Concentrations Of Inorganic Ions Research Articles

The isotopic patterns and source apportionment of nitrate and ammonium in atmospheric aerosol

Nitrate (NO3-) and ammonium (NH4+) are the major components in inorganic aerosol. However, their sources and formation processes remain unclear. This study conducted a year-round field measurement of TSP, PM2.5 and PM1.0 in five different sites in the Beijing-Tianjin-Hebei (BTH) region to determine the concentrations of water-soluble inorganic ions (WSIIs) and the isotopic compositions of inorganic nitrogen (δ15N-NH4+, δ15N-NO3-, and δ18O-NO3-). The results showed the highest concentration of WSIIs in winter and lowest in summer. δ15N-NO3-, δ18O-NO3-, and δ15N-NH4+ were in the range of -6.1–18.2, 52.2–103.8, and -28.7–36.2‰, respectively. The seasonal variations of δ15N-NO3- and δ15N-NH4+ were an indication of relative contributions of the main sources and effects of meteorological conditions. The source apportionment identified fossil fuel combustion (38.2–50.6%), agricultural emissions (18–24.7%), biomass burning (16.3–22.7%), and road dust/soil (8.7–23.4%) were the main sources of inorganic aerosols. The local sources and regional migration contributed to the level of inorganic aerosol pollution. In winter, the aerosol in the BTH region was affected by the air mass from the northwest. While in spring and summer, the air mass was mainly from the South China. The low temperature and high relative humidity favored to the formation of inorganic nitrogen aerosol, and solar radiation affected the formation processes of inorganic aerosols by changing the oxidation pathway of NO3- and accelerating the volatilization and dissociation of ammonium nitrate (NH4NO3). This study discovered the main source contributions of inorganic nitrogen aerosol using N and O isotopes composition, and the obtained information has a great importance in understanding the effects of meteorological conditions on formation and the contribution of regional transport.

Chemical characteristics of size-resolved fog water at an urban site in Nanjing and the summit of Mt. Lu, East China

The chemical characteristics of fog water are closely related to the droplet size. This study used a three-stage Caltech Active Strand Cloud Collector (CASCC) to collect 170 size-resolved fog samples from eight fog events in the winter of 2013–2017 at an urban site in Nanjing and the summit of Mt. Lu. The pH, electrical conductivity (EC), and inorganic ion concentration were analyzed, and the sources of pollutants in size-dependent droplets were discussed according to the local emission source type. The pH, EC, total ion concentration (TIC), and ion composition of fog water at Nanjing were dependent on the droplet size. The TIC of fog water at Nanjing was approximately 10 times that measured at Mt. Lu. The concentration of different chemical species in the droplet was also size-dependent: Ca2+ concentration was higher in larger droplets with the diameter (D) ≥ 22 μm, whereas SO42−, NO3−, and NH4+ concentrations were higher in smaller droplets with D ranging 4–16 μm. The ion concentration of fog water at Mt. Lu first decreased then increased as the fog developed. Owing to the faster drop rate of larger droplets, coarse particles (2.5–10 μm) exhibited a faster response to fog removal, and the final mass concentration of fine particles (<2.5 μm) decreased the most due to competition between deposition and gravity. Different pollution sources exhibited different contribution rates to the chemical components of size-dependent droplets. Soil sources mainly affected the Ca2+ content of large droplets, whereas industrial sources and vehicles affected the NO3− and SO42− concentrations of medium and small droplets. Soil sources, industrial sources, and vehicles were the main sources of fog water at the urban site in Nanjing, whereas industrial sources, vehicles, soil sources, biomass combustion, and secondary aerosols were the main sources of fog water at the summit of Mt. Lu.

