 composite and their characterization. Based on the characterization material synthetic, chitosan-Fe2O3 (1:1) composite showed the best material with the smallest crystal size (1.13 nm), the surface morphology was lumpy and had an uneven shape with the composition of the constituent (Carbon (C) 42.88%, Oxygen (O) 48.68%, and Iron (Fe) 29.90%), and showed the smallest energy band gap (1.41 eV) which led us to conclude that the formation of the chitosan-Fe2O3 composite can reduce the energy band gap of Fe2O3. The best composite material then was used to evaluate the activity in degrading methylene blue. The optimum condition in degrading was reached at a contact time of 180 min and pH 9 with a percentage decrease in methylene blue concentration of 90.00%. The effect of concentration variations occurred at 5 ppm with a decrease of 89.62%. Total organic carbon analysis showed that the decrease in methylene blue concentration reached 92.20%. Based on that, it is concluded that the chitosan-Fe2O3 composite could be a potential alternative material to degrade methylene blue.

Chemical oxygen demand and biochemical oxygen demand analysis of discharge waters from laundry industry: monitoring, temporal variability, and biodegradability

In Europe, chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) are used as organic indicators for the analytical characterization of laundry water. However, the values of these indicators are derived from one-off analytical measurements at a defined frequency. In addition, there are few data on the temporal variability of COD and BOD5 parameters and on water biodegradability beyond 5 days. In this work, samples of physicochemical treated wastewater were collected for 1 year and their content in COD and BOD5 measured, with BOD monitored over 35 days. The results showed that, for the 24 samples studied, the average and standard deviation values were 835 ± 176 mg/L for COD and 445 ± 114 mg/L for BOD5, indicating a biodegradability index of 2.0 ± 0.4. The interpretation of the data also indicated that the concentrations were close to emission limit value, particularly for BOD5. BOD21 values were particularly high compared to the initial COD, indicating the biodegradability of water. Laundry effluents were also rich in substances very quickly biodegradable, which has been demonstrated by the values of the ratio between BOD7 and BOD5. However, a significant proportion of surfactants is not degraded, as shown by measurements of total organic carbon and anionic surfactant analysis. The results of this study could help the industrial partner involved in our project to guide its choice of the complementary method to better treat wastewater and to reduce its organic load.

Intensification of organic pollutant degradation under visible light irradiation using ZnO nanostructured photocatalysts doped with praseodymium

Zinc oxide nanostructures doped with praseodymium (ZnO:Pr) at varying Pr content (0.05 % to 1.0 % w/w) were synthesized using the electrospinning-calcination technique. Comprehensive morphological and structural characterizations were conducted through SEM, XRD, and XPS analyses. In addition, diffuse reflectance and photoluminescence spectroscopy measurements were performed to assess the optical properties of materials. The produced photocatalysts (ZnO:Pr) were then employed for the degradation of methylene blue dye and oxytetracycline under visible-light irradiation. ZnO:Pr(0.1 %) demonstrated the best photocatalytic performance against methylene blue showing a pseudo-first-order rate constant of k = 3.630 × 10-2 min−1. Investigation of oxytetracycline photodegradation with ZnO:Pr(0.1 %) revealed a pseudo-second-order rate constant of ks = 1.165 × 10-1 L mg−1 min−1, resulting in a reaction half-life (τ½) of approximately 1 min under optimal conditions. Total organic carbon and mass spectrometry analyses highlighted mineralization and identified the main reaction intermediates, respectively, for the oxytetracycline photodegradation. The photodegradation mechanism of oxytetracycline was proposed by the photocatalytic degradation measurements in the presence of scavengers such as hydroquinone and isopropanol. These nanostructures exhibited robust photocatalytic activity over multiple cycles, demonstrating excellent stability. This study underlines the promising potential of ZnO:Pr(0.1 %) as an efficient photocatalyst able to intensify the photodegradation of organic pollutants.

