Molecular Organic Compounds Research Articles

Slot Blot- and Electrospray Ionization-Mass Spectrometry/Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry-Based Novel Analysis Methods for the Identification and Quantification of Advanced Glycation End-Products in the Urine.

Proteins, saccharides, and low molecular organic compounds in the blood, urine, and saliva could potentially serve as biomarkers for diseases related to diet, lifestyle, and the use of illegal drugs. Lifestyle-related diseases (LSRDs) such as diabetes mellitus (DM), non-alcoholic steatohepatitis, cardiovascular disease, hypertension, kidney disease, and osteoporosis could develop into life-threatening conditions. Therefore, there is an urgent need to develop biomarkers for their early diagnosis. Advanced glycation end-products (AGEs) are associated with LSRDs and may induce/promote LSRDs. The presence of AGEs in body fluids could represent a biomarker of LSRDs. Urine samples could potentially be used for detecting AGEs, as urine collection is convenient and non-invasive. However, the detection and identification of AGE-modified proteins in the urine could be challenging, as their concentrations in the urine might be extremely low. To address this issue, we propose a new analytical approach. This strategy employs a method previously introduced by us, which combines slot blotting, our unique lysis buffer named Takata's lysis buffer, and a polyvinylidene difluoride membrane, in conjunction with electrospray ionization-mass spectrometry (ESI)/matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). This novel strategy could be used to detect AGE-modified proteins, AGE-modified peptides, and free-type AGEs in urine samples.

Dielectric Barrier Discharge (DBD) enhanced Fenton process for landfill leachate nanofiltration: Organic matter removal and membrane fouling alleviation

This study investigated a sustainable approach through dielectric barrier discharge (DBD) enhanced Fenton technology coupling nanofiltration (NF) process for landfill leachate treatment. The DBD/Fe(II)/H2O2 system exhibited significant synergistic effects, removing 55.07 % of TOC and 53.79 % of UV254 within 60 min, respectively. Additionally, the DBD/Fe(II)/H2O2 system demonstrated exceptional performance in removing fluorescent substances and large molecular organic compounds, thereby reducing the formation of cake layer on the nanofiltration membrane. Moreover, membrane flux increased by 2.34 times, with reversible and irreversible resistances decreasing by 75.79 % and 81.55 %, respectively. Quenching experiments revealed ·OH as the primary active species for perfluorooctanoic acid (PFOA) degradation in the DBD/Fe(II)/H2O2 process. The degradation pathway of PFOA was also elucidated via capillary electrophoresis-quadrupole time-of-flight mass spectrometry analysis. Correlation analysis indicated that TOC and EEM were the primary fouling factors. Lastly, through an assessment of energy consumption, economic costs, and carbon dioxide emissions, the advantages and practical application potential of the DBD/Fe(II)/H2O2 system were demonstrated. In summary, the DBD/Fe(II)/H2O2 system emerges as a feasible strategy for NF pretreatment, holding immense potential for treating landfill leachate.

Isolation of native microorganisms from Shengli lignite and study on their ability to dissolve lignite.

To more greenly and efficiently utilize the abundant lignite resources and explore the microbial degradation and transformation potential of lignite for its environmentally friendly and resourceful utilization, Shengli lignite from the Hulunbuir region of Inner Mongolia, China, was selected as the research subject. Through the dilution plating method and streaking method, 31 native microorganisms were successfully isolated from the Shengli lignite, including 16 bacteria and 15 fungi. After microbial coal dissolution experiments, it was found that certain microorganisms have a significant dissolving effect on lignite, with some bacterial and fungal strains showing strong dissolution capabilities. In particular, the bacterium SH10 Lysinibacillus fusiformis and the fungus L1W Paecilomyces lilacinus demonstrated the best coal-dissolving abilities, with dissolution rates both reaching 60%. The products of microbial dissolution of lignite were analyzed using gas chromatography-mass spectrometry (GC-MS) technology, identifying a variety of small molecular organic compounds, including alkanes, alcohols, esters, and phenols. The results of this study provide a new perspective on the biodegradation of lignite and lay the foundation for the development of new lignite treatment and utilization technologies.