Chemical Components and Sources of PM2.5 and Their Evolutive Characteristics in Zhengzhou

To explore the main sources of PM2.5 and the characteristics of seasonal differences in Zhengzhou, PM2.5 sampling was conducted in 2019 and the concentrations of inorganic water-soluble ions, carbon components, and various elements were analyzed. Results showed that the average mass concentration of PM2.5 in 2019 was (67.0±37.2) μg ·m-3 with the highest concentration in winter and the lowest in summer. The main components of PM2.5 were nitrate, ammonium, sulfate, organic matter, crustal matter, and elemental carbon. In spring and autumn, PM2.5 was greatly affected by crustal matter and elemental carbon, and In summer, concentrations were mainly affected by sulfate. In winter, the concentrations of organic matter and nitrate increased significantly, produced by photochemical reactions in summer and aqueous-phase reactions under high humidity in winter. Carbonaceous aerosols were greatly influenced by automobile exhaust emission, coal combustion, and biomass combustion. Source apportionment showed that secondary sources were the greatest contributors in all four seasons, particularly in in winter (56.5%). Among the primary sources, the proportion of dust in spring (15.2%) and autumn (11.4%) was slightly higher, and the contribution of motor vehicle pollution was the largest (12.3%) in summer. In winter, PM2.5was greatly affected by coal combustion (13.2%). From 2014 to 2019, PM2.5 in Zhengzhou increased annually under the influence of secondary sources. The contribution of industrial sources, biomass combustion sources, and coal combustion sources exhibited a downward trend over this period.

Muscle-inspired ion-sensitive hydrogels with highly tunable mechanical performance for versatile industrial applications

Human muscles are notably toughened or softened with specific inorganic ions. Inspired by this phenomenon, herein we report a simple strategy to endow hydrogels with comparable ion-responsive mechanical properties by treating the gels with different ionic solutions. Semi-crystalline poly(vinyl alcohol) hydrogels are chosen as examples to illustrate this concept. Similar to muscles, the mechanical property of hydrogels demonstrates strong dependence on both the nature and concentration of inorganic ions. Immersed at the same salt concentration, the hydrogels treated with different ionic solutions manifest a broad-range tunability in rigidity (Young’s modulus from 0.16 to 9.6 MPa), extensibility (elongation ratio from 100% to 570%), and toughness (fracture work from 0.82 to 35 MJ m−3). The mechanical property well follows the Hofmeister series, where the “salting-out” salts (kosmotropes) have a more pronounced effect on the reinforcement of the hydrogels. Besides, the hydrogels’ mechanical performance exhibits a positive correlation with the salt concentration. Furthermore, it is revealed both the polymer solubility from amorphous domains and polymer crystallinity from crystalline domains are significantly influenced by the ions, which synergistically contribute to the salt-responsive mechanical performance. Benefitting from this feature, the hydrogels have demonstrated promising industrial applications, including tunable tough engineering soft materials, anti-icing coatings, and soft electronic devices.

A Comparative Study on Low and High Salinity Tolerance of Two Strains of Pinctada fucata

This study compares salinity tolerance between red and black shell Pinctada fucata salinity stress of 20 and 50‰, while 35‰ was used as a control. The hemolymph osmotic pressure, inorganic ion concentration, the activities of Na+-K+ -ATPase, respiratory metabolism related enzymes and liver tissue antioxidant related enzymes were measured at 12 and 24 h after salinity stress. The osmotic pressure and inorganic ion concentration of hemolymph of two strains P. fucata increased significantly with the increase of salinity. The activity of Na+-K+ -ATPase of red P. fucata only decreased under low salinity at 24 h, and was significantly higher than that the control under low salinity at 12 h and high salinity at 12 and 24 h. The succinate dehydrogenase (SDH) activities of the P. fucata treatment groups were significantly higher than those the control at 12 h. The lactate dehydrogenase (LDH) activity increased significantly with salinity at 12 h. and the black P. fucata LDH activity was significantly higher than the control at 24 h, while the LDH activity of red P. fucata was significantly lower than that the control in 50‰ salinity. The superoxide dismutase (SOD) activity of black P. fucata was significantly lower than that the control, while that of red P. fucata was significantly higher than that the control within 24. At 12 h, the catalase (CAT) activity of red P. fucata increased significantly with salinity, but decreased significantly with salinity at 24 h. The CAT activity of black P. fucata was highest at 24 h under low salinity. Glutathione peroxidase (GSH-Px) and alkaline phosphatase (AKP) activities of red P. fucata were significantly higher than those the control under low or high salinity. At high salinity for 24 h, the GSH-Px activity was lowest in black P. fucata, AKP activity was highest. The present study indicates that the physical responses of P. fucata to the salinity stress vary with shell colors. The red P. fucata can quickly respond positively to the change of environmental salinity and reduce the damage caused by the change of environmental salinity.

