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1.
J Vis Exp ; (206)2024 Apr 19.
Article in English | MEDLINE | ID: mdl-38709074

ABSTRACT

Utilizing vegetable oil as a sustainable feedstock, this study presents an innovative approach to ultrasonic-assisted transesterification for biodiesel synthesis. This alkaline-catalyzed procedure harnesses ultrasound as a potent energy input, facilitating the rapid conversion of extra virgin olive oil into biodiesel. In this demonstration, the reaction is run in an ultrasonic bath under ambient conditions for 15 min, requiring a 1:6 molar ratio of extra virgin olive oil to methanol and a minimum amount of KOH as the catalyst. The physiochemical properties of biodiesel are also reported. Emphasizing the remarkable advantages of ultrasonic-assisted transesterification, this method demonstrates notable reductions in reaction and separation times, achieving near-perfect purity (~100%), high yields, and negligible waste generation. Importantly, these benefits are achieved within a framework that prioritizes safety and environmental sustainability. These compelling findings underscore the effectiveness of this approach in converting vegetable oil into biodiesel, positioning it as a viable option for both research and practical applications.


Subject(s)
Biofuels , Plant Oils , Plant Oils/chemistry , Esterification , Hydroxides/chemistry , Olive Oil/chemistry , Ultrasonic Waves , Potassium Compounds/chemistry , Catalysis
2.
Sci Rep ; 14(1): 11248, 2024 05 16.
Article in English | MEDLINE | ID: mdl-38755228

ABSTRACT

An effective strategy for enhancing fruit production continuity during extended sweet pepper season involves adopting innovative biostimulants such as potassium silicate (PS) and vinasse. Adjusting PS and vinasse concentrations are crucial for maintaining the balance between vegetative and fruit growth, particularly in sweet pepper with a shallow root system, to sustain fruiting over prolonged season. However, the interaction between PS and vinasse and the underlying physiological mechanisms that extend the sweet pepper season under greenhouse conditions remain unclear. This study aimed to investigate the impact of PS and vinasse treatments on the yield and biochemical constituents of perennial pepper plants cultivated under greenhouse conditions. For two consecutive seasons [2018/2019 and 2019/2020], pepper plants were sprayed with PS (0, 0.5, and 1 g/l) and drenched with vinasse (0, 1, 2, and 3 l/m3). To estimate the impact of PS and vinasse on the growth, yield, and biochemical constituents of pepper plants, fresh and dry biomass, potential fruit yield, and some biochemical constituents were evaluated. Results revealed that PS (0.5 g/l) coupled with vinasse (3 l/m3) generated the most remarkable enhancement, in terms of plant biomass, total leaf area, total yield, and fruit weight during both growing seasons. The implementation of vinasse at 3 l/m3 with PS at 0.5 and 1 g/l demonstrated the most pronounced augmentation in leaf contents (chlorophyll index, nitrogen and potassium), alongside improved fruit quality, including total soluble solid and ascorbic acid contents, of extended sweet pepper season. By implementing the optimal combination of PS and vinasse, growers can significantly enhance the biomass production while maintaining a balance in fruiting, thereby maximizing the prolonged fruit production of superior sweet pepper under greenhouse conditions.


Subject(s)
Capsicum , Fruit , Silicates , Capsicum/growth & development , Capsicum/drug effects , Capsicum/metabolism , Fruit/growth & development , Fruit/drug effects , Fruit/metabolism , Biomass , Potassium/metabolism , Potassium/analysis , Seasons , Plant Leaves/growth & development , Plant Leaves/metabolism , Plant Leaves/drug effects , Biometry , Potassium Compounds/pharmacology
3.
J Adhes Dent ; 26(1): 125-134, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38770704

ABSTRACT

PURPOSE: To investigate the effect of adhesive type and long-term aging on the shear bond strength (SBS) between silica-based ceramics and composite cement (CC). MATERIALS AND METHODS: Lithium-silicate (LS), feldspathic (FD) and polymer-infiltrated ceramic (PIC) blocks were sectioned (10 x 12 x 2 mm) and divided into 24 groups considering the factors: "ceramics" (LS, FD, and PIC), "adhesive" (Ctrl: without adhesive; 2SC: 2-step conventional; 3SC: 3-step conventional; 1SU: 1-step universal), and "aging" (non-aged or aged [A]). After the surface treatments, CC cylinders (n = 15, Ø = 2 mm; height = 2 mm) were made and half of the samples were subjected to thermocycling (10,000) and stored in water at 37°C for 18 months. The samples were submitted to SBS testing (100 kgf, 1 mm/min) and failure analysis. Extra samples were prepared for microscopic analysis of the adhesive interface. SBS (MPa) data was analyzed by 3-way ANOVA and Tukey's test (5%). Weibull analysis was performed on the SBS data. RESULTS: All factors and interactions were significant for SBS (p<0.05). Before aging, there was no significant difference between the tested groups and the respective control groups. After aging, the LS_1SU (22.18 ± 7.74) and LS_2SC (17.32 ± 5.86) groups exhibited significantly lower SBS than did the LS_Ctrl (30.30 ± 6.11). Only the LS_1SU group showed a significant decrease in SBS after aging vs without aging. The LS_1SU (12.20) group showed the highest Weibull modulus, which was significantly higher than LS_2SC_A (2.82) and LS_1SU_A (3.15) groups. CONCLUSION: No type of adhesive applied after silane benefitted the long-term adhesion of silica-based ceramics to CC in comparison to the groups without adhesive.


