scholarly journals Environmental Risk Assessment of Industrial by-product Gypsum Utilized in Filling Abandoned Mine

2021 ◽  
Author(s):  
XueHong Du ◽  
Xiangdong Li ◽  
Qiyan Feng ◽  
Lei Meng ◽  
Yue Sun
Keyword(s):  
Abandoned Mines ◽  
Filling Material ◽  
Metallic Elements ◽  
Migration Ability ◽  
Fgd Gypsum ◽  
Metal Elements ◽  
Leaching Toxicity ◽  
Result Show ◽  
Acidic Conditions ◽  
Ph Conditions

Abstract This paper conducts sequential batch extraction experiments on phosphorus gypsum, titanium gypsum and desulfurized gypsum to explore their leaching characteristics and evaluate the hazards of the three types of gypsum. In addition, COMSOL Multiphysics is used to numerically solve the filling models of the three gypsum materials and the patterns of migration of metal elements in gypsum are observed. The result show that the leaching concentration of metal elements of the three gypsums is much lower than the leaching toxicity identification standard, so none of the three have the characteristics of leaching toxicity, and they are not classified as hazardous solid wastes; phosphorus gypsum and FGD gypsum are easier to release metal elements under low pH conditions, while the release of metal elements in titanium gypsum is not obvious under acidic conditions; the simulation results show that the diffusion concentration of metal elements increases with the passage of time, and its migration ability decreases with the increase of depth. The three gypsums can be considered as filling material for abandoned mines. During the filling process, the diffusion rate, diffusion distance and final concentration of metallic elements in gypsum are all affected by the initial concentration.

Soil and Vegetation Pollution from an Abandoned Mining Area Situated in Hunedoara County, Romania

2018 ◽  
Vol 69 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Cristina Dinu ◽  
Eleonora Mihaela Ungureanu ◽  
Gabriela Geanina Vasile ◽  
Lidia Kim ◽  
Ioana Ionescu ◽  
...  
Keyword(s):  
Mine Waste ◽  
High Mobility ◽  
Mining Area ◽  
Soil Samples ◽  
Dermal Absorption ◽  
Abandoned Mines ◽  
Emission Spectrometry ◽  
Metallic Elements ◽  
Vegetation Samples ◽  
Nickel Lead

The soils situated near the abandoned mines are highly polluted with metals due to the discharge and dispersion of mine waste into nearby air, water (surface and groundwater) and soil. Heavy metals may be transferred to humans through ingestion, inhalation or dermal absorption and can produce serious health problems affect the nervous, endocrine and immune systems, hematopoietic function and cellular metabolism. This paper investigates the presence of metallic elements from fourteen soil samples (seven sampling points) and thirty-six vegetation samples (different types of leaves, plants, roots and tree barks). The samples were collected from six different sites located in an abandoned mining area and from a point (blank sample) located 5 km in the SV direction of the quarry. The results obtained for soil samples show an overrun of the alert and / or intervention threshold for the following metals: arsenic, cadmium, cobalt, copper, manganese, nickel, lead and zinc. The analytical investigation for vegetation samples indicated that concentration for calcium, magnesium, cadmium, chromium, manganese, nickel, lead, zinc were situated over the normal range in some samples. The analytical investigations were performed by optical emission spectrometry (ICP-OES). The study�s conclusion indicates that, as result of soil acidic pH and high mobility of some metals, metallic elements migrate from soil to vegetation.

scholarly journals Fly Ash Modified Coalmine Solid Wastes for Stabilization of Trace Metals in Mining Damaged Land Reclamation: A Case Study in Xuzhou Coalmine Area

2018 ◽  
Vol 15 (10) ◽  
pp. 2317 ◽  
Author(s):  
Jiu Huang ◽  
Peng Wang ◽  
Chaorong Xu ◽  
Zhuangzhuang Zhu
Keyword(s):  
Fly Ash ◽  
Trace Metal ◽  
Soil Layer ◽  
Fly Ashes ◽  
Migration Ability ◽  
Metal Elements ◽  
Trace Metal Elements ◽  
Simulated Precipitation ◽  
Backfill Materials

