scholarly journals Inorganic salts interact with oxalic acid in submicron particles to form material with low hygroscopicity and volatility

2014 ◽  
Vol 14 (10) ◽  
pp. 5205-5215 ◽  
Author(s):  
G. Drozd ◽  
J. Woo ◽  
S. A. K. Häkkinen ◽  
A. Nenes ◽  
V. F. McNeill
Keyword(s):  
Oxalic Acid ◽  
Current Knowledge ◽  
Cloud Condensation Nuclei ◽  
Inorganic Ions ◽  
Submicron Particles ◽  
Organic Salt ◽  
Formation Mechanisms ◽  
Particle Volume ◽  
Organic Salts ◽  
Organic Complexes

Abstract. Volatility and hygroscopicity are two key properties of organic aerosol components, and both are strongly related to chemical identity. While the hygroscopicities of pure salts, di-carboxylic acids (DCA), and DCA salts are known, the hygroscopicity of internal mixtures of these components, as they are typically found in the atmosphere, has not been fully characterized. Here we show that inorganic–organic component interactions typically not considered in atmospheric models can lead to very strongly bound metal–organic complexes and greatly affect aerosol volatility and hygroscopicity; in particular, the bi-dentate binding of DCA to soluble inorganic ions. We have studied the volatility of pure, dry organic salt particles and the hygroscopicity of internal mixtures of oxalic acid (OxA, the dominant DCA in the atmosphere) and a number of salts, both mono- and di-valent. The formation of very low volatility organic salts was confirmed, with minimal evaporation of oxalate salt particles below 75 °C. Dramatic increases in the cloud condensation nuclei (CCN) activation diameter for particles with di-valent salts (e.g., CaCl2) and relatively small particle volume fractions of OxA indicate that standard volume additivity rules for hygroscopicity do not apply. Thus small organic compounds with high O : C ratios are capable of forming low-volatility and very low hygroscopicity particles. Given current knowledge of the formation mechanisms of OxA and M–Ox salts, surface enrichment of insoluble M–Ox salts is expected. The resulting formation of an insoluble coating of metal-oxalate salts can explain low-particle hygroscopicities. The formation of particles with a hard coating could offer an alternative explanation for observations of glass-like particles without the need for a phase transition.

scholarly journals Inorganic salts interact with organic di-acids in sub-micron particles to form material with low hygroscopicity and volatility

2013 ◽  
Vol 13 (11) ◽  
pp. 30653-30685
Author(s):  
G. Drozd ◽  
J. Woo ◽  
S. A. K. Häkkinen ◽  
A. Nenes ◽  
V. F. McNeill
Keyword(s):  
Current Knowledge ◽  
Inorganic Ions ◽  
Organic Salt ◽  
Formation Mechanisms ◽  
Organic Salts ◽  
Low Viscosity ◽  
Organic Complexes ◽  
Mass Fractions ◽  
Hygroscopic Salts ◽  
Divalent Salts

Abstract. Volatility and hygroscopicity are two key properties of organic aerosol components, and both are strongly related to chemical identity. Here we show that inorganic-organic component interactions typically not considered in atmospheric models may strongly affect aerosol volatility and hygroscopicity. In particular, bi-dentate binding of di-carboxylic acids (DCA) to soluble inorganic ions can lead to very strongly bound metal-organic complexes with largely undetermined hygroscopicity and volatility. These reactions profoundly impact particle hygroscopicity, transforming hygroscopic components into irreversibly non-hygroscopic material. While the hygroscopicities of pure salts, DCA, and DCA salts are known, the hygroscopicity of internal mixtures of hygroscopic salts and DCA, as they are typically found in the atmosphere, has not been fully characterized. We have studied the volatility of pure, dry organic salt particles and the hygroscopicity of internal mixtures of oxalic acid (OxA, the dominant DCA in the atmosphere) and a number of salts, both mono- and di-valent. The formation of very low volatility organic salts was confirmed, with minimal evaporation of oxalate salt particles below 75 °C. Dramatic increases in the CCN activation diameter for particles with divalent salts (e.g. CaCl2) and relatively small particle mass fractions of OxA indicate that standard volume additivity rules for hygroscopicity do not apply. Thus small organic compounds with high O:C are capable of forming low volatility and very low hygroscopicity particles. Given current knowledge of the formation mechanisms of OxA and M-Ox salts, surface enrichment of insoluble M-Ox salts is expected. The resulting formation of an insoluble coating of metal-oxalate salts can explain low particle hygroscopicities. The formation of particles with a hard coating could offer an alternative explanation for observations of glass-like particles with very low viscosity.

