Sulfate Content Research Articles

Effects of Different Proportions of Ammonium Sulfate Replacing Urea on Soil Nutrients and Rhizosphere Microbial Communities

In order to investigate the effects of ammonium sulfate, an industrial by-product, on soil nutrients and microbial community when applied in different proportions instead of using urea as nitrogen fertilizer, a pot corn experiment was conducted. A completely randomized block experimental design was used, with a total of five treatments:CK (no fertilization), U10S0 (100 % urea), U8S2 (80 % urea + 20 % ammonium sulfate), U6S4(60 % urea + 40 % ammonium sulfate), and U0S10 (100 % ammonium sulfate). The basic physical and chemical properties of soil and the dry weight of maize plants were determined by conventional methods, and microbial sequencing was performed using the Illumina NovaSeq platform. The experiment results showed that:① In each growth stage of maize, the pH of soil treated with fertilization (7.85-8.15) was decreased compared with that of CK (8.1-8.21), and the pH showed a decreasing trend with the increase in ammonium sulfate content. ② The soil available nitrogen content increased gradually with the increase in the ammonium sulfate ratio at each growth stage of maize. Compared with that in the CK and U10S0 treatments, the ratio in the U0S10 treatment increased 30.56 % to 63.68 % and 13.22 % to 38.43 %, respectively. The variation trend of organic carbon content was opposite to that of available nitrogen (U8S2 > U6S4 > U0S10), and the addition of ammonium sulfate was still higher than that of U10S0 at other growth stages except for the seedling stage. ③ The protease activity of all fertilization treatments was higher than that of the control, and the protease activity was gradually enhanced with the continuous growth of corn and the increase in the ammonium sulfate ratio. The protease activity of the U0S10 treatment was higher than that of the U10S0 treatment at each growth stage of corn, which increased by 10.54 %-100 %. Soil sucrase activity ranged from 0.04 to 0.24 mg·(g·24 h)-1, and those in the U0S10 treatments were significantly higher than those in the U10S0 and CK treatments at all growth stages, increasing by 20.32 % to 99.16 % and 24.31 % to 79.33 %, respectively. ④ The species abundance of bacteria and fungi in maize rhizosphere under all fertilization treatments were lower than those under the CK treatment, followed by those under the U10S0 treatment. The species diversity trend of the bacterial community in the three treatments with ammonium sulfate replacing urea were U8S2 > U0S10 > U6S4, and that of fungi were U6S4 > U8S2 > U0S10. ⑤ The maize dry weight of the U10S0 treatment and U0S10 treatment was the highest, which was 39.47 % and 36.16 % higher than that of the CK treatment, respectively, but the difference was not significant. The Pearson model showed that the species abundance and diversity of soil rhizosphere fungi and bacteria were affected by relevant environmental variables, among which pH value and soil available nitrogen content were the most important factors affecting microbial diversity. In conclusion, when corn planting in calcareous brown soil, replacing urea with a certain proportion of ammonium sulfate can improve soil nutrients more than urea alone, which affects the growth and rhizosphere microbial community of corn to a certain extent and has a greater yield.

Enhancing Rubber Industry Wastewater Treatment through an Integrated AnMBR and A/O MBR System: Performance, Membrane Fouling Analysis, and Microbial Community Evolution.

