Organic Compounds Research Articles

Atmospheric CFC-11 and CCl4: A free calibration standard for PTR-MS

Proton-transfer-reaction mass spectrometry (PTR-MS) is an analytical technique used to monitor volatile organic compounds in real-time. For quantitative analysis, compounds of interest are typically calibrated using gas standards, but PTR-MS is quantitative to uncalibrated compounds if the mass-dependent transmission is well defined. However, long-term measurements are challenging due to the drift in transmission over time. Performing frequent calibrations helps, but the methods are time-consuming and tedious, often leading to instruments being under-calibrated. Here we show the use of long-lived and globally monitored compounds in the atmosphere as a tool to constrain the transmission between calibrations. The major ion of trichlorofluromethane (CFC-11) and carbon tetrachloride (CCl4) is found at the mass-to-charge ratio (m/z) 116.9, which we propose using to retrieve the transmission of a PTR-MS. We determined the pseudo-reaction rate constants of CFC-11 and CCl4 to be 0.82 × 10−9 ± 0.05 × 10−9 cm3 s−1 molecule−1, and 1.65 × 10−9 ± 0.08 × 10−9 cm3 s−1 molecule−1, respectively. The method introduced here can improve data quality and accuracy, especially for long-term atmospheric measurements.

Characteristics and Source Apportionment of Volatile Organic Compounds in a Coastal Industrial Area: A Case Study in the Yangtze River Delta of China.

In recent years, the coastal area in East China has experienced elevated volatile organic compounds (VOCs) levels during specific periods. VOCs have become one of the major atmospheric pollutants in these areas. In this study, 64 compounds including alkanes, alkenes, halohydrocarbons, aromatics, and oxygenated VOCs (OVOCs) were obtained by the TO-15 method through a 12-month campaign in industrial, urban and suburban areas in the Yangtze River Delta of China. The overall trends of total VOC (TVOC) concentrations at eight sampling sites were as follows: winter > autumn > spring > summer. The proportion of VOC categories was various at industrial sites, while OVOCs and halohydrocarbons had high proportions at urban sites and suburban sites, respectively. Coating, vehicle emission, petrochemical source, industrial source, and gasoline volatilization were identified as the major VOC emission sources by the positive matrix factorization model. Petrochemical and coating sources were the prime VOC sources at industrial sites. Aromatics contributed the most ozone formation potential at industrial sites, while OVOCs provided the main contributions at both urban and suburban sites during four seasons. According to the health risk assessment, a high probability of non-carcinogenic risk existed at three industrial sites. Special attention should be given to certain VOCs, such as acrolein and 1,2-dibromoethane in industrial areas.

Modification of crystalline graphitic carbon nitride for improve efficiency in photocatalytic destruction of volatile organic compounds (VOCs) under visible light irradiation

Modification of crystalline graphitic carbon nitride for improve efficiency in photocatalytic destruction of volatile organic compounds (VOCs) under visible light irradiation

Influence of anthropogenic activities on the trace organic contamination of lakes

Anthropogenic activities and urbanization can lead to the discharge of organic compounds into surface waters. It is important to investigate these relationships further to mitigate contamination better and prioritize protection efforts. This study aimed to verify the effect of specific anthropogenic factors on lake water contamination caused by trace organic contaminants (TrOCs) such as pharmaceuticals, pesticides and consumer product additives. Data on the detection and concentration levels of 54 TrOCs, major anthropogenic land use, and human activities from a large-scale study on Canadian lakes were used to reach this goal. The association of population and livestock densities, the presence of wastewater treatment plants (WWTPs) and hospitals as well as the agricultural and urban land use in the lakes' watersheds on lake water contamination was investigated by applying negative binomial and ordinal logistic regression models. These models were also controlled for lake/watershed area ratio, lake depth, water, residence time, watershed slope, precipitation, and sampling date. The statistical analysis confirmed that agricultural land use, urban land use, and WWTPs plants in lake watersheds are significantly associated with the number of TrOCs detected (incidence rate ratio > 1, p < 0.001) and the summed concentration of targeted TrOCs (odds ratio > 1, p < 0.001). Agricultural land use (odds ratio = 1.58, p < 0.001) and urban land use (odds ratio = 1.19, p < 0.02) were also significantly associated with the summed concentration of the targeted pesticides. This latter outcome thus suggests that urban centers are also important contributors to the concentration levels of pesticides in lakes. Overall, these results demonstrate that even in complex ecosystems such as lakes, it is possible to use a limited number of factors to explain anthropogenic contamination. This can help policymakers make informed decisions on contamination mitigation and provide insights into watershed management.