Contributions of aerosol chemical composition and sources to light extinction during haze and non-haze days in Taiyuan, China

To better understand the causes of visibility degradation in Taiyuan, the concentrations of PM1.5 and main chemical compositions were analyzed during the period from July 28, 2014 to April 26, 2015. The average concentration of PM1.5 during the sampling period was 107.6 ± 51.0 μg/m3. The concentrations of secondary inorganic water-soluble ions (SIA, the sum of SO42−, NO3− and NH4+), OC and EC were 31.0 μg/m3, 14.6 μg/m3 and 6.0 μg/m3, accounting for 28.8%, 13.5% and 5.6% of PM1.5, respectively. Light extinction coefficients (bext) were estimated by the revised US Interagency Monitoring of Protected Visual Environments (IMPROVE) equation. (NH4)2SO4 (48.7%) was the largest contributor to bext in summer, while the contribution of organic matter (OM) to bext was the highest in spring (25.0%) and winter (42.0%). Compared with non-haze days in summer and winter, the contributions of (NH4)2SO4 and NH4NO3 to bext during haze days increased, while the contributions of OM, EC, fine soil and coarse matter (PM1.5-10) decreased. Air masses from the southern areas had the largest bext and contribution of (NH4)2SO4 in summer and winter. The results of source apportionment by positive matrix factorization model found that secondary sulfate, secondary nitrate, coal combustion, vehicle emission, fugitive dust, biomass burning were the main sources to bext in Taiyuan. Secondary sulfate (81.7%) and coal combustion (43.1%) were the largest contributors to the bext in summer and winter during haze days, respectively. The results of our study could improve the understanding of the major sources that affect visibility degradation in Taiyuan.

Drivers of Organic Molecular Signatures in the Amazon River

AbstractAs climate‐driven El Niño Southern Oscillation (ENSO) events are projected to increase in frequency and severity, much attention has focused on impacts regarding ecosystem productivity and carbon balance in Amazonian rainforests, with comparatively little attention given to carbon dynamics in fluvial ecosystems. In this study, we compared the wet 2012 La Niña period to the following normal hydrologic period in the Amazon River. Elevated water flux during the La Niña period was accompanied by dilution of inorganic ion concentrations. Furthermore, the La Niña period exported 2.77 Tg C yr−1 more dissolved organic carbon (DOC) than the normal period, an increase greater than the annual amount of DOC exported by the Mississippi River. Using ultra‐high‐resolution mass spectrometry, we detected both intra‐ and interannual differences in dissolved organic matter (DOM) composition, revealing that DOM exported during the dry season and the normal period was more aliphatic, whereas compounds in the wet season and following the La Niña event were more aromatic, with ramifications for its environmental role. Furthermore, as this study has the highest temporal resolution DOM compositional data for the Amazon River to‐date we showed that compounds were highly correlated to a 6‐month lag in Pacific temperature and pressure anomalies, suggesting that ENSO events could impact DOM composition exported to the Atlantic Ocean. Therefore, as ENSO events increase in frequency and severity into the future it seems likely that there will be downstream consequences for the fate of Amazon Basin‐derived DOM concurrent with lag periods as described here.

