Low Sulfur Dioxide Research Articles

Antimicrobial Activity of Chitosan from Different Sources Against Non-Saccharomyces Wine Yeasts as a Tool for Producing Low-Sulphite Wine

Chitosan is used as an antimicrobial agent in different agri-food applications; in winemaking, the use of chitosan from Aspergillus niger is authorized, but other sources of chitin, and consequently of chitosan, are available, such as crustaceans and insects. This work investigates the antimicrobial efficiency of chitosan from crustaceans and insects (Hermetia illucens) against non-Saccharomyces yeasts in wine. For this aim, the first step was to evaluate the effect of crustacean chitosan, tested both alone and in combination with low sulphur dioxide (SO2) concentrations, on the cell viability of 20 non-Saccharomyces strains in the first step of fermentations inoculated with each strain. Furthermore, the strain resistance to crustacean- and insect-based chitosan was evaluated in agarized media, together with the addition of different antimicrobial concentrations. Finally, the efficiency of different antimicrobial treatments was evaluated during laboratory-scale fermentations inoculated with a selected S. cerevisiae strain. The tested strains exhibited medium/high resistance to the chitosan; in some cases, the behaviour varied in the function of species/strain, and only four strains exhibited different resistance levels, depending on the chitosan source. The addition of chitosan alone during fermentation inoculated with S. cerevisiae showed lower antimicrobial activity than SO2, but the combined use with SO2 showed a better effect than chitosan alone. The evaluation of the suitability of chitosan obtained from a sustainable source, such as insects, will allow us to give new information on the future applications of this natural compound for the production of wine with low sulphite content.

Modeling and simulation of a novel chemical process for clean hydrogen and power generation

The present work aims to develop a novel chemical process for clean hydrogen and power production and simulate it accordingly through a unique thermodynamic equilibrium model. This particular process is based on a partial oxidation of hydrogen sulfide (H2S) at superadiabatic conditions to study its respective chemical products. The simulation of superadiabatic partial oxidation of H2S is developed through the present model for the first time in the Aspen Plus. The process is further studied by varying different operating variables with an overall goal of optimizing the H2S conversion into hydrogen. The developed model predicts a satisfactory H2 production flow rate coupled with a low-sulfur dioxide (SO2) output within the superadiabatic partial oxidation regime at an operating pressure below 0.5 bar. The H2S conversion into H2 is then found to be 23.48 % at 0.25 bar. The overall energy and exergy efficiencies of the system are found to be 87.51 % and 70.08 % respectively. The dissociation of H2S in the presence of stoichiometric air results in elemental sulfur and hydrogen production rates of 0.0019 kg/s and 0.0012 kg/s, respectively.

Качество и безопасность продукции в процессе хранения в системе «вино – упаковка, укупорка»

Poor packaging often affects the quality and safety indicators of wine during storage. The need to preserve and prolong wine stability during long-term storage requires a comprehensive study of processes that occur in wines packaged and capped in various ways.
 This research featured 56 samples of white and red dry wines, which were bottled in four types of packages and stopper for 18 months. The effect of synthetic and natural stopper methods involved a model system that simulated the main composition of wine in line with the EAEU standards. The contents of free SO2 and dissolved oxygen, as well as the microbiology of natural corks, were studied using standard methods. The analysis of volatile substances relied on gas chromatography, mass spectrometry, and solid phase micro-extraction.
 The study recorded critical changes in the quality of wine products, characterized by increased oxidation markers and low free sulfur dioxide, which fell below 10 mg/dm3. In polyethylene terephthalate bottles, these changes occurred after 12 months of storage, while it took them 18 months to develop in multilayer bags and combined packaging materials. The components of natural and artificial plugs of microbial and chemical origin entered the model systems after 10 days of contact. The microbiological contamination was twice as high as the permissible level. The migration of microbial and chemical substances into the wine samples spoiled their quality and safety.
 The effect of packaging on the oxidative processes in white and red dry wines during storage resulted in different concentrations of dissolved oxygen and sulfur dioxide. The results can help wine producers to choose the most appropriate packaging and stopper means depending on the wine sort and its subsequent storage conditions. Alternative types of packaging proved to have a limited shelf life.