This study explores the effectiveness of an integrated anaerobic membrane bioreactor (AnMBR) coupled with an anoxic/oxic membrane bioreactor (A/O MBR) for the treatment of natural rubber industry wastewater with high sulfate, ammonia, and complex organic contents. This study was conducted at the lab-scale over a duration of 225 days to thoroughly investigate the efficiency and sustainability of the proposed treatment method. With a hydraulic retention time of 6 days for the total system, COD reductions were over 98%, which reduced the influent from 22,158 ± 2859 mg/L to 118 ± 74 mg/L of the effluent. The system demonstrates average NH3-N, TN, and total phosphorus (TP) removal efficiencies of 72.9 ± 5.7, 72.8 ± 5.6, and 71.3 ± 9.9, respectively. Despite an average whole biological system removal of 50.6%, the anaerobic reactor eliminated 44.9% of the raw WW sulfate. Analyses of membrane fouling revealed that organic fouling was more pronounced in the anaerobic membrane, whereas aerobic membrane fouling displayed varied profiles due to differential microbial and oxidative activities. Key bacterial genera, such as Desulfobacterota in the anaerobic stage and nitrifiers in the aerobic stage, are identified as instrumental in the biological processes. The microbial profile reveals a shift from methanogenesis to sulfide-driven autotrophic denitrification and sulfammox, with evidence of an active denitrification pathway in anaerobic/anoxic conditions. The system showcases its potential for industrial application, underpinning environmental sustainability through improved wastewater management.

Comprehensive Glycomic and Proteomic Analysis of Mouse Striatum and Lateral Hypothalamus Following Repeated Exposures to Cocaine or Methamphetamine

Substance use disorder is a major concern, with few therapeutic options. Heparan sulfate (HS) and chondroitin sulfate (CS) interact with a plethora of growth factors and their receptors and have profound effects on cellular signaling. Thus, targeting these dynamic interactions might represent a potential novel therapeutic modality. In the present study, we performed mass spectrometry–based glycomic and proteomic analysis to understand the effects of cocaine and methamphetamine (METH) on HS, CS, and the proteome of two brain regions critically involved in drug addiction: the lateral hypothalamus and the striatum. We observed that cocaine and METH significantly alter HS and CS abundances as well as sulfate contents and composition. In particular, repeated METH or cocaine treatments reduced CS 4-O-sulfation and increased CS 6-O-sulfation. Since C4S and C6S exercise differential effects on axon growth, regeneration, and plasticity, these changes likely contribute to drug-induced neural plasticity in these brain regions. Notably, we observed that restoring these alterations by increasing CS 4-0 levels in the lateral hypothalamus by adeno-associated virus delivery of an shRNA to arylsulfatase B (N-acetylgalactosamine-4-sulfatase) ameliorated anxiety and prevented the expression of preference for cocaine in a novelty induced conditioned place preference test during cocaine withdrawal. Finally, proteomics analyses revealed a number of aberrant proteins in METH- and cocaine-treated versus saline-treated mice, including myelin proteolipid protein, calcium/calmodulin-dependent protein kinase type II subunit alpha, synapsin-2, tenascin-R, calnexin, annexin A7, hepatoma-derived growth factor, neurocan, and CSPG5, and oxidative phosphorylation among the top perturbed pathway. Taken together, these data support the role of HS, CS, and associated proteins in stimulants abuse and suggest that manipulation of HSPGs can represent a novel therapeutic strategy.

Characterization, antioxidant and α-amylase inhibition of polysaccharides and phosphorylated derivatives from finger citron (Citrus medica L. var. sarcodactylis Swingle)

In this study, the structure-activity relationship of finger citron polysaccharides (FCPs) and their phosphorylated derivatives (P-FCPs) was investigated. Three FCPs (FCP20, FCP40 and FCP60) were successively fractionated by ethanol, and were phosphorylated modification to obtain P-FCPs (P-FCP20, P-FCP40 and P-FCP60). FCPs and P-FCPs are acidic heteropolysaccharides composed of mannose, rhamnose, glucose, galactose, arabinose and galacturonic acid, and exhibited different content of neutral sugar, uronic acid, proteins, polyphenols and sulfates. FTIR and NMR analyses determined the structures of FCPs and P-FCPs, indicating that the phosphorylation modification was successful. P-FCPs possessed the smaller molecular weight distribution and particle size, with significant changes in microstructure than FCPs. Additionally, P-FCPs showed significantly increased antioxidant and α-amylase inhibitory activities compared to FCPs. The inhibitory mechanisms of FCP40 and P-FCP40 on α-amylase was a mixed-type manner and dynamic fluorescence quenching. The results demonstrate that phosphorylation modification can alter the structural features and bioactivities of FCPs, providing an approach for the further development of finger citron in the field of medicinal and functional foods.