Subject(s)
Ceramics , Dental Bonding , Materials Testing , Resin Cements , Shear Strength , Silicon Dioxide , Silicon Dioxide/chemistry , Ceramics/chemistry , Time Factors , Resin Cements/chemistry , Computer-Aided Design , Surface Properties , Dental Stress Analysis , Cementation/methods , Dental Porcelain/chemistry , Humans , Composite Resins/chemistry , Dental Cements/chemistry , Potassium Compounds/chemistry , Aluminum Silicates/chemistry , Temperature
4.
BMC Oral Health ; 24(1): 507, 2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38685035

ABSTRACT

BACKGROUND: Dentin hypersensitivity, often occurring after dental treatments or from erosive lesions, is a prevalent patient complaint. This study introduces a paste combining 8% L-arginine, calcium carbonate, and potassium nitrate to evaluate its impact on dentinal tubules occlusion, dentin permeability, and tooth sensitivity. METHODS: Dentin surfaces from 24 third molars (thickness: 2 mm) were divided into two groups of 12. One received the experimental paste, while the other received a placebo without desensitizer. Permeability and sealing ability were assessed through scanning electron microscopy (SEM) and dentin permeability measurement. The pastes' effects on hypersensitivity were then examined in a triple-blind, randomized parallel-armed clinical trial with 16 eligible patients. Sensitivity to cold, touch, and spontaneous stimuli was recorded using the VAS scale at various intervals post-treatment. Statistical analysis was conducted using Shapiro-Wilk, Mann-Whitney U, Friedman, and Wilcoxon tests (α = 0.05). RESULTS: The permeability test demonstrated a significant reduction in dentin permeability in the experimental group (P = 0.002) compared to the control (P = 0.178). SEM images revealed most dentinal tubules in the intervention samples to be occluded. Clinically, both groups showed a significant decrease in the three types of evaluated sensitivity throughout the study. However, no significant difference in sensitivities between the two groups was observed, with the exception of cold sensitivity at three months post-treatment (P = 0.054). CONCLUSION: The innovative desensitizing paste featuring 8% L-arginine, calcium carbonate, and potassium nitrate effectively occluded dentinal tubules and reduced dentin permeability. It mitigated immediate and prolonged dentin hypersensitivity to various stimuli, supporting its potential role in managing dentin hypersensitivity. TRIAL REGISTRATION: http://irct.ir : IRCT20220829055822N1, September 9th, 2022.


Subject(s)
Arginine , Calcium Carbonate , Dentin Desensitizing Agents , Dentin Sensitivity , Microscopy, Electron, Scanning , Nitrates , Potassium Compounds , Humans , Dentin Sensitivity/drug therapy , Arginine/therapeutic use , Calcium Carbonate/therapeutic use , Nitrates/therapeutic use , Male , Female , Potassium Compounds/therapeutic use , Dentin Desensitizing Agents/therapeutic use , Adult , Dentin Permeability/drug effects , Dentin/drug effects , Toothpastes/therapeutic use , Young Adult , Middle Aged
5.
Environ Sci Pollut Res Int ; 31(21): 31108-31122, 2024 May.
Article in English | MEDLINE | ID: mdl-38625474