Study of Sulphides Production Affecting the Fermentation Process of the Lager Beer

In the lager brewing production process, volatile sulphides such as sulphur dioxide, hydrogen sulphide, thiols and thioesters are produced by yeast metabolism during the fermentation of lager beer. Fluctuations in malt raw materials, yeast strain characteristics and fermentation process parameter adjustments can all have an impact on sulphides, and the concentration of sulphides in finished beer can have a negative impact on the sensory tasting of lager beer. This study investigated the fermentation of sulphides in lager beer under the conditions of dissolved wort oxygen, yeast recovery, fermentation temperature and pressure, and the results showed that the longer the yeast growth time, the later the fermentation of sulphur dioxide and the lower the sulphur dioxide content in the final beer by 10mg/L. The longer the yeast recovery days, the higher the fermentation of sulphur dioxide and hydrogen sulphide. The higher the content, the higher the fermentation temperature of the lager and the faster the fermentation rate, which favours a low sulphur dioxide content at the end of the main fermentation.

Reversible sulfur dioxide capture by amino acids containing a single amino group at low sulfur dioxide concentrations.

SO2, an air pollutant, is harmful to human health and causes air pollution; therefore, numerous studies have focused on the development of SO2 control technologies. Although limestone- and ammonia-based absorbents have been widely used in wet desulfurization, they are difficult to regenerate and do not enable the recycling of SO2, which is a useful resource. Recently, amino acids have attracted attention as reversible SO2 absorbents because they are eco-friendly and have excellent reactivity with SO2, as well as high regeneration performance. Glycine, L-alanine, β-alanine, 4-aminobutyric acid, 5-aminovaleric acid, and 6-aminohexanoic acid were analyzed to investigate the relationship between SO2 absorption and the amino acid molecular structure using the simulated actual flue gas (200 ppmv SO2 + 13% CO2 in N2 balance). The SO2 absorption of amino acids (with the molecular structure of glycine and alkyl chains of various lengths) improved as the alkyl chain length increased, possibly owing to a decrease in the inductive effect in the molecular structure of the amino acid. Furthermore, 13C-nuclear magnetic resonance spectroscopy was conducted to analyze the SO2 absorption reaction mechanism (including the possible generation of irreversible species), and experiments involving a number of consecutive absorption-desorption cycles were used to confirm the reusability of the amino acids. The tested amino acids exhibited higher cyclic capacities compared to those of deep eutectic solvents and ionic liquids reported in the literature, thereby exhibiting excellent potential as SO2 absorbents. Thus, this study can guide the future design and development of eco-friendly SO2 absorbents.

Effect of added sulphur dioxide levels on the aroma characteristics of wines from Panciu wine region

In the wine-making process, the yeasts form over 20 higher alcohols that improve the sensation of palatine veil for the wine. The amount of higher alcohols is lower for white and rosé wines obtained from clarified musts fermented at moderate temperatures. The formation of higher alcohols is confirmed by the fact that the addition of certain nitrogen compounds to a glucose-containing culture medium leads, after the fermentation, to an increase in the higher alcohol content. Data evaluate by comparison the levels of higher alcohols, esters and aldehydes, important to fermentation process in case of several wines from Panciu region. The wine-making was done by classical methods and by using specific protocols for low content sulphur dioxide. This study is focused to compare wines obtained from two grape varieties produced at industrial level: Feteasca regala vs. Feteasca regala Frizzante and Cabernet Sauvignon rosé vs. Cabernet Sauvignon. The compounds were analyzed by GC-FID method with head-space technique for methanol, 1-propanol, 2-methyl-propanol, 1-butanol, ethyl acetate, ethyl lactate, isoamyl acetate and acetaldehyde. The results showed that in almost every comparative study the levels of aroma compounds are maintained, when compared with the wines with low content of sulphur dioxide. Tuckey test showed that 1-propanol and ethyl acetate register statistically significant differences for Cabernet Sauvignon rosé and for Feteasca regala Frizzante.

Association between the long-term exposure to air pollution and depression.

