Water Sulfate Research Articles

Evaluation and mechanism of ultrasound-assisted electrochemical desulfurization using citric acid as the electrolyte solution

ABSTRACT Achieving the clean utilization of coal is the priority of the coal industries. This paper proposed an efficient electrochemical technology for coal desulfurization before combustion. It was explored that citric acid can chemically provide enough acidic conditions for desulfurization reactions, and the ultrasonic-enhanced treatment physically helps to remove sulfur from coal due to its cavitation effect and mechanical effect. So the experiments of ultrasound-assisted electrochemical desulfurization using citric acid as the electrolyte solution were conducted. They combined physical and chemical methods to effectively remove sulfur from coal. The optimal operating parameters of the desulfurization effect were achieved by qualitative and quantitative analysis of coal samples(coal slurry concentration of 66 g/L, electrolysis time of 8 h, electrolyte concentration of 1.5 mol/L, electrolysis voltage of 4 V, electrolysis temperature of 30°C, ultrasonic strengthening time of 1 h and ultrasonic intensity of 320 W.). The total sulfur removal efficiency reached 45.09%. The electrolytic desulfurization experiments removed samples’ sulfur contents, ash contents, and water. The crystal structures of gypsum, white iron ore, zinc sulfide, and the molybdenite mineral composition were also destroyed for purification. Gaussian simulations showed that C-S bonds and S-S bonds contained in non-thiophene organic sulfur are easier to remove, and S-S bonds are more likely to break than C-S bonds. This study realized the promotion of desulfurization with the ultrasonic wave and citric acid solution. It provides a new idea of synergistic desulfurization and is beneficial to reduce atmospheric sulfur pollution.

Novel composites of activated carbon and layered double oxide for the removal of sulfate from synthetic and brackish groundwater

Sulfate (SO42−) is a major water and environmental concern that causes severe diarrhea, death of invertebrates and plant species, and clogging of industrial pipes. In the current work, treatment of SO42− from synthetic and real groundwater having 3901 mg(SO42−)/L was investigated for the first time using Zn–Al and Mg–Al layered double oxides doped granular activated carbon (GAC/Mg–Al LDO and GAC/Zn–Al LDO). The co-precipitation method was followed to synthesize the GAC/LDO composites using an Mg or Zn to Al molar ratio of 3:1. The GAC/Mg–Al LDO possessed a higher specific surface area (323.9 m2/g) compared to GAC/Zn–Al LDO (195.1 m2/g). The GAC/Mg–Al LDO demonstrated more than 99% removal of SO42− from synthetic water, while it was 50.9% for GAC/Zn–Al LDO and less than 1% for raw GAC at an initial concentration of 50 mg/L. The GAC/Mg–Al LDO was selected for further batch experiments and modeling investigation. The equilibrium data followed the Redlich-Peterson and Langmuir models with determination coefficients of 0.943 and 0.935, respectively. The maximum Langmuir adsorption capacity was 143.5 mg/g. In the real groundwater adsorption study, the screening experiment revealed high selectivity towards SO42− with 62% removal efficiency. The optimum dosage was found to be 50 g/L with an uptake capacity of 61.5 mg/g. The kinetic data of SO42− removal from synthetic and brackish water were in excellent agreement with the pseudo-second order model, and the equilibrium was attained in 5 h. Accordingly, it can be concluded that the GAC/Mg–Al LDO is an efficient material for treating SO42− from real groundwater and can be utilized as a pretreatment unit for high sulfate water resources.

Fluorescent Guanidinium-Azacarbazole for Oxoanion Binding in Water.

Oxoanions such as carboxylates, phosphates, and sulfates play important roles in both chemistry and biology and are abundant on the cell surface. We report on the synthesis and properties of a rationally designed guanidinium-containing oxoanion binder, 1-guanidino-8-amino-2,7-diazacarbazole (GADAC). GADAC binds to a carboxylate, phosphate, and sulfate in pure water with affinities of 3.6 × 104, 1.1 × 103, and 4.2 × 103 M-1, respectively. Like 2-azacarbazole, which is a natural product that enables scorpions to fluoresce, GADAC is fluorescent in water (λabs = 356 nm, λem = 403 nm, ε = 13,400 M-1 cm-1). The quantum yield of GADAC is pH-sensitive, increasing from Φ = 0.12 at pH 7.4 to Φ = 0.53 at pH 4.0 as a result of the protonation of the aminopyridine moiety. The uptake of GADAC into live human melanoma cells is detectable in the DAPI channel at low micromolar concentrations. Its properties make GADAC a promising candidate for applications in oxoanion binding and fluorescence labeling in biological (e.g., the delivery of cargo into cells) and other contexts.

