Acid Sulfate Research Articles

Effect of Carbide Slag Combined with Biochar on Improving Acidic Soil of Copper Sulfide Mines

Heavy metal-rich acidic soils of copper sulfide mines can easily cause harm to the surrounding environment and ecosystem safety if not treated properly. Currently, the most common method of mine ecological remediation is to improve acidic soils of copper sulfide mines by adding different types of amendments. In this paper, different dosages of biochar and carbide slag applied singly and in combination were designed to investigate the changes of physicochemical properties and ryegrass growth in the acidic soil of copper sulfide mines. Through soil incubation experiments and potting tests, different treatments explored the improvement effect of carbide slag combined with biochar on the acidic soil of copper sulfide mines. Then, it was found that 2% (w/w) carbide slag in combination with 10% (w/w) biochar had the best effect on the improvement of copper-sulfide mine acidic soil. Among them, carbide slag significantly increased the pH, cation exchange capacity (CEC) and acid neutralization capacity (ANC), and reduced the electrical conductivity (EC), net acid generation (NAG) and sulfate ion (SO42−) concentrations in the acidic soil of copper sulfide mines; biochar obviously reduced the bio-effectiveness of heavy metals Cu, Pb and Zn, and DPTA-Cu, Pb and Zn decreased by 8~80%, 7~76% and 17~79%, respectively. Apart from that, there was a positive cooperativity between carbide slag and biochar, and their application effectively controlled the acidification process and heavy metal toxicity in the acidic soil of copper sulfide mines. In summary, the results will provide a theoretical basis for the large-scale reclamation of carbide slag and biochar in improving acidic soils of copper sulfide mines, filling the gap of calcium carbide slag and biochar in soil remediation.

Metabolomic identification of predictive and early biomarkers of cisplatin-induced acute kidney injury in adult head and neck cancer patients.

Cisplatin causes acute kidney injury (AKI) in approximately one third of patients. Serum creatinine and urinary output are poor markers of cisplatin-induced AKI. Metabolomics was utilized to identify predictive or early diagnostic biomarkers of cisplatin-induced AKI. Thirty-one adult head and neck cancer patients receiving cisplatin (dose ≥70 mg/m2) were recruited for metabolomics analysis. Urine and serum samples were collected prior to cisplatin (pre), 24-48 h after cisplatin (24-48 h) and 5-14 days (post) after cisplatin. Based on serum creatinine concentrations measured at the post timepoint, 11/31 patients were classified with clinical AKI. Untargeted metabolomics was performed using liquid chromatography-mass spectrometry (LC-MS). Metabolic discrimination was observed between "AKI" patients and "no AKI" patients at all timepoints. Urinary glycine, hippuric acid sulfate, 3-hydroxydecanedioc acid and suberate were significantly different between AKI patients and no AKI patients prior to cisplatin infusion. Urinary glycine and hippuric acid sulfate were lower (-2.22-fold and -8.85-fold), whereas 3-hydroxydecanedioc acid and suberate were higher (3.62-fold and 1.91-fold) in AKI patients relative to no AKI patients. Several urine and serum metabolites were found to be altered 24-48 h following cisplatin infusion, particularly metabolites involved with mitochondrial energetics. We propose glycine, hippuric acid sulfate, 3-hydroxydecanedioc acid and suberate as predictive biomarkers of predisposition to cisplatin-induced AKI. Metabolites indicative of mitochondrial dysfunction may serve as early markers of subclinical AKI.

Theoretical Study on the Gas Phase and Gas–Liquid Interface Reaction Mechanism of Criegee Intermediates with Glycolic Acid Sulfate

Criegee intermediates (CIs) are important zwitterionic oxidants in the atmosphere, which affect the budget of OH radicals, amines, alcohols, organic/inorganic acids, etc. In this study, quantum chemical calculation and Born-Oppenheimer molecular dynamic (BOMD) simulation were performed to show the reaction mechanisms of C2 CIs with glycolic acid sulfate (GAS) at the gas-phase and gas-liquid interface, respectively. The results indicate that CIs can react with COOH and OSO3H groups of GAS and generate hydroperoxide products. Intramolecular proton transfer reactions occurred in the simulations. Moreover, GAS acts as a proton donor and participates in the hydration of CIs, during which the intramolecular proton transfer also occurs. As GAS widely exists in atmospheric particulate matter, the reaction with GAS is one of the sink pathways of CIs in areas polluted by particulate matter.