Air pollution has a negative influence on neurological and psychiatric disorders. However, findings concerning the impact of air pollution on depression remain inconclusive. A deeper insight into these associations is warranted. To evaluate the impact of long-term exposure to air pollution on the incidence of depression among residents of 13 counties in the Lower Silesia region of Poland. We used data on cases of depression from the National Health Fund (Narodowy Fundusz Zdrowia - NFZ) from 13 counties of Lower Silesia between January 1, 2010, and December 31, 2015. Patients with a confirmed diagnosis of depression were included. Data on air pollution levels were extracted from the Chief Inspectorate of Environmental Protection (Główny Inspektorat Ochrony Środowiska - GIOŚ), and demographic data were extracted from Statistics Poland (Główny Urząd Statystyczny - GUS). The percentage of people diagnosed with depression over the 6-year study period depended on the group of counties homogeneous in terms of air pollution exposure (p < 0.001). We showed statistically significant correlations between different depression diagnoses and exposure to air pollutants. Elevated concentration of airborne fine particles with a diameter less than 2.5 μm (PM2.5) and carbon monoxide (CO), and low benzo(a)pyrene (BaP), sulfur dioxide (SO2) and cadmium (Cd) levels were independent risk factors for major depressive episodes with psychotic symptoms (F32.3). There was a significant negative correlation between ozone (O3) levels and depression incidence. Regions with heavy air pollution had a higher incidence of depression. There is a significant association between the exposure to air pollutants and different depression diagnoses.

Pillared-layer ultramicroporous material for highly selective SO2 capture from CO2 mixtures

Removal of low concentration sulfur dioxide (SO2) from gas mixture is of great significance in gas purification, but the selective recognition of SO2 from carbon dioxide (CO2) still remains a great challenge with low separation selectivity. Herein, we reported a highly-stable pillared-layer ultramicroporous material CPL-1-NH2 for efficient separation of SO2 and CO2 with benchmark IAST selectivity (485) in metal organic frameworks (MOFs). The high separation selectivity is attributed to the narrow channel with lined amino groups, which exhibits significantly higher affinity to SO2 than CO2. Even in the presence of CO2 and trace moisture, the dynamic SO2 capture performance is hardly affected, demonstrating its great promise for SO2 capture. Simulation studies were conducted to gain the deep insight into the microscopic adsorption behaviors of SO2 and CO2.

Methanol/Ethanol/Butanol-Gasoline Blends Use in Transportation Engine—Part 1: Combustion, Emissions, and Performance Study

Abstract Primary alcohols such as methanol, ethanol, and butanol have exhibited excellent potential as possible alternative fuels for spark ignition (SI) engines because they are renewable, cleaner, and safer to store and transport. However, it is important to investigate the technical feasibility of adapting these primary alcohols in existing SI engines. In this research, a multi-point port fuel injection (MPFI) system equipped SI engine was used for assessing and comparing the combustion, performance, and emission characteristics of various alcohol-gasoline blends (gasohols) vis-à-vis baseline gasoline. The experiments were performed at different engine loads at rated engine speed. Experimental results exhibited relatively superior combustion characteristics of the engine fueled with gasohol than the baseline gasoline, especially at medium engine loads. Among different test fuels, the methanol-gasoline blend (GM10) exhibited relatively more stable combustion characteristics than the ethanol-gasoline blend (GE10) and butanol-gasoline blend (GB10). In this study, relatively superior engine performance of the gasohol-fueled engine was observed at all engine loads and speeds. GB10 exhibited the highest brake thermal efficiency (BTE), followed by GM10 amongst all test fuels. The effect of improved combustion was also reflected in the emission characteristics, which exhibited that GB10 emitted relatively lower carbon monoxide (CO) and hydrocarbons (HCs) than other test fuels. GB10 emitted relatively higher nitrogen oxides (NOx) than GM10 and GE10. Unregulated emission results exhibited that the engine fueled with gasohols emitted relatively lower sulfur dioxide (SO2), ammonia (NH3), and various other saturated and unsaturated HCs than the baseline gasoline. The GM10-fueled engine was relatively more effective in reducing unregulated emissions among all test fuels. This study concluded that methanol and butanol blending with gasoline resulted in superior engine performance and reduced harmful emissions in MPFI transport engines. This offered an excellent option to displace fossil fuels partially and reduce emissions simultaneously.