Effect of 2-acrylamide-2-methylpropane sulfonic acid on the early strength enhancement of calcium silicate hydrate seed

Nanomaterials are becoming widely used in cement to enhance the properties of cement-based materials. Artificially synthesized nano-C-S-H serves as a nucleation site for the hydration product C–S–H gel, facilitating its formation. This is deemed as an early strength agent to effectively promote cement hydration. Introducing comb-like polycarboxylate ether (PCE) during the synthesis of C–S–H can effectively reduce the size of C–S–H, resulting in better early strength effects. In this study, the acid-ether ratio of PCE is set at 6:1, and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) substitutes acrylic acid (AA) at varying molar ratios to obtain modified PCE. Calcium silicate hydrate seed-polycarboxylate ether (C-S-Hs-PCE) is synthesized using co-precipitation technique. This study investigated impacts of AMPS on the particle size of C-S-Hs-PCE and the early strength of cement-based materials using dynamic light scattering analysis, total organic carbon analyzer, X-ray diffraction analysis, low-field nuclear magnetic resonance, scanning electronic microscopy, isothermal calorimeter, and compressive strength testing. The results show that the C-S-Hs-PCE, synthesized at an AMPS to AA molar ratio of 5:95, turns out to possess a reduced particle size compared to use of PCE without AMPS. This is pivotal in promoting the hydration of the silicate phase and the formation of calcium hydroxide and C–S–H gel in the paste, and thereby reducing the total porosity while improving the early mechanical strength of the mortar, especially within first 24 h.

Synthesis and characterization of bi-functional Cu and Ni co-doped ZnO photocatalysts for organic pollutant degradation and antimicrobial activity

The study of visible light active photocatalysts for organic pollutants degradation and antimicrobial activity has gained significant attention in recent years. Herein, we report the synthesis of pure ZnO, Ni-doped ZnO (Ni-ZnO), Cu-doped ZnO (Cu-ZnO), and Cu and Ni co-doped ZnO (CuNi-ZnO) photocatalysts via a facile coprecipitation method. These photocatalyst materials were characterized using various analytical techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–Vis), photoluminescence (PL), and total organic carbon (TOC) analysis. XRD patterns confirm the presence of a mixed phase in the CuNi-ZnO sample. The presence of Cu, Ni, and Zn in CuNi-ZnO was verified through the XPS spectra. The nanoparticle-like morphology of the CuNi-ZnO photocatalyst was confirmed using HRTEM analysis. The FTIR spectra reveal the chemical bonds present in the materials. UV–visible spectroscopy was employed to determine the band gap of the materials, revealing a value of 3.10 eV for CuNi-ZnO. The mitigation in recombination of excited electrons (e−) and holes (h+) in CuNi-ZnO is validated through photoluminescence (PL) studies. The synthesized materials were used for the degradation of Indigo carmine (IC) dye and antimicrobial activity. The results showed that the optimized CuNi-ZnO sample displayed a better visible light photocatalytic performance (93.32 % IC dye degradation efficiency in 60 min) than the other samples. A notable degree of mineralization was observed with a reduction in total organic carbon (TOC) reaching 65.91 %. Additionally, the photocatalyst showed antimicrobial activity against both S. aureus and E. coli. Furthermore, a plausible visible light photocatalytic mechanism was proposed for the degradation of IC dye using the CuNi-ZnO photocatalyst.

Organic geochemistry of the middle Paleozoic Ora Formation in Iraq: Implications for source rock assessment and hydrocarbon potentiality