The Effect of Treated Sulfur Water on the Microbial Content of the Soil and the Extent of Resistance of These Bacteria to Antibiotics

The research began on March 7, 2021, as the regions of Ain Al-Wusta and Ain Jarura were chosen to take soil samples. The sulfuric water was treated using laboratory batch reactors. Locally manufactured glass tubes were used, with dimensions 17 * 17 * 55 in length, width and height, respectively, Subsequently, microbiological and chemical analyzes of the soil were performed. The results of the study showed success of the physical treatment process that was used to reduce the levels of sulfur in the water Depending on the source of water and the type of material used, the triple-magnetic treatment achieved the highest removal rate of 73% in Ain Al-Wusta soil, 40% in soil sample B1, and 27% in soil sample B2 of Ain Jarura. The results of bacterial culture showed that Gram-negative bacteria were dominant by 100% in soil samples from Ain Jarura region treated with untreated sulfuric water (WA1, WA2, WA3) (Table- 4), as well as for the same soil samples treated with sulfuric water treated with sand filter (GB1), charcoal filter (GB2) and magnetic field filter. (GB3) Soil samples treated with untreated sulfur water were dominated by Pseudomonas aeruginosa with a percentage of 66.7% and Acinetobacter lwoffii with a percentage of 33.3%.The results of the bacterial count of soil samples from the Ain Jarura region showed that there were significant differences between the bacterial number with sulfuric water treated with the three filters, As for soil samples from Ain Al-Wusta region, only soil samples added to sulfuric water treated with charcoal filter (WB2) gave significant differences with a significant decrease of number (84×102 CFU) for the species Aerococcus viridans. The results of the antibiotic sensitivity test showed that Elizabethkingia meningoseptica gave the highest rate of resistance to antibiotics about 66%. The results of the study showed that the resistance of bacterial isolates to antibiotics did not show significant differences between soil samples treated with treated and untreated sulfur water, except for the GB2 isolate.

The impact of water table fluctuation and salinity on LNAPL distribution and geochemical properties in the smear zone under completely anaerobic conditions

Climate and groundwater are always in a state of dynamic equilibrium. Subsurface systems contaminated by light non-aqueous phase liquid (LNAPL) present a challenge to understand the overall impact of water table dynamics, due to various interacting mechanisms, including volatilization, and LNAPL mobilization/dissolution along the groundwater flow direction and oscillating redox conditions. We investigated the impact of water table fluctuations on LNAPL natural attenuation and soil geochemical characteristics in semi-arid coastal areas under saline conditions. Four soil columns operated for 151 days under anoxic conditions where a layer of benzene and toluene were subjected to a stable and fluctuating water table associated with low and high salinity conditions. The bottom of stable and fluctuating columns reached an anaerobic state after 40 days, while the middle of stable column took 60 days. pH values of the fluctuating columns covered a wide range, and at the end shifted towards alkaline conditions, unlike the stable columns. In fluctuating columns, pore water sulfate decreased in the middle, but in stable columns, it decreased in the first 40 days, which suggested that sulfate was the primary electron donor and sulfate-reducing bacteria were present. At the source zone, benzene and toluene reached their maximum concentration after 30 and 10 days for the stable and the fluctuating columns, respectively. Significant decrease in benzene and toluene concentrations occurred under the fluctuating water table. Salinity did not affect benzene and toluene concentrations in the aqueous phase, although water table fluctuations have the most effect. Soil solid-phase analysis shows fluctuating columns have less toluene than stable columns. Solid-phase analysis showed the fluctuating columns have less benzene and toluene concentrations as compared to the stable columns.

Improvement of Plasterboard Properties by the Control of Polymethylhydrosiloxane Dosage, Stirring Time, and Drying Temperature Applied to the Calcium Sulfate Hemihydrate and Water Mixture.