ABSTRACT

Salinity stress significantly constrains agricultural productivity and vegetation decline worldwide, particularly in Iran. Potassium, the second most prevalent nutrient in plants, is well known to be essential for cell metabolism. Here, the effects of potassium fertilizer in two biogenic nanoparticles (K-NPs) and conventional (potassium sulfate) forms (0.1 mg/ml) on Melissa officinalis L. under salinity (0, 50, 100, and 150 mM) were investigated. The results demonstrated that stress markers (electrolyte leakage, malondialdehyde, and hydrogen peroxide) increased as salinity levels increased. Plant growth parameters (shoot and root length, fresh and dry weight of shoot and root) and physiological and photosynthetic parameters (stomatal conductance, relative water content, chlorophyll fluorescence, and photosynthetic pigments) were reduced in salinized plants. The highest reduction in fresh weight root, dry weight root, fresh weight shoot, dry weight shoot, root length, and shoot length was recorded under 150 mM NaCl by 30.2%, 51.6%, 30.5%, 24.7%, 26.4%, and 21%, respectively. In contrast, bulk potassium sulfate and K-NPs increased these parameters. Furthermore, K-NPs improved M. officinalis tolerance to NaCl toxicity by enhancing the content of osmolytes such as proline, soluble sugars, and antioxidant enzymes, improving antioxidant contents such as phenols, tannins, anthocyanins, and flavonoids; increasing total protein; and lowering stress markers in plant tissues. Given the results of the physiological, biochemical, and phytochemical parameters obtained from this study, it can be stated that K-NPs, in comparison to the conventional form of potassium fertilizer, exhibit a greater potential to mitigate damages caused by salinity stress in M. officinalis plants.


Subject(s)
Melissa , Potassium , Salt Stress , Sulfates , Melissa/drug effects , Salt Stress/drug effects , Nanoparticles , Phytochemicals , Iran , Plant Leaves/drug effects , Potassium Compounds , Photosynthesis/drug effects
7.
Eur Heart J ; 45(18): 1647-1658, 2024 May 13.
Article in English | MEDLINE | ID: mdl-38513060

ABSTRACT

BACKGROUND AND AIMS: Contrast-induced nephropathy (CIN), also known as contrast-associated acute kidney injury (CA-AKI) underlies a significant proportion of the morbidity and mortality following coronary angiographic procedures in high-risk patients and remains a significant unmet need. In pre-clinical studies inorganic nitrate, which is chemically reduced in vivo to nitric oxide, is renoprotective but this observation is yet to be translated clinically. In this study, the efficacy of inorganic nitrate in the prevention of CIN in high-risk patients presenting with acute coronary syndromes (ACS) is reported. METHODS: NITRATE-CIN is a double-blind, randomized, single-centre, placebo-controlled trial assessing efficacy of inorganic nitrate in CIN prevention in at-risk patients presenting with ACS. Patients were randomized 1:1 to once daily potassium nitrate (12 mmol) or placebo (potassium chloride) capsules for 5 days. The primary endpoint was CIN (KDIGO criteria). Secondary outcomes included kidney function [estimated glomerular filtration rate (eGFR)] at 3 months, rates of procedural myocardial infarction, and major adverse cardiac events (MACE) at 12 months. This study is registered with ClinicalTrials.gov: NCT03627130. RESULTS: Over 3 years, 640 patients were randomized with a median follow-up of 1.0 years, 319 received inorganic nitrate with 321 received placebo. The mean age of trial participants was 71.0 years, with 73.3% male and 75.2% Caucasian; 45.9% had diabetes, 56.0% had chronic kidney disease (eGFR <60 mL/min) and the mean Mehran score of the population was 10. Inorganic nitrate treatment significantly reduced CIN rates (9.1%) vs. placebo (30.5%, P < .001). This difference persisted after adjustment for baseline creatinine and diabetes status (odds ratio 0.21, 95% confidence interval 0.13-0.34). Secondary outcomes were improved with inorganic nitrate, with lower rates of procedural myocardial infarction (2.7% vs. 12.5%, P = .003), improved 3-month renal function (between-group change in eGFR 5.17, 95% CI 2.94-7.39) and reduced 1-year MACE (9.1% vs. 18.1%, P = .001) vs. placebo. CONCLUSIONS: In patients at risk of renal injury undergoing coronary angiography for ACS, a short (5 day) course of once-daily inorganic nitrate reduced CIN, improved kidney outcomes at 3 months, and MACE events at 1 year compared to placebo.


Subject(s)
Acute Coronary Syndrome , Acute Kidney Injury , Contrast Media , Coronary Angiography , Nitrates , Humans , Coronary Angiography/adverse effects , Coronary Angiography/methods , Contrast Media/adverse effects , Male , Female , Double-Blind Method , Nitrates/administration & dosage , Nitrates/therapeutic use , Acute Kidney Injury/chemically induced , Acute Kidney Injury/prevention & control , Aged , Middle Aged , Glomerular Filtration Rate/drug effects , Potassium Compounds/administration & dosage , Potassium Compounds/therapeutic use
8.
Arch Microbiol ; 206(4): 157, 2024 Mar 13.
Article in English | MEDLINE | ID: mdl-38480543