The Ora Formation (late Devonian–early Carboniferous) is thought to be a potential source rocks for the Paleozoic petroleum system of Iraq. The source potential from the Ora Formation is evaluated for the first time ever in this study from western and northern Iraq which integrates data from organic geochemistry including Total Organic Carbon (TOC) analysis, HAWK pyrolysis, gas chromatography (GC), and gas chromatography mass spectrometry (GC-MS) and mineralogical X-ray diffraction and scanning electron microscopy. The shale and muddy carbonate succession within the Ora Formation from surface section in northernmost Iraq and subsurface section from two wells (Akkas-1 and Akkas −3) from western Iraq have been employed to assess the source rock potentiality, thermal maturity, kerogen type, organic content, and depositional environment. In addition to organic geochemical analyses, mineralogical XRD and SEM-EDS were used to support the paleoenvironmental interpretation of the Ora Formation. The results from TOC and HAWK analyses reveal that the Ora Formation ranges from poor to good as a source rock. However, the HAWK data suggests that the surface samples from northernmost Iraq are highly mature, highly weathered, or both. Kerogen analysis revealed that the Ora Formation contains immature type III and mixed II-III kerogens. Low TOC values were attributed to factors such as significant clastic input, weathering effects, and the prevailing oxic environment during deposition. The presence of detrital influx of quartz and feldspars, along with the occurrence of illite and kaolinite clay minerals, suggest a detrital input with weathering influence under hot arid and warm humid conditions. Biomarker analysis of the light hydrocarbons using GC and GC-MS revealed that these light hydrocarbons were generated from marine planktonic algae sources, possibly with some contributions from terrestrial and/or microbially reworked organic matter. These high mature light hydrocarbons in subsurface section were originated from anoxic marine shale source rocks. They were most likely from the Cambro-Ordovician Khabour Formation and were contaminated from another source.

Removal of Cadmium from Public Smoking area Soil using indoor Plants and Electrical Grounding

Objectives : In this study, the absorption of heavy metals in the soil from smoking areas using indoor plants and electrical grounding was investigated to increase the utility of indoor plants for soil decontamination.Methods : Soil from plant pots in a smoking area was collected for the experimental plant pot preparations. Some of the prepared pots were connected to electrical ground via an electrode. Kidney beans (<i>Phaseolus vulgaris</i>) were seeded, and their growth were observed. After 30 days of the cultivation, TOC (Total Organic Carbon), and metagenomics profiles in the soil was analyzed. To estimate the behavior of the heavy metals in soil and plants, Cadmium concentrations in the samples were analyzed using ICP-MS (Inductively Coupled Plasma-Mass Spectrometry).Results and Discussion : The connection of the electrical ground to the plant pot induced the rapid growth of plant (48.2 ± 2.3% increase in stem growth), compare to the plant in the pot without the electrical ground. TOC analysis showed that the soil from the grounded pots showed the highest value, compared to the control soil (3.08 ± 1.22%), and the soil from the pot without ground connection (2.3 ± 0.1%). The ICP-MS analysis indicated that the plant body in the grounded pot had the highest cadmium concentration at 0.33 ± 0.018 μg/kg. Using the metagenomic analysis, biomineralization related bacterial species (<i>Nocardioides</i> sp., <i>Streptomyces</i> sp., <i>Sphingomonas</i> sp. etc.) were identified from the grounded soil sample. These results suggested that the indoor plant cultivation with the electrical ground connection as an electrical fertilizer enhances the cadmium absorption by plant, exudate secretion from the plant root, and bacterial flora change in the rhizosphere.Conclusion Cadmium in the soil from the smoking area was absorbed by indoor plant with the electrical ground. Therefore, the application of the electrical ground connection (earth) to the electrically insulated outdoor plant pots might enhance the plant growth rate and physiological activity. This application could be a novel soil decontamination method using plants.