Plasterboard is an important building material in the construction industry because it allows for quick installation of walls, partitions, and ceilings. Although a common material, knowledge about its performance related to modern polymers and fabrication conditions is still lacking. The present work analyzes how some manufacturing factors applied during the plaster board fabrication impact on some plasterboard properties, including water absorption, flexural strength, and thermal conductivity. The manufacturing variables evaluated are the dose (D) of polymethylhydrosiloxane (PMHS), the agitation time of the mixture (H), and the drying temperature of the plaster boards after setting (T). The results suggest that factors D, H, and T induce changes in the porosity and the morphological structure of the calcium sulfate dihydrate crystals formed. Performance is evaluated at two levels of each factor following a statistical method of factorial experimental design centered on a cube. Morphological changes in the crystals of the resulting boards were evaluated with scanning electron microscopy (SEM) and the IMAGEJ image analysis program. Porosity changes were evaluated with X-ray microcomputed tomography (XMT) and 3D image analysis tools. The length-to-width ratio of the crystals decreases as it goes from low PMHS dosage to high dosage, favoring a better compaction of the plasterboard under the right stirring time and drying temperature. In contrast, the porosity generated by the incorporation of PMHS increases when going from low-level to high-level conditions and affects the maximum size of the pores being generated, with a maximum value achieved at 0.6% dosage, 40 s, and 140 °C conditions. The presence of an optimal PMHS dosage value that is approximately 0.6-1.0% is evidenced. In fact, when comparing trails without and with PMHS addition, a 10% decrease in thermal conductivity is achieved at high H (60 s) and high T (150 °C) level conditions. Water absorption decreases by more than 90% when PMHS is added, mainly due to the hydrophobic action of the PMHS. Minimum water absorption levels can be obtained at high drying temperatures. Finally, the resistance to flexion is not affected by the addition of PMHS because apparently there are two opposing forces acting: on one hand is the decrease in the length-width ratio giving more compactness, and on the other hand is the generation of pores. The maximum resistance to flexion was found around a dosage of 0.6% PMHS. In conclusion, the results suggest that the addition of PMHS, the correct agitation time of the mixture, and the drying temperature reduce the water absorption and the thermal conductivity of the gypsum boards, with no significant changes in the flexural resistance.

Multiscale study of the road performance of cement and fly ash stabilized aeolian sand gravel base

To alleviate the scarcity of road construction materials in desert areas, the feasibility of 100% replacement of fine aggregates by aeolian sand for semirigid base pavement was studied. First, complete the design of the proportion of cement, fly ash, aeolian sand and gravel was completed by orthogonal testing. Second, based on mechanical property tests, compressive strength and splitting strength of each mix proportion were investigated at the maintenance ages of 7 d and 28 d. The resistance to sulfate erosion and water stability of each mix proportion were investigated at different ages with durability tests. Moreover, the strength development and deterioration mechanism of aeolian sand mixtures were analysed by SEM and EDS test systems. The results show that the increasein aeolian sand content significantly degrades the strength of the road performance of cement and fly ash stabilized aeolian sand gravel base; the 7 d unconfined compressive strength was 2.8 MPa, and splitting strength was 0.61 MPa when the aeolian sand content was 66%. The erosion products and hydration products of the binding material during the dry and wet cycles of the specimens under different ages filled the voids between the aggregates which improved the structural density, increasing the water stability coefficient and sulfate erosion resistance coefficient more than 95%. The complete replacement of fine aggregate by aeolian sand for semi-rigid type bases meets the design requirements of highway roadbases, which shows that the replacement of fine aggregate by 100% aeolian sand for a semirigid base was feasible.

Solubility, Crystallization, and Characterization of Cytidine Sulfate.