Effects and Mechanism of Organic Acids on Aluminum Availability of Dark Brown Forest Soil

2011 ◽  
Vol 393-395 ◽  
pp. 709-712 ◽  
Author(s):  
Fu Xing Cui ◽  
Jin Feng Song ◽  
Ya Fen Guo ◽  
Jin Zhong Xu
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Organic Acid ◽  
Forest Soil ◽  
Dissociation Constants ◽  
Organic Salt ◽  
Brown Forest Soil ◽  
Organic Salts ◽  
Complexation Reactions

The effects and mechanism of different concentration organic acids and organic salts solution on Al availability of dark brown forest soil were studied. It was resulted that, oxalic acid/oxalate and citric acid/citrate substantially stimulated soil Al release of dark brown forest soil. The effect of organic acids/salts on Al release would be strengthen with increasing of their concentrations.The contents of Al released from A1 horizon was higher than that from B horizon. Organic salt solutions had much higher effects than organic acid the same in concentration, i.e. citrate>citric acid, oxalate>oxalic acid. Therefore, the mechanism of organic acid/salts triggering release of soil Al was assumed to be dominated by complexation reactions of organic anions. Citric acid/ citrate had much higher effect than oxalic acid/ oxalate at same concentration to A1 and B horizons, i.e. citrate> oxalate, citric acid>oxalic acid, which was primarily related with the greater complexing capacities and dissociation constants of citric acid.

scholarly journals Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 712
Author(s):  
Harry Watts ◽  
Yee-Kwong Leong
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Organic Salt ◽  
Organic Salts ◽  
Organic Complexes ◽  
Proposed Model ◽  
Oxalate Precipitation ◽  
Salt Selection ◽  
Logarithmic Distribution ◽  
The Stability

Thermodynamic modelling of a leaching system that involves concurrent precipitation depends on an understanding of how the metals distribute into the precipitate before an assessment of solubility can be made. It has been suggested in the past that a pair of rare earths (A and B) in solution will separate from each other by oxalate precipitation according to a logarithmic distribution coefficient (λ), determined by the kinetics of the precipitation. By contrast, the present study hypothesises that λ may be approximated from thermodynamic terms, including the solubility product (KSp) of each rare earth oxalate and the stability constant (β1) for the mono-oxalato complex of each rare earth. The proposed model was used to calculate λ between pairs of rare earths. An experimental study was conducted to determine λ between selected pairs using homogenous precipitation through the hydrolysis of an oxalic acid ester, with fairly close agreement to the values under the proposed model. Though this model requires more thorough testing, as well as application to other organic salts, it may provide insight into distribution factors of a precipitate formed by a sequence of organic complexes.

scholarly journals Seminal Plasma: Relevant for Fertility?

2021 ◽  
Vol 22 (9) ◽  
pp. 4368
Author(s):  
Heriberto Rodriguez-Martinez ◽  
Emilio A. Martinez ◽  
Juan J. Calvete ◽  
Fernando J. Peña Vega ◽  
Jordi Roca
Keyword(s):  
Seminal Plasma ◽  
Current Knowledge ◽  
Inorganic Ions ◽  
Vitro Fertilization ◽  
Dna And Rna ◽  
Model Animal ◽  
Sexual Glands ◽  
Species Specific

Seminal plasma (SP), the non-cellular component of semen, is a heterogeneous composite fluid built by secretions of the testis, the epididymis and the accessory sexual glands. Its composition, despite species-specific anatomical peculiarities, consistently contains inorganic ions, specific hormones, proteins and peptides, including cytokines and enzymes, cholesterol, DNA and RNA—the latter often protected within epididymis- or prostate-derived extracellular vesicles. It is beyond question that the SP participates in diverse aspects of sperm function pre-fertilization events. The SP also interacts with the various compartments of the tubular genital tract, triggering changes in gene function that prepares for an eventual successful pregnancy; thus, it ultimately modulates fertility. Despite these concepts, it is imperative to remember that SP-free spermatozoa (epididymal or washed ejaculated) are still fertile, so this review shall focus on the differences between the in vivo roles of the SP following semen deposition in the female and those regarding additions of SP on spermatozoa handled for artificial reproduction, including cryopreservation, from artificial insemination to in vitro fertilization. This review attempts, including our own results on model animal species, to critically summarize the current knowledge of the reproductive roles played by SP components, particularly in our own species, which is increasingly affected by infertility. The ultimate goal is to reconcile the delicate balance between the SP molecular concentration and their concerted effects after temporal exposure in vivo. We aim to appraise the functions of the SP components, their relevance as diagnostic biomarkers and their value as eventual additives to refine reproductive strategies, including biotechnologies, in livestock models and humans.