Baltic Sea shipwrecks as a source of hazardous pollution

Background Shipwrecks on the Baltic Sea seabed pose a serious threat to the marine environment. Fuel, ammunition and chemicals in their holds can enter the ecosystem at any time, causing an ecological disaster. It is known that oil spills from ship accidents can affect life and health of different species of animals, both immediately after catastrophe and for many years thereafter. This article discusses the negative impact of shipwrecks on the ecological status of the Baltic Sea and presents the contamination status of bottom sediment core samples taken in the vicinity of shipwrecks located in the South Baltic, i.e., S/s Stuttgart, t/s Franken, S/T Burgmeister Petersen and m/s Sleipner. It is based on the results of research carried out by the Maritime Institute between 2011 and 2016. Methods Core samples were taken by a VKG-2 vibrating probe and analysed towards content of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), total petroleum hydrocarbons (TPHs) and total organic carbon (TOC). Seven PAHs and Seven PCBs were determined using solid phase extraction (SPE) technique followed by gas chromatography-mass spectrometry (GC-MS) detection. In order to determine the concentration of TPH, the SPE technique was applied followed by gas chromatography with flame ionisation detector (GC-FID) analysis. TOC content was established by TOC analyser using infrared detection. Results Samples taken in the vicinity of the S/s Stuttgart shipwreck have shown the highest concentrations of all analysed parameters compared to the examined wrecks and significantly differed from the results typical for these areas. This studies have shown that the S/s Stuttgart shipwreck poses a serious threat to the marine environment of Baltic Sea and it is necessary to continue studies in this area and to perform a wider range of analysis.

Oil-source correlation and Paleozoic source rock analysis in the Siwa Basin, Western Desert: Insights from well-logs, Rock-Eval pyrolysis, and biomarker data

Understanding the origins of potential source rocks and unraveling the intricate connections between reservoir oils and their source formations in the Siwa Basin (Western Desert, Egypt) necessitate a thorough oil-source correlation investigation. This objective is achieved through a meticulous analysis of well-log responses, Rock-Eval pyrolysis, and biomarker data. The analysis of Total Organic Carbon across 31 samples representing Paleozoic formations in the Siwa A-1X well reveals a spectrum of organic richness ranging from 0.17 wt% to 2.04 wt%, thereby highlighting diverse levels of organic content and the presence of both Type II and Type III kerogen. Examination of the fingerprint characteristics of eight samples from the well suggests that the Dhiffah Formation comprises a blend of terrestrial and marine organic matter. Notably, a significant contribution from more oxidized residual organic matter and gas-prone Type III kerogen is observed. Contrarily, the Desouky and Zeitoun formations exhibit mixed organic matter indicative of a transitional environment, and thus featuring a pronounced marine influence within a more reducing setting, which is associated with Type II kerogen. Through analysis of five oil samples from different wells—SIWA L-1X, SIWA R-3X, SIWA D-1X, PTAH 5X, and PTAH 6X, it is evident that terrestrial organic matter, augmented by considerable marine input, was deposited in an oxidizing environment, and contains Type III kerogen. Geochemical scrutiny confirms the coexistence of mixed terrestrial organic matter within varying redox environments. Noteworthy is the uniformity of identified kerogen Types II and III across all samples, known to have potential for hydrocarbon generation. The discovery presented in this paper unveils captivating prospects concerning the genesis of oil in the Jurassic Safa reservoir, suggesting potential links to Paleozoic sources or even originating from the Safa Member itself. These revelations mark a substantial advancement in understanding source rock dynamics and their intricate relationship with reservoir oils within the Siwa Basin. By illuminating the processes of hydrocarbon genesis in the region, this study significantly enriches our knowledge base.

Experimental and computational insights into the mechanism of destabilization of poly(acrylic acid)-capped silver nanoparticles induced by weak conjugate bases

Herein we report a systematic study of the effects of H2PO4− and ClO4− on the stability of poly(acrylic acid)-capped silver nanoparticles (PAA-AgNPs). Spectroscopic titration revealed that a smaller amount of ClO4− is required to detach PAA, and a blue-shift in surface plasmon resonance (SPR) was observed relative to H2PO4−, owing to its electron accepting nature which leads to a weaking of the PAA-AgNP donor bond. Experimental observations were supported by DFT calculations, which revealed that complexation of AgNPs with ionized PAA, H2PO4– and ClO4− is mediated by the electron affinity of the AgNP and the conjugated bases. Electron donation by the weak acids leads to the weakening of the PAA-AgNP donor bond, whereby ClO4− contributes more to the destabilization of the PAA capped AgNPs due to its greater electron affinity. Additionally, H2PO4− can form hydrogen bonds with PAA, which promotes the formation of aggregates. Moreover, DFT calculations have shown that the structure of the model Ag14 cluster is significantly distorted in the presence of H2PO4−, more so than in the case of ClO4−. The findings are supported by the experimental quantification of residual PAA by differential scanning calorimetry and solid-state total organic carbon analysis (SSM-TOC), and powder X-ray diffraction (XRD).