Metabolomics Profiling of Age-Associated Metabolites in Malay Population.

Aging is a complex process characterized by progressive loss of functional abilities due to the accumulation of molecular damages. Metabolomics could offer novel insights into the predictors and mechanisms of aging. This cross-sectional study is aimed at identifying age-associated plasma metabolome in a Malay population. A total of 146 (90 females) healthy participants aged 28-69 were selected for the study. Untargeted metabolomics profiling was performed using liquid chromatography-tandem mass spectrometry. Association analysis was based on the general linear model. Gender-associated metabolites were adjusted for age, while age-associated metabolites were adjusted for gender or analyzed in a gender-stratified manner. Gender-associated metabolites such as 4-hydroxyphenyllactic acid, carnitine, cortisol, and testosterone sulfate showed higher levels in males than females. Deoxycholic acid and hippuric acid were among the metabolites with a positive association with age after being adjusted for gender, while 9(E),11(E)-conjugated linoleic acid, cortisol, and nicotinamide were negatively associated with age. In gender-stratified analysis, glutamine was one of the common metabolites that showed a direct association with age in both genders, while metabolites such as 11-deoxy prostaglandin F2β, guanosine monophosphate, and testosterone sulfate were inversely associated with age in males and females. This study reveals several age-associated metabolites in Malays that could reflect the changes in metabolisms during aging and may be used to discern the risk of geriatric syndromes and disorders later. Further studies are required to determine the interplay between these metabolites and environmental factors on the functional outcomes during aging.

Remediation of Acid Mine Drainage (AMD) Using Steel Slag: Mechanism of the Alkalinity Decayed Process.

Steel slag has been proven to be an effective environment remediation media for acid neutralization, and a potential aid to mitigate acid mine drainage (AMD). Yet its acid neutralization capacity (ANC) is frequently inhibited by precipitate after a period of time, while the characteristics of the precipitate formation process are unclear yet. In this study, ANC for basic oxygen steel slag was conducted by neutralization experiments with dilute sulfuric acid (0.1 M) and real AMD. Some partially neutralized steel slag samples were determined by X-ray diffraction (XRD), scanning electron microscopy combined with an energy dispersive spectrometer (SEM-EDS), and N2 adsorption tests to investigate the potential formation process of the precipitate. The results indicated that Ca-bearing constitutes leaching and sulfate formation were two main reactions throughout the neutralization process. A prominent transition turning point from leaching to precipitate was at about 40% of the neutralization process. Tricalcium silicate (Ca3SiO5) played a dominant role in the alkalinity-releasing stage among Ca-bearing components, while the new-formed well crystalline CaSO4 changed the microstructure of steel slag and further hindered alkaline components releasing. For steel slag of 200 mesh size, the ANC value for the steel slag sample was 8.23 mmol H+/g when dilute sulfate acid was used. Neutralization experiments conducted by real AMD confirmed that the steel slag ANC was also influenced by the high contaminants, such as Fe2+, due to the hydroxides precipitate reactions except for sulfate formation reactions.

Influence of dicarboxylic acid polymer in enhancing the growth and productivity of sweet potato (Ipomoea batatas L.) in acidic soil.

The available phosphorus (P) in acid sulfate soils (ASSs) is low because of fixation by aluminum (Al) and iron (Fe), resulting in decreased P use efficiency and crop yield. At present, the use of dicarboxylic acid polymer (DCAP) coated on P fertilizer is expected to improve P use efficiency and plant productivity. However, the influence of DCAP on P solubility and on the yield of sweet potato cultivated in acidic soils has not been elucidated. Thus, the aimed of this study was to evaluate the effect of the use of DCAP-coated P fertilizer on the availability and nutrient uptake of P as well as the yield of sweet potato. Under the greenhouse condition, the use of DCAP significantly improved P availability (~3 mg P kg-1), increasing tuber diameter and length by ~0.5 and ~1.0 cm, respectively. Thus, the productivity of sweet potato in the treatment 40-kg P2O5 and 60-kg P2O5 ha-1 coated with DCAP was higher by about 100 g pot-1 than that in the same rate of P fertilizers (40- and 60-kg P2O5 ha-1) not coated with DCAP. In the field experiment, P accumulation (82.7 kg P2O5 ha-1) and tuber yield (22.0 t ha-1) in the treatment of DCAP-coated with 60-kg P2O5 ha-1 were not significantly different compared with that in the treatment of 80-kg P2O5 ha-1 (82.1 kg P2O5 and 21.7 t ha-1, respectively). Furthermore, the use of DCAP combined with 75% P fertilizer increased the P availability by the same amount as that with the use of 100% P fertilizer. Hence, the use of DCAP reduced about 25% of the chemical P fertilizer applied in soil.