Why is the Indo-Gangetic Plain the region with the largest NH&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; column in the globe during pre-monsoon and monsoon seasons?

Abstract. Satellite observations show a global maximum in ammonia (NH3) over the Indo-Gangetic Plain (IGP), with a peak from June to August. However, it has never been explained explicitly. In this study, we investigated the causes of high NH3 loading over the IGP during the pre-monsoon and monsoon seasons using WRF-Chem (Weather Research and Forecasting model coupled to chemistry). The IGP has relatively high NH3 emission fluxes (0.4 t km−2 month−1) due to intensive agricultural activities and high air temperature from June to August. Additionally, low sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions and high air temperature limit the gas-to-particle conversion of NH3, particularly for ammonium nitrate formation. Moreover, the barrier effects of the Himalayas in combination with the surface convergence weaken the horizontal diffusion of NH3. The high NH3 loading over the IGP mainly results from the low gas-to-particle partitioning of NH3 caused by low SO2 and NOx emissions. It contrasts to those in the North China Plain, where high SO2 and NOx emissions promote the conversion of gaseous NH3 into particulate ammonium.

Are Exporters More Environmentally Friendly? A Re-Appraisal that Uses China’s Micro-Data

Is a firm’s ability to export an important determinant of environmental performance? To answer this question, we construct a unique micro dataset that merged two rich firm-level datasets for China for 2007. When combining this new dataset with well-received empirical specifications, we found that both export status and export intensity are associated with lower sulfur dioxide (SO2) emissions intensity. In addition to the traditional OLS estimation, we verified this association by using the propensity score matching method. Our findings show that the baseline result still holds. In short, exporters are more environmentally friendly than non-exporters, which is in line with previous evidence reported for developed economies. We further discuss mechanisms that explain the observed pattern and show that exporters realize higher abatement efforts compared to non-exporters. This study complements the literature in terms of providing China’s micro evidence on SO2 abatement efforts. It also serves as a first step toward a better understanding of the impact of trade on the environment, especially in developing countries.

Effects of low sulfur dioxide concentrations on bioactive compounds and antioxidant properties of Aglianico red wine

This study analyzed the effect of low sulfur dioxide concentrations on the chromatic properties, phytochemical composition and antioxidant activity of Aglianico red wines with respect to wines produced from conventional winemaking. We determined the phytochemical composition by spectrophotometric methods and HPLC-DAD analysis and the in vitro antioxidant activity of different wine samples by the ORAC assay. The main important classes of fluorophore molecules in red wine were identified by Front-Face fluorescence spectroscopy, and the emission intensity trend was investigated at various sulfur dioxide concentrations. Lastly, we tested the effects of both conventional and low sulfite wines on ex vivo human erythrocytes under oxidative stimulus by the cellular antioxidant activity (CAA) assay and the hemolysis test. The addition of sulfur dioxide, which has well-known side effects, increased the content of certain bioactive components but did not raise the erythrocyte antioxidant capacity.

Protection of Aroma Volatiles in a Red Wine with Low Sulphur Dioxide by a Mixture of Glutathione, Caffeic Acid and Gallic Acid

The levels of several esters and other volatiles in Merlot-Cabernet Sauvignon blend red wines with typical sulphur dioxide (35 mg/L), with low sulphur dioxide (25 mg/L), and with low sulphur dioxide (25 mg/L) plus a mixture of antioxidants (glutathione 20 mg/L, caffeic acid 60 mg/L and gallic acid 20 mg/L), were evaluated at bottling, and after 18 and 36 months of ageing. Most volatiles decreased during wine storage. At bottling and after 18 months of storage, all three wines exhibited similar levels of volatiles. After 36 months of storage, wines with low sulphur dioxide exhibited lower levels of many volatiles, such as ethyl acetate, ethyl hexanoate, ethyl octanoate and 2-phenylethanol. On the other hand, wines with low sulphur dioxide plus the mixture of antioxidants exhibited similar levels of most volatiles in comparison with wines with typical sulphur dioxide. The present results indicate that a mixture of glutathione, caffeic acid and gallic acid can protect esters and other volatiles in young red wine with low sulphur dioxide, and can replace part of sulphur dioxide typically used.