Expeditive carbofuran pesticide degradation by submerged thermal plasma and its accelerated mineralization by persulfate addition

Rapid degradation of carbofuran (CBF) pesticide is effectively achieved by submerged thermal plasma (STP) without and with the addition of persulfate (PS) at two different concentrations (10 and 20 ppm). Degradation efficiency was examined using high-performance liquid chromatography (HPLC), and mineralization percentage was determined by total organic carbon (TOC) analysis. Adding 10 ppm PS showed higher degradation and mineralization percentages of 99.5% and 65.2%, respectively, than mere plasma treatment and 20 ppm PS addition to CBF solution. A relatively higher energy yield of 40 mg/kWh and a first order kinetic reaction rate of 0.262 min−1 were obtained in the 10 PS added STP treatment. Liquid chromatography mass spectrometry (LCMS) analysis illustrated reaction intermediates formed during plasma treatment. Scavenger investigation implied that •OH radical is the prime cause of CBF degradation, as degradation percentage declined to 50% in all conditions. Toxicity assessment of CBF and its degradation products was predicted using Toxicity estimation software tool (TEST), and plasma treated solutions (PTS) were experimentally investigated on Eudrilus eugeniae earthworms by monitoring its mortality rate, self-assemblage, and histopathological analysis. A lower mortality rate (46%) and self-assemblage (167 s) of earthworms were detected for plasma treated CBF than for the other conditions. The results reveal that PTS is less toxic for earthworms than untreated CBF solution. These findings imply that STP is an effective technique for bio-recalcitrant pollutants degradation in agrochemical industries.

Organic matter accumulation in response to tectonism: New data from the Upper Permian Dalong Formation black shales in the Western Hubei Basin, South China and its implications for the end-Permian mass extinction

Redox conditions and primary productivity are proposed to be the major controls of organic matter accumulation in sediments. Studies of the impacts of tectonic processes on organic matter accumulation are still limited. We took the Late Permian-Early Triassic Western Hubei Basin, located in the north of South China, as an example. In black shales in the Dalong Formation, bottom-water redox conditions and surface-water productivity are constrained as shown by the analysis of total organic carbon (TOC) as well as geochemical (enrichment of Mo, U, Ni, Cd and Zn) and mineralogical characteristics. The highest productivity is present in the lower Dalong Formation, and the most intensively anoxic and restricted conditions are found in the middle Dalong Formation. The correlation of the sedimentary successions on the two sides of the basin's boundary fault indicates a subsidence of the basement during the deposition of the lower-middle Dalong Formation, followed by an uplift during the deposition of the upper Dalong Formation. When looked at in conjunction with the tectonic background of the basin, the new data in the present study support that: (1) the collision of the South and North China plates controlled the paleoceanographic and hydrographic evolution of the Western Hubei Basin, as well as organic matter accumulation in sediments; (2) upwelling-induced high productivity and good preservation in an anoxic environment jointly contributed to organic matter enrichment in the lower Dalong Formation, while good preservation in an anoxic environment was the major cause of organic matter enrichment in the middle-upper Dalong Formation. This study indicates that tectonism can act as the ultimate drive mechanism for organic matter accumulation in black shales. Our data also suggest that plate tectonism in related to the assembly of East Asian blocks with the main body of Pangea can also be treated as one of the ultimate drive mechanisms of the end-Permian mass extinction as it created the restricted, anoxic Paleo-Tethys Ocean, which greatly disturbed- global seawater circulation.

