Sulfate Retention Research Articles

In situ study of microstructural evolution of borosilicate glass–sulfate mixture at high temperatures

AbstractMicrostructural evolution of borosilicate glass–sulfate (BaSO4 or Na2SO4) mixture was observed in situ using a high‐temperature confocal scanning laser microscope. The phase compositions and sulfate retention of the mixture at different temperatures were also examined. The results indicate that for the glass–BaSO4 sample (abbreviated as BS), the borosilicate glass begins to melt at about 900°C, and the triangular BaSO4 crystals grow obviously between 900°C and 1100°C. At temperatures above 1100°C, the BaSO4 crystals gradually melt and decompose. For the glass–Na2SO4 sample (abbreviated as NS), strip‐shaped BaSO4 crystals begin to form at about 820°C after the borosilicate glass melting, and then gradually melt with further increasing temperature. When the temperature increases to 1000°C, the upper layer of the NS sample possesses Na2SO4, LiNaSO4, and BaSO4 phases, while the lower layer possesses an amorphous phase. Moreover, the SO3 retention in the BS sample remains almost unchanged with temperature increases from 900°C to 1100°C, and then decreases with further increasing temperature. The SO3 retention retained in the NS sample decreases rapidly at temperatures above 900°C. These findings can provide a guidance for vitrifying sulfur‐rich high‐level liquid waste.

RNA sequencing and lipidomics uncovers novel pathomechanisms in recessive X-linked ichthyosis.

Recessive X-linked ichthyosis (RXLI), a genetic disorder caused by deletion or point mutations of the steroid sulfatase (STS) gene, is the second most common form of ichthyosis. It is a disorder of keratinocyte cholesterol sulfate retention and the mechanism of extracutaneous phenotypes such as corneal opacities and attention deficit hyperactivity disorder are poorly understood. To understand the pathomechanisms of RXLI, the transcriptome of differentiated primary keratinocytes with STS knockdown was sequenced. The results were validated in a stable knockdown model of STS, to confirm STS specificity, and in RXLI skin. The results show that there was significantly reduced expression of genes related to epidermal differentiation and lipid metabolism, including ceramide and sphingolipid synthesis. In addition, there was significant downregulation of aldehyde dehydrogenase family members and the oxytocin receptor which have been linked to corneal transparency and behavioural disorders respectively, both of which are extracutaneous phenotypes of RXLI. These data provide a greater understanding of the causative mechanisms of RXLI's cutaneous phenotype, and show that the keratinocyte transcriptome and lipidomics can give novel insights into the phenotype of patients with RXLI.

Indoxyl Sulphate Retention Is Associated with Microvascular Endothelial Dysfunction after Kidney Transplantation.

Kidney transplantation (KTx) is the preferred form of renal replacement therapy in chronic kidney disease (CKD) patients, owing to increased quality of life and reduced mortality when compared to chronic dialysis. Risk of cardiovascular disease is reduced after KTx; however, it is still a leading cause of death in this patient population. Thus, we aimed to investigate whether functional properties of the vasculature differed two years post-KTx (postKTx) compared to baseline (time of KTx). Using the EndoPAT device in 27 CKD patients undergoing living-donor KTx, we found that vessel stiffness significantly improved while endothelial function worsened postKTx vs. baseline. Furthermore, baseline serum indoxyl sulphate (IS), but not p-cresyl sulphate, was independently negatively associated with reactive hyperemia index, a marker of endothelial function, and independently positively associated with P-selectin postKTx. Finally, to better understand the functional effects of IS in vessels, we incubated human resistance arteries with IS overnight and performed wire myography experiments ex vivo. IS-incubated arteries showed reduced bradykinin-mediated endothelium-dependent relaxation compared to controls via reduced nitric oxide (NO) contribution. Endothelium-independent relaxation in response to NO donor sodium nitroprusside was similar between IS and control groups. Together, our data suggest that IS promotes worsened endothelial dysfunction postKTx, which may contribute to the sustained CVD risk.

Evaluation of Nanofiltration Membranes for the Purification of Monosaccharides: Influence of pH, Temperature, and Sulfates on the Solute Retention and Fouling.