Rice Soil Fertility Classification in the Mekong Delta, Vietnam

The rice crop intensification led to soil degradation and yield decline in the Mekong Delta, Vietnam. Therefore, it is necessary to classify soil fertility and identify the constraints for proper soil use. The soil legend classified by World Reference Based was converted to the Fertility Capability Classification system. The soil constraints and recommendations for appropriate services are suggested. The findings indicate seven primary soil categories, ten diagnostic layers, three diagnostic features, and three diagnostic materials in the rice soils of the Mekong Delta. Eleven soil constraints were found, most of which were associated with acid sulfate and saline soils. These constraints included low acidity, strong acidity, low available P, high P fixation, high potential Fe toxicity, slightly actual acid sulfate and shallow potential acid sulfate, deep potential acid sulfate, slight salinity, and strong salinity, low mineral supply capacity, limited organic carbon content, and low nutrient retention capacity. Reclamation of acid sulfate and saline soils by leaching soil toxicity and boosting soil nutritional status with organic matter and P, K treatment were recommended for degraded, acid sulfate, and saline soils.

Amorphous aluminosilicates as efficient ion exchangers for ammonium cation removal from aqueous solutions

The efficient removal of ammonium cation, one of the main causes of the eutrophication of water sources, has been achieved by using amorphous aluminosilicates as low-cost ion exchangers. The materials with a Si/Al ratio that varied from 1 to 5 were prepared by the coprecipitation method just by mixing an acidic aluminium sulphate solution with a basic sodium silicate solution, and the products were characterized by XRD, SEM and 27Al MAS NMR spectroscopy. All the amorphous solids presented a higher cation exchange capacity (CEC) than a synthetic mordenite (Si/Al = 9.5) and a natural zeolite (Si/Al = 4.6). The ammonium uptake was investigated as a function of contact time and initial ammonium concentration; additionally, the presence of Na+ and K+ as coexisting cations in the solutions was also evaluated. Langmuir and Freundlich models were applied to describe the data obtained in the ammonium exchange isotherms. The amorphous aluminosilicate with Si/Al = 3 was regenerated with a KCl aqueous solution and was reused 5 times keeping a stable removal efficiency. The reusability of the amorphous aluminosilicate combined with the superior cation exchange capacity manifests the promising use of this type of materials as ion exchangers to remove ammonium cations from wastewater.

Globin X: A target for surfactant-like molecules.

Globin X (GbX) is recognized as a novel, intrinsically hexacoordinate, member of the vertebrate globin family. Previously we showed that GbX is significantly more stable than pentacoordinate vertebrate globins (Hb and Mb) at elevated temperatures, acidic pH as well as in the presence of denaturants. Such a unique feature of this protein led us to examine how the GbX interacts with surfactant-like molecules such as perfluorooctanoic acid (PFOA) and sodium dodecyl sulfate (SDS). In addition to GbXWT protein, the effect of intraprotein disulfide bridge and the heme iron pentacordination on GbX interactions with surfactant-like molecules was investigated by characterizing the GbXC65A and GXH90V constructs. The impact of surfactant on the structural properties of GbX was evaluated based on changes in the Soret band region and the emission properties of intrinsic Trp residues. The Kd values for SDS binding to the deoxy form of GbXWT, GbXC65A, and GbXH90V were determined to be 251 ± 4 μM, 188 ± 7 μM, and 358 ± 91 μM respectively, indicating that the intramolecular disulfide bond and hexacoordination do not have a significant effect on the surfactant-protein complex. However, the met form of GbXWT and GbXC65A binds SDS with Kd of 1426 ± 224 μM and 2106 ± 26 μM, pointing towards a lower affinity of the met form of the protein for SDS surfactant. Interestingly, PFOA produces a minimal change in the Soret band region, suggesting a distinct mechanism of binding. Based on the Trp emission data, the Kd values for PFOA binding to the met form of the protein were determined to be 40 ± 28 μM for GbX WT and 25 ± 1 μM for GbXC65A. The molecular mechanism of surfactant-like molecules binding to GbX was also evaluated using molecular dynamic simulations.