Cytidine is an important kind of nucleoside that can be applied to drug development and food industry. Cytidine sulfate is one of its popular forms, which is promising as a medicinal intermediate, especially in antiviral and antitumor drugs. Product refining is the key point of industrial development, and crystallization is a significant way of refining. In this work, the solubility of cytidine sulfate in pure water from 278.15 to 328.15 K and in water-ethanol binary solvents at 298.15 K was measured by the UV spectroscopic method. The solubility data were correlated with temperature and solvent composition using the modified Apelblat, van't Hoff, and CNIBS/R-K equations. On this basis, we investigated and compared three crystallization processes, and the coupling method was developed to prepare crystals with a large particle size, concentrated distribution, and high yield and packing density. In addition, the structure and stability of the products were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and dynamic vapor sorption analysis. It was found that cytidine sulfate has only one crystal form in our research process, and the product of coupling crystallization is stable and favorable for industrial development.

Dynamics of land cover changes and condition of soil and surface water quality in a Mining–Altered landscape, Ghana

This study investigated the dynamics of mining effects on land use land cover changes and the chemical and physical characteristics of soil and surface water in the Ahafo mining area in Ghana. Landsat imagery was used to analyze land use-land cover changes (LULC) using a supervised classification technique. Soil samples were collected within 600 m from active mining operations and at depths of up to 75 cm, as well as surface water samples from upstream and downstream of the mine. Atomic Absorption Spectrometry was used to determine the concentration of heavy metals in the soil and water samples. The results demonstrated a significant loss of forest and other vegetation covers, which decreased from 44% to 31% to 8% and 20%, respectively, with corresponding increases in the mining site, mine water, settlement/bare surface, cropland and plantation. Organic matter, organic carbon, exchangeable bases, cation exchange capacity, available phosphorus, and pH were all moderate in the soil surrounding the mine. Except for As (4.027 mg/kg) and Hg (1 mg/kg), all heavy metals found in the soil were within FAO/WHO guidelines. Total Dissolved Solids (TDS) (416.18 mg/L), Total Suspended Solids (55.08 mg/L), Turbidity (54.49 NTU), Ca (84.49 mg/L), Mg (31.97 mg/L), nitrate (10.23 mg/L), and sulphate (606.83 mg/L) in the downstream water were higher than those in the upstream and USEPA/WHO limits for drinking water except for TDS. Because of the geology of the area, there were high concentrations of iron, manganese, and aluminum in the surface water. The results show that mining induced severe land cover changes and impaired surface water and soil quality in the mine's vicinity. The findings have implications for stakeholder education, appropriate community water interventions, and company-community-regulator participatory monitoring to avoid health risk exposure and further water and soil quality and vegetation degradation.

On the Influence of Atmospheric Ions on Aerosol Formation: Numerical Modeling

A new mathematical model of the global transport of multicomponent gas impurities and aerosols has been constructed, including the formation of sulfate aerosols in the atmosphere in both hemispheres. Calculations of the nucleation rates and particle number concentrations were performed for the winter period in the troposphere using a unified model that takes into account chemical and kinetic transformation processes (photochemistry, nucleation, condensation/evaporation, and coagulation). Binary nucleation of sulfuric acid and water vapor was coupled with new-particle formation due to atmospheric ions. The numerical results indicate a significant role of ion nucleation in aerosol formation in the Northern and Southern hemispheres in winter. The factors controlling the dynamics of ionic processes in the atmosphere and their influence on the spatiotemporal distribution of aerosol particles involve not only the level of air ionization but also temperature, relative humidity, and the content of sulfur and water vapor in the air. At a height of 4.2 km, the formation of particle nuclei with the participation of ions occurs only over the Lake Baikal and Kamchatka regions as well as the regions of the northeast and northwest of the American continent. Within the regions of localization of this process in the atmosphere, the rate of new particle generation varies by more than an order of magnitude.

Распространение и формирование подземных содовых вод на водосборной площади Верхней Колымы

In the Upper Kolyma basin, mostly hydrocarbonate and sulfate waters are distributed with a predominance of alkaline earth metal cations in the composition. Hydro-carbonates with alkali metal cations (Na+ + K+), distinguished as soda, are found only in local areas in fault zones and those of granite intrusion contacts. They are the least mineralized (no more than 100 mg/dm3) in the seasonally thawed layer and river valley taliks, but even there, in separate foci at the elevation of above 1600 m, soda water springs with the mineralization exceeding 200 mg/dm3 occur. Soda waters in Cretaceous coal-bearing deposits within intermountain artesian basins are the most mineralized (up to 3000 mg/dm3). The association of these waters with deep fault zone has been assumingly traced. The sharp increase of the dissolved carbon dioxide and the carbonic acid anions in waters at local river valley sites is offered as the indicator of the current ingress of carbon dioxide into underground waters. Soda waters with mineralization exceeding 600 mg/dm3 , contained in some samples, are referred to balneal. Hydrogeochemical methods are proposed for further study of the role of deep faults in soda waters formation as well as for the possible use of them for curing and preventing diseases.