Study on membrane fouling mechanisms and mitigation strategies in a pilot-scale anaerobic membrane bioreactor (P-AnMBR) treating digestate

Anaerobic Membrane Bioreactor (AnMBR) are employed for solid-liquid separation in wastewater treatment, enhancing process efficiency of digestion systems treating digestate. However, membrane fouling remains a primary challenge. This study operated a pilot-scale AnMBR (P-AnMBR) to treat high-concentration organic digestate, investigating system performance and fouling mechanisms. P-AnMBR operation reduced acid-producing bacteria and increased methane-producing bacteria on the membrane, preventing acid accumulation and ensuring stable operation. The P-AnMBR effectively removed COD and VFA, achieving removal rates of 82.3 % and 92.0 %, respectively. Higher retention of organic nitrogen and lower retention of ammonia nitrogen were observed. The membrane fouling consisted of organic substances (20.3 %), predominantly polysaccharides, and inorganic substances (79.7 %), primarily Mg ions (10.1 %) and Ca ions (4.5 %). To reduce the increased transmembrane pressure (TMP) caused by fouling (a 10.6-fold increase in filtration resistance), backwash frequency experiment was conducted. It revealed a 30-min backwash frequency minimized membrane flux decline, facilitating recovery to higher flux levels. The water produced amounted to 70.3 m³ over 52 days. The research provided theoretical guidance and practical support for engineering applications, offering practical insights for scaling up P-AnMBR.

Efficient CO2 Conversion through a Novel Dual-Fiber Reactor System.

Carbon dioxide (CO2) can be converted to valuable organic chemicals using light irradiation and photocatalysis. Today, light-energy loss, poor conversion efficiency, and low quantum efficiency (QE) hamper the application of photocatalytic CO2 reduction. To overcome these drawbacks, we developed an efficient photocatalytic reactor platform for producing formic acid (HCOOH) by coating an iron-based metal-organic framework (Fe-MOF) onto side-emitting polymeric optical fibers (POFs) and using hollow-fiber membranes (HFMs) to deliver bubble-free CO2. The photocatalyst, Fe-MOF with amine-group (-NH2) decoration, provided exceptional dissolved inorganic carbon (DIC) absorption. The dual-fiber system gave a CO2-to-HCOOH conversion rate of 116 ± 1.2 mM h-1 g-1, which is ≥18-fold higher than the rates in photocatalytic slurry systems. The 12% QE obtained using the POF was 18-fold greater than the QE obtained by a photocatalytic slurry. The conversion efficiency and product selectivity of CO2-to-HCOOH were up to 22 and 99%, respectively. Due to the dual efficiencies of bubble-free CO2 delivery and the high QE achieved using the POF platform, the dual-fiber system had energy consumption of only 0.60 ± 0.05 kWh mol-1, 3000-fold better than photocatalysis using slurry-based systems. This innovative dual-fiber design enables efficient CO2 valorization without the use of platinum group metals or rare earth elements.

Foliar spraying with amino acids and their chitosan nanocomposites as promising way to alleviate abiotic stress in iceberg lettuce grown at different temperatures