Passivation of Ni-Cr and Ni-Cr-Mo Alloys in Low and High pH Sulfate Solutions

The kinetics of passive oxide film formation, its thickening, and composition on Ni-22Cr and Ni-22Cr-6Mo wt% alloys were investigated at selected anodic potentials. Experiments were performed in acidic and alkaline sulfate environments using a number of characterization techniques including a combination of potentiodynamic polarization, on-line atomic emission spectro-electrochemistry (AESEC), in situ potentiostatic passive film growth, along with in situ neutron reflectometry (NR) and ex situ X-ray photoelectron spectroscopy (XPS). The roles of solution pH and Mo on the passivation behavior were discussed in terms of thermodynamic and kinetic factors governing passivation. The pH was found to have an impact on the relative chemical compositions of passive film of the Ni-22Cr alloy but not noticeably for the Ni-22Cr-6Mo alloy. Ni-rich films formed early during the passivation process while Cr(III) enrichment was observed at longer times, albeit less extensively than observed previously in Cl− solutions. The fraction of Cr(III) cations also increased with alloying of Mo at low and high pH demonstrating a strong effect of Mo on Cr(III) content during aqueous passivation in Ni based superalloys, however, a larger effect is seen in Cl−. This is a noteworthy finding as Mo is usually assumed to mainly influence pit and crevice stabilization.

Nitrate detection at Pd-Cu-modified carbon screen printed electrodes

Carbon nanofibers (CNF) and single-walled carbon nanotubes (SWCNT) screen printed electrodes (SPEs) are used for bi-metal, Pd-Cu, modification. Pd nanoparticles (NPs) are deposited first on the pre-reduced carbon SPEs by means of a spontaneous electroless process in the absence of solute reductants. Copper is deposited in a next step under galavanostatic conditions. For both electrodes the Pd deposit consists of NPs with sizes in the 10-ths of nm range with a much denser population and larger amount of the metallic phase in the SWCNT case. The copper deposit on the Pd-modified SPEs differs markedly depending on the type of the underlying substrate with a three times larger mass ratio Pd/Cu of the deposited metals for the SWCNT electrode compared to the CNF one. Nitrate detection is studied on the Cu- and Pd-Cu-modified electrodes in slightly acidic sulfate solution by means of linear sweep voltammetry. The comparison of the mono- and bi-metal- modified electrodes shows a significant enhancement of the nitrate-related reductive currents at the Pd-Cu-modified carbon SPEs. Between the two bi-metal modified electrodes the SWCNT-based one has a higher sensitivity and a larger concentration range of reproducible electroanalytical signal. The non-linear concentration dependence of the nitrate reduction peak currents is modeled by means of a Langmuir type of equation and used for recovery measurements. The Pd-Cu-modified SWCNT-based SPE shows a good stability of the metallic phases over extended nitrate reduction measurements series.

Chemical processes and sustainability of rice-shrimp farming on saline acid sulfate soils in mekong delta

In the history of rice-shrimp farming (RSF) in the Mekong Delta, in saline acid sulfate soils (ASS), RSF has proved its sustainability as there is no long-term accumulation of acidity and salinity that adversely affect RSF production. However, the soil processes involved in this phenomenon are not well understood. This study aimed to determine the significant changes in soil and water chemical indicators associated with soil processes during different stages of RSF. Sampling was conducted in six stages to determine the pH and electrical conductivity (EC) of canal and field water, and the pHe, ECe, and sodium-soluble saturated extract (Na-sol) of surface soil (surS) and subsurface soil (subS) in the low-salinity area (LSA) and high salinity area (HSA) of Bac Lieu province. Putative exchange (exch.) Na+ hydrolysis occurs at the beginning of the rainy season when excess salts are leached. This drastically increases the pH of the field water by 0.6 pH units, from 8.2 to 8.8 in stages 1 to 2, respectively. Putative sulfurization has been shown to occur in subS in both LSAs and HSAs, with a significant decrease of 0.5 pH units from stages 4 to 5, leading to a decrease in the Na-sol of subS through exch. Na+ transformation. Simultaneously, with active soil preparation and liming for RSF, chemical processes such as exch. Na+ hydrolysis, sulfurization, and Na+ transformation are the main factors promoting exch. Na+ desorption, which help to reduce the long-term build-up of salinity and acidity that adversely affect RSF production. Although gypsum is considered an effective material in improving saline soils, in Vietnam, gypsum is the liming material of CaSO4; however, it is not commonly used in agriculture because of its high cost. By using CaCO3 or dolomite as a liming material in saline ASS, the dissolution of lime by sulfuric acid can provide a good opportunity for soil improvement and rice growth in RSF.

