Water-soluble Organic Compounds Research Articles

Construction of PTFE/PI-PI/PANI-PA composite nanofibrous membrane for efficient photothermal membrane distillation and VOCs interception

Water-soluble volatile organic compounds (VOCs) are one of the difficult substances in seawater and industrial wastewater treatment. Photothermal membrane distillation (PMD) technology has great advantages in solving the problems of low energy conversion efficiency and serious pollution of traditional membrane distillation (MD) technology, but it still faces the challenge that VOCs cannot be effectively removed.To solve this problem, we prepared photothermal Polytetrafluoroethylene/Polyimide-Polyimide/Polyaniline-Polyamide (PTFE/PI-PI/PANI-PA) composite membranes with VOCs interception. The composite membrane was fabricated by applying the previously studied PTFE/PI-PI/PANI/PANI membrane by interfacially polymerising an ultrathin PA layer with controllable pore sizes. Among them, the PTFE/PI-PI/PANI base membrane in the composite membrane not only provides strong support and durability as a backbone structure, but the PANI photothermal layer also provides photothermal conversion for effective PMD operation. In addition, the ultra-thin PA layer acts as a molecular sieve separator to effectively intercept VOCs in the feed solution. When the feed solution was 35 g⋅L−1 NaCl, the average permeate flux of the #M-PA-0.1 membrane was 1.44 ± 0.02 L⋅m−2⋅h−1 with a salt interception rate of 99.99 % or more after 80 h of PMD testing. Meanwhile, when 50 mg⋅L−1 of VOCs was added to the feed solution, the VOCs retention rate >99.35 %, and the concentration of VOCs on the permeate side was much lower than the corresponding concentration in the drinking water standards recommended by the World Health Organisation (WHO) and the US Environmental Protection Agency (EPA). This study effectively combines the molecular sieve effect with the solar-powered evaporation process, which provides a research basis for the preparation of high-performance PMD membranes that can effectively remove volatile organic compounds.

Single crystal structure features, optimization of ultrasonic conditions, density functional theory studies, and antibacterial activity of a new organic compound

The synthesis of a novel water-soluble organic compound, N’-acetyl-4-nitrobenzohydrazide, was successfully achieved using hydrothermal and sonochemical methods. The resulting products, denoted as 1 and 2, were obtained as single crystals and powder, respectively. Characterization of the crystals through single-crystal X-ray diffraction (SC-XRD) indicated a monoclinic system with space group -P 2yn. Elemental analysis (CHN), energy-dispersive X-ray spectrometer (EDS), Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TGA/DTA), and powder X-ray diffraction pattern (PXRD), were utilized to analyze the molecular structure of 1 and 2, confirming their identical nature. Furthermore, scanning electron microscopy (SEM) was employed to examine the surface morphology of compounds 1 and 2, revealing distinct morphological features and varying particle dimensions. The impact of time, temperature, and ultrasonic energy was examined to optimize the morphology and particle size of compound 2. A density functional theory (DFT) study was performed to find the role of intramolecular hydrogen bond (IHB) interactions on the capability of the different tautomers of newly synthesized organic compounds. Various properties such as total energies of tautomers, energies of the most important molecular orbitals, electronegativity, thermodynamic functions, molecular electrostatic potential (MEP) maps, electron charge densities, and aromaticity were computed. The antimicrobial activity of 1, and 2 have been evaluated against one Gram-positive (Staphylococcus aureus, ATCC 25923) and one Gram-negative (Escherichia coli, ATCC 25922) using the disc diffusion method. The analysis of the inhibition zones revealed that 2 exhibit enhanced antibacterial efficacy compared to 1. This observation suggests that particle size reduction may contribute to increased antibacterial activity, potentially due to enhanced interaction with bacterial targets.