scholarly journals Characteristics of aerosol pollution during heavy haze events in Suzhou, China

2016 ◽  
Vol 16 (11) ◽  
pp. 7357-7371 ◽  
Author(s):  
Mi Tian ◽  
Huanbo Wang ◽  
Yang Chen ◽  
Fumo Yang ◽  
Xiaohua Zhang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Inorganic Ions ◽  
Weather Conditions ◽  
Water Soluble ◽  
Chemical Components ◽  
Formation Mechanisms ◽  
Visibility Impairment ◽  
Aerosol Pollution ◽  
Haze Formation ◽  
High Concentrations

Abstract. Extremely severe haze weather events occurred in many cities in China, especially in the east part of the country, in January 2013. Comprehensive measurements including hourly concentrations of PM2.5 and its major chemical components (water-soluble inorganic ions, organic carbon (OC), and elemental carbon (EC)) and related gas-phase precursors were conducted via an online monitoring system in Suzhou, a medium-sized city in Jiangsu province, just east of Shanghai. PM2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less) frequently exceeded 150 µg m−3 on hazy days, with the maximum reaching 324 µg m−3 on 14 January 2013. Unfavorable weather conditions (high relative humidity (RH), and low rainfall, wind speed, and atmospheric pressure) were conducive to haze formation. High concentrations of secondary aerosol species (including SO42−, NO3−, NH4+, and SOC) and gaseous precursors were observed during the first two haze events, while elevated primary carbonaceous species emissions were found during the third haze period, pointing to different haze formation mechanisms. Organic matter (OM), (NH4)2SO4, and NH4NO3 were found to be the major contributors to visibility impairment. High concentrations of sulfate and nitrate might be explained by homogeneous gas-phase reactions under low RH conditions and by heterogeneous processes under relatively high RH conditions. Analysis of air mass trajectory clustering and potential source contribution function showed that aerosol pollution in the studied areas was mainly caused by local activities and surrounding sources transported from nearby cities.

scholarly journals The potential contribution of organic salts to new particle growth

2009 ◽  
Vol 9 (9) ◽  
pp. 2949-2957 ◽  
Author(s):  
K. C. Barsanti ◽  
P. H. McMurry ◽  
J. N. Smith
Keyword(s):  
Organic Acids ◽  
Particle Growth ◽  
Estimation Methods ◽  
Organic Salt ◽  
Pure Liquid ◽  
Potential Contribution ◽  
Salt Formation ◽  
Organic Salts ◽  
Acids And Bases ◽  
Atmospherically Relevant

Abstract. Field and lab measurements suggest that low-molecular weight (MW) organic acids and bases exist in accumulation and nucleation mode particles, despite their relatively high pure-liquid vapor pressures. The mechanism(s) by which such compounds contribute to the mass growth of existing aerosol particles and newly formed particles has not been thoroughly explored. One mechanism by which low-MW compounds may contribute to new particle growth is through the formation of organic salts. In this paper we use thermodynamic modeling to explore the potential for organic salt formation by atmospherically relevant organic acids and bases for two system types: one in which the relative contribution of ammonia vs. amines in forming organic salts was evaluated, the other in which the decrease in volatility of organic acids and bases due to organic salt formation was assessed. The modeling approach employed relied heavily on group contribution and other estimation methods for necessary physical and chemical parameters. The results of this work suggest that amines may be an important contributor to organic salt formation, and that experimental data are greatly needed to improve our understanding of organic salt formation in atmospherically relevant systems and to accurately predict the potential contribution of such salts to new particle growth.