Effects of different agricultural systems on organic matter and aggregation of a medium-textured soil in subtropical region

This work evaluates the impact of different agricultural systems on the humic fractions of organic matter (SOM) and soil aggregation in a medium-textured soil in a subtropical region of Brazil. Three managed areas and a reference area were evaluated: permanent pasture (PP), no-till (NT), no-till+Brachiaria (NT+B) and native forest (NF). Deformed soil samples were collected in the layers 0-0.05; 0.05-0.10; 0.10-0.20 and 0.20-0.40 m, and unformed soil samples in the layers 0-0.05 and 0.05-0.10 m. After collection, total organic carbon (TOC) analysis, chemical fractioning of SOM and aggregate stability analysis were performed. The PP area presented the highest TOC and C-FA contents in the first three layers evaluated. In the 0.10-0.20 m layer, the C-HUM contents in the NT+B area were 1.9 times higher than in the NT area, and in 0.20-0.40 m they were 6.6 times higher. The PP area obtained the best structural indicators, especially higher WMD, GMD and % of macroaggregates. The two areas using direct seeding presented a percentage of macroaggregates higher than 37.28% in the superficial layer. The PP management provided increases in TOC levels and, consequently, humic substances, besides the formation of more stable aggregates. The NT+B system showed promise in increasing TOC and humic substances, especially at depth, even with a short implementation period. The increase in TOC and humic substances provided by the grasses contributes to the formation of more stable aggregates and, consequently, to the improvement of the quality of medium-textured agricultural soils. Keywords: aggregate stability, carbon fractions, climate change, humic substances.

Investigation of the Photocatalytic Performance, Mechanism, and Degradation Pathways of Rhodamine B with Bi2O3 Microrods under Visible-Light Irradiation.

In the present work, the photodegradation of Rhodamine B with different pH values by using Bi2O3 microrods under visible-light irradiation was studied in terms of the dye degradation efficiency, active species, degradation mechanism, and degradation pathway. X-ray diffractometry, polarized optical microscopy, scanning electron microscopy, fluorescence spectrophotometry, diffuse reflectance spectra, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, UV-visible spectrophotometry, total organic carbon, and liquid chromatography-mass spectroscopy analysis techniques were used to analyze the crystal structure, morphology, surface structures, band gap values, catalytic performance, and mechanistic pathway. The photoluminescence spectra and diffuse reflectance spectrum (the band gap values of the Bi2O3 microrods are 2.79 eV) reveals that the absorption spectrum extended to the visible region, which resulted in a high separation and low recombination rate of electron-hole pairs. The photodegradation results of Bi2O3 clearly indicated that Rhodamine B dye had removal efficiencies of about 97.2%, 90.6%, and 50.2% within 120 min at the pH values of 3.0, 5.0, and 7.0, respectively. In addition, the mineralization of RhB was evaluated by measuring the effect of Bi2O3 on chemical oxygen demand and total organic carbon at the pH value of 3.0. At the same time, quenching experiments were carried out to understand the core reaction species involved in the photodegradation of Rhodamine B solution at different pH values. The results of X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffractometer analysis of pre- and post-Bi2O3 degradation showed that BiOCl was formed on the surface of Bi2O3, and a BiOCl/Bi2O3 heterojunction was formed after acid photocatalytic degradation. Furthermore, the catalytic degradation of active substances and the possible mechanism of the photocatalytic degradation of Rhodamine B over Bi2O3 at different pH values were analyzed based on the results of X-ray diffractometry, radical capture, Fourier-transform infrared spectroscopy, total organic carbon analysis, and X-ray photoelectron spectroscopy. The degradation intermediates of Rhodamine B with the Bi2O3 photocatalyst in visible light were also identified with the assistance of liquid chromatography-mass spectroscopy.