Characteristics of Aerosol and Effect of Aerosol-Radiation-Feedback in Handan, an Industrialized and Polluted City in China in Haze Episodes

In order to investigate the chemical characteristics of aerosol pollution including PM1 and PM2.5 in Handan, the offline sampling campaign was conducted and the concentrations of total water-soluble inorganic ions (TWSI), carbonaceous components (OC and EC) were analyzed. The average concentrations were 88.5 μg/m3 for PM1 and 122 μg/m3 for PM2.5, and the corresponding ratios of PM1 versus PM2.5 on non-pollution, mild-moderate pollution and heavy pollution were 0.67, 0.70 and 0.77, respectively. TWSI and OC accounted for 43.2% and 15.4% in PM1, 41.8% and 16.0% in PM2.5. Secondary components in PM2.5 and PM1 increased with heavy pollution, SNA (SO42−, NO3− and NH4+) was enriched in PM1 but SOC (Secondary Organic Carbon) was more enriched in PM1–2.5. Furthermore, for evaluating the effect of aerosol feedback the WRF-Chem model was applied to identify the aerosol-radiation interaction of aerosol feedback influence on the PM2.5 concentration and various meteorological factors in Handan. The results indicated that the aerosol radiative effects will result in an average 32.62%(36.18 W/m2) decrease in downward short wave flux at ground surface (SWDOWN), an average 17.52% (39.15 m) and 0.16% (0.44 K) decrease in planetary boundary layer height(PBLH) and surface temperature (T2). The wind speed at 10 m (WS) and relative humidity (RH) will be increased by about 4.16%(0.11 m/s) and 1.89% (0.78%), respectively.

Analysis of the Water Quality of the Ishim River within the Akmola Region (Kazakhstan) Using Hydrochemical Indicators

For the first time in scientific literature, this work addresses the current situation of the Ishim River water quality in the Akmola Region (Northern Kazakhstan). This work uses environmental monitoring techniques to analyze the current state of surface waters in the river. The content of main ions, biogenic and inorganic ions, heavy metals, organic impurities in seasonal and annual dynamics have been studied. Results show that, despite the tightening of requirements for wastewater discharge into the Ishim River basin, a number of water quality indicators did not fulfill the regulatory requirements for surface water bodies during 2013–2019. It has been identified that the greatest pollution in the Ishim River is brought by enterprises of the Karaganda-Temirtau technogenic region, located in the upper reaches of the river. Future water quality monitoring is needed and should include increasing the number of sampling locations and the sampling frequency in order to characterize the spatial and temporal variability of hydrochemical parameters and allow a comprehensive monitoring of legally fixed water quality parameters/indicators.

Chemical speciation of iron in the euphotic zone along the Kuroshio Current

The distributions of dissolved iron (DFe) and organic iron-binding ligands (LFe) in the Kuroshio Current and its neighboring waters were elucidated from four cross-sectional surveys from the eastern coast of Taiwan to Sagami Bay. The Kuroshio surface water was characterized by a high salinity, low concentration of DFe, high concentration of LFe, and low fluorescence of humic-like substances, in comparison to the neighboring waters. The neighboring waters of the Kuroshio can be categorized into two types: the East China Sea water and coastal water. The East China Sea water was found near the Okinawa Trough, and characterized by a steep vertical gradient of DFe concentration, almost as low as that in the Kuroshio within the surface mixed layer, but reached ~0.5 nM below the mixed layer. Coastal water was observed on the southern coast of Japan, and its DFe concentration was high throughout the upper 200 m. The concentration of LFe in the Kuroshio water was significantly higher at 10-m depth than in the deeper layers. This suggests that humic-like substances, which are a major component of LFe in estuarine and deep waters, play a relatively minor role in the Kuroshio surface waters. Mixing with coastal waters can increase the concentration of bioavailable inorganic ferric ions in the Kuroshio surface water in two ways, by increasing the DFe concentration and decreasing the LFe concentration.