ABSTRACT

Potassium-solubilizing microorganisms are capable of secreting acidic chemicals that dissolve and release potassium from soil minerals, thus facilitating potassium uptake by plants. In this study, three potassium-dissolving filamentous fungi were isolated from the rhizosphere soil of a poplar plantation in Jiangsu Province, China. Phylogenetic analyses based on ITS, 18 S, and 28 S showed that these three isolates were most similar to Mortierella. These strains also possessed spherical or ellipsoidal spores, produced sporangia at the hyphal tip, and formed petal-like colonies on PDA media resembling those of Mortierella species. These findings, along with further phenotypic observations, suggest that these isolates were Mortierella species. In addition, the potassium-dissolution experiment showed that strain 2K4 had a relatively high potassium-solubilizing capacity among these isolated fungi. By investigating the influences of different nutrient conditions (carbon source, nitrogen source, and inorganic salt) and initial pH values on the potassium-dissolving ability, the optimal potassium-solubilization conditions of the isolate were determined. When potassium feldspar powder was used as an insoluble potassium source, isolate 2K4 exhibited a significantly better polysaccharide aggregation ability on the formed mycelium-potassium feldspar complex. The composition and content of organic acids secreted by strain 2K4 were further detected, and the potassium-dissolution mechanism of the Mortierella species and its growth promotion effect were discussed, using maize as an example.


Subject(s)
Aluminum Silicates , Mortierella , Potassium Compounds , Soil , Soil/chemistry , Phosphates , Mortierella/genetics , Potassium , Rhizosphere , Phylogeny , Soil Microbiology , Fungi
9.
J Vis Exp ; (205)2024 03 01.
Article in English | MEDLINE | ID: mdl-38497623

ABSTRACT

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by symptoms such as dry mouth, dry eyes, and other systematic symptoms. Due to the hyposalivation experienced by pSS patients, oral dysbacteriosis often occurs. A common complication of pSS is the oral Candida infection. In this article, the authors describe systematic methods that can effectively diagnose oral Candida infection and identify the Candida strains using saliva, oral mucosal swabs, or mouthwash from pSS patients. The Sabouraud's Dextrose Agar (SDA), hyphal formation assay, potassium hydroxide (KOH) smear test, and calcofluor white (CFW) staining assay are used for the diagnosis of oral Candida infection. A Candida diagnostic agar is used for the identification of Candida strains. Finally, antifungal susceptibility testing is used to determine appropriate antifungal drug treatment. This standardized method can enhance the diagnosis, treatment, and future research of pSS-related oral Candida infections. Early diagnosis, using this method, can also prevent any complications arising due to delay in receiving appropriate treatment.


Subject(s)
Antifungal Agents , Candidiasis , Hydroxides , Potassium Compounds , Humans , Agar , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Candida
10.
J Environ Manage ; 357: 120749, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38552517

ABSTRACT

The traditional solidification/stabilization (S/S) technology, Ordinary Portland Cement (OPC), has been widely criticized due to its poor resistance to chloride and significant carbon emissions. Herein, a S/S strategy based on magnesium potassium phosphate cement (MKPC) was developed for the medical waste incineration fly ash (MFA) disposal, which harmonized the chlorine stabilization rate and potential carbon emissions. The in-situ XRD results indicated that the Cl- was efficiently immobilized in the MKPC system with coexisting Ca2+ by the formation of stable Ca5(PO4)3Cl through direct precipitation or intermediate transformation (the Cl- immobilization rate was up to 77.29%). Additionally, the MFA-based MKPC also demonstrated a compressive strength of up to 39.6 MPa, along with an immobilization rate exceeding 90% for heavy metals. Notably, despite the deterioration of the aforementioned S/S performances with increasing MFA incorporation, the potential carbon emissions associated with the entire S/S process were significantly reduced. According to the Life Cycle Assessment, the potential carbon emissions decreased to 8.35 × 102 kg CO2-eq when the MFA reached the blending equilibrium point (17.68 wt.%), while the Cl- immobilization rate still remained above 65%, achieving an acceptable equilibrium. This work proposes a low-carbon preparation strategy for MKPC that realizes chlorine stabilization, which is instructive for the design of S/S materials.