We analyzed the effects of foliar spraying with amino acids, chitosan (CHS) and nanocomposites (NCs) of chitosan with the amino acids proline, l-cysteine and glycine betaine (CHS-Pro NCs; CHS-Cys NCs, CHS-GB NCs, respectively) on the changes in the physiological and biochemical parameters of iceberg lettuce grown at the control temperature (20 °C) and under chilling conditions (4 °C). The physicochemical parameters of the phospholipid monolayers (PLs) extracted from plants showed the effects of the treatments on the properties of the monolayers, namely, the packing density and flexibility. We observed increased accumulation of proline at 4 °C, and differences in the concentrations of sugars in most of the analyzed variants were a consequence of the lowered temperature and/or the use of organic compounds. A temperature of 4 °C caused a significant increase in the l-ascorbic acid level compared with that at 20 °C. Differences were also found in glutathione (GSH) content depending on the temperature and treatment with the tested organic compounds. CHS NCs loaded with Pro and GB were effective at increasing the amount of phenols under stress temperature conditions. We noted that a significant increase in the antioxidant activity of plants at 4 °C occurred after priming with Cys, CHS-Cys NCs, Pro and CHS-Pro NCs, and the CHS nanocomposites were more effective in this respect. Both low-temperature stress and foliar spraying of lettuce with various organic compounds caused changes in the activity of antioxidant enzymes. Two forms of dismutase (SOD), iron superoxide dismutase (FeSOD) and copper/zinc superoxide dismutase (Cu/ZnSOD), were identified in extracts from the leaves of iceberg lettuce seedlings. The application of the tested organic compounds, alone or in combination with CHS, increased the amount of malondialdehyde (MDA) in plants grown under controlled temperature conditions. Chilling caused an increase in the content of MDA, but some organic compounds mitigated the impact of low temperature. Compared with that of plants subjected to 20 °C, the fresh weight of plants exposed to chilling decreased. However, the tested compounds caused a decrease in fresh weight at 4 °C compared with the corresponding control samples. An interesting exception was the use of Cys, for which the difference in the fresh weight of plants grown at 20 °C and 4 °C was not statistically significant. After Cys application, the dry weight of the chilled plants was greater than that of the chilled control plants but was also greater than that of the other treated plants in this group. To our knowledge, this is the first report demonstrating that engineered chitosan–amino acid nanocomposites could be applied as innovative protective agents to mitigate the effects of chilling stress in crop plants.

An Enzyme-Induced Carbonate Precipitation Method for Zn2+, Ni2+, and Cr(VI) Remediation: An Experimental and Simulation Study

Heavy metal contamination has long been a tough challenge. Recently, enzyme-induced carbonate precipitation (EICP) has been proposed to handle this problem. This paper aims to explore the efficacy, process, and mechanisms of EICP using crude sword bean urease extracts to remediate Zn2+, Ni2+, and Cr(VI) contamination. A series of liquid batch tests and geochemical simulations, as well as microscopic analyses, were conducted. The liquid batch test results show that Zn2+, Ni2+, and Cr(VI) can be effectively immobilized by the EICP method, and the highest immobilization percentage was observed for Zn2+, reaching up to 99%. Ni2+ and Cr(VI) were immobilized at 62.4% and 24.4%, respectively. Additionally, the immobilization percentage of heavy metals increased with the concentration of added Ca2+. The simulation results and XRD results reveal that the organic molecules in crude sword bean urease can promote ZnCO3, Zn(OH)2, Zn5(CO3)2(OH)6, and NiCO3 precipitation. The FTIR and SEM-EDS results provide evidence for heavy metal adsorption by the functional groups in crude urease and calcium carbonate. The liquid batch test results, as well as the simulation results and the microscopic analysis results, indicate that the mechanism of EICP in heavy metal remediation can be summarized as biomineralization to form heavy metal carbonate precipitates and metal hydroxide precipitates, adsorption by calcium carbonate, and adsorption or complexation or promoting nucleation by organic molecules.

Models for predicting corrosion inhibition efficiency of common drugs on steel surfaces: A rationalized comparison among methodologies

Several anticorrosive treatments have been proposed over time to create protective layers to hinder the corrosion phenomenon. In recent years, organic molecules from plant extracts and expired drugs have been tested due to their potential corrosion inhibition properties. However, direct corrosion inhibition efficiency (IE%) evaluation requires costly reactants and a specific experimental setup. Quantitative-structure activity relationship (QSAR) proposes modeling IE% in terms of variables measured in previous experiments or determined by theoretical approaches. Computed descriptors, such as ionization energy (I), electronic affinity (A), or global hardness, were added to a database of physicochemical properties. This work compares several methodologies to obtain precise yet portable mathematical models for predicting corrosion inhibition efficiency. As an original approach from this research group, nonlinear autoregressive moving average with exogenous inputs (NARMAX), using forward regression with orthogonal least squares (FROLS), models were implemented as a robust method to get nonlinear portable models and to determine the most important variables impacting IE%. Contrastingly, ordinary least squares (OLS) methodology was employed with the novelty of applying power series expansions from the promoted FROLS variables for linear and polynomial regression with only one independent variable, which resulted in clearer graph visualization of trends and the ease of proposing thumb rules based on raw information. Finally, IBM Watson was also compared as a robust yet non-portable and highly parametrized alternative to conventional mathematical approaches, based on extra trees regressor (ETR). The models were compared using mean absolute percentage error (MAPE), mean-squared error (MSE), and root-mean-squared error (RMSE). Overall, models with fewer variables and up to second-order terms show improved performance. The main tendencies of IE%, drawn by inferences for 630 substances by second-order NARX, are analyzed. Also, the determinant role of the highest occupied molecular orbital energy was reported. Experimentalists can take advantage of a “cost-free” general approach that can obtain estimations for IE% values with errors of about 6 %, in particular the second-order NARX model.