Application of bio and NPK fertilizer to improve yield soybean and acid sulfate soil properties in Indonesia

In Indonesia, soybean (Glycine max (L.) Merr.) is the second most important staple food with low production compared to the demand. This problem can be overcome by using marginal land such as acid sulfate soil of tidal swampland, however, the optimal application of fertilizer in such soil is minimal. Therefore, this study aims to examine the application of fertilizer in acid sulfate soil in South Kalimantan, Indonesia. It was conducted using a split-plot design with three replicates and the main plot was biofertilizer, which consisted of no-biofertilizer (P1); biofertilizer consortium of decomposer fungi, P-solubilizing bacteria, N-fixing bacteria (P2), and biofertilizer consortium of N-fixing bacteria symbiotic and nonsymbiotic, P-solubilizing bacteria and phytohormone-producing bacteria (P3). Meanwhile, the subplot was NPK fertilizer dosage, consisting of no-fertilizer (A1), dose of 150% (A2), dose of 100% (A3), and dose of 50% (A4) of the recommendation. The results showed that the biofertilizer and NPK fertilization dose did not show an interaction with soil pH and Al3+. The highest N and K nutrient uptake was in P2 at 50% NPK fertilizer dosage, while P in P3 at 150% NPK fertilization dose. The highest soybean yields were obtained in the application of biofertilizer P3 with 150% NPK, i.e., 1.6 t ha-1, followed by the 1.5 t ha-1 in the application of P2 + 50% NPK. This showed that the use of P2 biofertilizer can reduce NPK fertilizer application to 50% in soybean plants in acid soil tidal lands. Furthermore, the application of biofertilizers can increase soybean productivity in acid sulfate soil in Indonesia.

Dynamic changes in the glycocalyx and clinical outcomes in patients undergoing endovascular treatments for large vessel occlusion.

We aimed to verify the prognostic value of the glycocalyx as a marker of blood-brain barrier damage in patients with acute ischemic stroke undergoing endovascular therapy. We recruited patients with large vessel occlusion who were undergoing recanalization and tested their glycocalyx at multiple time points. On the basis of the 90-day follow-up data, the patients were divided into a survivor group and a nonsurvivor group. In addition, neurological function was tracked, and patients were divided into a neurological deterioration group and a group without neurological deterioration. Associations between outcomes and dynamic changes in the glycocalyx were determined using a linear mixed model, and significant factors were used as covariates. Nonsurvivors and patients with neurological deterioration had significantly higher syndecan-1 concentrations than survivors and patients without neurological deterioration, and syndecan-1 tended to decline after endovascular therapy (p < 0.05). The increased level of syndecan-1 at 36 h after endovascular treatment was positively correlated with the National Institute of Health Stroke Scale score for neurological deterioration (r = 0.702, p = 0.005). However, there was no significant difference in the level of hyaluronic acid or heparan sulfate in the plasma of patients with different clinical outcomes. Pre-reperfusion syndecan-1 levels in patients with large vessel occlusion stroke are associated with 90-day mortality and the re-degradation of syndecan-1 is positively associated with neurological deterioration.