Polysaccharides from Artemisia argyi leaves: Environmentally friendly ultrasound-assisted extraction and antifatigue activities

Artemisia argyi leaf polysaccharide (AALPs) were prepared through ultrasound-assisted extraction (UAE), and their antifatigue activities were evaluated. Extraction was optimized using response surface methodology (RSM), which yielded the following optimal UAE conditions: ultrasonication power of 300 W, extraction temperature of 51 °C, liquid:solid ratio of 20 mL/g, and ultrasonication time of 47 mins. The above optimal conditions resulted in the maximum extraction rate of 10.49 %. Compared with hot water extraction (HWE), UAE supported higher yields and total sugar, uronic acid, and sulfate contents of AALPs. Meanwhile, AALP prepared through UAE (AALP-U) exhibited higher stability due to its smaller particle size and higher absolute value of zeta potential than AALP prepared through HWE (AALP-H). In addition, AALP-U demonstrated stronger antioxidant activity than AALP-H. In forced swimming tests on mice, AALP-U could significantly prolong swimming time with a dose-dependent effect, increase liver and muscle glycogen levels, and improve other biochemical indices, thus showing great potential for application in functional food.

Anti-inflammatory activity and structural analysis of fucoidan extracted from Sargassum fusiforme via ESI-TOF MS spectrometry

This study used Celluclast-assisted hydrolysis and DEAE-cellulose anion-exchange chromatography to extract, purify, and assess the anti-inflammatory activity of fucoidan derived from Sargassum fusiforme. The Celluclast-assisted hydrolysate was used for obtaining ethanol-precipitated S. fusiforme fucoidans (SFF) which were rich in polysaccharides and sulfates. Five fractions obtained through DEAE-cellulose chromatography, notably SFF-F5, displayed high sulfate content (29.16 ± 0.15%). The anti-inflammatory potential of these fractions was tested in lipopolysaccharide-induced RAW 264.7 macrophages. SFF-F5 was found to significantly reduce NO production at non-toxic concentrations of 12.5, 25, and 50 μg/mL. Structural analysis using Matrix assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOF MS) revealed repetitive patterns in the fucoidan fractions. And Electrospray ionization mass spectrometry (ESI-TOF MS) spectrum of SFF fractions identified various structures of glycans bound with fucose and sulfate (Fuc1(SO3)1, Fuc2(SO3)1, Hex5Fuc1(SO3)1). In-silico evaluation based on the detected glycan structures indicated that fucoidan fractions could inhibit the dimerization of the TLR4-MD2 complex, demonstrating their potential as anti-inflammatory agents. This result confirm that the anti-inflammatory activity varies depending on the glycan composition of fucoidan. This study provides a foundation for further exploration into the relationship between the structure and anti-inflammatory activity of S. fusiforme-derived fucoidan, facilitating its effective industrial application.

A Review Article on the Formulation and Evaluation of Herbal Hair Oil

The excellent activity of herbal formulations and their little or nonexistent adverse effects as compared to synthetic medications have always drawn a lot of attention. This study's objective is to make herbal hair oil using amla, hibiscus, Brahmi, and methi. and it will be assessed to see if it promotes healthy hair development, the oil of different concentrations was water soluble, water insoluble, sulphated, total ash, acid insoluble, and moisture content are among the characteristics that make it suitable for proximate analysis. Excellent outcomes for hair development were observed in the formulation made using the boiling method for preparing oils. In order to achieve this goal, the current study will prepare herbal hair oil using substances such as Amlawhich is known as Jatamansi or hibiscus Bhringraj Raw garlic includes methi, mimosa pudica handspringing, papaya leaves, curry-leaf Moringa, guava leaves, and muskmelon seeds.. Based on the aforementioned findings, a combination of unrefined medications was made by boiling and then formed into herbal hair oil. Using various herbal drugs, we have created five different formulas, all of which exhibit anti-hair fall properties along with additional beneficial effects like reducing hair pigmentation, improving the flow of blood to the forehead and roots, reducing dandruff, and reducing hair whitening.