Subject(s)
Magnesium Compounds , Medical Waste , Metals, Heavy , Phosphates , Potassium Compounds , Refuse Disposal , Coal Ash , Magnesium , Calcium , Potassium , Chlorine , Carbon , Chlorides , Incineration/methods , Metals, Heavy/analysis , Solid Waste , Particulate Matter , Refuse Disposal/methods
11.
Int J Mol Sci ; 25(5)2024 Feb 29.
Article in English | MEDLINE | ID: mdl-38474075

ABSTRACT

To identify suitable potassium fertilizers for grape (Vitis vinifera L.) production and study their mechanism of action, the effects of four potassium-containing fertilizers (complex fertilizer, potassium nitrate, potassium sulfate, and potassium dihydrogen phosphate) on sugar and organic acid metabolism in grape fruits were investigated. Potassium-containing fertilizers increased the activity of sugar and organic acid metabolism-related enzymes at all stages of grape fruit development. During the later stages of fruit development, potassium-containing fertilizers increased the total soluble solid content and the sugar content of the different sugar fractions and decreased the titratable acid content and organic acid content of the different organic acid fractions. At the ripening stage of grape fruit, compared with the control, complex fertilizer, potassium nitrate, potassium sulfate, and potassium dihydrogen phosphate increased the total soluble solid content by 1.5, 1.2, 3.5, and 3.4 percentage points, decreased the titratable acid content by 0.09, 0.06, 0.18, and 0.17 percentage points, respectively, and also increased the total potassium content in grape fruits to a certain degree. Transcriptome analysis of the differentially expressed genes (DEGs) in the berries showed that applying potassium-containing fertilizers enriched the genes in pathways involved in fruit quality, namely, carbon metabolism, carbon fixation in photosynthetic organisms, glycolysis and gluconeogenesis, and fructose and mannose metabolism. Potassium-containing fertilizers affected the expression levels of genes regulating sugar metabolism and potassium ion uptake and transport. Overall, potassium-containing fertilizers can promote sugar accumulation and reduce acid accumulation in grape fruits, and potassium sulfate and potassium dihydrogen phosphate had the best effects among the fertilizers tested.


Subject(s)
Nitrates , Phosphates , Potassium Compounds , Sulfates , Vitis , Vitis/genetics , Sugars/metabolism , Fruit/metabolism , Fertilizers , Potassium/metabolism , Carbohydrates
12.
Environ Pollut ; 346: 123641, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38428791

ABSTRACT

The excessive accumulation of hexavalent chromium (Cr(VI)) in the environment poses a risk to environment and human health. In the present study, a potassium bicarbonate-modified pyrite/porous biochar composite (PKBC) was prepared in a one-step process and applied for the efficient removal of Cr(VI) in wastewater. The results showed that PKBC can significantly remove Cr(VI) within 4 h over a wide range of pH (2-11). Meanwhile, the PKBC demonstrated remarkable resistance towards interference from complex ions. The addition of potassium bicarbonate increased the pore structure of the material and promoted the release of Fe2+. The reduction of Cr(VI) in aqueous solution was primarily attributed to the Fe(II)/Fe(III) redox cycle. The sulphur species achieved Fe(II)/Fe(III) cycle through electron transfer with iron, thus ensuring the continuous reduction capacity of PKBC. Besides, the removal rate was also maintained at more than 85% in the actual water samples treatment process. This work provides a new way to remove hexavalent chromium from wastewater and demonstrates the potential critical role of potassium bicarbonate and sulphur.


Subject(s)
Bicarbonates , Potassium Compounds , Sulfides , Wastewater , Water Pollutants, Chemical , Humans , Ferric Compounds , Potassium , Porosity , Iron/chemistry , Charcoal/chemistry , Chromium/chemistry , Ferrous Compounds , Water Pollutants, Chemical/analysis , Adsorption
13.
Sci Total Environ ; 926: 171614, 2024 May 20.
Article in English | MEDLINE | ID: mdl-38508276

ABSTRACT

The phosphate-modified biochar (BC) immobilizes cadmium (Cd), yet little is known about how phosphate species affect Cd detoxification in contaminated soils. We developed phosphate-modified biochar through the pyrolysis of wheat straw impregnated with three types of phosphate: mono­potassium phosphate (MKP), dipotassium hydrogen phosphate (DKP), and tripotassium phosphate (TKP). The Cd adsorption mechanism of modified biochar was investigated by biochar characterization, adsorption performance evaluation, and soil incubation tests. The results demonstrated that the efficiency of biochar in immobilizing Cd2+ followed the order: TKP-BC > DKP-BC > MKP-BC. The TKP-BC had the highest orthophosphate content, the fastest adsorption rate, and the largest adsorption capacity (Langmuir) of 257.28 mg/g, which is 6.31 times higher than that of the unmodified BC (CK). In contrast, pyrophosphate was predominant in MKP-BC and DKP-BC. The primary adsorption mechanism for Cd2+ was precipitation, followed by cation exchange, as evidenced by the formation of CdP minerals on the BC surface, and an increase of K+ in solution (compared to water-soluble K+) and a decrease of K+ in the biochar during adsorption. Desorption of Cd from the TKP-BC after adsorption was 9.77 %-12.39 % at a pH of 5-9, much lower than that of CK. The soil incubation test showed the diethylenetriaminepentaacetic acid extracted Cd of TKP-BC, MKP-BC, and DKP-BC was reduced by 67.93 %, 18.41 % and 31.30 % over CK, respectively. Using the planar optodes technique, we also found that TKP-BC had the longest effect enhancing in situ soil pH. This study provides a theoretical basis for developing heavy metal pollution control technology using green remediation materials and offers insights into the remediation mechanisms.