In China, coalmine wastes, such as gangues, are used for reclamation of mining subsided land. However, as waste rocks, gangues contain several trace metal elements, which could be released under natural weathering and hydrodynamic leaching effects and then migrate into the reclamed soil layer. However, it is very difficult to find adequate other backfill materials for substitution of gangues. In this paper, we present a novel method and case study to restrict the migration ability of trace metal elements in gangues by using another kind of coalmine solid waste—fly ashes from coal combustion. In this study, fly ashes were mixed with gangues in different mass proportions 1:0.2, 1:0.4, 1:0.6 and 1:0.8 as new designed backfill materials. Due to the help of fly ash, the occurrence states of studied trace metal elements were greatly changed, and their releasing and migration ability under hydrodynamic leaching effect were also significantly restricted. In this research seven trace metal elements in gangues Cu, Zn, Pb, Cd, Cr, Mn and Ni were studied by using soil column hydrodynamical leaching method and simulated precipitation for one year. The results show that under the driving of natural precipitation trace metal elements were generally transported deep inside the reconstructed land base, i.e., far away from soil layer and most of the trace metal elements were transformed into a bonded state, or combined in inert occurrence states, especially the residual state. With this method, the migration activities of tested trace metal elements were greatly restricted and the environmental potential risk could be significantly reduced.

scholarly journals A New pH-Dependent Macrocyclic Rhodamine B-Based Fluorescent Probe for Copper Detection in White Wine

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4514 ◽  
Author(s):  
Nour Doumani ◽  
Elias Bou-Maroun ◽  
Jacqueline Maalouly ◽  
Maya Tueni ◽  
Adrien Dubois ◽  
...  
Keyword(s):  
Rhodamine B ◽  
White Wine ◽  
Green Solvent ◽  
Acidic Media ◽  
One Pot ◽  
Acidic Conditions ◽  
Ph Conditions ◽  
Ph Dependent ◽  
Copper Detection ◽  
Color Emission

For efficiently measuring copper (II) ions in the acidic media of white wine, a new chemosensor based on rhodamine B coupled to a tetraazamacrocyclic ring (13aneN4CH2NH2) was designed and synthesized by a one-pot reaction using ethanol as a green solvent. The obtained chemosensor was characterized via NMR, UV and fluorescent spectra. It was marked with no color emission under neutral pH conditions, with a pink color emission under acidic conditions, and a magenta color emission under acidic conditions where copper (II) ions were present. The sensitivity towards copper (II) ions was tested and verified over Ca2+, Ag+, Zn2+, Mg2+, Co2+, Ni2+, Fe2+, Pb2+, Cd2+, Fe3+, and Mn2+, with a detection limit of 4.38 × 10−8 M in the fluorescence spectrum.

scholarly journals Preparation and Characterization of Alginate and Psyllium Beads ContainingLactobacillus acidophilus

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Farzaneh Lotfipour ◽  
Shahla Mirzaeei ◽  
Maryam Maghsoodi
Keyword(s):  
Lactobacillus Acidophilus ◽  
Encapsulation Efficiency ◽  
Alginate Beads ◽  
Probiotic Bacteria ◽  
Partial Substitution ◽  
Narrow Size Distribution ◽  
Acidic Conditions ◽  
Ph Conditions

This paper describes preparation and characterization of beads of alginate and psyllium containing probiotic bacteria ofLactobacillus acidophilusDMSZ20079. Twelve different formulations containing alginate (ALG) and alginate-psyllium (ALG-PSL) were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology and surface properties, encapsulation efficiency, viabilities in acid (pH 1.8, 2 hours) and bile (0.5% w/v, 2 hours) conditions, and release in simulated colon pH conditions. The results showed that spherical beads with narrow size distribution ranging from1.59±0.04to1.67±0.09 mm for ALG and from1.61±0.06to1.80±0.07mm for ALG-PSL with encapsulation efficiency higher than 98% were achieved. Furthermore, addition of PSL into ALG enhanced the integrity of prepared beads in comparison with ALG formulations. The results indicated that incorporation of PSL into alginate beads improved viability of the bacteria in acidic conditions as well as bile conditions. Also, stimulating effect of PSL on the probiotic bacteria was observed through 20-hour incubation in simulated colonic pH solution. According to ourin vitrostudies, PSL can be a suitable polymer candidate for partial substitution with ALG for probiotic coating.

scholarly journals Membrane fusion process of Semliki Forest virus. II: Cleavage-dependent reorganization of the spike protein complex controls virus entry.