The Influence of Retreated Lithium Slag with a High Content of Alkali, Sulfate and Fluoride on the Composition and the Microstructure of Autoclaved Aerated Concrete.

In this paper, the possibility of retreated lithium slag (RTLS) with a high content of alkali, sulfate and fluoride as a partial replacement for fly ash (FA) to produce autoclaved aerated concrete (AAC) was investigated. The influence of the RTLS dosage on the AAC performance were examined. The composition and microstructure of hydrates as well as the microstructure of the RTLS-FA-based AAC compositions were determined by XRD, FTIR, TG-DSC and SEM. The results illustrated that the incorporation of RTLS changed the crystal structure and the microstructure of the tobermorite. With increased RTLS contents, the morphology of tobermorite was changed, and the grass-like tobermorite gradually transformed into network-like tobermorite. The newly formed tobermorite improved the mechanical performance of the AAC. Compared with the RTLS10, the content of tobermorite in the RTLS30 increased by 8.6%.

Chondroitin sulfate from heads of corb: Recovery, structural analysis and assessment of anticoagulant activity

In this study, glycosaminoglycans (GAGs) were extracted from corb (Sciaena umbra) heads and thoroughly examined for their structure. Through cellulose acetate electrophoresis, the GAGs were identified as chondroitin sulfate (CS), with a recovery yield of 10.35 %. The CS exhibited notable characteristics including a high sulfate content (12.4 %) and an average molecular weight of 38.32 kDa. Further analysis via 1H NMR spectroscopy and SAX-HPLC revealed that the CS primarily consisted of alternating units predominantly composed of monosulfated disaccharides at positions 6 and 4 of GalNAc (52.6 % and 38.8 %, respectively). The ratio of sulfate groups between positions 4 and 6 of GalNAc (4/6 ratio) was approximately 0.74, resulting in an overall charge density of 0.98. Thermal properties of the CS were assessed using techniques such as differential scanning calorimetry and thermogravimetric analysis. Notably, the CS demonstrated concentration-dependent prolongation of activated partial thromboplastin time (aPTT) and thrombin time (TT) while showing no effect on platelet function. At 200 μg/mL, aPTT and TT coagulation times were 1.4 and 3.7 times faster than the control, respectively. These findings suggest that CS derived from corb heads holds promise as an anticoagulant agent for therapy, although further clinical investigations are necessary to validate its efficacy.

Application of Urea and Ammonium Nitrate Solution with Potassium Thiosulfate as a Factor Determining Macroelement Contents in Plants

The following research hypotheses were established in this study: the applied urea and ammonium nitrate solution with potassium thiosulfate (UAN-KTS) has a positive effect on the chemical composition of spring wheat, spring rape and maize; fertilization with nitrogen, potassium and sulfur increases their contents in the usable parts of plants; the forms of applied fertilizers reduce the antagonistic effect of nitrogen and potassium on the content of other elements in plants. Two doses of nitrogen (N 1—optimal dose of nitrogen for a plant species; N 2—25% lower dose of nitrogen) and different ratios of N:K:S elements (N:K:S—without K and S; N:K1:S1—a narrowed ratio; N:K2:S2—the optimal ratio; N:K3:S3—an expanded ratio) were applied. The experiment was carried out on two soils of different quality. The improved soil quality resulted in a significant increase in the calcium (as opposed to magnesium) content of the three crops, in the nitrogen and sulfate–sulfur (VI) content of spring wheat grain and spring rapeseed, and in the phosphorus content of spring rapeseed and maize aerial parts. Reducing the dose (N 2) had a negative effect on the nitrogen content of spring wheat and on the sulfate–sulfur (VI) content of spring rape, maize and especially spring wheat. Increasing the N:K:S ratio had a small but usually antagonistic effect on the nitrogen content of all plant species, but a synergistic one on the potassium content of spring wheat, maize and partly of spring rape, and especially on the content of sulfate–sulfur (VI) in the crops. The effect of type of soil and fertilizers with different N:K:S ratios on the content of other macronutrients was related to plant species. The new fertilizer with the N:K2:S2 ratio had the greatest effect on the content of the tested macronutrients in spring wheat, spring rape and maize. In order to confirm the obtained relationships, it seems justified to carry out field experiments and studies with other plant species.