Furfural, acetic acid, and sulfates are found in the hemicellulose (HMC) fraction of lignocellulosic biomass. Separation of furfural, acetic acid, and sulfates from monosaccharides by four nanofiltration (NF) membranes was evaluated with a model solution of glucose, xylose, furfural, acetic acid, and sulfates. Results showed that Alfa Laval NF99HF is the most promising membrane to purify monosaccharides, with the retentions of xylose (85%), glucose (95%), and with the minimum sulfate retention. pH has the highest impact on the retention of all solutes and there is no significant effect of temperature on the retentions of sulphates and acetic acid. Lower pH and temperature are favored to maximize the monosaccharide retention and to remove acetic acid while retaining more furfural with the monosaccharides. Moreover, fouling tendency is maximized at lower pH and higher temperatures. According to the statistical analysis, the retentions of glucose, xylose, furfural, sulfates, and acetic acid are 95%, 90%, 20%, 88%, and 0%, respectively at pH 3 and 25 °C. The presence of sulfates favors the separation of acetic acid and furfural from monosaccharides.

Removal of Sulphate Ions from Borehole Water Using Nanofiltration and Reverse Osmosis

Consumption of contaminated water poses health hazards to humanity and hence increases the need for treatment. An excessive level of sulphate in borehole water was detected in the drinking water supply of Garpéné village in Burkina Faso. This study aimed to evaluate the performance of nanofiltration and reverse osmosis for the removal of sulphate ions from borehole water. A combined nanofiltration and reverse osmosis pilot was used for the treatment of the raw borehole water and some prepared synthetic solutions. Different experimental conditions were used to evaluate the effects of the pressure, the nature of the solution to be filtered, and the ions accompanying the sulphate. The filtration tests were conducted at transmembrane pressures of 1, 2.5 and 4 bar with a nanofiltration NF270 membrane and at transmembrane pressures of 4, 6 and 8 bar with a reverse osmosis TW30 membrane. The membrane used were a thin-film composite (TFC) membrane from Filmtec. The pilot was fed with real water from the Garpéné borehole and synthetic solutions of calcium sulphate and sodium sulphate at three different concentrations (250, 500 and 1400 mg/L). The results demonstrated that the nanofiltration and reverse osmosis membranes achieved retention rates of sulphate ions ranging from 97.0% to 98.7% and 98.4% to 99.0%, respectively. The results also showed that the operating conditions had a significant effect on the retention of sulphate by reverse osmosis and nanofiltration membranes. With regard to the effect of the counter ion, it was observed that during nanofiltration, the retention rate of sulphate ions in the water to be treated was lower in the presence of calcium ions than that of sodium ions, whereas in reverse osmosis little influence of the counter ion was observed.

Disease correction in mucopolysaccharidosis type IIIB mice by intraparenchymal or cisternal delivery of a capsid modified AAV8 codon-optimized NAGLU vector.

Mucopolysaccharidosis type IIIB (MPS IIIB) is an autosomal recessive lysosomal storage disease caused by mutations in the gene that encodes the protein N-acetyl-glucosaminidase (NAGLU). Defective NAGLU activity results in aberrant retention of heparan sulfate within lysosomes leading to progressive central nervous system (CNS) degeneration. Intravenous treatment options are limited by the need to overcome the blood-brain barrier and gain successful entry into the CNS. Additionally, we have demonstrated that AAV8 provides a broader transduction area in the MPS IIIB mouse brain compared with AAV5, 9 or rh10. A triple-capsid mutant (tcm) modification of AAV8 further enhanced GFP reporter expression and distribution. Using the MPS IIIB mouse model, we performed a study using either intracranial six site or intracisterna magna injection of AAVtcm8-codon-optimized (co)-NAGLU using untreated MPS IIIB mice as controls to assess disease correction. Disease correction was evaluated based on enzyme activity, heparan sulfate storage levels, CNS lysosomal signal intensity, coordination, activity level, hearing and survival. Both histologic and enzymatic assessments show that each injection method results in supranormal levels of NAGLU expression in the brain. In this study, we have shown correction of lifespan and auditory deficits, increased CNS NAGLU activity and reduced lysosomal storage levels of heparan sulfate following AAVtcm8-coNAGLU administration and partial correction of NAGLU activity in several peripheral organs in the murine model of MPS IIIB.