Experimental investigation on detonation characteristics of boron-rich gelled propellant in static premixed combustible gases

A detonation in multiphase air-kerosene-boron mixtures is studied experimentally and the initiation and propagation characteristics of multiphase pulse detonation are emphasized. The boron-rich kerosene gelled propellants are taken as the fuel to analyze its detonation characteristics in static premixed combustible gases. The factors affecting detonation initiation including component, atomization, and ignition method of propellant are elucidated respectively. Considering atomization, evaporation and combustion, a small molecular organic compound is employed to fabricate metallized gelled propellants enriched with substantial boron particles. The dynamic atomization of gelled propellant with varying boron content is imaged by means of visual observation devices, and the ejecting parameters are optimized properly from actual initiation conditions. A flame jet by hot turbulent jet is applied to amplify the ignition energy of deflagration to detonation transition in boron-rich gelled propellant, which has not been seen ever. Results show that the ignition energy is positively correlated with initial pressure formed by combustible gas products. The multiphase detonation wave of boron-rich gelled propellant is successfully induced by premixed H2/O2 mixtures, and its detonation propagation characteristic is closely associated with the increase of initial pressure of premixed gas and mass mixing ratio of working medium. The pressure peak and propagation velocity of detonation wave show a considerable improvement with increasing initial pressure of premixed combustible gas and mass mixing ratio, and the highest values can reach up to 8.65 MPa and 2750 m/s respectively.

The effect of non-Saccharomyces yeasts on biogenic amines in Sauvignon Blanc wine and Gewürztraminer wine

Biogenic amine (BA) is a class of nitrogen-containing small molecular organic compounds with biological activity. Excessive BAs in wine affect flavor and quality of wine and are hazardous to human health. However, little attention has been paid to the effect of non-Saccharomyces yeasts and Saccharomyces cerevisiae mixed fermentation on BAs in white wine. The effect of mixed fermentation on BAs and amino acids in wine was investigated using two white grapes of Sauvignon Blanc and Gewürztraminer. Higher levels of total amino acids and BAs in Gewürztraminer wine compared to Sauvignon Blanc wine may be due to different grape varieties. Mixed fermentation did not influence BA profiles in Sauvignon Blanc wine, while it increased total BAs content. VL3 (VL) fermented wine has 33.7% less BAs content than EC1118 (EC) single-strain fermented wine. Similar phenomenon was found in Gewürztraminer wine produced by different fermentation combinations except that cadaverine was only detected in wine produced by Hanseniaspora uvarum participated in mixed fermentations. Principal coordinate analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA) revealed that the effects on BAs were related to grape varieties and yeast species in white wine. Ethanolamine, tryptamine, isoamylamine and histamine content in wine were related to grape varieties. Collectively, mixed fermentation increased BAs content in Sauvignon Blanc and Gewürztraminer wine. The content of BAs in wine fermented by VL single-strain fermentation was lower than that fermented by EC single-strain fermentation, which is more suitable for the winemaking of white wine.

Giant enhancement of fluorescence resonance energy transfer based on nanoporous gold with small amount of residual silver

Fluorescence resonance energy transfer (FRET) was found strongly enhanced by plasmon resonance. In this work, Nanoporous Gold with small amount of residual silver was used to form nanoporous gold/organic molecular layer compound with PSS and PAH. The ratio of its specific gold and silver content is achieved by controlling the time of its dealloying. Layered films of polyelectrolyte multilayers were assembled between the donor–acceptor pairs and NPG films to control distance. The maximum of FRET enhancement of 80-fold on the fluorescence intensity between the donor–acceptor pairs (CFP-YFP) is observed at a distance of ∼10.5 nm from the NPG film. This Nanoporous Gold with small amount of residual silver not only enhanced FRET 4-fold more than nanoporous gold of only gold content almost, but also effectively realized the regulation of FRET enhancement. The ability to precisely measure and regulate the enhancement of FRET enables the rational selection of plasmonic nanotransducer dimensions for the particular biosensing application.