Formulation and Evaluation of Herbal Facewash Preventing Dermatological Problem

Abstract: Facewash is one type of cosmeceuticals as well as semisolid dosage forms used for external purposes. It is applied on the skin surface to protect the skin from various microbial attacks. This type of cosmeceutical is also used to clean different types of skin problems like skin acne, skin pimples, skin rashes, dark circles, black spot, oily skin, skin discolored, etc. In this study, we have formulated one herbal face wash containing different extraction of herbal materials like fresh aloevera gel, leaves of neem, turmeric, lemon juice, Fresh leaves of Tulsi, fresh pudina leaves, Chandan, liquorice, Honey, Coffee, Multani mati, rose water as well as various types of excipients like sodium CMC, sodium lauryl sulphate, sodium benzoate, glycerol and distilled water. After formulation study we focused the evaluation cum validation of the formulated new herbal facewash like testing of pH ,Spreadability test, foam forming test, etc.

Bioaccessibility by perspiration uptake of minerals from two different sulfurous peloids

The risks associated with the use of peloids in thermal centers, spas, or at home, must be tested to develop appropriate safety guidelines for peloids formulations and the release of substances of high concern. Additionally, the beneficial effects of some elements on human health should be assessed to aid in interpreting the therapeutic action and effectiveness of pelotherapy on dermatological or osteomuscular disorders. Therefore, a methodology was developed to better understand the biogeochemical behavior of the elements in formulated peloids. Two peloids were formulated with the same clay and two different sulfurous mineral-medicinal waters for 90 days, with light stirring every 15 days. Bentonite clay, with a high content of smectite and Ca and Mg as the main exchangeable cations, and high heat capacity, was used. The selected mineral-medicinal waters were collected from two Portuguese thermal centers with recognized therapeutic efficacy for rheumatic, respiratory and dermatological pathologies. The peloids were used without drying and withdrawn directly from the maturation tank, and a mixture of bentonite and demineralized water was prepared as a reference sample. A stabilized, ready-to-use, artificial perspiration test was used to simulate the peloids’ interaction with skin. Thirty-one elements extracted from the two prepared peloids were analyzed using ICP-MS. The data were analyzed and related to the mineralogical composition of the original clay and supernatant composition of the maturation tanks. The content of some potentially toxic elements and metals’ bioaccessibility by perspiration showed very low solubility and undetectable amounts extracted from the studied samples. This analytical method provided reliable information on dermal exposure and the identification of some elements that may enter the systemic circulation, requiring implementation of surveillance and control measures.Graphical abstract

A review of technologies for the removal of sulfate from drinking water

AbstractBecause of the current water crisis worldwide, it is of great importance to find alternative sources of drinking water, such as sulfur water. This review analyses laboratory, pilot and industrial‐scale technologies available for sulfate removal from water produced for human consumption, from naturally occurring sulfur water and that resulting from human activities. Most of them exceed 90% removal efficiencies. However, the concentrations treated in each study were different; some technologies evaluate concentrations below recommended limits (250 mg L−1), while others evaluate much higher concentrations but require previous treatments. The technologies with higher energy requirements such as reverse osmosis and ion exchange have better removal efficiencies but require larger initial investments and have higher operational costs. Biological treatments, on the other hand, with lower energy and material requirements, are less expensive but require long retention times and depend on the season of the year and/or environmental conditions. Lastly, adsorption removal technologies fall in the middle, especially for energy requirements and operational costs and retention times. This review shows that although there are a variety of sulfate removal technologies suitable for use, there is still room for a novel methodology that removes sulfates from a wider range of concentrations more economically, more effectively and in less time than what is currently available.