The interplay of Brown carbon (BrC) surrogates and copper: Implications for the oxidative potential of ambient particles

Atmospheric particulate matter (PM) poses adverse effects on human via producing reactive oxygen species (ROS). Oxidative potential (OP, ability to generate ROS) can be induced by various chemicals in PM, while their interplay remains poorly characterized. Here, we systematically assessed influences of Cu2+ on OP of Brown carbon (BrC) (e.g., imidazoles) using dithiothreitol (DTT) assay. Results showed DTT consumption rate exhibited an initial rise and later decline (0.25 −0.56 µM/min) along with increase of BrC concentration (0.1 − 2 µM), while no general trend was observed for •OH formation. Although Cu2+ showed either antagonism or synergism with BrC against DTT consumption, Cu2+ displayed antagonism with most BrC against •OH generation. Fluorescence quenching experiments provided evidence of complexation between Cu2+ and water-soluble organic compounds (WSOCs, from ambient PM2.5), which was influenced by Cu2+ concentration. Further parallel factor analysis of spectra showed that polycarboxylate-type humic acid-like substances (complexation site number (n): 0.46, complexation equilibrium constant (k): 0.51) and fulvic acid-like compounds (n: 0.42, k: 0.62) were the main components in WSOCs that complexed with Cu2+. Our results suggest the interactions of BrC and copper play a crucial role in PM OP and highlight complexation in evaluation of PM OP.

Epicatechin ameliorates palmitate-induced insulin resistance in C2C12 myogenic cells by alleviating oxidative stress and activating the AMPK/ACC pathway

ABSTRACT Epicatechin (EC) is a water-soluble natural organic compound belonging to the flavanol class of compounds. It exhibits various physiological activities such as anti-inflammatory, antioxidant, treatment of mitochondrial diseases, and prevention of cardiovascular diseases.To examineEC’s impact and mechanism on adult myoblasts’ insulin resistance. The effects of various EC concentrations on the viability of C2C12 adult myoblasts were measured, as were glucose consumption and glycogen content; in vitro antioxidant activity of EC was measured; cellular oxidative marker content and apoptosis were measured; and protein expression was detected by Western blot. A model of insulin resistance in C2C12 myogenic cells was established using palmitic acid. EC significantly increased the glucose consumption and glycogen content; EC increased the levels of CAT, SOD and GSH and decreased the levels of NO, MDA and ROS; EC decreased the apoptosis rate of cells; EC treatment upregulated the levels of GLUT4, p-AMPK, p-ACC, NRF2, and HO-1 proteins. These results suggest that EC can regulate the NRF2/HO-1 signaling pathway, enhance GLUT4 transport, activate AMPK/ACC pathway, enhance cellular uptake of glucose, thus effectively improving insulin resistance in C2C12 cells.

Water-soluble organic compounds (WSOC) from atmospheric aerosols in Bou-Ismail (Algeria).

In this contribution, we report the study of nuclear resonance magnetic spectroscopy techniques (1H-NMR, 13C-NMR, and 2D-NMR) efficiency in the characterisation of the functional composition of water-soluble organic compounds (WSOC) from atmospheric aerosols. The chosen site was our scientific and technical center of research (CRAPC) situated in Algerian Bou-Ismail city. where the concentrations of PM10 were found to be between 15.66 and 142.19µg.m-3. As results, 1H-NMR analysis showed the coexistence of biological material and emissions from urban and biomass burning. The dominant source was identified by quantitative integration of each 1H NMR spectral region. By using the HSQC technique, many peaks are revealed in biogenic samples including biomass burning. On the other hand, the identification of the source of various organic compounds and their functional composition is possible through specific NMR spectra, which can also be used to adjust the surrounding organic aerosol sources.

Anthropogenic sources and liquid water drive secondary organic aerosol formation over the eastern Himalaya