Particles liquid water and acidity determine formation of secondary inorganic ions in Urumqi, NW China

Secondary atmospheric pollutants are an important component of the particles found in Urumqi city, China, Further, secondary inorganic aerosols, in particular, increase significantly during the winter heating period. In this study, samples collected from October 2017 to August 2018 from Urumqi were analyzed. Results showed that the average concentration of water-soluble inorganic ions (WSIs) in the heating period (86.9 ± 31.1 μg·m−3) was significantly higher than that in the non-heating period (14.1 ± 8.67 μg·m−3). SNA (SO42−, NO3−, NH4+) accounted for 90.7% of the total WSIs (TWSIs) in the heating period. Simulations revealed that the in situ pH (3.1) was higher in the heating period than that in non-heating period (0.66) when they were calculated by the aerosol thermodynamic model. The particles were found to be acidity during the entire period. The liquid water content of the particulates (LWC) was found to higher in the heating period (55.5 ± 51.8 μg·m−3) than the non-heating period (21.3 ± 40.3 μg·m−3). The average nitrogen oxidation rate (NOR) and sulfur oxidation rate (SOR) were 0.16 and 0.36, respectively, indicating a significant secondary formation of nitrate and sulfate in the atmosphere of Urumqi. Further analysis indicated that sulfate was significantly affected by the LWC and acidity of the particulates; nitrate was produced under ammonia-rich conditions in Urumqi, and the LWC facilitated the production of nitrate. This study provides information about the formation of secondary sulfate and nitrate aerosols during different periods in suburban Urumqi.

Sunlight-active Cu/Fe@ZnWO4-kaolinite composites for degradation of acetaminophen, ampicillin and sulfamethoxazole in water

This study reports the development of biomass-assisted sunlight-active semiconductor-tungstate-clay photocatalytic composite for the removal of pharmaceutical contaminants (PCs): Acetaminophen (ACT), Ampicillin (AMP) and Sulfamethoxazole (SMX), from water. Materials prepared (Cu@ZnWO4–K, Fe@ZnWO4–K and Cu/Fe@ZnWO4–K) composites, were characterized using Scanning Electron Microscopy (SEM), Fourier Transformed Infrared spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Raman Spectroscopy, High Resolution TEM and X-ray Diffraction (XRD). XRD analysis showed the presence of Scheelite (CuWO4), Ferberite (FeWO4) and Sanmartinite (ZnWO4) crystal phases in the composites. Moreover, results showed that Cu@ZnWO4–K composite gave the best efficiency for the photodegradation of AMP (100%), ACT (83%), and SMX (68%) molecules. This composite showed more preference for the photodegradation of AMP molecules (>98%) even in the presence of ACT and SMX molecules. After five reuse cycles, the composite still had ca. 90% efficiency for AMP molecules but far less for the other two molecules. The presence of anions reduced the photocatalytic efficiency of this composite but increased the photodegradation of SMX molecules. The rate of photodegradation of the PCs was comparably fast, leading to high removal capacity. The concentrations of inorganic ions released as by-products of photodegradation, were far below WHO standard limits for their presence in drinking water.

Chemical and Optical Characteristics and Sources of PM2.5 Humic-Like Substances at Industrial and Suburban Sites in Changzhou, China