scholarly journals Role of Sea Surface Microlayer Properties in Cloud Formation

2021 ◽  
Vol 7 ◽  
Author(s):  
Brianna N. Hendrickson ◽  
Sarah D. Brooks ◽  
Daniel C. O. Thornton ◽  
Richard H. Moore ◽  
Ewan Crosbie ◽  
...  
Keyword(s):  
North Atlantic ◽  
Cloud Condensation Nuclei ◽  
Sea Surface ◽  
Cloud Formation ◽  
Organic Salt ◽  
Surface Microlayer ◽  
Marine Aerosols ◽  
Bisphosphate Carboxylase ◽  
Formation Potential ◽  
Sea Surface Microlayer

To date, the relative contribution of primary marine organic matter to the subset of atmospheric particles that nucleate cloud droplets is highly uncertain. Here, cloud condensation nuclei (CCN) measurements were conducted on aerosolized sea surface microlayer (SML) samples collected from the North Atlantic Ocean during the NASA North Atlantic Aerosols and Marine Ecosystems Study (NAAMES), κ values were predicted for three representative high molecular weight (HMW) organic components of marine aerosol: 6-glucose, humic acid, and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). The predicted κ values for pure organic aerosols varied by only ±0.01 across all of the organics chosen. For the desalted SML samples, calculations assuming an organic composition of entirely RuBisCO provided the closest predicted κ values for the desalted SML samples with a mean κ value of 0.53 ± 0.10. These results indicate that it is the sea salt in the SML which drives the cloud formation potential of marine aerosols. While the presence of organic material from the ocean surface waters may increase aerosol mass due to enrichment processes, cloud formation potential of mixed organic/salt primary marine aerosols will be slightly weakened or unchanged compared to sea spray aerosol.

scholarly journals Modulating cellular cytotoxicity and phototoxicity of fluorescent organic salts through counterion pairing

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Deanna Broadwater ◽  
Matthew Bates ◽  
Mayank Jayaram ◽  
Margaret Young ◽  
Jianzhou He ◽  
...  
Keyword(s):  
Fluorescent Dyes ◽  
Control Cell ◽  
Disease Diagnosis ◽  
Frontier Molecular Orbital ◽  
Organic Salt ◽  
Organic Salts ◽  
Guided Surgery ◽  
Decoupled Control ◽  
Selective Generation ◽  
High Cytotoxicity

Abstract Light-activated theranostics offer promising opportunities for disease diagnosis, image-guided surgery, and site-specific personalized therapy. However, current fluorescent dyes are limited by low brightness, high cytotoxicity, poor tissue penetration, and unwanted side effects. To overcome these limitations, we demonstrate a platform for optoelectronic tuning, which allows independent control of the optical properties from the electronic properties of fluorescent organic salts. This is achieved through cation-anion pairing of organic salts that can modulate the frontier molecular orbital without impacting the bandgap. Optoelectronic tuning enables decoupled control over the cytotoxicity and phototoxicity of fluorescent organic salts by selective generation of mitochondrial reactive oxygen species that control cell viability. We show that through counterion pairing, organic salt nanoparticles can be tuned to be either nontoxic for enhanced imaging, or phototoxic for improved photodynamic therapy.

scholarly journals Catalogue of new Herbig Ae/Be and classical Be stars

2020 ◽  
Vol 638 ◽  
pp. A21 ◽  
Author(s):  
M. Vioque ◽  
R. D. Oudmaijer ◽  
M. Schreiner ◽  
I. Mendigutía ◽  
D. Baines ◽  
...  
Keyword(s):  
Main Sequence ◽  
Current Knowledge ◽  
Machine Learning Techniques ◽  
High Mass ◽  
Formation Mechanisms ◽  
Be Stars ◽  
Homogeneous Sample ◽  
Applied Machine Learning ◽  
Learning Techniques ◽  
Order Of Magnitude