1992 ◽  
Vol 116 (2) ◽  
pp. 349-357 ◽  
Author(s):  
A Salminen ◽  
J M Wahlberg ◽  
M Lobigs ◽  
P Liljeström ◽  
H Garoff
Keyword(s):  
Membrane Fusion ◽  
Semliki Forest Virus ◽  
Wild Type Virus ◽  
Wild Type ◽  
Cell Binding ◽  
Virus Budding ◽  
Virus Particles ◽  
Acidic Conditions ◽  
Ph Conditions ◽  
Heterodimeric Complex

The envelope of the Semliki Forest virus (SFV) contains two transmembrane proteins, E2 and E1, in a heterodimeric complex. The E2 subunit is initially synthesized as a precursor protein p62, which is proteolytically processed to the mature E2 form before virus budding at the plasma membrane. The p62 (E2) protein mediates binding of the heterodimer to the nucleocapsid during virus budding, whereas E1 carries the entry functions of the virus, that is, cell binding and low pH-mediated membrane fusion activity. We have investigated the significance of the cleavage event for the maturation and entry of the virus. To express SFV with an uncleaved p62 phenotype, BHK-21 cells were transfected by electroporation with infectious viral RNA transcribed from a full-length SFV cDNA clone in which the p62 cleavage site had been changed. The uncleaved p62E1 heterodimer was found to be used for the formation of virus particles with an efficiency comparable to the wild type E2E1 form. However, in contrast to the wild type virus, the mutant virus was virtually noninfectious. Noninfectivity resulted from impaired uptake into cells, as well as from the inability of the virus to promote membrane fusion in the mildly acidic conditions of the endosome. This inability could be reversed by mild trypsin treatment, which converted the viral p62E1 form into the mature E2E1 form, or by treating the virus with a pH 4.5 wash, which in contrast to the more mild pH conditions of endosomes, effectively disrupted the p62E1 subunit association. We conclude that the p62 cleavage is not needed for virus budding, but regulates entry functions of the E1 subunit by controlling the heterodimer stability in acidic conditions.

scholarly journals Odstraňování rtuti z kyselých roztoků chloridu rtuťnatého sorbenty připravenými katalyzovanou vulkanizací rostlinných olejů

2022 ◽  
Vol 116 (1) ◽  
pp. 48-55
Author(s):  
Karel Svoboda ◽  
Tomáš Ružovič ◽  
Michael Pohořelý ◽  
Miloslav Hartman ◽  
Michal Šyc
Keyword(s):  
Flue Gas ◽  
Hot Water ◽  
Metallic Elements ◽  
Mercury Ions ◽  
Metallic Mercury ◽  
Acidic Solutions ◽  
Mercury Compounds ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Neutral Conditions

Mercury is a metallic element, dangerous and toxic for the environment. Presently, the incineration of municipal solid waste (MSW) belongs to important sources of Hg emissions. Methods of conversion of metallic mercury and mercury compounds from soluble and toxic forms into water insoluble/non-toxic form (HgS) are sought after. Gaseous HCl and a significant part of HgCl2 vapors present in flue gas from incineration of MSW can be removed there by absorption in hot water. Efficiencies of Hg2+ removal from acidic water solutions by means of sorbents prepared by catalyzed reaction of sulfur with vegetable oils (inverse vulcanization) were studied. These kinds of sorbents were tested and found to be exploitable for selective removal of mercury ions from aqueous solutions, particularly from acidic solutions containing HCl at higher temperatures (50–75 °C). Presence of relatively high concentrations of salts of some other metallic elements (Fe, Zn, Ca) had only very small effects on Hg-sorption. Mercury adsorbed on such sorbents converts relatively quickly into a non-toxic form (HgS). Reactive sulfides and SH‑groups present on the surface of the sorbent particles contribute to a faster sorption of mercury and its conversion to HgS. Leaching of zinc from the catalyst (Zn‑diethyldithiocarbamate) present in the vulcanized sorbents is negligible at neutral conditions and small (about 10 %) at acidic conditions (pH = 1.5).

