Solubility and transport of phosphate and the accompanying ions as influenced by sulphate salts in a model calcareous soil system

2009 ◽  
Vol 89 (5) ◽  
pp. 589-601 ◽  
Author(s):  
S O Olatuyi ◽  
O O Akinremi ◽  
D N Flaten ◽  
G H Crow

Plant availability of phosphorus (P) in calcareous soil can be improved by modifying the chemical environment of the soil-P fertilizer reaction zone through the banding of non-phosphate fertilizer with P. We investigated the solubility and diffusive transport of P as influenced by addition of two sulphate salts [(NH4)2SO4 and K2SO4] to NH4H2PO4 and KH2PO4. The salts were applied to a series of wax columns packed with approximately 223 g of Ca2+-saturated cation exchange resin-sand mixture buffered with CaCO3. The background pH of the mixture was 8.8. Each treatment contained approximately 204.5 mg P kg-1 soil, while 632.3 mg SO42- kg-1 soil was added to each P source for treatments containing the dual bands to provide a molar concentration of P and SO42- of 6.6 mmol kg-1 soil. After 2 wk of incubation, column segmentation and extraction showed that H+ moved deeper into the columns on addition of the sulphate salts compared with adding NH4H2PO4 or KH2PO4 alone. The maximum depth of P penetration in the columns containing NH4H2PO4 was 4.2 cm, while P transport in the columns treated with KH2PO4 was restricted to the top 4.0 cm depth. Addition of (NH4)2SO4 or K2SO4 to NH4H2PO4 increased the concentration of water-extractable P by 43 and 21%, respectively, above that in NH4H2PO4 alone. Similarly, addition of (NH4)2SO4 or K2SO4 increased the concentration of water-soluble P by 48 and 41%, respectively, above the amount in KH2PO4 alone. The increased water solubility of P on addition of the sulphate salts was attributed to anion competition between HPO42- and SO42- for precipitation with Ca2+. We also observed ionic competition between NH4+ and K+ when both cations were added together, causing K+ to travel farther into the column and with increased solubility than when applied alone. Our results showed that anion and cation competition can be used to modify the transport and solution concentration of ions through dual banding. These results also suggested that the combination of anion competition by SO42- and pH reduction due to salt effect could have a positive influence on the availability of P in calcareous soils. Key words: Phosphate, sulphate, columns, solubility, diffusive transport, resin

2009 ◽  
Vol 89 (2) ◽  
pp. 179-188 ◽  
Author(s):  
S O Olatuyi ◽  
O O Akinremi ◽  
D N Flaten ◽  
G H Crow

Mixing non-phosphate salts with phosphate fertilizer modifies the chemical environment of the soil-phosphorus (P) fertilizer reaction zone due to induced changes in soil pH and the interactions of P with soil components and other ions. The objective of this study was to examine the effects of cation and anion interactions on the solubility and diffusive transport of P in columns packed with a mixture of inert quartz sand and Ca2+-saturated cation exchange resin, buffered with CaCO3. The background pH of the resin-sand mixture was 9.4. Three types of cations (K+, NH4+, and Mg2+) were combined with four anions (NO3-, Cl-, SO42-, and CO32-) to produce 12 non-phosphate salts. Each of these salts was mixed with 0.4 g of KH2PO4 to provide 408.9 mg P kg-1 soil. The experiment was carried out in three replicates. Following 2 wk of incubation, columns were sectioned at 3-mm intervals and the pH of each section was measured. The samples were extracted with deionized water and subsequently with 1 mol L-1 HCl. Addition of KH2PO4 alone reduced the pH at the surface (first 3-mm section) of the resin-sand column to 7.1, while pH remained unchanged at 9.1 on addition of K2CO3 and KH2PO4. Addition of MgCl2 and KH2PO4 resulted in the lowest pH in the column and the greatest depth of H+ penetration compared with other treatments. None of the treatments containing NO3- or Cl- salts enhanced the solubility and movement of P. Addition of (NH4)2SO4 or (NH4)2CO3 to KH2PO4 produced the greatest amount of water-extractable P, followed by K2SO4. The lowest solubility of P occurred on addition of K2CO3 (P < 0.05). We attributed the enhanced solubility of P by SO42- and CO32- associated with NH4+ to competition between these anions and HPO42- for precipitation with solution Ca2+. Phosphate ion moved to depths of 5.0, 6.0 and 7.5 cm on addition of K2SO4, (NH4)2SO4, and MgSO4 to the column, respectively. These results suggested that salts such as K2SO4, (NH4)2CO3, (NH4)2SO4 and MgSO4 would enhance the lability of fertilizer P in a calcareous soil system. Key words: Solubility, precipitation, diffusive transport, resin, cation exchange, anion competition, dual banding


Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 130
Author(s):  
Dario Fornara ◽  
Elizabeth M. E. Ball ◽  
Christina Mulvenna ◽  
Henry Reyer ◽  
Michael Oster ◽  
...  