A nationwide acid sulfate soil study — A rapid and cost-efficient approach for characterizing large-scale features

Acid sulfate soils are sulfide-rich soils that pose a notable environmental risk as their strong acidity and low pH mobilizes metals from soil minerals leading to both acidification and metal contamination of the surrounding environment. In this study a rapid and cost-efficient approach was developed to resolve the main distribution patterns and geochemical features of acid sulfate soils throughout coastal plains stretching for some 2000 km in eastern, southern, and western Sweden. Of the investigated 126 field sites, 47 % had acid sulfate soils including 33 % active, 12 % potential, and 2 % pseudo acid sulfate soils. There were large regional variations in the extent of acid sulfate soils, with overall much higher proportions of these soils along the eastern coastal plains facing the Baltic Sea than the western coastal plains facing the Kattegatt/Skagerrak (Atlantic Ocean). The sulfur concentrations of the soil's parent material, consisting of reduced near-pH neutral sediments, were correlated inversely both with the minimum pH of the soils in situ (rS = −0.65) and the pH after incubation (oxidation) of the reduced sediments (rS = −0.77). This indicated the importance of sulfide levels in terms of both present and potential future acidification. Hence, the higher proportion of acid sulfate soils in the east was largely the result of higher sulfur concentrations in this part of the country. The study showed that the approach was successful in identifying large-scale spatial patterns and geochemical characteristics of importance for environmental assessments related to these environmentally unfriendly soils.

Inactivation of Staphylococcus aureus by Levulinic Acid Plus Sodium Dodecyl Sulfate and their Antibacterial Mechanisms on S. aureus Biofilms by Transcriptomic Analysis

The combination of levulinic acid (LVA) and sodium dodecyl sulfate (SDS) in recent years has shown a considerable potential to use as an antimicrobial intervention. The objectives of this study were to evaluate the antimicrobial efficacy of the combination against Staphylococcus aureus in both planktonic and biofilm states and to investigate the transcriptional changes in S. aureus biofilms coincubated with sublethal concentrations of LVA and/or SDS. The minimum inhibitory concentrations (MICs) of LVA and SDS determined by the microdilution method were 3.125 and 0.039 mg/mL, respectively. An additive bacteriostatic interaction (fractional inhibitory concentration index = 1) between the two compounds was observed by the checkerboard assay, whereas a synergistic bactericidal activity was displayed by the time-kill assay. The biomass and viable cells in the biofilms were reduced by both antimicrobials either alone or in combination in a dose-dependent manner. Transcriptomics indicated that more differentially expressed (DE) genes were observed in the biofilm treated with SDS (103 up- and 205 downregulated DE genes) and LVA + SDS (187 up and 162 down) than that coincubated with LVA (34 up and 32 down). The SDS and LVA + SDS treatments mainly affected the expression of genes responsible for cell surface proteins, virulence factors, adhesins, and capsular polysaccharides. Both the antibiofilm assay and the transcriptomics indicated that SDS, not LVA, was the major chemical contributing to the antibacterial efficacy of the combination. This study reveals the behavioral responses and protective mechanisms of S. aureus to LVA and SDS applied individually or in combination.

Efficacy of esophagus protection in complex treatment of erosive gastroesophageal reflux disease: a systematic review and meta-analysis of controlled trials

To review the data about the efficacy of esophagus protective agent based on the fixed combination of hyaluronic acid and chondroitin sulfate dissolved in the bioadhesive carrier (poloxamer 407) in the complex therapy of patients with erosive gastroesophageal reflux disease (GERD). A search in MEDLINE/PubMed, EMBASE, Cochrane, and Russian Science Citation Index of Scientific Electronic Library electronic databases was performed. Relevant original controlled studies of a fixed combination of hyaluronic acid and chondroitin sulfate as an esophagus protective agent in a population of patients with erosive GERD were included. The final analysis included three studies that enrolled 181 patients with erosive GERD. All the studies had a uniform design with the assessment of the primary endpoints (complete epithelialization of esophageal erosions and complete resolution of heartburn) 28 days after the start of therapy. Meta-analysis of the three controlled trials has demonstrated that combination therapy with proton pump inhibitors (PPIs) and esophagus protective agents is significantly more effective than PPI monotherapy for complete epithelialization of esophageal erosions at 28 days of treatment (relative risk 1.267, 95% confidence interval 1.082-1.483, p=0.003; I2=21.19%), but did not differ for complete resolution of heartburn on the day 28 of treatment (relative risk 1.638, 95% confidence interval 0.660-4.067, p=0.287; I2=92.59%). Combined therapy with PPI and Alfasoxx is significantly more effective than PPI monotherapy for the epithelialization of esophageal erosions in patients with erosive GERD.