The influence and mechanism analysis of aluminum sulfate as an environmentally friendly early strength agent on the properties of cement-based materials

Environmentally friendly chemical admixtures are becoming important in the cement industry. The research objective of this paper is to use aluminum sulfate as an early-strengthening agent to achieve the goals of a large increase in early strength and a reduction in CO2 emissions. The experimental design was as follows: The macroscopic properties and microscopic characteristics of aluminum sulfate were experimentally investigated on five different replacement ratios of 0%, 1%, 2%, 3%, and 4% paste specimens of cement at different ages. The results show that (1) AS4 demonstrated a notable enhancement in early strength, while AS2 and AS3 contributed to increased late-stage strength. Over time, the Ultrasonic Pulse Velocity (UPV) of all samples exhibited a steady rise. Additionally, aluminum sulfate was found to reduce the electrical resistivity of the samples. (2) aluminum sulfate increased the rate of exothermic heat release of samples at induction and acceleration phases, advanced the accumulated heat was high in the samples with high aluminum sulfate content, and the accumulated heat was strongly correlated with the compressive strength. FT-IR and XRD results show that aluminum sulfate promoted the formation of AFt while depleting the CH content, and the TGA results show the content of bound water in the samples increased from Day 1 to Day 28, which had a positive effect on the compressive strength. UHR-SEM results show that increasing aluminum sulfate substitution results in the formation of a denser microstructure. (3) for all the various mixtures, AS2 has the lowest CO2 emissions per unit strength.

Optimization of oxalic acid treatment for ulvan extraction from Ulva linza biomass and its potential application as Fe(III) chelator

This study investigated the use of oxalic acid as an eco-friendly compound for extracting ulvan from Ulva linza biomass. The concentration of oxalic acid, temperature, and period of extraction were optimized using Box-Behnken design in response of ulvan yield, molecular weight (MW), sulphate content, uronic acid content, purity ratio (total sugars/total phenolics and proteins), and Fe(III) chelation properties. Under the optimized conditions (1.7 % w/v oxalic acid, 64 °C, and 2.63 h), ulvan yield, MW, sulphate content, uronic acid content, and purity ratio were 29.90 % (w/w), 32.22 kDa, 11.01 % (w/w), 8.12 % (w/w), and 12.84, respectively. The optimized ulvan exhibited good Fe(III) chelation of 18.58 % (w/w). The synthesized Fe-ulvan complex released approximately 73 % of the chelated Fe(III) under in vitro simulated gastro-intestinal conditions. Furthermore, both ulvan and Fe-ulvan complex exhibited potent antioxidant properties. FT-IR analysis confirmed the fundamental role played by hydroxyl, carboxyl and sulphate groups in the coordination of Fe(III). Furthermore, MW, MW/sulphate ratio, and MW/uronic acid ratio should be low to enhance the Fe(III) chelation properties of ulvan. The results of the present study shed light on the use of oxalic acid as a simple and environmentally-benign treatment for ulvan extraction, especially for the recovery of low MW ulvan with high yield and good Fe(III)-binding properties.