The over-supplementation of animal feeds with phosphorus (P) within livestock-production systems leads to high rates of P excretion and thus to high P loads and losses, which negatively impact the natural environment. The addition of phytase to pig and poultry diets can contribute to reducing P excretion; however, cascading effects of phytase on plant–soil systems remain poorly understood. Here, we addressed how three different diets containing various levels of exogenous phytase, i.e., (1) no-phytase, (2) phytase (250 FTU), and (3) superdose phytase (500 FTU) for pigs (Sus scrofa domesticus) and broilers (Gallus gallus domesticus) might affect P dynamics in two different plant–soil systems including comfrey (Symphytum ×uplandicum) and ryegrass (Lolium perenne). We found that differences in phytase supplementation significantly influenced total P content (%) of broiler litter and also pig slurry (although not significantly) as a result of dietary P content. P Use Efficiency (PUE) of comfrey and ryegrass plants was significantly higher under the intermediate ‘phytase’ dose (i.e., commercial dose of 250 FTU) when compared to ‘no-phytase’ and ‘superdose phytase’ associated with pig slurry additions. Soil P availability (i.e., water soluble P, WSP) in both comfrey and ryegrass mesocosms significantly decreased under the intermediate ‘phytase’ treatment following pig slurry additions. Dietary P content effects on P losses from soils (i.e., P leaching) were variable and driven by the type of organic amendment. Our study shows how commercial phytase levels together with higher dietary P contents in pig diets contributed to increase PUE and decrease WSP thus making the plant–soil system more P conservative (i.e., lower risks of P losses). Our evidence is that dietary effects on plant–soil P dynamics are driven by the availability of P forms (for plant uptake) in animal excretes and the type of organic amendment (pig vs. broiler) rather than plant species identity (comfrey vs. ryegrass).


2019 ◽  
Author(s):  
Jenna Franke ◽  
Benjamin Raliski ◽  
Steven Boggess ◽  
Divya Natesan ◽  
Evan Koretsky ◽  
...  

Fluorophores based on the BODIPY scaffold are prized for their tunable excitation and emission profiles, mild syntheses, and biological compatibility. Improving the water-solubility of BODIPY dyes remains an outstanding challenge. The development of water-soluble BODIPY dyes usually involves direct modification of the BODIPY fluorophore core with ionizable groups or substitution at the boron center. While these strategies are effective for the generation of water-soluble fluorophores, they are challenging to implement when developing BODIPY-based indicators: direct modification of BODIPY core can disrupt the electronics of the dye, complicating the design of functional indicators; and substitution at the boron center often renders the resultant BODIPY incompatible with the chemical transformations required to generate fluorescent sensors. In this study, we show that BODIPYs bearing a sulfonated aromatic group at the meso position provide a general solution for water-soluble BODIPYs. We outline the route to a suite of 5 new sulfonated BODIPYs with 2,6-disubstitution patterns spanning a range of electron-donating and -withdrawing propensities. To highlight the utility of these new, sulfonated BODIPYs, we further functionalize them to access 13 new, BODIPY-based voltage-sensitive fluorophores. The most sensitive of these BODIPY VF dyes displays a 48% ΔF/F per 100 mV in mammalian cells. Two additional BODIPY VFs show good voltage sensitivity (≥24% ΔF/F) and excellent brightness in cells. These compounds can report on action potential dynamics in both mammalian neurons and human stem cell-derived cardiomyocytes. Accessing a range of substituents in the context of a water soluble BODIPY fluorophore provides opportunities to tune the electronic properties of water-soluble BODIPY dyes for functional indicators.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1140
Author(s):  
Silvana Alfei ◽  
Gabriella Piatti ◽  
Debora Caviglia ◽  
Anna Maria Schito