Rh-Catalyzed Enantioselective Single-Carbon Insertion of Alkenes.

The interest in the discovery and development of skeletal editing processes that selectively insert, exchange, or delete an atom in organic molecules has significantly increased over the last few years. However, processes of this class that proceed through the creation of a chiral center with high asymmetric induction have been largely unexplored. Herein, we report an enantioselective single-carbon insertion in aryl- and alkyl-substituted alkenes mediated by a catalytically generated chiral Rh-carbynoid and phosphate nucleophiles that produce enantioenriched allylic phosphates (enantiomeric ratio (e.r.) = 89.5:10.5-99.5:0.5). The key to the process was a diastereo- and enantioselective cyclopropanation of the alkene with a chiral Rh-carbynoid and the formation of a transient cyclopropyl-I(III) intermediate. The addition of the phosphate nucleophile provided a cyclopropyl-I(III)-phosphate intermediate that undergoes disrotatory ring opening following the Woodward-Hoffmann-DePuy rules. This process led to a chiral intimate allyl cation-phosphate pair that evolved with excellent enantioretention. The evidence of an SN1-like SNi mechanism is provided by linear free-energy relationship studies, kinetic isotope effects, X-ray crystallography, and control experiments. We demonstrated the utility of the enantioenriched allylic phosphates in late-stage N-H allylations of natural products and drug molecules and in cross-coupling reactions that occurred with excellent enantiospecificity.

Application prospects of graphene in environmental science

Nanomaterials and graphene, as cutting-edge materials, have play a crucial role in environmental governance. The introduction of nanomaterials brings new hope to environmental governance. Graphene not only improves the efficiency and cost-effectiveness of water treatment but also drives innovation and development in environmental technologies. This article provides a summary and analysis review starting from the characteristics of nanomaterials and Graphene, comprehensively reviewing Graphenes advantage in environmental technologies and discovered its application in this area. The research summarized the conclusion that Graphenes characteristics make it suitable for addressing environmental issues such as water pollution, its composites can play an important role in water treatment process including water purification, heavy metal adsorption, organic compound adsorption and removal through different preparation and reaction mechanisms. By introducing Nanopore structures and artificially designed stacking structures on graphene membranes, the permeation performance could be modulated and improved. By the way of physical and chemical adsorption, ion exchange, electrochemical and photocatalysis, Graphene and its oxide could be applied to remove heavy metal ion and organic substances from polluted water. The article also introduced the main preparation methods of Graphene and its potential secondary pollution problem. This article provides valuable insights for scientific research and engineering practices in environmental protection and sustainable development.

Efficient photocatalytic degradation of 24 imidazolium ionic liquids in an N-ZnO/simulated sunlight irradiation system and its mechanism

An efficient nitrogen (N)-ZnO photocatalytic composite was synthesized and well characterized to demonstrate its superior photocatalytic performance as well as the degradation kinetics of 24 ILs in an N-ZnO/Xe lamp irradiation system, as well as the pathways and mechanisms of the photocatalytic degradation (PCD) of typical ionic liquids [OMIm]Br was systematically studied. To investigate the catalytic effect, nitrogen was synthesized from various inorganic and organic nitrogen compounds to ZnO. The NH4NO3-ZnO composite calcined at 300 °C with a molar ratio of NH4NO3 to Zn(NO3)2·6H2O of 10:1 exhibited superior catalytic performance as assessed by SEM, TEM, FT-IR, UVDRS, BET surface area, XPS, and XRD characterizations. After 24 h of exposure to Xe lamp irradiation, all 24 ILs were significantly degraded by the introduction of 0.125 g/L of catalyst, whereas simulated sunlight alone resulted in minimal degradation. The pseudo-first-order rate coefficients (k) for PCD were closely related to the carbon chain length of the alkyl substituents and the type of anion. Multiple linear regression analysis indicated no linear correlation between the parameters E, H°, Eth, and Cv° from the Gaussian calculation and k. Conversely, a positive correlation was observed for EHOMO (B=0.742, β = 1.282, P = 0.011), qH+ (B=1.040, β = 3.284, P = 0.006), and G° (B=0.001, β = 5.400, P = 0.007) with k. Mass spectrometry analysis revealed that the primary PCD pathway for [OMIm]Br involved C-N and/or C-C bond breaking, mono-, di-, and tri-hydroxylation, single and double oxygen transfer, and bromo-substitution reactions.