The chemical and optical properties and sources of atmospheric PM2.5 humic-like substances (HULIS) were investigated from October to December 2016 in both industrial and suburban areas in Changzhou, China, during polluted and fair days. The average PM2.5 concentration in the industrial region was 113.06 (±64.3) μg m−3, higher than 85.27 (±41.56) μg m−3 at the suburban site. The frequency of polluted days was significantly higher in the industrial region. In contrast, the chemical compositions of PM2.5 at the two sampling sites exhibited no statistically significant differences. Rapidly increased secondary inorganic ions (SNA = NH4+ + SO42− + NO3−) concentrations suggested secondary formation played an important role in haze formation. The daily mean concentration of humic-like substance (HULIS) was 1.8–1.9 times that of HULIS-C (the carbon content of HULIS). Our results showed that HULIS accounted for a considerable fraction of PM2.5 (industrial region: 6.3% vs. suburban region: 9.4%). There were no large differences in the mass ratios of HULIS-C/WSOC at the two sites (46% in the industrial region and 52% in the suburban region). On average, suburban HULIS-C constituted 35.1% of organic carbon (OC), higher than that (21.1%) in the industrial region. Based on different MAE (mass absorption efficiency) values under different pollution levels, we can infer that the optical properties of HULIS varied with PM levels. Moreover, our results showed no distinct difference in E2/E3 (the ratio of light absorbance at 250 nm to that at 365 nm) and AAE300–400 (Absorption Angstrom Exponent at 300–400 nm) for HULIS and WSOC. the MAE365 (MAE at 365 nm) value of HULIS-C was different under three PM2.5 levels (low: PM2.5 &lt; 75 μg m−3, moderate: PM2.5 = 75–150 μg m−3, high: PM2.5 &gt; 150 μg m−3), with the highest MAE365 value on polluted days in the industrial region. Strong correlations between HULIS-C and SNA revealed that HULIS might be contributed from secondary formation at both sites. In addition, good correlations between HULIS-C with K+ in the industrial region implied the importance of biomass burning to PM2.5-bound HULIS. Three common sources of HULIS-C (i.e., vehicle emissions, biomass burning, and secondary aerosols) were identified by positive matrix factorization (PMF) for both sites, but the contributions were different, with the largest contribution from biomass burning in the industrial region and secondary sources in the suburban region, respectively. The findings presented here are important in understanding PM2.5 HULIS chemistry and are valuable for future air pollution control measures.

A long-term chemical characteristics and source apportionment of atmospheric rainfall in a northwest megacity of Xi'an, China.

A long-term measurement on rainfall was conducted in urban Xi'an, China, from 2009 to 2016. The seasonal and annual variations of major inorganic components and their chemical properties in the rainfall were studied. The annual rainfall ranged from 165.3 to 916.3 mm. The pH value of the rainfall ranged from 6.36 to 7.19, with an average value of 6.70. The electric conductivity (EC) in the rainfall was in a range of 55.91 to 227.44 μS·cm-1. Ammonium (NH4+), calcium (Ca2+), nitrate (NO3-), and sulfate (SO42-) were the four major components, accounting for 88.5% of the total quantified inorganic ion concentration. Neutralization factors were determined for Ca2+ (1.03), NH4+ (0.57), Mg2+ (0.10), Na+ (0.06), and K+ (0.04). The high abundance of NH4+ that formed from its precursor of ammonia gas (NH3) suggested the contribution of agricultural fertilization. Ca2+ in the rainfall was mainly from natural sources such as soil dust, while anions of NO3- and SO42- originated from fossil fuel combustion. Source apportionment was conducted with positive matrix factorization (PMF) which identified that secondary inorganic formation, crustal dust, coal combustion, and biomass burning are the contributors to the rainfall. In between, secondary inorganic formation was the largest contributor, which accounted for 27.8-58.1% of the total sources, followed by crustal dust of 0.4-42.6%. The results of this long-term study demonstrated the decreasing trends of contributions from coal combustion and biomass burning under a series of air pollution control measures implemented by the government. However, continuous urbanization and development of the city caused substantial increases of the construction activities, inducing more crustal dusts to the environment in urban Xi'an.