Subject(s)
Cadmium , Potassium Compounds , Soil Pollutants , Cadmium/analysis , Soil/chemistry , Triticum/chemistry , Charcoal/chemistry , Phosphates , Soil Pollutants/analysis , Adsorption
14.
Sci Rep ; 14(1): 5420, 2024 03 05.
Article in English | MEDLINE | ID: mdl-38443435

ABSTRACT

The microalgae Haematococcus pluvialis are the main source of the natural antioxidant astaxanthin. However, the effective extraction of astaxanthin from these microalgae remains a significant challenge due to the rigid, non-hydrolyzable cell walls. Energy savings and high-efficiency cell disruption are essential steps in the recovery of the antioxidant astaxanthin from the cysts of H. pluvialis. In the present study, H. pluvialis microalgae were first cultured in Bold's Basal medium under certain conditions to reach the maximum biomass concentration, and then light shock was applied for astaxanthin accumulation. The cells were initially green and oval, with two flagella. As the induction time increases, the motile cells lose their flagellum and become red cysts with thick cell walls. Pre-treatment of aqueous two-phase systems based on deep eutectic solvents was used to decompose the cell wall. These systems included dipotassium hydrogen phosphate salt, water, and two types of deep eutectic solvents (choline chloride-urea and choline chloride-glucose). The results of pre-treatment of Haematococcus cells by the studied systems showed that intact, healthy cysts were significantly ruptured, disrupted, and facilitated the release of cytoplasmic components, thus facilitating the subsequent separation of astaxanthin by liquid-liquid extraction. The system containing the deep eutectic solvent of choline chloride-urea was the most effective system for cell wall degradation, which resulted in the highest ability to extract astaxanthin. More than 99% of astaxanthin was extracted from Haematococcus under mild conditions (35% deep eutectic solvent, 30% dipotassium hydrogen phosphate at 50 °C, pH = 7.5, followed by liquid-liquid extraction at 25 °C). The present study shows that the pre-treatment of two-phase systems based on deep eutectic solvent and, thus, liquid-liquid extraction is an efficient and environmentally friendly process to improve astaxanthin from the microalgae H. pluvialis.


Subject(s)
Charadriiformes , Chlorophyceae , Cysts , Microalgae , Phosphates , Potassium Compounds , Animals , Deep Eutectic Solvents , Antioxidants , Biomass , Water , Solvents , Choline , Urea , Xanthophylls
15.
Int J Biol Macromol ; 266(Pt 1): 131193, 2024 May.
Article in English | MEDLINE | ID: mdl-38552703

ABSTRACT

Beyond the conventional consideration of pretreatment severity (PS) responsible for biomass disruption, the influence of reagent properties on biomass (LCB) disruption is often overlooked. To investigate the LCB disruption as a function of reagent properties, reagents with distinct cations (NaOH and KOH) and significantly higher delignification potential were chosen. NaOH solution (3 % w/v) with a measured pH of 13.05 ± 0.01 is considered the reference, against which a KOH solution (pH = 13.05 ± 0.01) was prepared for LCB pretreatment under the same PS. Despite comparable lignin content, varying glucose yield of NaOH (68.76 %) and KOH (46.88 %) pretreated residues indicated the presence of heterogeneously disrupted substrate. Holocellulose extracted from raw poplar (ASC, control) and alkaline pretreated residues (C-NaOH and C-KOH) were analyzed using HPLC, XRD, SEM, TGA/DTG, XPS, and 13CP MAS NMR to investigate the pretreatment-induced structural modification. Results revealed that, despite the same pretreatment severity, better disruption in C-NaOH (higher accessible fibril surface and less-ordered region) leading to higher digestibility than C-KOH, likely due to the smaller ionic radius of Na+, facilitates better penetration into dense LCB matrix. This study elucidates the importance of considering the reagent properties during LCB pretreatment, eventually enhancing consciousness while selecting reagents for efficient LCB utilization.