Atmospheric aerosols have a serious impact on altering the radiation balance of the vulnerable Himalayan atmosphere. Organic aerosol (OA), one of the least resolved aerosol fractions in the Himalayas, constrain our competence to assess their climate impacts on the region. Here we investigate water-soluble OA molecules in PM10 samples collected from March to May 2019 at Lachung (27.4°N and 88.4°E), a high-altitude location (2700 m a.s.l.) in the eastern Himalaya, to elucidate their origin and formation process. The dominance of oxalic acid (C2) reveals that water-soluble OA in the eastern Himalaya are atmospherically processed. Backward air mass trajectories and mass concentration ratios of organic tracers as well as relationships with inorganic species (K+, SO42−, NH4+) suggest an anthropogenic origin of water-soluble OA with significant atmospheric processing during long-range transport to the eastern Himalayan region. We used the thermodynamic prediction of aerosol liquid water (ALW) to examine the formation mechanism of secondary OA (SOA) such as oxalic acid. Correlations of ALW with SO42− and water-soluble organic matter show that ALW is sensitive to both anthropogenic sulfate and water-soluble organic compounds in Himalayan aerosols. A strong positive relationship of C2 acid with predicted ALW provides evidence of extensive SOA formation from precursors via aqueous phase photochemical processes. This inference is supported by positive correlations of C2 acid relative abundance with diagnostic mass concentration ratios of C2 acid to precursor molecules. Our findings underscore the importance of anthropogenic sources and ALW in SOA formation through aqueous phase processes in the eastern Himalaya.

Enhancing Molecular Characterization of Dissolved Organic Matter by Integrative Direct Infusion and Liquid Chromatography Nontargeted Workflows.

Dissolved organic matter (DOM) in aquatic systems is a highly heterogeneous mixture of water-soluble organic compounds, acting as a major carbon reservoir driving biogeochemical cycles. Understanding DOM molecular composition is thus of vital interest for the health assessment of aquatic ecosystems, yet its characterization poses challenges due to its complex and dynamic chemical profile. Here, we performed a comprehensive chemical analysis of DOM from highly urbanized river and seawater sources and compared it to drinking water. Extensive analyses by nontargeted direct infusion (DI) and liquid chromatography (LC) high-resolution mass spectrometry (HRMS) through Orbitrap were integrated with novel computational workflows to allow molecular- and structural-level characterization of DOM. Across all water samples, over 7000 molecular formulas were calculated using both methods (∼4200 in DI and ∼3600 in LC). While the DI approach was limited to molecular formula calculation, the downstream data processing of MS2 spectral information combining library matching and in silico predictions enabled a comprehensive structural-level characterization of 16% of the molecular space detected by LC-HRMS across all water samples. Both analytical methods proved complementary, covering a broad chemical space that includes more highly polar compounds with DI and more less polar ones with LC. The innovative integration of diverse analytical techniques and computational workflow introduces a robust and largely available framework in the field, providing a widely applicable approach that significantly contributes to understanding the complex molecular composition of DOM.

Ferrocene Bis(Sulfonate) Salt as Redoxmer for Fast and Steady Redox Flow Desalination.

Desalination is considered a promising solution to alleviate water shortages, yet current methods are often restricted, due to challenges like high energy consumption, significant cost, or limited desalination capacity. In this study, we present a novel approach of redox flow desalination (RFD) utilizing the highly aqueous-soluble and reversible redox-active compound, potassium 1,1'-bis(sulfonate) ferrocene (1,1'-FcDS). This water-soluble organic compound yielded stable and rapid desalination, sustaining extended operation without notable decay and achieving an impressive desalination rate of up to 457.5 mmol·h-1·m-2 and energy consumption as low as 40.2 kJ·molNaCl-1. Specifically, the RFD device effectively desalinated a 50 mM NaCl solution to potable standards within 6000 s using 1,1'-FcDS. It maintained an average energy consumption of 178.16 kJ·molNaCl-1 and exhibited negligible deterioration in desalination rate, energy efficiency, and charge efficiency throughout a rigorous 12,000 s cycling test. Furthermore, the versatility of this method was demonstrated by effectively treating saline water with varying initial concentrations from 10 mM to 50 mM, showcasing its potential across a broad spectrum of applications.

Chemical characterization of atmospheric aerosols at a high-altitude mountain site: a study of source apportionment