The growing resistance of bacteria to current chemotherapy is a global concern that urgently requires new and effective antimicrobial agents, aimed at curing untreatable infection, reducing unacceptable healthcare costs and human mortality. Cationic polymers, that mimic antimicrobial cationic peptides, represent promising broad-spectrum agents, being less susceptible to develop resistance than low molecular weight antibiotics. We, thus, designed, and herein report, the synthesis and physicochemical characterization of a water-soluble cationic copolymer (P5), obtained by copolymerizing the laboratory-made monomer 4-ammoniumbuthylstyrene hydrochloride with di-methyl-acrylamide as uncharged diluent. The antibacterial activity of P5 was assessed against several multi-drug-resistant clinical isolates of both Gram-positive and Gram-negative species. Except for strains characterized by modifications of the membrane charge, most of the tested isolates were sensible to the new molecule. P5 showed remarkable antibacterial activity against several isolates of genera Enterococcus, Staphylococcus, Pseudomonas, Klebsiella, and against Escherichia coli, Acinetobacter baumannii and Stenotrophomonas maltophilia, displaying a minimum MIC value of 3.15 µM. In time-killing and turbidimetric studies, P5 displayed a rapid non-lytic bactericidal activity. Due to its water-solubility and wide bactericidal spectrum, P5 could represent a promising novel agent capable of overcoming severe infections sustained by bacteria resistant the presently available antibiotics.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).


Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1008 ◽  
Author(s):  
Qilei Yang ◽  
Chang Zu ◽  
Wengang Li ◽  
Weiwei Wu ◽  
Yunlong Ge ◽  
...  

Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography–mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.


Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1155 ◽  
Author(s):  
Ghada A. Soliman

Observational studies have shown that dietary fiber intake is associated with decreased risk of cardiovascular disease. Dietary fiber is a non-digestible form of carbohydrates, due to the lack of the digestive enzyme in humans required to digest fiber. Dietary fibers and lignin are intrinsic to plants and are classified according to their water solubility properties as either soluble or insoluble fibers. Water-soluble fibers include pectin, gums, mucilage, fructans, and some resistant starches. They are present in some fruits, vegetables, oats, and barley. Soluble fibers have been shown to lower blood cholesterol by several mechanisms. On the other hand, water-insoluble fibers mainly include lignin, cellulose, and hemicellulose; whole-grain foods, bran, nuts, and seeds are rich in these fibers. Water-insoluble fibers have rapid gastric emptying, and as such may decrease the intestinal transit time and increase fecal bulk, thus promoting digestive regularity. In addition to dietary fiber, isolated and extracted fibers are known as functional fiber and have been shown to induce beneficial health effects when added to food during processing. The recommended daily allowances (RDAs) for total fiber intake for men and women aged 19–50 are 38 gram/day and 25 gram/day, respectively. It is worth noting that the RDA recommendations are for healthy people and do not apply to individuals with some chronic diseases. Studies have shown that most Americans do not consume the recommended intake of fiber. This review will summarize the current knowledge regarding dietary fiber, sources of food containing fiber, atherosclerosis, and heart disease risk reduction.


2021 ◽  
Vol 12 ◽  
Author(s):  
Hitesh Kumar Dewangan

: Poor solubility of some medicinal compounds is a serious challenge that can be addressed by using a nano-suspension for improved delivery. The nanoparticles enhance the bioavailability along with the aqueous solubility of the drug, which is accomplished by increasing the active surface area of the drug. The gained attention of the nanosuspension is due to its stabilization facility, which is achieved by polymers, such as polyethylene glycol (PEG), having a particular size range of 10 - 100 nm. Hence, these nanoparticles have the capacity of binding to the targeted with very low damage to the healthy tissues. These are prepared by various methods, such as milling, high-pressure homogenization, and emulsification, along with melt emulsification. Moreover, surface modification and solidification have been used to add specific properties to the advanced therapies as post-processing techniques. For many decades, it has been known that water solubility hampers the bioavailability and not all drugs are water-soluble. In order to combat this obstacle, nanotechnology has been found to be of specific interest. For elevating the bioavailability by increasing the dissolution rate, the methodology of reduction of the associated drug particles into their subsequent submicron range is incorporated. For oral and non-oral administration, these nanosuspension formulations are used for the delivery of drugs.


Author(s):  
Sejal Patel ◽  
Anita P. Patel

In the interest of administration of dosage form oral route is most desirable and preferred method. After oral administration to get maximum therapeutic effect, major challenge is their water solubility. Water insoluble drug indicate insufficient bioavailability as well dissolution resulting in fluctuating plasma level. Benidipine (BND) is poorly water soluble antihypertensive drug has lower bioavailability. To improve bioavailability of Benidipine HCL, BND nanosuspension was formulated using media milling technique. HPMC E5 was used to stabilize nanosuspension. The effect of different important process parameters e.g. selection of polymer concentration X1(1.25 mg), stirring time X2 (800 rpm), selection of zirconium beads size X3 (0.4mm) were investigated by 23 factorial design to accomplish desired particle size and saturation solubility. The optimized batch had 408 nm particle size Y1, and showed in-vitro dissolution Y2 95±0.26 % in 30 mins and Zeta potential was -19.6. Differential scanning calorimetry (DSC) and FT-IR analysis was done to confirm there was no interaction between drug and polymer.


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