Context. The intermediate-mass pre-main sequence Herbig Ae/Be stars are key to understanding the differences in formation mechanisms between low- and high-mass stars. The study of the general properties of these objects is hampered by the lack of a well-defined, homogeneous sample, and because few and mostly serendipitously discovered sources are known. Aims. Our goal is to identify new Herbig Ae/Be candidates to create a homogeneous and well defined catalogue of these objects. Methods. We have applied machine learning techniques to 4 150 983 sources with data from Gaia DR2, 2MASS, WISE, and IPHAS or VPHAS+. Several observables were chosen to identify new Herbig Ae/Be candidates based on our current knowledge of this class, which is characterised by infrared excesses, photometric variabilities, and Hα emission lines. Classical techniques are not efficient for identifying new Herbig Ae/Be stars mainly because of their similarity with classical Be stars, with which they share many characteristics. By focusing on disentangling these two types of objects, our algorithm has also identified new classical Be stars. Results. We have obtained a large catalogue of 8470 new pre-main sequence candidates and another catalogue of 693 new classical Be candidates with a completeness of 78.8 ± 1.4% and 85.5 ± 1.2%, respectively. Of the catalogue of pre-main sequence candidates, at least 1361 sources are potentially new Herbig Ae/Be candidates according to their position in the Hertzsprung-Russell diagram. In this study we present the methodology used, evaluate the quality of the catalogues, and perform an analysis of their flaws and biases. For this assessment, we make use of observables that have not been accounted for by the algorithm and hence are selection-independent, such as coordinates and parallax based distances. The catalogue of new Herbig Ae/Be stars that we present here increases the number of known objects of the class by an order of magnitude.

scholarly journals Multiphase MCM–CAPRAM modeling of the formation and processing of secondary aerosol constituents observed during the Mt. Tai summer campaign in 2014

2020 ◽  
Vol 20 (11) ◽  
pp. 6725-6747 ◽  
Author(s):  
Yanhong Zhu ◽  
Andreas Tilgner ◽  
Erik Hans Hoffmann ◽  
Hartmut Herrmann ◽  
Kimitaka Kawamura ◽  
...  
Keyword(s):  
Oxalic Acid ◽  
Aqueous Phase ◽  
Glyoxylic Acid ◽  
Northern China ◽  
Chemical Mechanism ◽  
Radical Mechanism ◽  
Formation Mechanisms ◽  
Major Pathway ◽  
Voc Emissions ◽  
Secondary Aerosol

Abstract. Despite the high abundance of secondary aerosols in the atmosphere, their formation mechanisms remain poorly understood. In this study, the Master Chemical Mechanism (MCM) and the Chemical Aqueous-Phase Radical Mechanism (CAPRAM) are used to investigate the multiphase formation and processing of secondary aerosol constituents during the advection of air masses towards the measurement site of Mt. Tai in northern China. Trajectories with and without chemical–cloud interaction are modeled. Modeled radical and non-radical concentrations demonstrate that the summit of Mt. Tai, with an altitude of ∼1.5 km a.m.s.l., is characterized by a suburban oxidants budget. The modeled maximum gas-phase concentrations of the OH radical are 3.2×106 and 3.5×106 molec. cm−3 in simulations with and without cloud passages in the air parcel, respectively. In contrast with previous studies at Mt. Tai, this study has modeled chemical formation processes of secondary aerosol constituents under day vs. night and cloud vs. non-cloud cases along the trajectories towards Mt. Tai in detail. The model studies show that sulfate is mainly produced in simulations where the air parcel is influenced by cloud chemistry. Under the simulated conditions, the aqueous reaction of HSO3- with H2O2 is the major contributor to sulfate formation, contributing 67 % and 60 % in the simulations with cloud and non-cloud passages, respectively. The modeled nitrate formation is higher at nighttime than during daytime. The major pathway is aqueous-phase N2O5 hydrolysis, with a contribution of 72 % when cloud passages are considered and 70 % when they are not. Secondary organic aerosol (SOA) compounds, e.g., glyoxylic, oxalic, pyruvic and malonic acid, are found to be mostly produced from the aqueous oxidations of hydrated glyoxal, hydrated glyoxylic acid, nitro-2-oxopropanoate and hydrated 3-oxopropanoic acid, respectively. Sensitivity studies reveal that gaseous volatile organic compound (VOC) emissions have a huge impact on the concentrations of modeled secondary aerosol compounds. Increasing the VOC emissions by a factor of 2 leads to linearly increased concentrations of the corresponding SOA compounds. Studies using the relative incremental reactivity (RIR) method have identified isoprene, 1,3-butadiene and toluene as the key precursors for glyoxylic and oxalic acid, but only isoprene is found to be a key precursor for pyruvic acid. Additionally, the model investigations demonstrate that an increased aerosol partitioning of glyoxal can play an important role in the aqueous-phase formation of glyoxylic and oxalic acid. Overall, the present study is the first that provides more detailed insights in the formation pathways of secondary aerosol constituents at Mt. Tai and clearly emphasizes the importance of aqueous-phase chemical processes on the production of multifunctional carboxylic acids.

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