Evaluation of black carbon source apportionment based on one year's daily observations in Beijing

Combustion-derived black carbon (BC) is increasingly recognized as a significant pollutant that can have adverse effects on the atmospheric environment, human health, and regional climate. Fossil fuel combustion is the main source of BC, yet understanding of the relative contributions to BC from coal and liquid fuel combustion remains incomplete. Moreover, few studies have assessed the relative contributions based on long-term continuous daily field observations. This study adopted a Bayesian model of a three-dimensional array of a stable carbon isotope and the ratios of non-sea-salt K+ to BC and ΔBC/ΔCO of one year's daily observations (from September 1, 2017 to August 31, 2018) to constrain source apportionment of BC in Beijing (China). Results showed that both the BC and the carbon isotope concentrations exhibited strong seasonal variability, and that the annual BC concentration has decreased significantly in recent years. The Bayesian model results also revealed that the relative contributions from the combustion of coal, liquid fuel, and biomass were 42% ± 18%, 42% ± 18%, and 16% ± 11%, respectively, with a larger contribution from coal (liquid fuel) combustion in winter and spring (summer and autumn). The seasonal variation of source appointment was attributed to local and regional fuel combustion coupled with meteorological conditions. With increasing PM2.5 level, the BC concentration derived from biomass burning increased fastest, followed by that derived from coal combustion. But concentration of secondary inorganic ions increased faster than BC as PM2.5 increased.

Can arbuscular mycorrhizal fungi and biochar enhance plant resistance to low‐temperature stress?

AbstractImproving plant resistance to abiotic stress, such as low temperature, is conducive to plant normal growth and development. The aim of this study was to clarify whether arbuscular mycorrhizal fungi (AMF) and biochar have a synergistic effect on plant growth and resistance to low‐temperature stress in perennial ryegrass (Lolium perenne L.). A pot experiment was conducted to measure the effects of AMF (Glomus intraradices) inoculation, biochar addition (4%, w/w), and their combination on the biomass, inorganic ion contents, antioxidant enzyme activities, and osmotic regulator contents in L. perenne plants growing under room temperature and low temperature conditions. A saline soil with the total salt content of 5.21 g kg–1 was used in the experiment. Results showed that the AMF‐only treatment decreased biomass growth under room temperature condition, whereas the biochar‐only treatment increased total biomass under low temperature condition. The combined treatment with AMF and biochar evidently increased biomass growth via a synergistic effect under both room temperature and low temperature conditions. Under low‐temperature stress, the AMF‐ and biochar‐only treatments increased proline content in the plant leaves. Meanwhile, superoxide dismutase and peroxidase activities were enhanced substantially in the AMF‐only group compared to the control group. The combined treatment with AMF and biochar considerably increased catalase activity and proline content and reduced malondialdehyde content in the plant leaves under low‐temperature stress. In conclusion, AMF and biochar exhibited a synergistic effect in promoting plant growth of L. perenne and played a role in improving plant resistance to low‐temperature stress in the saline soil.

Enhanced photocatalytic activity of Bi24O31Br10 microsheets constructing heterojunction with AgI for Hg0 removal

A range of AgI modified Bi24O31Br10 heterojunction microsheets were produced by a hydrothermal subsequent deposition-precipitation method for highly efficient photocatalytic removal of Hg0 under fluorescent light irradiation. Diverse characterization techniques such as XRD, BET, SEM, TEM, UV − vis DRS, XPS, PL, and ESR were implemented to investigate the properties of the as-fabricated materials. The experimental parameters such as AgI content, sample dosage, pH value of solution, reaction temperature, FSL illumination, inorganic anions, SO2 and NO were employed to evaluate the activity of the materials. It was found that the AgI material was successfully deposited on the surface of Bi24O31Br10 microsheets. In comparison, the dramatic enhancement photocatalytic performance of AgI-Bi24O31Br10 could be assigned to synergies of Bi24O31Br10 and AgI under fluorescent light irradiation, including effective electron-hole separations and generation of photocatalytic active substances at the interfaces of the two semiconductors. AgI loading, inorganic carbonate ion contents and SO2 gas all had significant influence on the removal of Hg0. The 2% AgI-Bi24O31Br10 sample was testified to exhibit an extraordinary enhanced photocatalytic activity. On the basis of the results of ESR detection and radical trapping experiments, reactive substances O2− and h+ were significant players in the photocatalytic reaction.