Abstract. The study of aerosols in high mountain regions is essential because particulate matter can play a role in altering the energy balance of high mountain regions, and aerosols can accelerate glacier melting in high mountain areas by darkening the ice surface, reducing its reflectivity (albedo). Studying aerosols in high mountain areas provides insights into long-range transport of pollutants, atmospheric dynamics, and climate change impacts. These regions can serve as valuable observatories for studying atmospheric processes. The main aim of this paper is to define the main sources of aerosols over an entire year of sampling at the Col Margherita Atmospheric Observatory (MRG; 46°22′0.059′′ N, 11°47′30.911′′ E; 2543 m a.s.l.), a high-altitude background site in the eastern Italian Alps. Here, we discuss the potential origins of more than 100 chemical markers (major ions, water-soluble organic compounds, trace elements, and rare earth elements) using different approaches. Some diagnostic ratios were applied, but source apportionment using positive matrix factorization (PMF) was used to define the main inputs of PM10 collected at this high-altitude site, resulting in the identification of four factors: (1) Saharan dust events, (2) long-range marine/anthropogenic influence, (3) biogenic sources, and (4) biomass-burning and anthropogenic emissions. It can be inferred that, despite the distant location of the Col Margherita site, both regional pollution and long-range anthropogenic pollution have discernible effects on this area.

Study on the Influence of UV Light on Selective Antibacterial Activity of Silver Nanoparticle Synthesized Utilizing Protein/Polypeptide-Rich Aqueous Extract from The Common Walkingstick, Diapheromera femorata.

Common walkingstick (Diapheromera femorata) aqueous extract (CWSAE) can induce the synthesis of useful bionanomaterials. CWSAE is rich in water-soluble organic compounds such as proteins and polypeptides that function as reducing/stabilizing agents for nanoparticle formation from Ag+ ion precursors. The synthesized AgNPs exhibited a moderately uniform size, with the majority falling within the range of 20-80 nm. These AgNPs were UV-treated and tested as antibacterial agents to inhibit the growth of four pathogenic bacteria (Burkholderia cenocepacia K-56, Klebsiella pneumoniae ST258, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus USA300), as well as one common bacterium (Escherichia coli BW25113). The disk diffusion test demonstrated that the UV-treated AgNPs significantly and selectively inhibited the growth of Staphylococcus aureus USA300 and P. aeruginosa, while showing a small effect on the other two species. This suggests the potential application of green-chemically synthesized AgNPs as selective antibacterial agents. Furthermore, we studied the effects of short-term (1-2 min) and long-term (5-30 min) UV treatment on the selective cytotoxicity of the AgNPs and found that the cytotoxicity of the AgNPs could depend on the duration of UV exposure against certain bacteria.

Positive matrix factorization of seasonally resolved organic aerosol at three different central European background sites based on nuclear magnetic resonance Aerosolomics data

Concentration data derived from 1H NMR analysis of the water-soluble organic compounds from fine aerosol (PM2.5) at three Central European background stations, Košetice, Frýdlant (both in the Czech Republic), and Melpitz (Germany), were used for detailed source apportionment analysis. Two winter and two summer episodes (year 2021) with higher organic concentrations and similar wind directions were selected for NMR analyses. The concentration profiles of 61 water-soluble organic compounds were determined by NMR Aerosolomics and a principal component analysis (PCA) was performed on this dataset. Based on the PCA results, 23 compounds were selected for positive matrix factorization (PMF) analysis in order to identify dominant aerosol sources at rural background sites in Central Europe. Both the PCA and the subsequent PMF analyses clearly distinguished the characteristics of winter and summer aerosol particles.In summer, four factors were identified from PMF and were associated with biogenic aerosol (61–78 %), background aerosol (9–15 %), industrial biomass combustion (7–13 %), and residential heating (5–13 %). In winter, only 3 factors were identified - industrial biomass combustion (33–49 %), residential heating (37–45 %) and a background aerosol (8–30 %). The main difference was observed in the winter season with a stronger contribution of emissions from industrial biomass burning at the Czech stations Košetice and Frýdlant (47–49 %) compared to the Melpitz station (33 %). However, in general, there were negligible differences in identified sources between stations in the given seasons, indicating a certain homogeneity in PM2.5 composition within Central Europe at least during the sampling periods.

Research progress on the characteristics, sources, and environmental and potential health effects of water-soluble organic compounds in atmospheric particulate matter.