Mild and Efficient Preparation of N-Heterocyclic Organic Molecules by Catalyst-free and Solvent-free Methods.

The small organic molecular compounds with biological activity containing C-C and C-N or C-O bonding were efficiently prepared without catalyst and solvent in the hydrothermal synthesis reactor. Our goal was to explore new applications for the more environmentally friendly and efficient synthesis of bis(indolyl)methyl, xanthene, quinazolinone, and N-heterocyclic derivatives in hydrothermal synthesis reactors under solvent-free and catalyst-free conditions. A greener and more efficient method was successfully developed for the synthesis of bis(indolyl)methyl, heteroanthracene, quinazolinone, and N-heterocyclic derivatives using a hydrothermal synthesis reactor in a solvent- and catalyst-free manner. In a hydrothermal synthesis reactor, bis(indoyl)methyl, xanthene, quinazolinone, and N-heterocyclic derivatives were synthesized without catalysts and solvents. Overall, it is proved once again that the catalyst-free and solvent-free synthesis method has universal value and is a more ideal and environmentally friendly new method, especially the hydrothermal reactor for synthesis.

Detection of medically relevant volatile organic compounds with graphene field-effect transistors and separated by low-frequency spectral and time signatures.

Exhaled human breath contains a mixture of gases including nitrogen, oxygen, carbon dioxide, water vapour and low molecular weight volatile organic compounds (VOCs). Different VOCs detected in human breath condensate have been recently related to several metabolic processes occurring inside body tissues in the pathological state, as candidate biomarkers for monitoring conditions such as lung injury, airway inflammation, immunity dysfunction, infection, and cancer. Current techniques for detecting these compounds include several types of mass spectroscopy, which are highly costly, time-consuming and dependent on trained personnel for sample analysis. The need for fast and label-free biosensors is paving the way towards the design of novel and portable electronic devices for point-of-care diagnosis with VOCs such as E-noses, and based on the measurement of signal signatures derived from their chemical composition. In this paper, we propose a device for VOC detection that was tested inside a controlled gas flow setup, resorting to graphene field-effect transistors (GFETs). Electrical measurements from graphene directly exposed to nitrogen plus VOC vapours involved cyclic measurements for the variation of graphene's resistance and low-frequency spectral noise in order to obtain distinctive signatures of the tested compounds in the time and frequency domains related, respectively, to Gutmann's theory for donor-acceptor chemical species and spectral sub-band analysis.

Molecular-scale investigation on the composition, sources and secondary generation of organic aerosols in polluted central China

Molecular analyses help to better understand the overall picture of characteristics, meteorological effects, sources, and secondary transformations of organic aerosols (OA). A two-year observation campaign was conducted in polluted central China during 2019–2021, and 130 compounds of molecular OA (quantified organic compounds, QOCs) were quantified. The average concentration of QOCs was 1971 ng/m3, showing the highest normalized QOCs in PM2.5 (31 ng/μg) compared to others. Among the QOCs, the polar category contributed 84%, with the dominated abundant fatty acids observed. The enhanced acid ratios of malonic/succinic and octadecanoic/oleic in summer indicated higher aerosol age, significantly promoted by temperature. Three benzenetricarboxylic acids, mostly from secondary formation, also exhibited quite high concentrations in summer. The noticeable presence of carcinogenic polycyclic aromatic hydrocarbons (PAHs) (45% of ∑28PAHs) highlighted severe health risks associated with human exposure, particularly in winter (56 ng/m3, approximately 7 times that in summer). According to the random forest model assessments, meteorological conditions in summer were most conducive to eliminating pollutants, while that in winter contributed 19% of QOC concentration. The Positive Matrix Factorization analysis revealed that anthropogenic secondary organic aerosols (ASOA) and biogenic SOA (BSOA) jointly accounted for 32% of QOCs, followed by biomass burning (20%), coal combustion (17%), vehicle emissions (16%), and cooking (15%). ASOA was positively correlated with O3 (r = 0.58) and aerosol acidity facilitated ASOA production at 40% < relative humidity <80%. On polluted days, BSOA increased as NO2 and PM2.5 increased, contributing to worsened aerosol pollution. In spring and summer, gas-phase oxidation contributed more saturated dicarboxylic acids (52 and 55%), while aqueous-phase conversion predominated in autumn and winter (59 and 66%). This study provides new information on particulate molecular organic compounds as well as the secondary transformation, which is of great significance for formulating the prevention and control measures of aerosol pollution.