Copper(II) сomplexes with 2-hydrохy-5-ethylphenylphosphosphonic acid: synthesis, structure, cytotoxicity, and accumulation in HeLa cells

In order to study the physicochemical and biological properties of the coordination compounds of bioactive metal ions with 2-hydroxyphenylphosphonic acid derivatives, the reaction of 2-hydroxy-5-ethylphenylphosphonic acid (Н3L1) with copper(II) perchlorate, sulfate, nitrate, and acetate in water was studied for the first time. It has been established that, regardless of the ratio of reagents, in the case of copper(II) perchlorate, sulfate, and nitrate, a complex of the composition [Cu(H2L1)2(Н2О)2] is formed in high yield, while in the case of using copper(II) acetate a complex [Cu(HL1)(H2O)2] is formed, the composition of which is established on the basis of a combination of elemental analysis data, IR and electronic spectra. Quantum-chemical calculations of the structure of [Cu(H2L1)2(H2O)2] and [Cu(HL1)(H2O)2] complexes were performed for the first time by the density functional theory (DFT) method. The cytotoxic properties of H3L1 acid and copper complexes [Cu(HL1)(H2O)2] and [Cu(H2L1)2(H2O)2] with respect to HeLa tumor cells of human cervical adenocarcinoma were studied. The accumulation of the resulting copper(II) complexes in HeLa cells was proved by laser confocal microscopy.

Evaluation of Changeri Masi (Oxalis corniculata Linn.) in altering the copper concentration in water

Introduction: The presence of heavy metals in water has been increasing with industrial growth and human activities. The major source of copper in drinking water is corrosion of household plumbing, faucets, and water fixtures. Most commonly used copper salt is copper sulphate (CuSO4. 5H2O). It is used as a general pesticide rated as toxicity class 1 highly toxic. Unfortunately, most people are not aware of the safe level and they overuse it causing residue in soil, water, which endangers human and environment. According to EPA the permissible amount of copper in drinking water is 1.3mg/L. As Cu is non-biodegradable, poisonous, and easy to accumulate in living organisms in general and especially in the human body at low concentrations; they can cause major illnesses such as cancer, nervous system damage, and kidney failure, and can be fatal at high doses. hence, it’s important to remove Cu metal from water as well as wastewater. Materials and Methods: Changeri (Oxalis corniculata Lin.) plant is collected as a whole, dried and prepared Changeri Masi (ash) out of it. Copper contaminated water was prepared by adding copper sulphate in distilled water. Amount of copper were evaluated with AAS and fixed to 3mg/L. Different concentration of Changeri Masi was added to copper contaminated water and keep it for different contact time. Results: Changeri Masi mixed copper water filtered through a filter paper and reading was taken in atomic absorption spectroscopy. Significant reduction in copper was observed.

Determination of Critical Micelle Concentration of Sodium Dodecyl Sulfate in Distilled Water at 298.15K by Surface Tension Measurements

Surfactants are chemicals that adsorb to the interface between a solution and another phase (gases or solids) and self-assemble molecular clusters known as micelles in a solution (water or oil phase). Measurements of the surface tension of sodium dodecyl sulfate (SDS) in distilled water at 298.15K are reported. The increase of concentration of sodium dodecyl sulfate (SDS) in distilled water then decreased in surface tension at 298.15K. Critical micelle concentration (CMC) decreased with a decrease in surface tension. The graphs of surface tension versus concentration were made to determine the CMC of the solution.

Quality assessment and evaluation of irrigation water and soil used for maize (Zea mays L.) production in Boloso Sore district, southern Ethiopia