Molecule Engineering Metal-Organic Framework-Based Organic Photoelectrochemical Transistor Sensor for Ultrasensitive Bilirubin Detection.

The functionalization of metal-organic frameworks (MOFs) with organic small molecules by in situ postsynthetic modification has garnered considerable attention. However, the precise engineering of recognition sites using this method remains rarely explored in optically controlled bioelectronics. Herein, employing the Schiff base reaction to embed the small molecule (THBA) into a Zr-MOF, we fabricated a hydroxyl-rich MOF on the surface of titanium dioxide nanorod arrays (U6H@TiO2 NRs) to develop light-sensitive gate electrodes with tailored recognition capabilities. The U6H@TiO2 NR gate electrodes were integrated into organic photoelectrochemical transistor (OPECT) sensing systems to tailor a sensitive device for bilirubin (I-Bil) detection. In the presence of I-Bil, coordination effects, hydrogen bonding, and π-π interactions facilitated strong binding between U6H@TiO2 NRs and the target I-Bil. The electron-donating property of I-Bil influenced the gate voltage, enabling precise control of the channel status and modulation of the channel current. The OPECT device exhibited exceptional analytical performance toward I-Bil with wide linearity ranging from 1 × 10-16 to 1 × 10-9 M and a low limit detection of 0.022 fM. Leveraging the versatility of small molecules for boosting the functionalization of materials, this work demonstrates the great potential of the small molecule family for OPECT bioanalysis and holds promise for the advancement of OPECT sensors.

Deciphering the doublet luminescence mechanism in neutral organic radicals: spin-exchange coupling, reversed-quartet mechanism, excited-state dynamics.

Neutral organic radical molecules have recently attracted considerable attention as promising luminescent and quantum-information materials. However, the presence of a radical often shortens their excited-state lifetime and results in fluorescence quenching due to enhanced intersystem crossing (EISC). Recently, an experimental report introduced an efficient luminescent radical molecule, tris(2,4,6-trichlorophenyl)methyl-carbazole-anthracene (TTM-1Cz-An). In this study, we systematically performed quantum theoretical calculations combined with the path integral approach to quantitatively calculate the excited-state dynamics processes and spectral characteristics. Our theoretical findings suggest that the sing-doublet D1 state, originating from the anthracene excited singlet state, is quickly converted to the doublet (trip-doublet) state via EISC, facilitated by a significant nonequivalence exchange interaction, with ΔJ ST = 0.174 cm-1. The formation of the quartet state (Q1, trip-quartet) was predominantly dependent on the exchange coupling 3/2J TR = 0.086 cm-1 between the triplet spin electrons of anthracene and the TTM-1Cz radical. Direct spin-orbit coupling ISC to the Q1 state was minimal due to the nearly identical spatial wavefunctions of the and Q1 levels. The effective occurrence of reverse intersystem crossing (RISC) from the Q1 to D1 state is a critical step in controlling the luminescence of TTM-1Cz-An. The calculated RISC rate k RISC, including the Herzberg-Teller effect, was 3.64 × 105 s-1 at 298 K, significantly exceeding the phosphorescence and nonradiative rates of the Q1 state, thus enabling the D1 repopulation. Subsequently, a strong electronic coupling of 37.4 meV was observed between the D1 and D2 states, along with a dense manifold of doublet states near the D1 state energy, resulting in a larger reverse internal conversion rate k RIC of 9.26 × 1010 s-1. Distributed to the D2 state, the obtained emission rate of k f = 2.98-3.18 × 107 s-1 was in quite good agreement with the experimental value of 1.28 × 107 s-1, and its temperature effect was not remarkable. Our study not only provides strong support for the experimental findings but also offers valuable insights for the molecular design of high-efficiency radical emitters.