Water-soluble organic compounds (WSOCs) have received extensive attention due to their indistinct chemical components, complex sources, negative environmental impact, and potential health effects. To the best of our knowledge, until now, there has been no comprehensive review focused on the research progress of WSOCs. This paper reviewed the studies on chemical constituent and characterization, distribution condition, sources, environmental impact, as well as the potential health effects of WSOCs in the past 13 years. Moreover, the main existing challenges and directions for the future research on WSOCs were discussed from several aspects. Because of the complex composition of WSOCs and many unknown individual components that have not been detected, there is still a need for the identification and quantification of WSOCs. As modern people spend more time in indoor environments, it is meaningful to fill the gaps in the component characteristics and sources of indoor WSOCs. In addition, although in vitro cell experiments have shown that WSOCs could induce cellular oxidative stress and trigger the inflammatory response, the corresponding mechanisms of action need to be further explored. The current population epidemiology research of WSOCs is missing. Prospectively, we propose to conduct a comprehensive and simultaneous analysis strategy for concentration screening, source apportionment, potential health effects, and action mechanisms of WSOCs based on high throughput omics coupled with machine learning simulation and prediction.

Characteristics of polar organic compounds from diesel truck emissions measured by FT-ICR MS

Water-soluble organic compounds (WSOC) and dichloromethane: methanol-soluble organic compounds (DMSOC) in polar organic compounds (POCs) present in emissions from a diesel truck were characterized by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The main compositions and molecular structures of WSOC and DMSOC were investigated and classified into three groups based on their elemental compositions: CHO, CHON, and S-containing compounds (CHONS and CHOS) (namely WSOCCHO; WSOCCHON; WSOCOS; DMSOCCHO; DMSOCCHON and DMSOCOS). The main results are as follows. (1) The order of groups in WSOC and DMSOC in terms of peak response was CHO (WSOC: 52.2% and DMSOC: 64.5%), CHON (WSOC: 43.4% and DMSOC:25.9%), and S-containing compounds (WSOC: 4.35% and DMSOC: 9.57%). (2) The relative response of compounds with low H/C and O/C ratios and double-bond equivalents (DBE) > 10 in WSOCCHO was twice that of DMSOCCHO, indicating that the WSOC emitted by diesel trucks might contain many highly condensed benzene rings. Compounds with H/C = 2 and DBE = 1 in DMSOCCHO showed a strong relative response, presumably due to a fatty-acid structure, which might be used as a tracer to distinguish emissions from diesel trucks and other pollution sources. (3) The strongest relative response in WSOCCHON was for C11H7O5N2 with an aromaticity equivalent (Xc) = 2.5 and DBE = 9, suggesting that dinitrophenol or methyl nitrophenol might be present. Moreover, C39H76O8N1 with Xc = 0 and DBE = 2 was dominant in DMSOCCHON, suggesting the presence of carboxylic acids. (4) In both WSOC and DMSOC, long-chain aliphatic and organic sulfate compounds accounted for the largest proportion of S-containing compounds. However, the contents of condensed hydrocarbons and aromatic rings in DMSOCOS were higher than those in WSOCOS, which suggests that DMSOCOS has a strong optical absorption ability. Thus, this study effectively determined the POC compounds of diesel truck emissions and their possible structures, providing data for assessing the environmental effects of using diesel trucks.

Airborne desert dust in the Northern Adriatic area (Croatia): Different sources

During the implementation of the INTERREG IT-HR project ECOMOBILITY, whose one of the goals was to estimate the impact of ship emissions on air quality in the port city of Rijeka (Croatia) and Venice (Italy), two particular weekly samples were collected in Rijeka, during the first and the thirteen weeks of sampling, i.e. S01 (16.10.-23.10.2018) and S13 (24.04.-30.04.2019.), respectively. Both samples have similarities regarding species characteristic for desert dust contribution, but HYSPLIT analyses excluded Saharan desert to be the source of the S01 sample. Unlike Saharan dust, this sample had a high contribution of fine and ultrafine particles (>50 % and 9.8 %, respectively), as well as secondary inorganic (sulfates, ammonium) and organic (water soluble organic compounds - WSOC) aerosols. Detailed synoptic situation and HYSPLIT backward trajectories pointed out the Syrian Desert as the source of this collected sample. The same source was proved by MERRA-2 reanalysis of the desert dust emission. Although the Saharan dust episodes, mostly in precipitation, are well known in the Northern Adriatic area, this is the first time to indicate Syrian Desert as a source of airborne particulates. This assumption was confirmed with chemical species characteristic for the Syrian Desert, i.e. higher content of potassium from K- feldspar and phosphates.