Role of Ba(NO3) pretreatment in reducing the yellow phase formation during vitrification of nuclear waste

During vitrification of sulfate bearing high-level liquid waste (HLLW), Na2SO4 is easy to decompose at high temperatures and a water soluble “yellow phase” containing mainly alkali metal sulfates generally forms on the surface of glass melts. Herein, we report the SO42− ions present in the HLLW as Na2SO4 can be sequestrated as the form of BaSO4 by addition of Ba(NO3)2 solution and the formation of yellow phase can be effectively reduced during vitrification. XRD and SEM-EDX show that the main constituents of yellow phase consist of BaSO4, BaCrO4, and BaMoO4 by adding excess Ba(NO3)2, and the alkali metal sulfates phases almost disappear. In addition, the sulfate retention of waste glass is increased by the Ba(NO3)2 pretreatment, especially for vitrification of HLLW with relatively high sulfate content. The SO3 content in the waste glass remains almost unchanged in temperature range of 850‒1050°C. These results suggest that the Ba(NO3)2 pretreatment may provide an alternative new way to solve the yellow phase problem during the vitrification of sulfate bearing HLLW.

Critical loads of headwater streams in China using SSWC model modified by comprehensive F-factor

In order to evaluate the potential risk of surface water acidification in regions with historically-elevated acid deposition and to measure the recovery of such ecosystems after policy changes, critical loads and their exceedances were estimated for 349 headwater streams across China using a modified SSWC model. Such a model considered the acid-neutralizing capacity derived from high base cation deposition and the robust retention of sulfate and nitrate. Results indicated that China's streams had higher critical loads (averaged at 4.7 keq·ha−1·yr−1) and were less sensitive to acid deposition as compared to Europe and North America. The proportion of surveyed streams with acid deposition exceeded critical load decreased from 40.4% in 2005 to 29.5% in 2018, indicating a significant decrease in risk of surface water acidification, and thus a benefit from the emission abatement in recent years. Nonetheless, a relatively high risk of acidification still existed in southeast China with lower critical loads and most critical load exceedances. More efforts should be put into implementing emission control policies in the future.

A Study of Retention Behavior and Method Development of Salbutamol Sulfate in Hydrophilic Interaction Chromatography

For chromatographical separation and estimation of salbutamol sulfate, zwitterionic stationary phases with large capacity were obtained by zwitter-molecules attached to a polystyrene-divinylbenzene (PS/DVB) particle. Salbutamol sulfate retention activity was studied with eluent at various pH mobile phase, mobile phase concentrations, and acetonitrile (ACN) percentage. The methods of separation are based on separating the salbutamol sulfate into hydrophobic and cations interactions. Linearity of 0.01 to 0.9 μg.mL-1 for two columns was developed with direct calibration curves, %RSD percent (0.48 ± 0.12 and 0.49 ± 0.22), LoD (0.058 and 0.04 μg.mL-1), and LoQ (0.203 and 0.14 μg.mL-1) were created, respectively.

A comparison of sulfur isotope measurements of geologic materials by inductively coupled plasma and gas source mass spectrometry

Sulfur isotope measurements by multi collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) require up to one hundred times less sulfur than traditional measurements via elemental analyzer isotope ratio mass spectrometry (EA-IRMS). Here, we report an improved MC-ICP-MS protocol for measuring δ34S values in different natural samples, specifically, calcium-sulfate minerals, carbonate associated sulfate, and dissolved sulfate in water. Sample preparation and subsequent anion exchange chromatography quantitatively recovers sulfur as sulfate. However, for samples with high and complex anion budgets, such as meteoric water, a stronger retention of sulfate on the anion exchange resin is observed relative to samples that contain sulfur as pure sulfate such as calcium-sulfate minerals and carbonate associated sulfate. An extended elution scheme with HNO3 is therefore required to achieve full recovery of sulfur, and thus accurate and reproducible δ34S values for the different materials investigated. Sulfur isotope measurements were performed on a Neptune Plus MC-ICP-MS coupled to an Apex-Ω desolvator, resulting in a “dry” plasma, negligible level of isobaric interferences, a sensitivity of >40 V ppm−1 sulfur, and a precision of 0.2‰ (2 S.D.) for δ34S for as little as 70 ng sulfur of a pure sulfate solution. The accuracy of the procedure was tested against duplicate δ34S EA-IRMS measurements for eleven different geologic samples. The EA-IRMS and MC-ICPMS values generally agree well within analytical uncertainty. However, procedural blank levels are on the order of a few tens of nanogram sulfur, and are thus the main limiting factor for accurate low-level sulfur isotope measurements with MC-ICP-MS.