Petrocella pelovolcani sp. nov., an Alkaliphilic Anaerobic Bacterium Isolated from Terrestrial Mud Volcano

Diversity of extremophilic microorganisms in mud volcanoes is largely unexplored. Here we report the isolation of a novel alkaliphilic, mesophilic, fermentative bacterium (strain FN5sucT) from a terrestrial mud volcano located at the Taman Peninsula, Russia. Cells of strain FN5sucT are gram-stain-positive, non-sporeforming, motile rods. The temperature range for growth is 10–37°C, with an optimum at 30°C. The pH range for growth is 7.5–10.0, with an optimum at pH 9.0. The isolate utilizes various organic polymeric substances, organic acids, carbohydrates, and proteinaceous compounds. The end products of carbohydrates fermentation are acetate, CO2 and trace amounts of H2 and formate. The major cellular fatty acid compounds are C16:0, C16:1 ω7c, and monounsaturated dimethyl acetal C14:1. Phylogenetic analysis reveals that strain FN5sucT is most closely related to Petrocella atlantisensis = DSM 105309T (98.4% 16S rRNA gene identity). The total size of the genome of strain FN5sucT is 3.35 Mb, and a genomic DNA G+C content is 37.0 mol %. The genome contains complete glycolisis/glyconeogenesis pathway. We propose to assign strain FN5sucT to the genus Petrocella, as a new species, Petrocella pelovolcani sp. nov. The type strain is FN5sucT (=DSM 113898T = UQM 41591T).

Investigation of linear and nonlinear optical properties of 3, 6 –bis pyridine-1, 2, 4, 5 –tetrazine: a high nitrogen-energetic material

Of late, high-nitrogen energetic materials have garnered a lot of attention among researchers as they contribute to amplifying the progress of research and applications such that they typically leave a lasting impression which leads to significant scientific growth. 1,2,4,5-tetrazine and its 3,6-disubstituted derivatives continue to make inroads which pave the way for applications of diverse nature. On these lines, the organic compound of 3,6–bis Pyridine-1,2,4,5 – Tetrazine (BPTZ) has been preferred for the present investigation such that its synthesis and the basic characterizations of NMR, XRD and elemental analyses have been carried out. The required vibrational studies have been accomplished by employing FTIR as well as Raman spectroscopic analyses. The structure of BPTZ has been obtained theoretically by carrying out DFT/B3LYP calculations with the implementation of B3LYP/ 6-311G** basis set. Hyper Rayleigh scattering analysis has been accomplished and the first hyperpolarizability (b) of the title compound has been also computed making use of the technique of second harmonic light scattering (SHLS). The efficiency of SHG for BPTZ is 0.65 times greater than the standard KDP. BPTZ are excellent materials that make way for the development of their electrofluorochromism (EF) and the creation of electrofluorochromic as well as optoelectronic devices.

Effects of NIR-reflective pigments on waterborne polyurethane coatings and their thermal insulation performance

Waterborne coatings have garnered much attention and gradually occupied the coating market recently due to the significant advantages in volatile organic compound emissions compared with solvent-borne coatings. Waterborne polyurethane coatings are a majority portion of waterborne coatings. Unlike solvent-borne coatings, the film formation of waterborne coatings occurs in an inhomogeneous phase, which brings a challenge for pigmentation in waterborne coatings. However, the influence of pigment on film formation and the property of waterborne polyurethane coating remain unclear. In this study, the different contents of commercial black near-infrared (NIR) reflective pigments were incorporated into both commercial and synthetic waterborne polyurethane systems. The film formation process was monitored by multispeckle diffusing wave spectroscopy. The impact of the pigment content on dry films was assessed through scanning electron microscope, color and gloss measurements, dynamical thermal analyzer, and tensile testing. Furthermore, the thermal insulation performance of the waterborne polyurethane coatings was evaluated to study the function of the NIR reflective pigments. Our findings reveal that the addition of black NIR reflective pigments yields a multifaceted effect on film formation and coating morphology and improves thermal insulating property. Elevated pigment content correlated with increased crosslinking density, tensile stress, and Young's modulus.