Potential hazards of typical small molecular organic matters in shale gas wastewater for wheat irrigation: 2-butoxyethanol and dimethylbenzylamine

2-butoxyethanol (BE) and dimethylbenzylamine (DMBA) are small molecular organic compounds commonly found in shale gas wastewater (SGW) and environmental samples, yet their environmental risks in exposure and irrigation reuse have not been thoroughly studied. From the perspectives of physicochemical properties and toxicity, seven groups of irrigation treatment were designed for wheat irrigation according to the concentration gradient. Overall, wheat growth was normal, but higher DMBA concentrations resulted in more severe growth inhibition. The absorption of BE by various tissues of wheat was positively correlated with its concentration, while the absorption of DMBA by wheat stems showed the same trend. Interestingly, there was no significant difference in the absorption of DMBA by wheat grains in different groups. The detection results of nutritional and heavy metal elements in wheat tissues showed that the presence of organic compounds changed the relative sensitivity of wheat leaves and grains to some elements (such as Mg, Mn, Mo, etc.) enrichment. The Cd and Pb contents of wheat grains in all groups complied with national safety standards, but the As or Cr concentration in wheat grains treated with BE or DMBA exceeded the limits in some cases. Transcriptome sequencing, GO annotation, and KEGG enrichment analysis revealed similar gene functions and metabolic pathways enriched by BE and DMBA. The safe and sustainable agricultural reuse of SGW still has great potential as a promising water resources management strategy.

Diurnal source apportionment of organic and inorganic atmospheric particulate matter at a high-altitude mountain site under summer conditions (Sierra Nevada; Spain)

High-altitude mountain areas are sentinel ecosystems for global environmental changes such as anthropogenic pollution. In this study, we report a source apportionment of particulate material with an aerodynamic diameter smaller than 10 μm (PM10) in a high-altitude site in southern Europe (Sierra Nevada Station; SNS (2500 m a.s.l.)) during summer 2021. The emission sources and atmospheric secondary processes that determine the composition of aerosol particles in Sierra Nevada National Park (Spain) are identified from the concentrations of organic carbon (OC), elemental carbon (EC), 12 major inorganic compounds, 18 trace elements and 44 organic molecular tracer compounds in PM10 filter samples collected during day- and nighttime. The multivariate analysis of the joint dataset resolved five main PM10 sources: 1) Saharan dust, 2) advection from the urbanized valley, 3) local combustion, 4) smoke from a fire-event, and 5) aerosol from regional recirculation with high contribution of particles from secondary inorganic and organic aerosol formation processes. PM sources were clearly associated with synoptic meteorological conditions, and day- and nighttime circulation patterns typical of mountainous areas. Although a local pollution source was identified, the contribution of this source to PM10, OC and EC was small. Our results evidence the strong influence of middle- and long-range transport of aerosols, mainly from anthropogenic origin, on the aerosol chemical composition at this remote site.

Use of carbon-13 NMR to identify known natural products by querying a nuclear magnetic resonance database-An assessment.

The quick identification of known organic low molecular weight compounds, also known as structural dereplication, is a highly important task in the chemical profiling of natural resource extracts. To that end, a method that relies on carbon-13 nuclear magnetic resonance (NMR) spectroscopy, elaborated in earlier works of the author's research group, requires the availability of a dedicated database that establishes relationships between chemical structures, biological and chemical taxonomy, and spectroscopy. The construction of such a database, called acd_lotus, was reported earlier, and its usefulness was illustrated by only three examples. This article presents the results of structure searches carried out starting from 58 carbon-13 NMR data sets recorded on compounds selected in the metabolomics section of the biological magnetic resonance bank (BMRB). Two compound retrieval methods were employed. The first one involves searching in the acd_lotus database using commercial software. The second one operates through the freely accessible web interface of the nmrshiftdb2 database, which includes the compounds present in acd_lotus and many others. The two structural dereplication methods have proved to be efficient and can be used together in a complementary way.