Source Apportionment of Urban Ammonia and its Contribution to Secondary Particle Formation in a Mid-size European City

ABSTRACT Ambient air pollution caused by fine particulate matter (PM) and trace gases is a pressing topic as it affects the vast majority of the world's population, with a particularly heavy influence in densely populated urban environments. Alongside nitrogen oxides (NOx) and PM, ammonia (NH3) is also a relevant air pollutant due to its role as a precursor of particulate ammonium. This is a study about the short-term temporal dynamics of urban NH3 concentrations in Munster, northwest Germany, the role of road traffic and agriculture as NH3 sources and about the importance of ammonia for secondary particle formation (SPF). The NH3 mixing ratio was rather high (mean: 17 ppb) compared to other urban areas and showed distinct diurnal maxima around 10 a.m. and during the night at 9 p.m. The main source for ammonia in Munster was agriculture, but road traffic also contributed through local emissions from vehicle catalysts. NH3 from surrounding agricultural areas accumulated in the nocturnal boundary layer and contributed to SPF in the city center. Modeled emissions of NH3 as estimated by the Handbook for Emission Factors in combination with traffic counts were in the same magnitude for NH3. The size-resolved chemical composition of inorganic ions in PM10 was dominated by NH4+ (8.66 µg m–3), followed by NO3– (3.89 µg m–3), SO42– (1.58 µg m–3) and Cl– (1.33 µg m–3). Particles in the accumulation range (diameter: 0.1–1 µm) showed the highest inorganic ion concentrations. The ammonium neutralization index J (111%) indicated an excess of NH4+ leading to mostly alkaline PM. High ammonia emissions from surrounding agricultural areas combined with large amounts of NOx from road traffic play a crucial role for SPF in Munster.

Enhancement of lignite microwave dehydration by cationic additives

The addition of materials with high dielectric parameters can improve lignite’s microwave absorption, thereby, enhancing lignite microwave dehydration. In order to explore the promotion effect of cationic additives on this process, five kinds of same and different valence state additives were studied in this paper. The physicochemical properties of the solid and liquid products under each condition were compared and analyzed in detail. Process characteristics, dehydration kinetics, and moisture diffusion coefficient results showed that the higher the cationic valence, the weaker the promotion effect of additives on lignite dehydration. When the cationic valence was the same, the promotion effect of additives was affected by the hydration radius of cations and solubility of additives. After microwave treatment, the pore structure of solid products at first decreased, then increased, ultimately developing into mesopore and micropore regions. Their absorption capacity was weakened according to contact angle tests. The significance was that the combustion of solid products was more complete, and the number of pollutants released was reduced. For liquid products, the content of organic matter and inorganic ions increased greatly. The surface tension first increased, followed by a decrease, indicating that the removal of organic matter gradually exceeded that of inorganic matter, and that additive had an effect on the microwave process of lignite sequentially through dehydration, dissolution of inorganic substances, and destruction of organic structure.

The quality of Slovenian chestnut honey and its specific properties relevant for medical application and functional nutrition

Chestnut honey is well-described in terms of sensory properties, pollen and chemical composition. Specific bitter taste is accompanied with other typical sensory properties derived from its chemical composition, especially in the nectar of sweet chestnut. Compounds from other sources of nectar and honeydew, especially linden, fir and spruce, with smaller amounts from meadow plants, create the specific sensory and chemical properties of Slovene chestnut honey. Based on the chemical composition of the honey, especially the content and proportions of different inorganic ions, it is possible to track the geographical origin of the pasture. Bees contribute significantly to recognized antimicrobial properties of honey by secretion of enzymes and antimicrobial peptides via the food processing glands. When the honey is used for medical purposes, we have to take precautions to avoid microbial and chemical contamination. For the planning of specific use of honey as a medical application we need to explore in detail specific pharmacological properties of single compounds from the chestnut honey and its contribution to the whole activity during wound treatment. In this paper we present a review of most distinct properties of chestnut honey important for its medical application.