Developing Z-scheme Bi2MoO6@α-MnO2 beaded core-shell heterostructure in photoelectrocatalytic treatment of organic wastewater

Photoelectrocatalysis (PEC) oxidation technology with the combination of electrocatalysis and photocatalysis is an ideal candidate for treatment of dyeing wastewater containing multifarious intractable organic compounds with high chroma. Constructing high-quality heterojunction photoelectrodes can effectively suppress the recombination of photo-generated carriers, thereby achieving efficient removal of pollution. Herein, a beaded Bi2MoO6@α-MnO2 core-shell architecture with tunable hetero-interface was prepared by simple hydrothermal-solvothermal process. The as-synthesized Bi2MoO6@α-MnO2 had larger electrochemically active surface area, smaller charge transfer resistance and negative flat band potential, and higher separation efficiency of e−/h+ pairs than pure α-MnO2 or Bi2MoO6. It is noteworthy that the as-synthesized Bi2MoO6@α-MnO2 showed Z-scheme heterostructure as demonstrated by the free radical quenching experiments. The optimized Bi2MoO6@α-MnO2-2.5 exhibited the highest degradation rate of 88.64% in 120 min for reactive brilliant blue (KN-R) and accelerated stability with long-term(∼10000s) at the current density of 50 mA cm−2 in 1.0 mol L−1 H2SO4 solution. This study provides valuable insights into the straightforward preparation of heterogeneous electrodes, offering a promising approach for the treatment of wastewater in various industrial applications.

Processing of Salvinia auriculata biomass by semi-solid fermentation and green mechanochemical synthesis as agricultural inputs

Currently, the biomass of various plant species is being utilized to produce high-value agricultural inputs, and the technique of green mechanochemical synthesis is employed in this process due to its relatively simple nature. This technique utilizes biomass to produce new biologically active compounds with properties such as biofertilizers, biostimulants, and bioinsecticides. In the present study, Salvinia auriculata biomass was used to obtain a valuable plant substrate and subsequently processed to be applied in vegetable crops for productivity improvement in field conditions. The Salvinia biomass was subjected to semi-solid fermentation, resulting in an organic substrate. This substrate was tested for the germination of melon (Cucumis melo L.) and watermelon (Citrullus lanatus) seeds, demonstrating excellent results when compared to commercial substrates. Comparing melon seedlings grew on different commercial substrates with Salvinia substrate, the germination index (GI), germination speed index (GSI), number of leaves (NL), aerial part length (APL), root of length (RL), aerial part fresh mass (APFM), root fresh mass (RFM), aerial part dry mass (APDM) and root dry mass (RDM) presented, respectively, an increase of 35%, 42.79%, 52%, 56.72%, 143.4%, 97%, 111.4%, 112%, 49.5% and 103%, demonstrating that Salvinia substrate is superior to the commercial substrates evaluated. Similar results were obtained for watermelon plants grew on Salvinia substrate. Subsequently, a bionanofertilizer (BNF) from fermented biomass was produced through green mechanochemical synthesis, a technique that proved to be highly efficient for nanofertilizer production. The tests demonstrated that the BNF at different doses had effects in vegetable crops after foliar application in the field. In melon plants, the productivity per plant increased by 50% after the foliar application of BNF and the productivity per hectare went from 14 Kg/ha to approximately 20 Kg/ha after 12% BNF application. Therefore, Salvinia auriculata biomass is an excellent source of organic compounds for formulating agricultural inputs.

Pursuing the circularity of wind turbine blades: Thermochemical recycling by pyrolysis and recovery of valuable resources

Wind turbine blades (WTBs) are the primary waste generated by the wind energy industry and represent one of the major challenges associated with renewable energy from a disposal perspective. Therefore, it is necessary to develop recycling processes to address this environmental issue as circular economy strategies are implemented. This work investigates the technical feasibility of a combined thermochemical process to recover high-quality glass fibers from WTBs while optimizing the composition of the liquid and gaseous fractions. For this purpose, a thermal pyrolysis process in the range of 450–500 °C was studied in a laboratory-scale fixed-bed reactor, followed by thermal cracking of the vapors between 300 and 700 °C. The fixed bed reactor in which the pyrolysis was performed was also used to study a secondary thermochemical process under oxidizing conditions in order to remove residual exogenous organic compounds from the recovered fibers (RFs). For the sake of comparison, a muffle furnace was also used in this second stage. The results indicate that high yields of RFs can be recovered (75.8–77.5 wt%) and, depending on the temperature used in the cracking reactor, either valuable gas (up to 12.9 wt%) or phenol-rich oils (in the range of 8.8–18.7 wt%) can be produced. In addition, carbonaceous compounds can be completely cleaned of RFs after an oxidation process in the same pyrolysis unit, providing a highly versatile process. As an additional advantage, it is observed that after oxidation the RFs are functionalized. This work aims at creating a resource-efficient circular economy, specifically for waste generated from end-of-life renewable energy technologies such as wind turbines.