Mimicking the Fungal Decay Strategy for Promoting the Bacterial Production of Polyhydroxyalkanoate from Kraft Lignin

Producing polyhydroxyalkanoate (PHA) from lignin through biological conversion has great further potential, but is held by its high heterogeneous characteristic toxicity of the depolymerized products, and low bioconversion of the depolymerized products. In this study, a Fenton-like reaction, which is inspired by fungal decay strategy, was reported to cleave Kraft lignin linkages and produce low toxic mono-aromatic and low molecular organic compounds for microbial conversion. The treatment improved the bioconversion of lignin to PHA by 141.7% compared to Kraft lignin. The bond cleavage of Kraft lignin was characterized by Py-GC/MS and 2D NMR. Seven major depolymerized products were chosen to test their toxicity effect on bacterial fermentation. Furthermore, 920.4 mg of PHA was obtained from 1-L black liquor after Fenton-like reaction treatment. This is a novel attempt mimicking fungal decay strategy coupled with the microbial conversion of lignin into high-value PHA with a sustainable future.

Characteristics of the Low Molecular Weight Metabolome of Potamogeton Natans L. (Potamogetonaceae) from Lakes of Different Trophic State (Karelian Isthmus, Northwest Russia)

The qualitative and quantitative component composition of low molecular weight volatile organic compounds (VOCs) of the essential oil of the floating-leaf pondweed (Potamogeton natans L., Potamogetonaceae family) growing in various lakes of the Karelian Isthmus (North-West of the Russian Federation) in the fruiting stage was investigated in detail for the first time by gas chromatography-mass spectrometry. The low molecular weight metabolome (LMWM) of P. natans contained 138 components, 128 of which were identified. VOCs belonging to esters, alcohols, and various functional groups dominated the LMWM of floating leaf pondweed from mesotrophic and eutrophic lakes. A significant similarity was found between the component composition of VOCs of floating leaf pondweed from mesotrophic and eutrophic lakes. Many of the substances found in the LMWM of P. natans can be attributed to biologically active compounds. This opens up prospects for the use of this plant (particularly manool and ecdysteroids from its LMWM) for various economic applications as a valuable natural raw material. Due to the characteristic of the floating leaf pondweed's substantial resistance of its LMWM to the factor of the trophic status of the lakes, it is feasible to use it as an ecological indicator of significant disruptions in aquatic environments.

Real-time detection and analysis of foodborne pathogens via machine learning based fiber-optic Raman sensor

Food safety is a critical concern worldwide, and in recent years, it has become a growing public concern in the United States due to mass production and multi-channel distribution of high-nutrient and fresh-cut foods that have increased the prevalence and diversity of foodborne pathogens (e.g., Escherichia coli, Salmonella, Listeria, etc.). Traditional methods for the detection of these pathogens rely heavily on low-efficiency techniques, which may expose the public to contaminated foods that have not been tested or identified. Therefore, rapid, simple, sensitive, and inexpensive detection methods are urgently needed for food safety investigations with higher efficiency and accuracy. One of the promising methods for the detection of foodborne pathogens is Raman spectroscopy, which is a molecular-level analytical tool with the advantages of high selectivity and sensitivity and simple operation at a relatively low cost. In this study, a novel fiber-optic-based portable Raman probe was developed and used for real-time detection of a panel of pathogen-specific molecular fingerprint volatile organic compounds (VOCs). Furthermore, machine learning (ML) algorithms were applied to assist in the extraction of molecular information from the raw Raman spectra, resulting in high accuracy prediction of complex VOC mixtures, even at high dilution folds (100x). The developed ML-assisted Raman probe has immense potential for rapid on-site detection of complex chemical mixtures in food safety and beyond. This innovative approach achieves high accuracy in comprehensively sorting mixed chemicals with varying concentrations and provides several advantages over previous studies, including speed, portability, non-contact operation, and precise classification of foodborne pathogen VOCs.