scholarly journals Ultrafine bubbles as an augmenting agent for ozone-based advanced oxidation

2021 ◽  
Author(s):  
Tatek Temesgen ◽  
Mooyoung Han
Keyword(s):  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Negative Influence ◽  
Oh Radicals ◽  
Oh Radical ◽  
Oxidation Processes ◽  
Acidic Conditions ◽  
Ph Conditions ◽  
First Time ◽  
Influence Of Ph

Abstract In this study, the influence of nanobubbles (NBs) application in ozone (O3) based advanced oxidation processes (AOP) is investigated. The results demonstrate the potential of NBs application to O3 – based AOP. It was observed that NBs suppress the negative influence of pH and operating temperatures on the efficiency of ozonation. In addition, the application of NBs tends to improve the solubility of O3 and the rate of mass transfer under the influence of a broad range of temperature and pH conditions. The results of this research indicate that application of NBs minimized the reduction in concentration of dissolved O3 with an increase in temperature. Furthermore, application of NBs highly improved the OH radical formation in acidic conditions. The results of this research depicted for first time that the application of NBs strongly encourages the initiation of reactions involving OH radicals. It was found by this research that NBs can boost the concentration of OH radicals up to 3.5 fold compared to equivalent MB supported ozonation systems. This is assumed to improve the efficiency of currently existing conventional bubble supported O3 – based AOP systems.

scholarly journals The Impact of pH on Clostridioides difficile Sporulation and Physiology

2019 ◽  
Vol 86 (4) ◽  
Author(s):  
Daniela Wetzel ◽  
Shonna M. McBride
Keyword(s):  
Phenotypic Diversity ◽  
Toxin Production ◽  
Low Ph ◽  
Spore Morphology ◽  
Content Type ◽  
Clostridioides Difficile ◽  
Alkaline Environments ◽  
Acidic Conditions ◽  
Ph Conditions ◽  
The Impact

ABSTRACT Clostridioides difficile is a pathogenic bacterium that infects the human colon to cause diarrheal disease. Growth of the bacterium is known to be dependent on certain bile acids, oxygen levels, and nutrient availability in the intestine, but how the environmental pH can influence C. difficile is mostly unknown. Previous studies indicated that C. difficile modulates the intestinal pH, and prospective cohort studies have found a strong association between a more alkaline fecal pH and C. difficile infection. Based on these data, we hypothesized that C. difficile physiology can be affected by various pH conditions. In this study, we investigated the impact of a range of pH conditions on C. difficile to assess potential effects on growth, sporulation, motility, and toxin production in the strains 630Δerm and R20291. We observed pH-dependent differences in sporulation rate, spore morphology, and viability. Sporulation frequency was lowest under acidic conditions, and differences in cell morphology were apparent at low pH. In alkaline environments, C. difficile sporulation was greater for strain 630Δerm, whereas R20291 produced relatively high levels of spores in a broad range of pH conditions. Rapid changes in pH during exponential growth impacted sporulation similarly among the strains. Furthermore, we observed an increase in C. difficile motility with increases in pH, and strain-dependent differences in toxin production under acidic conditions. The data demonstrate that pH is an important parameter that affects C. difficile physiology and may reveal relevant insights into the growth and dissemination of this pathogen. IMPORTANCE Clostridioides difficile is an anaerobic bacterium that causes gastrointestinal disease. C. difficile forms dormant spores which can survive harsh environmental conditions, allowing their spread to new hosts. In this study, we determine how intestinally relevant pH conditions impact C. difficile physiology in the two divergent strains, 630Δerm and R20291. Our data demonstrate that low pH conditions reduce C. difficile growth, sporulation, and motility. However, toxin production and spore morphology were differentially impacted in the two strains at low pH. In addition, we observed that alkaline environments reduce C. difficile growth, but increase cell motility. When pH was adjusted rapidly during growth, we observed similar impacts on both strains. This study provides new insights into the phenotypic diversity of C. difficile grown under diverse pH conditions present in the intestinal tract, and demonstrates similarities and differences in the pH responses of different C. difficile isolates.