Effects of sulfate on survival, osmoregulation and immune inflammation of mud crab(Scylla paramamosain) under low salt conditions

Sulfate is an important chemical component in seawater, which has a profound influence on the survival, growth, physiology and biochemistry of aquaculture species. The aim of this experiment was to study the effects of sulfate concentration on survival, osmotic regulation, oxidative stress and immune inflammation of mud crab(Scylla paramamosain). The results showed that the 72-h semi-lethal concentration of the crab was 3.373 g/L (1.353–8.589 g/L). After 28 days of cultivation, the contents of Na+-K+-2Cl− cotransporter (NKCC) and Na+-K+ ATPase (NKA) in the gill tissue of the S1 group (0 g/L Na2SO4) were significantly higher than those in the other three groups, and the sulfate content increased and the SOD activity decreased.Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were affected by sulfate content, and the content levels in the S3 group (1 g/L Na2SO4) were significantly lower than those in the other three groups. The activities of ACP and AKP first increased and then decreased with the increase of sulfate content in prepare solution, and the activities of ACP and AKP in the S3 group (1 g/L Na2SO4) were significantly higher than those in the other three groups. The absence of sulfate or high concentration of sulfate will affect the survival rate of mud crabs, and have a stressful effect on the osmotic regulation of mud crabs, inhibit oxidative stress ability, and promote inflammatory response. The purpose of this study was to explore the feasibility of sulfate-type saline-alkali water aquaculture of mud crab by studying the effect of sulfate on the mud crab under low salt conditions, and to provide theoretical basis and technical guidance for the promotion of saline-alkali water aquaculture.

Compositional, structural, and functional characterization of fucoidan extracted from Sargassum polycystum collected from Saint Martin's Island, Bangladesh

Fucoidan is a sulphated polysaccharide with diversified biological activities commonly found in brown seaweeds. In our present study, fucoidan was extracted from Sargassum polycystum collected from Saint Martin's Island in three different extraction methods. The composition of the fucoidans was determined by measuring the total carbohydrate, sulfate, uronic acid, fucose, and protein contents. Fourier-transform infrared spectroscopy (FT-IR) and Proton nuclear magnetic resonance (1H NMR) were studied to determine the structural groups of extracted fucoidans. Functional activities were analyzed by antioxidant activity and anti-diabetic activity assay. Fucoidan yield was obtained highest in the acid extraction method (0.061 ± 0.007 g/g), followed by the water extraction method (0.058 ± 0.005 g/g) and salt extraction method (0.041 ± 0.005 g/g). Water extracted fucoidan showed the highest carbohydrate content (62.97 %), uronic acid content (6.46 %), and protein content (2.62 %). Sulphate content (28.56 %) was highest in salt extracted fucoidan, whereas fucose content (24.0 %) was highest in water extracted fucoidan. FT-IR and 1H NMR analysis confirm several characteristic picks for the extracted fucoidans. Extracted fucoidans presented comparable antioxidant activity, but salt-extracted fucoidan presented the highest DPPH radical scavenging assay (86.85 ± 0.74 %, IC50 = 0.03 mg/mL), ABTS radical scavenging assay (65.13 ± 0.92 %, IC50 = 1.94 mg/mL), Phosphomolybdenum assay (4.356 ± 0.11) and Nitric Oxide (NO) radical scavenging assay (57.08 ± 0.52 %, IC50 = 3.73 mg/mL) in dose-dependency manner. Further anti-diabetic activity assay resulted in the highest α-amylase inhibition activity (62.82 ± 1.36 %, IC50 = 2.30 mg/mL) and α-glucosidase inhibition activity (55.73 ± 0.84 %, IC50 = 3.71 mg/mL) by salt-extracted fucoidan. These functional potentials of seaweed may add significant value to the development of functional food and pharmaceutical materials.