CFD MODELING OF SO2 CAPTURE USING LIMESTONE IN INDUSTRIAL SCALE CIRCULATING FLUIDIZED BED BOILER

The unsteady state computational fluid dynamics model for gas-solid particle flow in industrial scale circulating fluidized bed boiler combining with combustion and desulfurization (using limestone solid sorbent) chemical reactions, both homogeneous and heterogeneous, was developed in this study. The effects of solid sorbent feeding position and solid sorbent particle size on sulfur dioxide concentration were investigated. The results showed that both the solid sorbent feeding position and solid sorbent particle size had an effect on the sulfur dioxide capture. Entering solid sorbent at the upper secondary air position gave lower sulfur dioxide concentration than the one at the lower secondary air position and fuel feed position, respectively. This can be explained by the influence of suitable temperature at the upper secondary air position for desulfurization chemical reaction. About the solid sorbent particle size, the sulfur dioxide capture was the lowest when using the largest solid sorbent particle size due to the system hydrodynamics.

Photocatalytic removal of low concentration SO2 by titanium dioxide

Titanium dioxide (TiO2) immobilized on glass beads synthesized by a simple physical method was used as a photocatalyst for the removal of low concentration sulfur dioxide (SO2) in flue gas. The performance of the composite was tested in a fixed bed reactor under UV irradiation. The effects of some important operating parameters, including SO2 concentration, oxygen, gas humidity, temperature, and space time, on SO2 removal efficiency were studied. With flue gas consisted of 5% O2, 2.9% H2O, and 40ppm SO2, the efficiency dramatically increased to 100% right after the UV lights were applied. And the removal efficiency maintained stable for approximately 100min. However, after the catalyst breakthrough, the efficiency dropped to 47%, mainly due to the deactivation of the catalyst. According to the X-ray photoelectric spectroscopy (XPS) analysis and experimental results, the deactivation was caused by the photo-oxidation products of SO2 and water vapor which blocked the further reaction on the TiO2 surface. The possible reaction mechanism of the photocatalytic removal process was also proposed in this report.

Is there convergence in per capita SO2 emissions in China? An empirical study using city-level panel data

As China's economy has grown rapidly in recent years, China's environmental pollution has become increasingly significant. Among all the traditional pollutants, sulfur dioxide has been monitored by the Chinese government since the 1990s. In this study, China's city-level panel data between 2002 and 2012 are utilized to investigate the existence of convergence in per capita sulfur dioxide emissions across Chinese cities. The conventional estimation methods for β-convergence suffer from an endogeneity problem and therefore produce biased results. To address the endogeneity problem and allow for dynamics, dynamic panel data estimators are utilized, and the static estimation results are conducted as a robustness check. In addition, the influential factors for convergence are examined. The empirical results indicate that, in the chosen sample period, there were absolute and conditional convergences in per capita sulfur dioxide emissions across cities within the whole nation as well as in the eastern, western and central regions of China. Because per capita Gross Domestic Product and the ratio of secondary industry to Gross Domestic Product are both positively related with per capita sulfur dioxide emissions, higher income per capita and greater importance of the secondary industry would cause the convergence speed to be lower. Therefore, the most straightforward policy implication for the empirical results is that the policies for controlling sulfur dioxide emissions should be regionally differentiated: for cities with high sulfur dioxide emissions per capita, the regulation could be tight, as the emissions would decrease faster because convergence exists; however, for cities with low sulfur dioxide emissions per capita, the target for reducing emissions should not be excessively aggressive.

Raman Spectroscopic Analysis on the Hydrate Formed in the Hydrate-Based Flue Gas Separation Process in Presence of Sulfur Dioxide and Tetra-n-butyl Ammonium Bromide