Application of response surface methodology (RSM) for optimizing and statistical analysis of ultrasound-assisted oxidative desulfurization (UAOD) of an Iranian heavy crude oil

In this study, optimization and statistical analysis of oxidative desulfurization (ODS) of an Iranian heavy crude oil (HCO) by applying ultrasonic waves were performed. The investigated HCO was from the West Paydar Field of Iran (sulfur: 38638 ppm, viscosity: 78.76 cSt (20 °C), API: 18.53). The process was performed in the presence of acetic acid (catalyst), hydrogen peroxide (oxidant), and copper sulfate (PTA, phase transfer agent). The studied parameters included power (10–15 W/ml), temperature (60–80 °C), PTA (0–1 wt%), and catalyst (4.8–19.2 wt%). The processing time was 10 min. Acetonitrile was an extraction solvent. The experimental design was performed based on Box Behnken design (BBD) and consisted of 27 experiments. RSM was applied to model the response and to investigate the effects of one factor, parameter interactions, and optimization. A quadratic polynomial equation was presented for the model of HCO sulfur reduction. Based on the results, power, PTA, and catalyst had significant effects on the response. The regression coefficient of 0.9273 indicated a good agreement between the experimental results and the model results. Optimization results showed that under optimal conditions including power: 14.63 w/ml, temperature: 72.47 °C, PTA: 0.79 wt%, and catalyst: 4.84 wt%, desulfurization was 45.10 wt%.

Dietary acidic calcium sulfate enhances growth, digestive enzyme activities, intestinal histology and resistance against Aeromonas hydrophila in juvenile largemouth bass, Micropterus salmoides

This study was conducted to investigate the effects of dietary supplementation with acidic calcium sulfate on growth, intestinal histology, and disease resistance of juvenile largemouth bass. Fish (19.88 ± 0.03 g) were fed on diets supplemented with 0 % (control), 1% acidic calcium sulfate (ACS1), 2 % acidic calcium sulfate (ACS2), 3 % acidic calcium sulfate (ACS3) and 0.03 % florfenicol (F) for 56 days. The results showed that the supplementation of 1 % acidic calcium sulfate to the diet significantly enhanced the growth performance (P < 0.05). Serum alanine aminotransferase activity in ACS2 and ACS3 groups was significantly higher than that in the control and ACS1 groups (P < 0.05). The serum alkaline phosphatase activity in ACS1 and F groups was significantly higher than that in the control and ACS3 groups (P < 0.05). The activity of serum superoxide dismutase in the control, ACS2 and ACS3 groups was significantly lower than that in ACS1 group (P < 0.05). Intestinal trypsin, amylase, and lipase activities increased significantly with increasing acidic calcium sulfate when compared to the control. (P < 0.05). The intestinal histology features showed that the villi height and width of ACS1 and ACS2 groups were significantly increased compared to that of the control (P < 0.05). The results of TOR pathway related genes in the liver showed that the expressions of TOR and ribosomal protein S6 of ACS1 group were significantly higher than the control, while the expression of 4E-BP1 was significantly decreased (P < 0.05). When challenged with Aeromonas hydrophila, the survival rate of the control was significantly lower than that of F, ACS1, and ACS2 groups (P < 0.05). In summary, the optimum amount of acidic calcium sulfate for this experiment is 1 %. 1 % acidic calcium sulfate can effectively improve the growth performance and disease resistance of juvenile largemouth bass.

Petrogypsic paleosols on Mars

Unlike the water planet Earth, or furnace planet Venus, Mars is a frigid soil planet, most like the Dry Valleys of Antarctica, which also has paleosols revealing a different past. This study examined rocks in early Amazonian (3000 Ma) sequences of western Candor Chasma, cemented by sulfates and iron oxides. Mars Reconnaissance Orbiter data were used to quantify elevations, and the gypsic bands proved to follow ancient dune surfaces, like petrogypsic horizons of soils. Hesperian-early Amazonian (3700-3000 Ma) gypsic paleosols are widespread on Mars, which also has Noachian (3800-4000 Ma) deeply weathered, kaolinitic paleosols. The Archean (3700-3000 Ma) Earth was similar with both gypsic and deeply weathered profiles. Archean fossil microbes and soils on Earth include acid sulfate and deeply weathered soils, but both life and soil diversified afterward on Earth. There is not yet a fossil record on Mars, but the red planet does have acid sulfate and deeply weathered paleosols of geological ages equivalent to Archean on Earth. Unlike Earth however, there is little evidence of later significant soil formation on Mars.