Physicochemical properties of water in the Nida valley, Poland

The investigation of Nida Valley water aimed to assess fluctuations in physicochemical properties. In this study, environmental monitoring method was utilized to evaluate the changes in physicochemical properties of water. Over a 24-month period, from June 2021 to May 2023, a total of 228 water samples were collected from 10 sampling sites, with a monthly sampling frequency. Statistical analyses were utilized including the Shapiro–Wilk test (α = 0.05), Kruskal–Wallis test and Wilcoxon (Mann–Whitney) rank sum test (α = 0.05), Pearson correlation analysis (α = 0.001) and principal component analysis (PCA). Statistical analyses revealed significant differences between months in GW samples for for temperature, dissolved oxygen, pH, total nitrogen, total phosphorus, chloride, manganese, and zinc in GW samples and for T and DO in SW samples. Pearson correlation coefficient analysis (α = 0.001) identified strong positive correlations within the SW dataset. Similarly, significant positive correlations were observed among the GW dataset. Noteworthy positive correlations were also detected between the GW and SW datasets. Principal component analysis (PCA) revealed a substantial dissimilarity between GW2 samples compared to others, characterized by elevated manganese, iron, and Sulfate content. Two distinct groups emerged: Group 1 included samples at GW1, GW2, GW3, GW5, and SW2, while Group 2 comprised all other samples. This study demonstrated the stability in the physicochemical properties of SW and underscore a discernible correlation between the hydrochemical compositions of both SW and GW in the riparian area. Outstanding characteristics in hydrochemical component of sample waters have been indicated.

Optimization of Sulfated Polysaccharides Extraction from Gracilaria fisheri Obtained Through Microwave-Assisted Extraction

Gracilaria fisheri is a red seaweed that possesses several biological activities. The major important compounds comprising this seaweed are sulfated polysaccharides. However, limited data exists on the optimal extraction conditions for this seaweed using eco-friendly techniques like microwave-assisted extraction (MAE). This work aimed to optimize the MAE conditions for extracting sulfated polysaccharides from G. fisheri. Three factors influencing MAE were investigated: microwave time, solvent-to-solid ratio, and microwave power. These factors were initially screened by varying one factor at a time to identify levels leading to high extraction yields. These levels were then included in a Box-Behnken design. Microwave time was varied from 20 to 40 s, solvent-to-solid ratio from 8:1 to 10:1 mL/g, and microwave power from 300 to 600 W. Two responses were monitored: extraction yield and sulfate content. The optimal condition for both high extraction yield and sulfate content was found to be 30 s of microwave time, a solvent-to-solid ratio of 9.5:1 mL/g, and 450 W of microwave power. This condition yielded 20.32-20.93% extraction yield and 48.28-49.95% sulfate content. The computer program's predictions were accurate and reliable, with a very low percentage error of less than 3%. Therefore, the Box-Behnken design proved to be an effective tool for optimizing the extraction of sulfated polysaccharides from G. fisheri using the MAE method.

Risk prediction for hydrogen sulfide emission based on sulfate-reducing bacteria in the water flooding oilfield

The water quality of the injection–production systems deteriorates as the water flooding oilfields are developed more deeply, and the content of sulfate-reducing bacteria (SRB) increases. Accordingly, hydrogen sulfide (H2S) emission related to SRB is intensified, which will arise safety and health problems. In order to investigate the effect of SRB on H2S emission in the water flooding oilfield, the contents of SRB and sulfide of the different nodes of a typical injection–production system of Daqing Oilfield were measured first, and then, H2S emission from water was simulated under different conditions. Consequently, a H2S emission prediction model was established based on Henry coefficient and the correlation between sulfide content and SRB content in the water. The measured sulfide contents were ranging from 0.25 to 6.34 mg/l, and the SRB contents were from 2.5 to 25 000 pcs/ml, and the highest SRB and sulfide contents were found in the settling tank. The correlation between sulfide content and SRB content was much remarkable, and the R2 value of the correlation analysis was 0.94. Henry coefficient of H2S emission was obtained from the simulated experiments under varied conditions such as sulfate content, oil content, and temperature. The established H2S emission prediction model was much reliable for predicting H2S emission for water flooding injection–production system, and the accuracy of the predicted H2S emission of four nodes of the injection–production system was larger than 95% compared to the measured results. This study provides theoretical guidance for predicting H2S emission risks in water flooding injection–production systems.