A low-methane rice with high-yield potential realized via optimized carbon partitioning

Global rice cultivation significantly contributes to anthropogenic methane emissions. The methane emissions are caused by methane-producing microorganisms (methanogenic archaea) that are favoured by the anoxic conditions of paddy soils and small carbon molecules released from rice roots. However, different rice cultivars are associated with differences in methane emission rates suggesting that there is a considerable natural variation in this trait. Starting from the hypothesis that sugar allocation within a plant is an important factor influencing both yields and methane emissions, the aim of this study was to produce high-yielding rice lines associated with low methane emissions. In this study, the offspring (here termed progeny lines) of crosses between a newly characterized low-methane rice variety, Heijing 5, and three high-yielding elite varieties, Xiushui, Huayu and Jiahua, were selected for combined low-methane and high-yield properties. Analyses of total organic carbon and carbohydrates showed that the progeny lines stored more carbon in above-ground tissues than the maternal elite varieties. Also, metabolomic analysis of rhizospheric soil surrounding the progeny lines showed reduced levels of glucose and other carbohydrates. The carbon allocation, from roots to shoots, was further supported by a transcriptome analysis using massively parallel sequencing of mRNAs that demonstrated elevated expression of the sugar transporters SUT-C and SWEET in the progeny lines as compared to the parental varieties. Furthermore, measurement of methane emissions from plants, grown in greenhouse as well as outdoor rice paddies, showed a reduction in methane emissions by approximately 70 % in the progeny lines compared to the maternal elite varieties. Taken together, we report here on three independent low-methane-emission rice lines with high yield potential. We also provide a first molecular characterisation of the progeny lines that can serve as a foundation for further studies of candidate genes involved in sugar allocation and reduced methane emissions from rice cultivation.

Sebacate intercalated Ca[sbnd]Al layered double hydroxide pigments for corrosion protection of low carbon steel: Anion exchange and electrochemical properties

Sebacate (SB) molecules were incorporated into CaAl layered double hydroxides (CaAL-LDH) using a hydrothermal method. The resulting products underwent characterization through X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. To investigate the release kinetics and thermodynamics of the corrosion inhibitor, total organic carbon analysis (TOC) was employed. A comparison was made with CaAl-LDH prepared without corrosion inhibitors, in which nitrates were the primary anions within the layered clay structure. An assessment of anion exchange between nitrates and chlorides was conducted using total nitrogen analysis (TN). The SB anion comprised approximately 49.2% of the total dried powder synthesized, with a maximum release efficiency of around 86.7% fitting a Langmuir model. For the evaluation of the corrosion inhibition effect on steel surfaces, electrochemical impedance spectroscopy, potentiodynamic polarization, and scanning vibrating electrode technique were employed. The corrosion inhibition impact was ascribed to the liberation of SB anions from the CaAl-LDH pigments, accompanied by alkalinization stemming from partial particle dissolution. Additionally, the incorporation of organic molecules notably enhanced the stability of pigments in aqueous solutions compared to similar ones hosting nitrates. These findings suggested that CaAl-LDH pigments have potential as nanocontainers for organic inhibitors, showing promising prospects in the field of corrosion research.

Selective vanadium etching and in-situ formation of δ-Bi2O3 on m-BiVO4 with g-C3N4 nanosheets for photocatalytic degradation of antibiotic tetracycline

Antibiotics play a vital role in treating microbial illnesses, but their presence in water bodies is a global concern. Despite the potential of polymeric graphitic carbon nitrate (g-C3N4) as a photocatalyst for wastewater treatment, its effectiveness is hindered by a fast charge carrier recombination rate. To overcome this challenge, we have developed a novel approach involving the surface etching-oxidation technique to introduce δ-Bi2O3 onto m-BiVO4. Subsequently, the modified δ-Bi2O3/m-BiVO4 (BBV) was synergistically coupled with g-C3N4 (CN) to create a hybrid photocatalyst (BBVCN). The photocatalytic activity of BBVCN was evaluated using tetracycline hydrochloride (TC) as a model wastewater antibiotic pollutant, demonstrating a 92 % degradation of TC within a 1 h reaction time. Total organic carbon analysis demonstrated a TC removal efficiency of 76 %, indicating significant mineralization by BBVCN.

