Heterogeneous formation and partitioning of nitrous acid on water surfaces: dependency on the acidity

2021 ◽  
Author(s):  
Jun Zheng ◽  
Yan Ma
Keyword(s):  
Liquid Water ◽  
Nitrous Acid ◽  
Ph Value ◽  
Water Solution ◽  
Formation Rate ◽  
Water Soluble ◽  
Wet Chemistry ◽  
Water Surfaces ◽  
Heterogeneous Formation ◽  
Hydrolysis Of

<p>Hydrolysis of nitrogen dioxide (NO<sub>2</sub>) has long been recognized as a major formation path of atmospheric nitrous acid (HONO), which is regarded as a dominant hydroxyl radical (OH) source, particularly in a polluted environment. Since HONO is moderately water soluble and its solubility can be highly dependent on the acidity of the water solution, the HONO formation rate and its ensuring fate may also be affected by the acidity of the water surfaces. In this work, we investigated the hydrolysis of NO<sub>2</sub> on dilute sulfuric acid water solutions with a pH value ranging from ~3 to ~6. Both the gaseous HONO and dissolved nitrous acid solution were quantified by a wet-chemistry based HONO analyzer and ion chromatography analyses, respectively. The results showed that significant amount of HONO can participate into the aqueous phase at low acidity and as the acidity increased gas-phase HONO also increased. These results indicated that liquid water on various surfaces may both provide a reaction site for HONO formation and serve as a reservoir of HONO that can be released when the liquid water was evaporated.</p>

SYNTHESIS AND OPTICAL PROPERTIES OF WATER SOLUBLE ZnSe NANOCRYSTALS

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3881-3884 ◽  
Author(s):  
N. Murase ◽  
M. Y. Gao ◽  
N. Gaponik ◽  
T. Yazawa ◽  
J. Feldmann
Keyword(s):  
Ph Value ◽  
Water Soluble ◽  
Final Solution ◽  
Blue Fluorescence ◽  
Wet Chemistry ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Mean Size ◽  
Surface Capping ◽  
Znse Nanocrystals

ZnSe nanocrystals are prepared in water by a wet chemistry method. By selecting an appropriate pH value and surface-capping agents, a whitish blue fluorescence peaking at 470 nm is observed under ZV irradiation. The intensity of this fluorescence increases dramatically under reflux and saturates after ~ 40 hrs. The final mean size of the ZnSe nanocrystals measured by transmission electron microscopy is aboyt 2 nm in diameter. The quantum efficiency of the fluorescence form the final solution is estimated to be ~1%, although the preparation conditions have not yet been completely optimized. These properties are discussed in comparison with those of similarly prepared CdTe and differently prepared ZnSe nanocrystals.

scholarly journals Evaluation of Microcrystalline Cellulose Derived from Saccharum officinarum L. (Sugarcane) Leaves as a Disintegrant in Tablet Formulations

2020 ◽  
Vol 10 (3) ◽  
pp. 418-422
Author(s):  
Julie Ann S. Ng
Keyword(s):  
Microcrystalline Cellulose ◽  
Crop Residues ◽  
Ph Value ◽  
Saccharum Officinarum ◽  
The Philippines ◽  
Water Soluble ◽  
Raw Material ◽  
Value Loss ◽  
Hydrolysis Of ◽  
Better Than

Purpose : Complete recycling of the crop residues of sugarcane in the Philippines remains to be achieved. This study purposed to derive microcrystalline cellulose (MCC) from sugarcane leaves and test its disintegrating properties in tablet formulation. Methods: Saccharum officinarum L. (sugarcane) leaves were used to prepare MCC powder. According to the conventional method, the preparation of cellulose powder requires heating the raw material with acid and alkali followed by washing, bleaching, and sieving. Hydrolysis of the bleached product was carried out using hydrochloric acid to obtain MCC powder, and the physicochemical properties of the produced MCC powder were studied including its organoleptic properties, pH value, %loss on drying, %water soluble substances and Fouriertransform infrared (FTIR) spectrum. Results: The resulting powder was evaluated for its disintegrating property in the preparation of blank tablets, which were compared to tablets prepared using commercially available MCC. MCC powder derived from sugarcane leaves had properties at par with commercially available MCC and was in conformance with National Formulary (NF) specifications. Conclusion: Disintegrating properties were also significantly better than the commercially available MCC.