Machine-Learning-Based Prediction of the Glass Transition Temperature of Organic Compounds Using Experimental Data.

Knowledge of the glass transition temperature of molecular compounds that occur in atmospheric aerosol particles is important for estimating their viscosity, as it directly influences the kinetics of chemical reactions and particle phase state. While there is a great diversity of organic compounds present in aerosol particles, for only a minor fraction of them experimental glass transition temperatures are known. Therefore, we have developed a machine learning model designed to predict the glass transition temperature of organic molecular compounds based on molecule-derived input variables. The extremely randomized trees (extra trees) procedure was chosen for this purpose. Two approaches using different sets of input variables were followed. The first one uses the number of selected functional groups present in the compound, while the second one generates descriptors from a SMILES (Simplified Molecular Input Line Entry System) string. Organic compounds containing carbon, hydrogen, oxygen, nitrogen, and halogen atoms are included. For improved results, both approaches can be combined with the melting temperature of the compound as an additional input variable. The results show that the predictions of both approaches show a similar mean absolute error of about 12-13 K, with the SMILES-based predictions performing slightly better. In general, the model shows good predictive power considering the diversity of the experimental input data. Furthermore, we also show that its performance exceeds that of previous parameterizations developed for this purpose and also performs better than existing machine learning models. In order to provide user-friendly versions of the model for applications, we have developed a web site where the model can be run by interested scientists via a web-based interface without prior technical knowledge. We also provide Python code of the model. Additionally, all experimental input data are provided in form of the Bielefeld Molecular Organic Glasses (BIMOG) database. We believe that this model is a powerful tool for many applications in atmospheric aerosol science and material science.

Efficient Mott insulator-metal transition by an intense terahertz electric field pulse via quantum tunneling

When a semiconductor is subjected to a strong electric field, carriers are generated via quantum tunneling; this is termed as dielectric breakdown. Thus, using a terahertz pulse to drive the dielectric breakdown in Mott insulators, which exhibit variations in their electronic structures under carrier doping, a filling-controlled transition can be induced in the subpicosecond time scale. However, to generate carriers via quantum tunneling in a material with a band gap in the visible or near-infrared regions, an electric field pulse significantly exceeding $1 \mathrm{MV} {\mathrm{cm}}^{\ensuremath{-}1}$ is necessary. In this paper, using an organic molecular compound, bis(ethylenedithio)tetrathiafulvalene-difluorotetracyanoquinodimethane, which is a typical one-dimensional (1D) Mott insulator with a Mott gap of 0.7 eV, we aimed at realizing carrier generation and metallization via a strong electric field component of a terahertz pulse enhanced with an organic nonlinear optical crystal up to $2.8 \mathrm{MV} {\mathrm{cm}}^{\ensuremath{-}1}$. Even after the terahertz electric field decays, the reflectivity change caused by the terahertz pulse remains; this is different from the case involving the use of weaker electric fields. More importantly, this response indicates a threshold behavior against the electric field amplitude, which is characteristic of carrier generation via the quantum tunneling process. Furthermore, transient reflectivity spectra across the mid-infrared region could be reproduced well by numerical simulations using the Drude model, in which inhomogeneous carrier distributions are considered. The observed Drude response of the doublons and holons was ascribed to the spin-charge separation characteristic of 1D strongly correlated electron systems. We also demonstrate that the energy efficiency of such carrier generation by the terahertz pulse excitation is at least five times greater than that when using photoexcitation beyond the Mott gap. This indicates that excitation with the strong terahertz pulse is more effective for carrier doping in solids; thus, the proposed method is expected to be widely applicable for the electronic-state control of various correlated electron materials in which chemical carrier doping is currently difficult.