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

Mining is an essential human activity, but results in several environmental impacts, notably the contamination of ground and surface water through the presence of toxic substances such as metals and sulfates in mine drainage. Permeable reactive barriers (PRB) have been applied to remediate this environmental impact, but the high costs associated with the maintenance of this system are still a challenge. The main objective of this study was to evaluate the use of kraft pulp mill alkaline residues, known as dregs and grits, as material for PRB, and to determine their capacity for retaining copper and sulfate. The work was carried out in laboratory adsorption kinetics assays, batch assays and column tests. Tests for elemental characterization, point of zero charge, acid neutralization capacity, total porosity, bulk density and moisture of the dregs and grits were conducted. The results showed high retention of Cu due to a chemical precipitation mechanism, notably for dregs (99%) at 5 min in adsorption kinetics. The grits presented similar results after 180 min for the same assay. Sulfate retention was effective at pH below 5, with an efficiency of 79% and 89% for dregs and grits, respectively. Dregs presented the best results for acid drainage remediation, notably with a solid:liquid (S:L) ratio of 1:10.

Electrogenic sulfide oxidation mediated by cable bacteria stimulates sulfate reduction in freshwater sediments.

Cable bacteria are filamentous members of the Desulfobulbaceae family that oxidize sulfide with oxygen or nitrate by transferring electrons over centimeter distances in sediments. Recent studies show that freshwater sediments can support populations of cable bacteria at densities comparable to those found in marine environments. This is surprising since sulfide availability is presumably low in freshwater sediments due to sulfate limitation of sulfate reduction. Here we show that cable bacteria stimulate sulfate reduction in freshwater sediment through promotion of sulfate availability. Comparing experimental freshwater sediments with and without active cable bacteria, we observed a three- to tenfold increase in sulfate concentrations and a 4.5-fold increase in sulfate reduction rates when cable bacteria were present, while abundance and community composition of sulfate-reducing microorganisms (SRM) were unaffected. Correlation and ANCOVA analysis supported the hypothesis that the stimulation of sulfate reduction activity was due to relieve of the kinetic limitations of the SRM community through the elevated sulfate concentrations in sediments with cable bacteria activity. The elevated sulfate concentration was caused by cable bacteria-driven sulfide oxidation, by sulfate production from an indigenous sulfide pool, likely through cable bacteria-mediated dissolution and oxidation of iron sulfides, and by enhanced retention of sulfate, triggered by an electric field generated by the cable bacteria. Cable bacteria in freshwater sediments may thus be an integral component of a cryptic sulfur cycle and provide a mechanism for recycling of the scarce resource sulfate, stimulating sulfate reduction. It is possible that this stimulation has implication for methanogenesis and greenhouse gas emissions.

Nanofiltration of Succinic Acid in Strong Alkaline Conditions.

Nanofiltration is considered to be an appropriate separation technique in the production of bio-based materials. For the utilization of process streams from the viscose-fiber production, understanding the separation behavior of organic compounds in highly alkaline solutions is necessary. Experiments with succinic acid in sodium hydroxide (NaOH) solutions with varying concentrations up to 5 mol L−1 were performed with the NP030 membrane from Microdyn Nadir. Furthermore, experiments with aqueous disodium succinate and solutions of sodium sulfate in sodium hydroxide were carried out. The influence of concentration ratios and temperature was studied. The Spiegler and Kedem model as well as the Pusch model were applied to fit the experimental data. Additionally, scanning electron microscopy (SEM) and infrared (ATR–IR) measurements were performed to validate the chemical and thermomechanical stability of the membrane. The succinic acid retention varies with its degree of dissociation. In a fully dissociated form, the NaOH concentration shows no impact on the retention. In contrast, the retention of sulfate decreases with increasing NaOH concentration.