Subject(s)
Biomass , Hydroxides , Lignin , Sodium Hydroxide , Lignin/chemistry , Sodium Hydroxide/chemistry , Hydroxides/chemistry , Hydrolysis , Populus/chemistry , Potassium Compounds/chemistry , Indicators and Reagents/chemistry , Hydrogen-Ion Concentration
16.
Waste Manag ; 178: 257-266, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38417311

ABSTRACT

One of the technical barriers to the wider use of biochar in the composting practices is the lack of accurate quantification linking biochar properties to application outcomes. To address this issue, this paper investigates the use of ammonia nitrogen adsorption capacity by biochar as a predictor of ammonia emission during composting in the presence of biochar. With this in mind, this work investigated the use of ammonia nitrogen adsorption capacity of biochar when mixed with solid digestate, and the reduction in ammonia emissions resulting from the addition of biochar during aerobic degradation of solid digestate. A biochar synthesized at 900 °C, another synthesized at 450 °C, and two derivatives of the latter biochar, one chemically modified with nitric acid and the other with potassium hydroxide, were tested. This study concluded that the chemical characteristics of the biochar, including pH and oxygen/carbon atomic ratio, had a greater influence on the adsorption of ammonia nitrogen than physical attributes such as specific surface area. In this regard, nitric acid modification had superior performance compared to hydroxide potassium modification to increase biochar chemical attributes and reduce ammonia emissions when applied to aerobic degradation. Finally, a significant linear correlation (p-value < 0.05, r2 = 0.79) was found between biochar ammonia nitrogen adsorption capacity and ammonia emissions along composting, showing the potential of this variable as a predictive parameter. This study provides insights for future explorations aiming to develop predictive tests for biochar performance.


Subject(s)
Ammonia , Hydroxides , Nitrogen , Potassium Compounds , Ammonia/analysis , Nitrogen/analysis , Nitric Acid , Adsorption , Soil/chemistry , Manure , Charcoal/chemistry
17.
Korean J Ophthalmol ; 38(2): 98-104, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38351488

ABSTRACT

PURPOSE: To compare the efficacy and rapidity of direct microscopic detection of fungal elements from corneal ulcers between 10% potassium hydroxide (KOH) and 1% Chicago Sky Blue 6B (CSB) in 10% KOH (CSB-KOH). METHODS: Thirty patients with clinically suspected fungal keratitis were recruited. Participants with impending corneal perforation were excluded. Two slides were smeared with corneal ulcer scrapings from the ulcer's edge and base for comparison of fungal staining solutions. One slide was infused with KOH, and the other slide was filled with CSB-KOH. Additional scraping was collected for inoculation on Sabouraud dextrose agar for fungal culture. The sensitivity, specificity and rapidity of both stainings were analyzed. RESULTS: The sensitivity of fungal culture, KOH, and CSB-KOH were 43.75% (95% confidence interval [CI], 19.75%-70.12%), 62.50% (95% CI, 35.43%-84.80%), and 87.50% (95% CI, 61.65%-98.45%), respectively. The specificity were 100% (95% CI, 69.15%-100%) of both stainings and fungal culture which analyzed from 16 fungal keratitis cases by laboratory and clinical diagnosis. Mean CSB-KOH examination time was quicker than KOH with the mean time difference of 5.6 minutes (95% CI, 3.22-7.98 minutes) and p-value < 0.001. CONCLUSIONS: CSB-KOH was more effective and faster than KOH in detecting fungal elements from corneal ulcers. Therefore, CSB-KOH may be beneficial in diagnosing fungal keratitis and preventing blindness. Moreover, to the best of our knowledge, this is the first use of CSB stain in fungal keratitis detection.


Subject(s)
Corneal Ulcer , Eye Infections, Fungal , Hydroxides , Potassium Compounds , Trypan Blue , Humans , Corneal Ulcer/diagnosis , Corneal Ulcer/drug therapy , Corneal Ulcer/microbiology , Coloring Agents , Ulcer , Cornea , Eye Infections, Fungal/diagnosis , Eye Infections, Fungal/microbiology
18.
Bull Environ Contam Toxicol ; 112(2): 33, 2024 Feb 11.
Article in English | MEDLINE | ID: mdl-38342847