Role of WSOCs and pH on Ammonium Nitrate Aerosol Efflorescence: Insights into Secondary Aerosol Formation.

Efflorescence of ammonium nitrate (AN) aerosols significantly impacts atmospheric secondary aerosol formation, climate, and human health. We investigated the effect of representative water-soluble organic compounds (WSOCs) (sucralose (SUC), glycerol (GLY), and citric acid (CA) on AN:WSOC aerosol efflorescence using vacuum Fourier transform infrared spectroscopy. Combining efflorescence relative humidity (ERH) measurements, heterogeneous nucleation rates, and model predictions, we found that aerosol viscosity, correlating with molecular diffusion, effectively predicted ERH variations among the AN:WSOC aerosols. WSOCs with higher viscosity (SUC and CA) hindered efflorescence, while GLY with a lower viscosity showed a minor effect. At a low AN:CA molar ratio (10:1), CA promoted ERH, likely due to CA crystallization. Increasing the droplet pH inhibited AN:CA aerosol efflorescence. In contrast, for AN:SUC and AN:GLY aerosols, efflorescence is pH-insensitive. With the addition of trivial sulfate, AN:SUC droplets exhibited two-stage efflorescence, coinciding with ammonium sulfate and AN efflorescence. Given the atmospheric abundance, the morphology, phase, and mixing state of nitrate aerosols are significant for atmospheric chemistry and physics. Our results suggest that AN:WSOCs aerosols can exist in the amorphous phase in the atmosphere, with efflorescence behavior depending on the aerosol composition, viscosity, pH, and the cation and anion interactions in a complex manner.

Cubic-shaped corylus colurna extract coated Cu2O nanoparticles-based smartphone biosensor for the detection of ascorbic acid in real food samples.

Ascorbic acid (AA) is a highly water-soluble organic chemical compound and plays a significant role in human metabolism. For the purpose of food quality monitoring, this study focuses on the development of a smartphone-integrated colorimetric and non-enzymatic electrochemical Corylus Colurna (CC) extract-Cu2O nanoparticles (Cu2O NPs) biosensor to detect AA in real food samples. The characterization of the CC-Cu2O NPs was determined using SEM, SEM/EDX, HRTEM, XRD, FTIR, XPS, TGA, and DSC. The CC-Cu2O NPs are cubic in shape with an approximate size of 10nm. According to electrochemical results, the oxidation of AA at the modified electrode exhibited a LOD of 27.92 nmolL-1 in a wide concentration range of 0.55-22 mmolL-1. The fabricated digital CC-Cu2O NPs sensor successfully detected AA in food samples. This strategy provides a nanoplatform to determine the detection of AA in food samples.

Water-soluble organic matter with various polarities in PM2.5 over Xi'an, China: Abundance, functional groups, and light absorption

Humic-like substances (HULIS) are a major component of brown carbon and consequently play a major role in climate change. In this study, 70 PM2.5 samples were collected from Xi'an in winter 2019 and summer 2020. Neutral HULIS (HULIS-n), acidic HULIS (HULIS-a), and high-polarity water-soluble organic compounds (HP–WSOC) were analyzed to determine their carbon concentrations and measure their ultraviolet–visible absorption and infrared spectra. Of the three components, HULIS-n had the highest carbon content in both winter (3.29 ± 1.45 μg m−3) and in summer (1.38 ± 1.10 μg m−3). The semiquantitative results for the functional groups revealed that HP-WSOC was rich in carboxylic acids and had high aromaticity in winter, whereas HULIS-n was rich in carboxylic acids in summer. Moreover, HULIS-a was richer in nitrate esters and saturated aliphatic hydrocarbons in summer than in winter. The results for specific ultraviolet absorbance (SUVA) and E250/E365 revealed that HULIS had higher molecular weight and aromaticity in winter than in summer. HULIS-n dominated in the total light absorption of HULIS + HP-WSOC in both winter (73.08%) and summer (48.57%). Overall, the results on the carbon content, optical properties, and functional groups of WSOCs with differing polarity can improve understanding of environmental and climatic effects.