Structural Characterization of Glycosaminoglycan Carbohydrates Using Ultraviolet Photodissociation.

Structural characterization of sulfated glycosaminoglycans (GAGs) by mass spectrometry has long been a formidable analytical challenge owing to their high structural variability and the propensity for sulfate decomposition upon activation with low-energy ion activation methods. While derivatization and complexation workflows have aimed to generate informative spectra using low-energy ion activation methods, alternative ion activation methods present the opportunity to obtain informative spectra from native GAG structures. Both electron- and photon-based activation methods, including electron detachment dissociation (EDD), negative electron transfer dissociation (NETD), and extreme ultraviolet photon activation, have been explored previously to overcome the limitations associated with low-energy activation methods for GAGs and other sulfated oligosaccharides. Further, implementation of such methods on high-resolution mass spectrometers has aided the interpretation of the complex spectra generated. Here, we explore ultraviolet photodissociation (UVPD) implemented on an Orbitrap mass spectrometer as another option for structural characterization of GAGs. UVPD spectra for both dermatan and heparan sulfate structures display extensive fragmentation including both glycosidic and cross-ring cleavages with the extent of sulfate retention comparable to that observed by EDD and NETD. In addition, the relatively short activation time of UVPD makes it promising for higher throughput analysis of GAGs in complex mixtures.

Microstructure, sulfate retention, and aqueous stability of barite-borosilicate glass-ceramics

In order to increase the solubility of sulfate in glass matrix, barite−borosilicate glass-ceramics were proposed and prepared by melt quenching method. The effects of SO3 addition (in the form of BaSO4, 0–8 wt%, abbreviated as S0S8) on microstructure, phase structure, and aqueous stability of barite–borosilicate glass-ceramics were studied. The sulfate retention of the glass-ceramics was evaluated. The results show that the samples with addition of 0–4 wt% SO3 possess the amorphous structure. Barite phase appears when the addition SO3 content increases to 5 wt%, and the amount of barite crystals increases with further increasing SO3 content. Furthermore, BaSO4 in borosilicate glass melts is more stable than that of Na2SO4. The sample S4 possesses SiO2 and BaSO4 phases in temperature range of 800–1150 °C. The SO3 content in the sample S4 remains almost unchanged when the temperature increases from 800 to 1050 °C, and decreases rapidly with further increasing temperature. About 2.17 wt% of SO3 can be retained in the sample S6 after melting at 1200 °C. Moreover, the normalized leaching rates of Na and B of the samples S4, S6, and S8 after 28 days are one order of magnitude higher than that of the sample S0. The sample S6 has a lower normalized leaching rate of SO42− (∼1.28 × 10−2 g m−2 d−1) after 28 days.

Arsenic, antimony, and nickel leaching from northern peatlands treating mining influenced water in cold climate

Increased metal mining in the Arctic region has caused elevated loads of arsenic (As), antimony (Sb), nickel (Ni), and sulfate (SO42−) to recipient surface or groundwater systems. The need for cost-effective active and passive mine water treatment methods has also increased. Natural peatlands are commonly used as a final step for treatment of mining influenced water. However, their permanent retention of harmful substances is affected by influent concentrations and environmental conditions. The effects of dilution, pH, temperature, oxygen availability, and contaminant accumulation on retention and leaching of As, Sb, Ni, and sulfate from mine process water and drainage water obtained from treatment peatlands in Finnish Lapland were studied in batch sorption experiments, and discussed in context of field data and environmental impacts. The results, while demonstrating effectiveness of peat to remove the target contaminants from mine water, revealed the risk of leaching of As, Sb, and SO42− from treatment peatlands when diluted mine water was introduced. Sb was more readily leached compared to As while leaching of both was supported by higher pH of 9. No straightforward effect of temperature and oxygen availability in controlling removal and leaching was evident from the results. The results also showed that contaminant accumulation in treatment peatlands after long-term use can lead to decreased removal and escalated leaching of contaminants, with the effect being more pronounced for As and Ni.