Poor quality of irrigation water and soil are among the major factors determining maize productivity in Ethiopia. This study assessed and evaluated the quality of irrigation water and soil under maize production in Soke and Woybo irrigation schemes in Boloso Sore district, Ethiopia. Four water samples per site per season were collected from the first point of the irrigation schemes and farm gate for dry and rainy seasons in 2019/2020. Soil samples of 108 were collected from 36 points, from which 18 composited samples were taken for laboratory analysis. Results show that irrigation water of the two schemes is non-saline (electrical conductivity <0.2 dS m−1) and in the normal pH range (6.5–7.5). Maximum concentration of cations in irrigation water was in the order of sodium (22.3 mg l−1) > potassium (7.3 mg l−1) > calcium (6.2 mg l−1) > magnesium (3.1 mg l−1). Moderate to severe sodicity (sodium adsorption ratio of 10.9) was also recorded. Sulfate, nitrate, and phosphate contents in water were trace, and increased during rainy seasons in downstream. Textural classes of soils are clay loam to clay, and less compact to restrict root penetration (bulk density ≤1.4 g cm−3), have slow infiltration rate (≤0.13 cm h−1), and medium level of total available water (≤178 mm m−1). Soils are strongly acidic to neutral (pH: 5–6.5), salt-free, and have low soil organic carbon (≤2.1%), low total nitrogen (≤0.1%), low available phosphorus and sulfur, and low Ca2+: Mg2+ ratio. It can be concluded that the irrigation water in the study area has cation imbalance (poor quality) which affects soil quality and maize productivity. Likewise, soils of the study area have poor quality. Lime application, efficient fertilizer use, and organic matter applications can be suggested. Further study on optimizing fertilizer rates and irrigation levels has to be conducted to improve maize productivity.

HDO and SO2thermal mapping on Venus

Since January 2012, we have been monitoring the behavior of sulfur dioxide and water on Venus using the Texas Echelon Cross-Echelle Spectrograph (TEXES) imaging spectrometer at the NASA InfraRed Telescope Facility (IRTF, Mauna Kea Observatory). We present here new data recorded in 2021 and 2022, after an 18-month interruption due to the Covid pandemic. Most of the observations were recorded in two spectral ranges: the 7.4 µm (1345 cm−1) range, where SO2, CO2, and HDO (used as a proxy for H2O) transitions are observed at the cloud top, at an altitude of about 62 km, and the 19 µm (530 cm−1) range, where SO2and CO2are probed within the clouds at an altitude of about 57 km. We recently added the 8.6 µm (1162 cm−1) range, which probes a few kilometers above the cloud top (z= 67 km). As in our previous studies, the volume mixing ratio of SO2is estimated using the SO2/CO2line depth ratio of weak transitions; the H2O volume mixing ratio is derived from the HDO/CO2line depth ratio, assuming a D/H ratio of 200 times the Vienna Standard Mean Ocean Water (VSMOW). As reported in our previous analyses, the SO2mixing ratio shows strong variations with time and also over the disk, showing evidence of the formation of SO2plumes. These local maxima appear sporadically on the SO2maps and stay visible over a few hours. In contrast, the H2O abundance is remarkably uniform over the disk and shows moderate variations as a function of time. The present dataset shows significant differences with respect to the 2012–2019 dataset: (1) the SO2mixing ratio at the cloud top has decreased by a factor of about 3 with respect to the maximum value observed in July 2018; (2) the long-term anti-correlation between SO2and H2O previously observed between 2014 and 2019 is no longer visible; (3) a very high SO2plume activity was observed in Nov. 2021, in spite of the low SO2mixing ratio at the cloud top. In contrast, the distribution of the SO2plume appearance over the disk is confirmed, with a maximum along the equator and around the morning terminator. Information on the SO2vertical gradient is retrieved from the simultaneous analysis of SO2at 7.4 µm and 19 µm. The gradient is constant in most cases with a few exceptions, especially in November 2021 when the plume activity was high. Finally, the temperature distributions retrieved from the continuum maps in September and November 2021 show an unusual pattern possibly associated with gravity waves, as previously observed by the longwave infrared camera camera aboard the Akatsuki spacecraft.

Cold Sulfur Springs-Neglected Niche for Autotrophic Sulfur-Oxidizing Bacteria.

Since the beginning of unicellular life, dissimilation reactions of autotrophic sulfur bacteria have been a crucial part of the biogeochemical sulfur cycle on Earth. A wide range of sulfur oxidation states is reflected in the diversity of metabolic pathways used by sulfur-oxidizing bacteria. This metabolically and phylogenetically diverse group of microorganisms inhabits a variety of environments, including extreme environments. Although they have been of interest to microbiologists for more than 150 years, meso- and psychrophilic chemolithoautotrophic sulfur-oxidizing microbiota are less studied compared to the microbiota of hot springs. Several recent studies suggested that cold sulfur waters harbor unique, yet not described, bacterial taxa.