Wet air oxidation of HTL aqueous waste

Hydrothermal Liquefaction (HTL) provides a pathway to reducing wet waste volumes and producing biofuels such as SAF or sustainable diesel. However, 20–30% of the carbon in wet-waste feed is converted to low molecular weight, water-soluble organic compounds resulting in an aqueous product requiring treatment before disposal. Extraction of fuels or chemicals from the aqueous product is an appealing but challenging route due to the low concentrations and the wide variety of the organic compounds. Herein, we report on wet air oxidation treatment of the HTL aqueous stream to reduce its complexity and increase the concentration of acetic acid in the aqueous product stream.Catalyst screening was carried out at small scale followed by batch reactor studies of selected catalysts. Oxidized products were analyzed to determine the impact of wet air oxidation on chemical oxygen demand (COD), nitrogen content, oxygen consumption and intermediate by-product formation. Batch reactor studies found that metal catalysts including WO3 and ZrO2 increased the concentration of acetic acid in the product stream by at least 10–20% compared to non-catalytic wet air oxidation. Under increasingly intense reaction conditions, COD was further reduced and acetic acid concentration increased. For example, using WO3 at 225 °C increased the concentration of acetic acid in the product stream by 72%, along with significant increases in formic acid. A continuous flow trickle bed reactor with a CeZr catalyst at temperatures ≥200 °C reduced the COD of the aqueous stream by 50% and increased acetic acid concentration by 40% (200 h run).

New insights in the treatment of real oilfield produced water: Feasibility of adsorption process with coconut husk activated charcoal

Naphthenic acids are water-soluble organic compounds (WSO), present in oilfield produced water (OPW), whose removal aims to comply with environmental legislation and ensure the correct disposal of OPW. In this study, the performance of the adsorptive process for the removal of WSO in synthetic (single- and multi-component) and real OPW was evaluated. It was observed that the lower the pH of the sample, the greater the adsorption capacity of WSO. Moreover, the kinetic parameters of adsorption followed the pseudo-second order model while the equilibrium parameters were represented by the isothermal BET (Brunauer, Emmett and Teller) model. In the desorption process followed the second-order model, and the aqueous solution of sodium hydroxide (0.3 and 0.1 M) showed the highest desorption efficiency (~70 %) in the synthetic and real systems, respectively. With this protocol, the adsorbent proved to be effective for the treatment of OPW, without significant loss of efficiency, for up to three consecutive cycles of adsorption-desorption. In addition, after treatment, the real effluent was classified within the legal parameters for offshore disposal, which enhances its industrial application.

The Effect of Various Forms of Sulfur on Soil Organic Matter Fractions and Microorganisms in a Pot Experiment with Perennial Ryegrass (Lolium perenne L.).

This article focuses on the agronomic evaluation of the supplementation of mineral NPKMg fertilizers with elemental sulfur, magnesium, potassium, or ammonium sulfates in pot experiments with ryegrass growing in a sandy Arenosol with very low sulfur content. A benefit evaluation was carried out on the basis of biomass production, crop nutritional status, and changes in the content of soil organic matter fractions. Furthermore, the total number of bacteria, nitrogen-fixing bacteria, and fungi was estimated using the qPCR technique in soil samples after 60 days of ryegrass growth. The combined application of NPKMg and sulfur or sulfate fertilizers significantly increased the summary yield of three cuttings of fresh ryegrass biomass in the range of 32.3% to 82.7%. The application, especially in the form of sulfates, significantly decreased the content of free phenolic acids. Furthermore, compared to the control, i.e., soil with NPKMg applied alone, an increase in the content of glomalin-related proteins and a decrease in the amount of water-soluble organic carbon compounds were observed. Neither the number of DNA marker copy numbers of the total bacterial community nor the nitrogen-fixing bacteria were noticeably different. In turn, the total number of genetic markers for fungi was significantly higher in soils with potassium or ammonium sulfates compared to the control soil. The general results suggest that the application of sulfur fertilizers with NPKMg mineral fertilizer can benefit crops and support soil fertility due to the stabilization of aggregates and the decrease in water-soluble organic compounds.