Dispersion of Multi-Walled Carbon Nanotubes Modified with Poly-L-Lysine in Water

2013 ◽  
Vol 275-277 ◽  
pp. 1785-1788 ◽  
Author(s):  
Ting Ting Zhang ◽  
Li Ming Zou ◽  
Xin Long Ling ◽  
Xi Li
Keyword(s):  
Carbon Nanotubes ◽  
Ring Opening ◽  
Ph Value ◽  
Water Solution ◽  
Water Soluble ◽  
Mass Ratio ◽  
Group Water ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Nmr Dispersion

A noncovalent method was presented in order to improve the solubility of multi-walled carbon nanotubes (MWCNTs) in water. Poly (ε-benzyloxycarbonyl-L-lysine) (PZLL) was prepared by ring-opening polymerization of ε-carbobenzoxy-L-lysine N-carboxyanhydride (Z-L-Lys NCA). After the removal of the benzyloxycarbonyl group, water-soluble poly-L-lysine (PLL) was obtained. The structure of PZLL and PLL was characterized by FTIR and 1H NMR. Dispersion of MWCNTs in the water solution of PLL was investigated by ultraviolet spectrophotometer and visual inspection. When the mass ratio of MWCNTs to PLL is 1:50 and the pH value of the water solution of PLL is 5, MWCNTs can be well dispersed in water.

Molecularly Imprinted Sensor for Ascorbic Acid Based on Gold Nanoparticles and Multiwalled Carbon Nanotubes

2020 ◽  
Vol 16 (7) ◽  
pp. 905-913
Author(s):  
Youyuan Peng ◽  
Qingshan Miao
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Multiwalled Carbon Nanotubes ◽  
Ph Value ◽  
Biological Fluids ◽  
Water Soluble ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Molecularly Imprinted

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Evidence for heterogeneous formation of nitrous acid on cloud droplets

2000 ◽  
Vol 31 ◽  
pp. 352-353 ◽  
Author(s):  
K. Acker ◽  
W. Wieprecht ◽  
R. Auel ◽  
D. Kalass ◽  
D. Möller
Keyword(s):  
Nitrous Acid ◽  
Cloud Droplets ◽  
Heterogeneous Formation

scholarly journals Optimizing Chitin Depolymerization by Lysozyme to Long-Chain Oligosaccharides

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 320
Author(s):  
Arnaud Masselin ◽  
Antoine Rousseau ◽  
Stéphanie Pradeau ◽  
Laure Fort ◽  
Rodolphe Gueret ◽  
...  
Keyword(s):  
Time Course ◽  
Water Soluble ◽  
Organic Fertilizers ◽  
Symbiotic Associations ◽  
Egg White Lysozyme ◽  
Hen Egg White ◽  
Ecological Transition ◽  
Optimized Conditions ◽  
Hydrolysis Of ◽  
Long Chain

Chitin oligosaccharides (COs) hold high promise as organic fertilizers in the ongoing agro-ecological transition. Short- and long-chain COs can contribute to the establishment of symbiotic associations between plants and microorganisms, facilitating the uptake of soil nutrients by host plants. Long-chain COs trigger plant innate immunity. A fine investigation of these different signaling pathways requires improving the access to high-purity COs. Here, we used the response surface methodology to optimize the production of COs by enzymatic hydrolysis of water-soluble chitin (WSC) with hen egg-white lysozyme. The influence of WSC concentration, its acetylation degree, and the reaction time course were modelled using a Box–Behnken design. Under optimized conditions, water-soluble COs up to the nonasaccharide were formed in 51% yield and purified to homogeneity. This straightforward approach opens new avenues to determine the complex roles of COs in plants.