Capillary Nanofiltration under Anoxic Conditions as Post-Treatment after Bank Filtration

Bank filtration schemes for the production of drinking water are increasingly affected by constituents such as sulphate and organic micropollutants (OMP) in the source water. Within the European project AquaNES, the combination of bank filtration followed by capillary nanofiltration (capNF) is being demonstrated as a potential solution for these challenges at pilot scale. As the bank filtration process reliably reduces total organic carbon and dissolved organic carbon (DOC), biopolymers, algae and particles, membrane fouling is reduced resulting in long term operational stability of capNF systems. Iron and manganese fouling could be reduced with the possibility of anoxic operation of capNF. With the newly developed membrane module HF-TNF a good retention of sulphate (67–71%), selected micropollutants (e.g., EDTA: 84–92%) and hardness (41–55%) was achieved together with further removal of DOC (82–87%). Fouling and scaling could be handled with a good cleaning concept with acid and caustic. With the combination of bank filtration and capNF a possibility for treatment of anoxic well water without further pre-treatment was demonstrated and retention of selected current water pollutants was shown.

Plant sulfur isotopic compositions are altered by marine fertilizers

This study presents sulfur isotope compositions (δ34S) for plants grown in a series of growth chamber and field experiments under controlled conditions. Maize, beans, and squash fertilized with a marine fertilizer (seabird guano) were significantly enriched in 34S relative to the unfertilized control plants (by +4.0 to +7.2‰) in the growth chamber experiments. No 34S enrichment was detected in the plants from the field experiment, which likely relates to the recent use of ammonium sulfate fertilizer in these fields and the retention of residual sulfate with a comparatively low δ34S. The field experiment provided a basis to estimate the apparent fractionation between soil and plant S associated with uptake and assimilation (Δ34S), which ranged between −4 and −6‰ depending on the taxon and tissue. The use of marine fertilizers has the capacity to increase plant δ34S values and complicate quantitative reconstructions of ancient diet based on bulk stable isotope data.

Annealing of Polyelectrolyte Multilayers for Control over Ion Permeation

AbstractPolyelectrolyte multilayer based membranes are highly promising systems to create stable and versatile nanofiltration membranes. One very popular and well‐studied polyelectrolyte pair, is the polycation poly(diallyldimethylammonium chloride) (PDADMAC) and polyanion poly(sodium 4‐styrenesulfonate) (PSS), due to its excellent separation properties and high chemical and physical stability. Membrane charge can be easily controlled by simply terminating the multilayer by either PDADMAC or PSS. Unfortunately, a phenomenon that occurs during multilayer coating, is overcompensation by PDADMAC. In this study, it is shown that overcompensation of PDADMAC results in a positive surface charge even when the multilayer is PSS‐terminated. In addition, it is shown that this leads to poorer membrane separation properties with sulfate retention decreasing from 94 to 39%. At the same time, it is demonstrated that a so‐called annealing cycle with a high salt concentration leads to recovery of the negative surface charge, increasing the sulfate retention from 39 to 95%. Even for multilayers at which no irreversible positive surface charge is measured, separation properties improved substantially (increasing sulfate retention from 94 to 97%, at a higher membrane permeability) after salt‐annealing. It is concluded that post‐treatment by salt‐annealing results in an improved membrane performance and allows an additional degree of control over the membrane separation properties.

Graphene oxide membranes for ion separation: Detailed studies on the effects of fabricating conditions

Graphene oxide (GO) membrane has potential application in desalination process. In this paper, vacuum filtration was employed to prepare GO membrane on the mixed cellulose support membrane, which had caused widespread concern due to its efficiency, simplicity, and uniform thickness of the prepared membrane. Our goal is to explore the optimal preparation conditions of GO membrane that we can get a membrane with high permeation performance. Here, the performance of pure GO membranes prepared in different conditions were described in detail, which would create an unexpected value for the stability of GO membrane permeation properties and its practical application. In addition, we obtained a high-performance GO membrane at a low pressure, which had a higher flux (∼70 L m−2 h−1) and surprising retention of sodium sulfate (1 g L−1, above 90%). It does demonstrate that GO membrane has great potential in nanofiltration process.