Agglutination Reactions of Artemisinin-Type Drugs and Other Substances

Artemisinin is a good antimalarial drug independently developed in China. It is highly effective and low toxic. In the process of studying the antimalarial mechanism of artemisinin drugs, we found that there was agglutination when the drugs came into contact with blood. Methods: ABO positive typing test card was used to detect the agglutination reaction of artemisinin and dihydroartemisinic with whole blood, red blood cells, hemolytic solution, hemin chloride, ferrous sulfate, ferric chloride, sodium chloride, DMSO and artemether. Results: artemisinin can agglutinate with many substances, such as red blood cells, red blood cell hemolytic solution, hemin chloride, ferrous sulfate, ferric chloride, sodium chloride and so on. The agglutination reaction in this paper is not related to antigen and antibody, but the result of the interaction between artemisinin drugs and various substances. Whole blood, red blood cells and hemolytic fluid contain biological macromolecular components. Hemin belongs to low molecular organic compounds, and the rest are simple inorganic compounds. Artemisinin drugs can interact with such a wide range of substances and agglutinate, indicating their strong effect. The mechanism is not clear. It is speculated that it is related to the “oxygen bridge” in artemisinin molecule, but the details of the action and how to agglutinate need to be studied. Interestingly, when artemether interacts with artemisinin and dihydroartemisinin, there is no agglutination, but there is a tendency of agglutination in the control, which is contrary to other results. This is a phenomenon, indicating that there is interaction, and its mechanism and significance need to be further studied. Artemisinin can interact with many substances.

Removal of organic micropollutants from municipal wastewater by powdered activated carbon - activated sludge treatment

In Powdered Activated Carbon (PAC)-Activated Sludge (AS) Treatment, PAC is directly dosed into the AS tank. In this study, batch and pilot plant experiments were carried out to investigate the efficacy of PAC-AS treatment concerning the removal of organic micropollutants (OMPs). Batch and pilot plant experiments showed comparable removal efficiency of nine OMPs: a mean removal of 80 % could be achieved at a specific PAC dose of 2.5 mg PAC/mg DOC; during a PAC cut-off experiment, the removal performance leveled off in the first 6 h without PAC dosage. A further investigation involving an intermittent dosage of PAC demonstrated that OMPs were removed stably when PAC was dosed every 6 h, which implies the possibility of reduced investment and maintenance costs of a dosing unit.DOC was removed by 18 ± 4 % when the PAC doses ranged from 1.9 to 2.3 mg PAC/mg DOC in this study. A more detailed characterization of the organic matter was performed by means of size exclusion chromatography coupled with organic carbon detection (SEC-OCD). The high molecular weight fraction (F1) and hydrophobic organic compounds (DOCh) were most adsorbed by PAC, revealed by batch and pilot plant experiments. It indicates a higher competition potential of these two fractions against OMP adsorption compared to other DOC fractions in the PAC-AS system.

Clindamycin removal from aqueous solution by non-thermal air plasma treatment: performance, degradation pathway and ensuing antimicrobial activity.

The present study set out to investigate clindamycin (CLN) removal from aqueous solution using non-thermal plasma (NTP) under atmospheric air conditions and to address the effects of some variables including pH, initial concentration of CLN, and working voltage on CLN degradation. The result showed that the NTP system exhibited excellent degradation rate and mineralization efficiency on CLN in 15 min under neutral conditions, which exceeded 90 and 45%, respectively, demonstrating its conversion to other organic by-products. Furthermore, CLN degradation was largely dependent upon the initial pH of solution, applied voltage, and reaction time. Specifically, under acidic conditions (pH = 3), working voltage of 24 kV and after 15 min of reaction, almost 100% of CLN was degraded. NTP-initiated CLN degradation products through LC-MS/MS analysis, determined within 10 min of reaction, inferred that the complex structure of CLN has undergone deterioration by active radical species which subsequently generated small molecular organic compounds. Chemical processes involved in CLN degradation were found to be demethylation, desulfonylation, dechlorination, hydroxylation and deamination. Lastly, antimicrobial susceptibility tests revealed that the activity of CLN was reduced following NTP treatment, which is also in good agreement with the minimum inhibitory concentration (MIC) values obtained from microdilution analyses.