Organic geochemical heterogeneity of cretaceous mudrocks and reassessment of oil sources in the Tano Basin, Ghana

The Tano Basin in Ghana, situated within the South Atlantic margin, is a significant area for petroleum exploration. Previous studies have recognized the presence of source rocks rich in organic matter from the Cretaceous period in this basin. However, the specific origins of this organic matter, as well as the thermal maturity and depositional environment of the Cretaceous source strata, are not well characterized in existing literature. Here, geochemical data are reported on the bulk geochemical composition of 45 Maastrichtian to Albian-aged rock cuttings via pyrolysis and total organic carbon (TOC) analysis. Out of these samples, 29 were selected for further biomarker and stable carbon isotope (δ13C) analysis. The biomarker and isotopic signatures of the 29 rock extracts and 6 crude oils from the basin's productive Jubilee and TEN oil fields were compared to establish oil-oil and oil-source correlations. The Cenomanian and Turonian source rocks showed the greatest oil generation potential based on current bulk geochemical analysis. These rocks are dominated by oil-prone organic matter and are at a more favorable maturity stage compared to the Maastrichtian, Santonian, and Coniacian (M-S-C) rock suites. In contrast, the Albian rock samples, characterized by mixed Type II/III and Type III kerogen, and their high thermal maturity, indicate a high potential for the generation of gaseous hydrocarbons. The biomarker and isotope data from the Cenomanian, Turonian, and Albian (T-C-A) source rocks suggest that they were deposited in a Transitional Marine-Lacustrine environment characterized by reducing redox conditions. This environment effectively preserved organic matter from diverse sources such as bacteria, algae, and higher plants. Furthermore, biomarker ratios indicated that the T-C-A source rocks are in the early-peak mature window. On the other hand, the M-S-C source rocks appear to have been deposited under suboxic conditions in a Coastal Marine environment. Lower aquatic organisms dominate these rocks, which have an immature to marginally mature level. The analysis of lower molecular weight hydrocarbons (≤C20), characterized by an unresolved complex mixture, did not reveal any obvious correlation between the oils and the Cretaceous source rocks. However, the analysis of higher molecular weight hydrocarbons (≥C20) and isotopic ratios indicated that the commercial discoveries in the Jubilee and TEN fields share a genetic similarity and are primarily sourced from the T-C-A source rocks. Furthermore, the molecular and isotopic characteristics suggest that the M-S-C source rocks do not appear to have contributed to the oils found in the Jubilee and TEN fields. These new geochemical findings shed light on the paleoenvironmental conditions and source rock characteristics of the region, significantly contributing to our understanding of the petroleum evolution and potential of the Tano Basin.

Photocatalytic degradation of acid blue 74 by Co: WO3 nanoparticles: Kinetics and response surface methodology studies

Energy-efficient sol-gel synthesis was achieved through the microwave assisted self-combustion route to produce hexagonal Tungsten oxide semiconductor (WO3). The photocatalytic activity was enhanced by doping Cobalt (Co) into the crystalline structure of the nanoparticle, which were subsequently sintered at 400 °C for an hour. The structural and morphological properties of the Co-doped WO3 were revealed using X-ray diffraction (XRD) characterization. The nanoparticles exhibited an amorphous structure before annealing, due to the short heating time during combustion synthesis. Sintering the nanoparticle transformed the nanoparticle from a monoclinic phase to orthorhombic phase structure. Additional analysis techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectrum analysis (EDS).To assess the photocatalytic performance of these particles, Acid Blue 74 (AB 74) was employed in photodegradation experiments under UV light irradiation within a semi-continuous reactor.The photodegradation of dye molecules was evaluated utilizing a UV–Vis spectrophotometer, and the mineralization efficiency of the dye was determined through total organic carbon analysis (TOC). The results indicated that the dimension of the synthesized nano catalyst fell within the range of 70–120 nm, and it exhibited the ability to completely degrade a solution with an initial dye concentration of 20 ppm within 60 min. Various parameters affecting the photocatalytic reaction, including the photocatalyst dosage, initial dye concentration, pH and temperature of the dye solution were also investigated. The experiments were designed using Response surface methodology (RSM), through which a mathematical model for the dye removal process was developed.