The genesis of uranium in manganese and phosphorite assemblages, Timna Basin, Israel

1987 ◽  
Vol 124 (3) ◽  
pp. 211-229 ◽  
Author(s):  
Miryam Bar-Matthews
Keyword(s):  
Lower Cambrian ◽  
Fission Track ◽  
Type A ◽  
Type B ◽  
Metallic Elements ◽  
Manganese Nodules ◽  
Reducing Conditions ◽  
Ph Conditions ◽  
Uranium Uptake ◽  
Secondary Type

AbstractUranium enrichments (up to 4000 ppm) occur in the manganese and phosphorite assemblages of the Lower Cambrian clastic marine sedimentary sequence, Timna Basin, Israel. Two types of mineralization assemblages can be defined. Sedimentary stratabound assemblages consist of uranium-enriched stratiform manganese and phosphatic laminae, diagenetic (type A) manganese nodules composed of pyrolusite and hollandite laminae and phosphorite lenses. Fission-track maps show that the uranium is homogeneously distributed within host manganese and phosphatic minerals of these assemblages. Epigenetic assemblages are mainly composed of manganese- and phosphorite-bearing veins and secondary (type B) manganese nodules with a coronadite dominant mineralogy. Uranium is depleted in these assemblages, relative to the sedimentary stratabound assemblages.The distribution of manganese and phosphorite assemblages has a marked bimodal character. Alternation between manganese and phosphatic laminae in the stratiform deposits reflects cycles of oxidizing and reducing conditions brought about by mixing and stratification of the waters in the Timna semi-closed depositional basins. Compaction of wet sediments led to remobilization and the formation of uranium-enriched manganese nodules at the aerated sediment–water interface, and uranium-enriched phosphorite lenses below the interface in reducing conditions. Epigenesis occurred through the passage of solution fronts which recrystallized the manganese and phosphatic minerals and remobilized metallic elements, particularly uranium which was leached away and is still being remobilized today.The mechanism of uranium uptake in manganese phases is shown most probably to involve adsorbtion of [(UO2)3. (OH)5]+ complexes on precipitating minerals. Uranium is enriched in both the pyrolusite and hollandite laminae of type A nodules, but is particularly concentrated in the former (4000–10000 ppm). Thermodynamic calculations of the relative stabilities of pyrolusite and hollandite suggest that the pH conditions of hollandite formation were close enough to the pH limit of efficient uranium adsorption to inhibit its uptake relative to pyrolusite.

The effects of reduced pH on chemical alarm signalling in ostariophysan fishes

2002 ◽  
Vol 59 (8) ◽  
pp. 1331-1338 ◽  
Author(s):  
Grant E Brown ◽  
James C Adrian, Jr. ◽  
Michael G Lewis ◽  
Jon M Tower
Keyword(s):  
Alarm Pheromone ◽  
Pimephales Promelas ◽  
Chemical Mechanism ◽  
Skin Extract ◽  
Alarm Pheromones ◽  
Loss Of Response ◽  
Ostariophysan Fishes ◽  
Antipredator Responses ◽  
Acidic Conditions ◽  
Ph Conditions

Under laboratory conditions, we examined the effects of acute exposure to weakly acidic conditions (pH 6.0) on the ability of fathead minnows (Pimephales promelas) and finescale dace (Phoxinus neogaeus) to detect and respond to conspecific and artificial alarm pheromones. Initially, minnows and dace exhibited normal antipredator responses when exposed to conspecific alarm pheromones under normal (pH 8.0) conditions. When retested at pH 6.0, we observed no significant antipredator response. However, when returned to normal pH conditions, both exhibited normal antipredator responses. Minnows exposed to the putative ostariophysan alarm pheromone (hypoxanthine-3-N-oxide) exhibited a similar trend in behavioural response. Finally, we manipulated the pH of minnow skin extract and hypoxanthine-3-N-oxide to determine the chemical mechanism responsible for this observed loss of response. Minnows exhibited significant antipredator responses to natural and artificial alarm pheromones at normal pH conditions, but did not respond to either stimulus once they had been buffered to pH 6.0 or acidified and rebuffered to pH 7.5. These data suggest that the ability of minnows and dace to detect and respond to alarm pheromones is impaired under weakly acidic conditions and that this loss of response is due to a nonreversible covalent change to the alarm pheromone molecule itself.

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