ABSTRACT

Abundant iron and sulfate resources are present in acid mine drainage. The synthesis of schwertmannite from AMD rich in iron and sulfate could achieve the dual objectives of resource recovery and wastewater purification. However, schwertmannite cannot emerge spontaneously due to the Gibbs free energy greater than 0. This results in the iron and sulfate in AMD only being able to use the energy generated by oxidation in the coupling reaction to promote the formation of minerals, but this only achieved partial mineralization, which limited the remediation of AMD through mineralization. In order to clarify the mechanism of iron and sulfate removal by the formation of schwertmannite in AMD, kinetic and thermodynamic parameters were crucial. This work used H2O2 oxidation of Fe2+ as a coupling reaction to promote the formation of schwertmannite from 64.4% of iron and 15.7% of sulfate in AMD, and determined that 99.7% of the iron and 89.9% of sulfate were immobilized in the schwertmannite structural, and only a small fraction was immobilized by the adsorption of schwertmannite, both of which were consistent with second-order kinetics models. The thermodynamic data suggested that reducing the concentration of excess sulfate ions or increasing the energy of the system may allow more iron and sulfate to be immobilized by forming schwertmannite. Experimental verification using the reaction of potassium bicarbonate with the acidity in solution to increase the energy in the system showed that the addition of potassium bicarbonate effectively promoted the formation of schwertmannite from Fe3+ and SO42-. It provided a theoretical and research basis for the direct synthesis of schwertmannite from Fe3+ and SO42- rich AMD for the removal of contaminants from water and the recovery of valuable resources.


Subject(s)
Bicarbonates , Iron Compounds , Iron , Potassium Compounds , Adsorption , Hydrogen Peroxide , Iron Compounds/chemistry , Oxidation-Reduction , Sulfates/chemistry , Hydrogen-Ion Concentration
19.
Waste Manag ; 177: 115-124, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38320451

ABSTRACT

Magnesium potassium phosphate cement (MKPC) is increasingly used in the solidification/stabilization (SS) of heavy metal (HM) pollutants. However, research on composite HM pollutants remains limited. In this study, four heavy metals (Pb/Zn/Cu/Cd) were individually and simultaneously introduced into MKPC systems with different magnesium/phosphorus (M/P) molar ratios. The introduction of HMs altered the extent of hydration and morphology of MgKPO4·6H2O. Among the MKPC pastes, those with M/P = 2 and 3 had the highest HM solidification efficiency and strength, respectively. The HM solidification efficiency of all specimens exceeded 99 %. In samples with M/P = 3, the codoping of four HMs slightly increased the M/P ratio, thereby increasing MgKPO4·6H2O content and enhancing strength. Pb could generate additional low-solubility precipitates, such as PbHPO4, Pb3 (PO4)2, Pb5 (OH) (PO4)3, and Pb (OH)2, which easily accumulated in pores and were encapsulated by MgKPO4·6H2O, leading to the highest solidification efficiency of Pb by MKPC. Pb and Cu could also form the composite phosphate products Pb2Cu (PO4)3 (OH)·4H2O, thus promoting the S/S effect of Cu. Therefore, the use of MKPC with M/P ratio of 2-3 for the S/S of complex pollutants containing Pb and Cu is a promising approach.


Subject(s)
Environmental Pollutants , Magnesium Compounds , Metals, Heavy , Potassium Compounds , Magnesium , Potassium , Lead , Phosphates
20.
J Environ Manage ; 354: 120268, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38364546

ABSTRACT

The combined process of biochar (BC) and potassium ferrate (PF) offers a fascinating technique for efficient dewatering of digestate. However, the effects of BC/PF treatment on the dewaterability and mechanisms of FWD are still unknown. This study aimed to reveal the impact mechanisms of BC/PF treatment on digestate dewatering performance. Experimental results indicated that BC/PF treatment significantly enhanced the dewaterability of digestate, with the minimum specific resistance to filtration of (1.05 ± 0.02) × 1015 m·kg-1 and water content of 57.52 ± 0.51% being obtained at the concentrations of 0.018 g·g-1 total solid (TS) BC300 and 0.20 g·g-1 TS PF, which were 8.60% and 13.59% lower than PF treatment, respectively. BC/PF treatment proficiently reduced the fractal dimension, bound water content, apparent viscosity, and gel-like network structure strength of digestate, as well as increased the floc size and zeta potential of digestate. BC/PF treatment promoted the conversion of extracellular polymeric substances (EPS) fractions from inner EPS to soluble EPS, increased the fluorescence intensity of the dissolved compounds, and enhanced the hydrophobicity of proteins. Mechanisms investigations showed that BC/PF enhanced dewatering through non-reactive oxygen species pathways, i.e., via strong oxidative intermediate irons species Fe(V)/Fe(IV). BC/PF treatment enhanced the solubilization of nutrients, the inactivation of fecal coliforms, and the mitigation of heavy metal toxicity. The results suggested that BC/PF treatment is an effective digestate dewatering technology which can provide technological supports to the closed-loop treatment of FWD.


Subject(s)
Charcoal , Food Loss and Waste , Iron Compounds , Iron , Potassium Compounds , Refuse Disposal , Food , Sewage/chemistry , Water/chemistry , Waste Disposal, Fluid/methods
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