Facilitating Ulvan Extraction from Ulva lactuca via Deep Eutectic Solvent and Peracetic Acid Treatment

Ulva lactuca is a green seaweed and commonly referred to as sea lettuce and contains sulphated polysaccharides that have biological activity. Strong acids (HCl) and strong bases (NaOH) are commonly used as solvents in the conventional extraction process for ulvan, despite its lack of ecological sustainability. Deep Eutectic Solvent (DES) is an alternative to ulvan extraction solvent which is more environmentally friendly and has low toxicity. Ulvan extraction using DES with a temperature of 85-95ºC for 1 hour, and adding 2% peracetic acid pretreatment, 0.1%, 0.5%, and 2% peracetic acid posttreatment were conducted. Peracetic acid pre- and post-treatment (PAA) was carried out with a 1:10 (w/v) ratio at room temperature for 30 minutes. This study aims to optimize the use of DES in ulvan extraction with pre- and post-treatment of ulvan quality. The analysis performed included moisture content, yield, functional groups, sulphate content, and color. The test results revealed that ulvan treated with 2% PAA pretreatment had the highest moisture content and sulphate content, at 18.71% and 33.39%, respectively, while ulvan treated with 0.1% PAA posttreatment had the highest yield, at 41.96%. The addition of peracetic acid concentration can increase the color quality of the ulvan. PAA pre- and post-treatment had a significant effect on all ulvan quality parameters.

SULPHATE REDUCTION IN WASTE CONCRETE AGGREGATE USING BACILLUS SUBTILIS

Waste concrete aggregate (WCA) can be re-utilised as a recycled material as it applies to numerous functions. High sulphate content in attached cement mortar was identified as a weakness of recycled material due to the developed expansion of delayed ettringite formation (DEF). The DEF results in micro-crack formation, which affects the compressive strength. The main objective of the present study was to treat WCA by Bacillus subtilis before being reused in recycled concrete mortar (RCM) production. The DEF of WCA was identified using X-ray diffractometric (XRD) techniques and soluble sulphate tests. The efficiency of B. subtilis in treating WCA was evaluated based on sulphate reduction on three variable factors, i.e., B. subtilis concentration, B. subtilis: WCA ratio, and retention time. Treated WCA (TWCA) from the WCA treatment by B. subtilis was reused as a part of RCM production. The compressive strength of RC was subsequently evaluated to determine its durability. Results revealed that WCA was rich in ettringite and contained 0.53% sulphate. The sulphate content in WCA was successfully reduced to 81.5% by B. subtilis when B. subtilis concentration was at 0.2 x 108 CFU mL1, the B. subtilis: WCA ratio was 1:1 and the retention time was increased up to the 4th day. The construction of RCM using TWCA can potentially replace the natural concrete aggregate due to its higher compressive strength (26 MPa) compared to control (20 MPa). The study indicated that B. subtilis efficiently reduced sulphate in WCA to avoid microcrack formation on the RC surface.

The Conventional Oil-Water Separator as A Polluter Due to Lack of Maintenance – A Case Study

In addition to the common knowledge that lack of maintenance of conventional oil-water separators causes release of excessive amounts of oil in the effluent wastewater, this study has revealed that excessive amounts of other pollutants are released alongside the oil. The disappearance of fishes from a stream in the Niger Delta after the continual discharge of the wastewater of a company prompted this study. The company has a conventional oil-water separator but no maintenance was done on it, five months after commissioning. Research methods include sampling of the effluent wastewater for a period of two weeks (ten working days) and analysis of the wastewater for pH, oil & grease content, total suspended solids, total dissolved solids, sulfate and chloride contents. Results showed that the concentration of total dissolved solids was consistently less than the regulatory limit but much higher than the concentration obtained at the commissioning of the separator. Results showed that the oil & grease content, chloride, sulfate and total suspended solids concentrations were consistently higher than the regulatory limits and also much higher than the concentrations obtained at the commissioning of the separator. Results showed that the pH values of the effluent wastewater were consistently outside the optimum range for survival of aquatic life. Monthly maintenance of the separator and further treatment of its effluent wastewater were recommended for protection of the environment and public health.