scholarly journals Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1316
Author(s):  
Vanessa Miglio ◽  
Chiara Zaccone ◽  
Chiara Vittoni ◽  
Ilaria Braschi ◽  
Enrico Buscaroli ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Water Solution ◽  
Synthesis Method ◽  
Textural Properties ◽  
Adsorption Properties ◽  
Water Soluble ◽  
Silica Monoliths ◽  
Physico Chemical ◽  
Gaseous Toluene ◽  
Mcm 41

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10−2 mM Rhodamine B in water solution.

scholarly journals Effects of Sugar Cane Molasses Addition on the Fermentation Quality, Microbial Community, and Tastes of Alfalfa Silage

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 355
Author(s):  
Runbo Luo ◽  
Yangdong Zhang ◽  
Fengen Wang ◽  
Kaizhen Liu ◽  
Guoxin Huang ◽  
...  
Keyword(s):  
Sugar Cane ◽  
Ph Value ◽  
Electronic Tongue ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Cane Molasses ◽  
Fermentation Quality ◽  
Alfalfa Silage ◽  
Additive Control

The objective was to study the effects of sugar cane molasses addition on the fermentation quality and tastes of alfalfa silage. Fresh alfalfa was ensiled with no additive (Control), 1% molasses (M1), 2% molasses (M2), and 3% molasses (M3) for 206 days. The chemical composition and fermentation characteristics of the alfalfa silages were determined, the microbial communities were described by 16S rRNA sequencing, and the tastes were evaluated using an electronic tongue sensing system. With the amount of added molasses (M), most nutrition (dry matter and crude protein) was preserved and water-soluble carbohydrates (WSC) were sufficiently used to promote the fermentation, resulting in a pH reduction from 5.16 to 4.48. The lactic acid (LA) content and LA/acetic acid (AA) significantly increased, indicating that the fermentation had turned to homofermentation. After ensiling, Enterococcus and Lactobacillus were the dominant genus in all treatments and the undesirable microbes were inhibited, resulting in lower propionic acid (PA), butyric acid (BA), and NH3-N production. In addition, bitterness, astringency, and sourness reflected tastes of alfalfa silage, while umami and sourness changed with the amount of added molasses. Therefore, molasses additive had improved the fermentation quality and tastes of alfalfa silage, and the M3 group obtained the ideal pH value (below 4.5) and the best condition for long-term preservation.

Theoretical Evaluation of Rheological State of Sand Cement Composite Systems with Polyoxyethylene Additive Using Topological Dynamics Concept

2016 ◽  
Vol 871 ◽  
pp. 96-103 ◽  
Author(s):  
Vladimir Erofeev ◽  
Aleksandr Bobryshev ◽  
Aleksandr Lakhno ◽  
Lenar Shafigullin ◽  
Ilnaz Khalilov ◽  
...  
Keyword(s):  
Water Solution ◽  
Cement Composite ◽  
Water Soluble ◽  
Viscosity Data ◽  
Active Components ◽  
Theoretical Evaluation ◽  
Composite Systems ◽  
Polymer Powder ◽  
Cement System ◽  
Phase Water

Presents the results of studies of contemporary materials in the field of rheological state. The topological mortar structure has been provided by theoretical evaluation of the rheological state of the cross-linked solutions and the experimental viscosity data of the sand cement mortar which has been modified by water-soluble additive – polyoxyethylene. The general model has been made for the structure of non-Newtonian liquideous systems including dilatant, pseudoplastic bodies with two main rheological active components in their structure – rigid and viscous phases. It is shown that in pseudoplastic systems, as the shear stress increases, the viscous phase grows because of the reduction of rigid phase content. In dilatant systems the converse situation has been observed. Furthermore, these phases are not clearly distinguishable, but to the contrary they are spatially interconnected in a complex way. The structure modeling has been made for non-Newtonian bodies using the Shklovskii-de Gennes model. The studies have found that the construction composite sand cement system is defined as the pseudoplastic body where cement and sand act as the rigid phase, water solution of polyoxyethylene – as the viscous phase. These findings can be used to prove the influence of polymer powder on the workability of dry mortar.

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