In this work, Raman spectroscopic analysis was applied to determine the structures and cage occupancies of the hydrates that formed from the system of flue gas (simulated by carbon dioxide–nitrogen–sulfur dioxide)–sulfur dioxide aqueous solution, and from the system of flue gas–sulfur dioxide containing tetra-n-butyl ammonium bromide (TBAB) aqueous solutions (sulfur dioxide mass concentration 0, 1.0, and 7.0 wt%). Comprehensive TBAB (solid, aqueous, and hydrate) Raman spectra were also obtained. The results reveal that when TBAB is used as promoter, both sulfur dioxide and carbon dioxide are encaged in the hydrate from systems of flue gas-TBAB solution with low sulfur dioxide concentration (0, 1.0 wt%), whereas in the hydrate from the system of flue gas-sulfur dioxide highly concentrated (7.0 wt%) TBAB solution, sulfur dioxide will be the sole gas guest encaged in the semi-clathrate hydrate. This suggests the sulfur dioxide concentration significantly influences the hydrate cage occupancies and separation selectivity of the hydrate-based technology. A two-stage hydrate-based flue gas purification process is proposed: one aims at desulfurization when sulfur dioxide concentrates to a relatively high level with the solutions recycling and in the other we can remove the sulfur dioxide and carbon dioxide simultaneously.

Co-pyrolysis behaviors of energy grass and lignite

A kind of energy grass (giant reedgrass) with high calorific value, high production, low land requirement and low sulfur dioxide emission is introduced into lignite pyrolysis process in this paper. Individual pyrolysis and co-pyrolysis characteristics of energy grass and lignite are investigated by the thermogravimetric analyzer together with mass spectrometer. The individual decomposition indicates that energy grass possesses higher thermochemical reactivity and shorter devolatilization time than lignite. The maximum decomposition rate increases with increasing the heating rate for both energy grass and lignite. The mass spectrometric analysis reveals that the emission of sulfur dioxide from energy grass is much lower than that from lignite. The co-pyrolysis of energy grass and lignite blend is characterized by two-stage thermal degradation processes, which is dominant by energy grass content in the first stage but lignite in the second stage. No obvious interaction between energy grass and lignite is observed during the co-pyrolysis process under the operational conditions investigated in this study. Moreover, the distributed activation energy model is applied to determine the activation energy for the pyrolysis of energy grass, lignite and their blends.

Meteorological controls on particle growth events in Beltsville, MD, USA during July 2011

During summer 2011, particle growth events were investigated in Beltsville, Maryland, USA where anthropogenic and biogenic hydrocarbon emissions heavily influenced the lower atmosphere. Aerosol sampling was made from a 5-m tower during July 2011. Ultrafine particle growth events occurred on 4 of the 25 days sampled. Regional particle growth events occurred after the passage of synoptic cold fronts. During regional particle growth events temperature and relative humidity were 2° Celsius lower and 3 % less than on non-event days and the local wind direction came from the northeast. With average growth rates of 3.5 nm hr−1, regional particle growth events happened around 15:00 Universal Time Coordinated, shortly after increased mixing within the atmospheric boundary layer. Regional particle growth events were associated with cooler, drier, mostly sunny days that had low sulfur dioxide mixing ratio (~0.6 parts per billion by volume). Regional particle growth events occurred when the atmospheric boundary layer was dominated by free convection and had lower sensible heat fluxes compared to short-lived events or non-particle growth event days.

Preparation of metal oxide doped ACNFs and their adsorption performance for low concentration SO2

Metal oxide (TiO2 or Co3O4) doped activated carbon nanofibers (ACNFs) were prepared by electrospinning. These nanofibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunner-Emmett-Teller method (BET). The results show that the average diameters of ACNFs were within the range of 200–500 nm, and the lengths were several tens of micrometers. The specific surface areas were 1146.7 m2/g for TiO2-doped ACNFs and 1238.5 m2/g for Co3O4-doped ACNFs, respectively. The electrospun nanofibers were used for adsorption of low concentration sulfur dioxide (SO2). The results showed that the adsorption rates of these ACNFs increased with an increase in SO2 concentration. When the SO2 concentration was 1.0 μg/mL, the adsorption rates of TiO2-doped ACNFs and Co3O4-doped ACNFs were 66.2% and 67.1%, respectively. The adsorption rate also increased as the adsorption time increased. When the adsorption time was 40 min, the adsorption rates were 67.6% and 69.0% for TiO2-doped ACNFs and Co3O4-doped ACNFs, respectively. The adsorption rate decreased as the adsorption temperature increased below 60°C, while it increased as the adsorption temperature increased to more than 60°C.