scholarly journals Cyclophospholipids Increase Protocellular Stability to Metal Ions

2019 ◽  
Author(s):  
Ö. Duhan Toparlak ◽  
Megha Karki ◽  
Veronica Egas Ortuno ◽  
Ramanarayanan Krishnamurthy ◽  
Sheref Mansy
Keyword(s):  
Fatty Acids ◽  
Life Cycle ◽  
Metal Ions ◽  
Metal Ion ◽  
Narrow Range ◽  
Ion Concentration ◽  
Darwinian Evolution ◽  
Early Earth ◽  
Biological Polymers ◽  
High Concentrations

<p>Model protocells have long been constructed with fatty acids, because these lipids are prebiotically plausible and can, at least theoretically, support a protocell life cycle. However, fatty acid protocells are stable only within a narrow range of pH and metal ion concentration. This instability is particularly problematic as the early Earth would have had a range of conditions, and life as we know it is completely reliant on metal ions for catalysis and the folding and activity of biological polymers. Here we show that prebiotically plausible monoacyl cyclophospholipids form robust vesicles that survive a broad range of pH and high concentrations of Mg2+, Ca2+, and Na+. Importantly, stability to Mg2+ and Ca2+ is improved by the presence of environmental concentrations of Na+. These results suggest that cyclophospholipids, or lipids with similar characteristics, may have played a central role during the emergence of Darwinian evolution.</p>

scholarly journals Cyclophospholipids Increase Protocellular Stability to Metal Ions

2019 ◽  
Author(s):  
Ö. Duhan Toparlak ◽  
Megha Karki ◽  
Veronica Egas Ortuno ◽  
Ramanarayanan Krishnamurthy ◽  
Sheref Mansy
Keyword(s):  
Fatty Acids ◽  
Life Cycle ◽  
Metal Ions ◽  
Metal Ion ◽  
Narrow Range ◽  
Ion Concentration ◽  
Darwinian Evolution ◽  
Early Earth ◽  
Biological Polymers ◽  
High Concentrations

<p>Model protocells have long been constructed with fatty acids, because these lipids are prebiotically plausible and can, at least theoretically, support a protocell life cycle. However, fatty acid protocells are stable only within a narrow range of pH and metal ion concentration. This instability is particularly problematic as the early Earth would have had a range of conditions, and life as we know it is completely reliant on metal ions for catalysis and the folding and activity of biological polymers. Here we show that prebiotically plausible monoacyl cyclophospholipids form robust vesicles that survive a broad range of pH and high concentrations of Mg2+, Ca2+, and Na+. Importantly, stability to Mg2+ and Ca2+ is improved by the presence of environmental concentrations of Na+. These results suggest that cyclophospholipids, or lipids with similar characteristics, may have played a central role during the emergence of Darwinian evolution.</p>

Use of agro-waste (Musa paradisiaca peels) as a sustainable biosorbent for toxic metal ions removal from contaminated water

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Contact Time ◽  
Metal Ion ◽  
Equilibrium Concentration ◽  
Ion Concentration ◽  
Contaminated Water ◽  
Musa Paradisiaca ◽  
Percentage Removal ◽  
Adsorbent Dose

A study of removal of heavy metal ions from heavy metal contaminated water using agro-waste was carried out with Musa paradisiaca peels as test adsorbent. The study was carried by adding known quantities of lead (II) ions and cadmium (II) ions each and respectively into specific volume of water and adding specific dose of the test adsorbent into the heavy metal ion solution, and the mixture was agitated for a specific period of time and then the concentration of the metal ion remaining in the solution was determined with Perkin Elmer Atomic absorption spectrophotometer model 2380. The effect of contact time, initial adsorbate concentration, adsorbent dose, pH and temperature were considered. From the effect of contact time results equilibrium concentration was established at 60minutes. The percentage removal of these metal ions studied, were all above 90%. Adsorption and percentage removal of Pb2+ and Cd2+ from their aqueous solutions were affected by change in initial metal ion concentration, adsorbent dose pH and temperature. Adsorption isotherm studies confirmed the adsorption of the metal ions on the test adsorbent with good mathematical fits into Langmuir and Freundlich adsorption isotherms. Regression correlation (R2) values of the isotherm plots are all positive (&gt;0.9), which suggests too, that the adsorption fitted into the isotherms considered.

Efficient Preconcentration of Cu2+, Zn2+ and Fe3+ with an Agarose-Schiff Base Sorbent

2007 ◽  
Vol 72 (7) ◽  
pp. 908-916 ◽  
Author(s):  
Payman Hashemi ◽  
Hatam Hassanvand ◽  
Hossain Naeimi
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Ion ◽  
Good Accuracy ◽  
Kinetic Studies ◽  
Sample Volume ◽  
Effects Of Ph ◽  
Glass Column ◽  
High Concentrations ◽  
Ph Range

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

Membrane transport systems. II. Transport of alkali metal ions against their concentration gradients

1981 ◽  
Vol 59 (12) ◽  
pp. 1734-1744 ◽  
Author(s):  
Thomas M. Fyles ◽  
Virginia A. Malik-Diemer ◽  
Dennis M. Whitfield
Keyword(s):  
Alkali Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Complex Function ◽  
Membrane System ◽  
Ion Concentration ◽  
Transport Systems ◽  
Alkali Metal Ions ◽  
Concentration Gradients ◽  
Membrane Transport Systems

An artificial membrane system based on a series of macrocyclic polyether carriers (crown ethers) is described. Under the influence of a proton gradient the carriers move alkali metal ions from basic to acidic solution through a chloroform membrane phase. Transport occurs against the concentration gradient of the transported ion as a result of a coupled counterflow of protons. Different transport behaviors are observed depending upon the metal ion concentration. At high metal ion concentration the amount transported is a linear function of time; at lower metal ion concentration the amount transported is a complex function of time which may be described as the result of a pair of consecutive first order processes. Effects of metal ion, carrier, and proton concentration on transport rate are considered. The rate increases with increasing metal ion or carrier concentration but is essentially independent of the pH of either aqueous phase. Increased lipophilicity of the carrier also results in a rate increase. Carriers derived from 18-crown-6 transport potassium selectively and all ions more rapidly than 15-crown-5 derivatives which are, however, selective for sodium. The overall efficiency of the system is discussed in terms of competing "leak" reactions, either of cations from the basic phase or of anions from the acidic phase.

scholarly journals Removal of barium, cobalt, strontium and zinc from solution by natural and synthetic allophane adsorbents

2018 ◽  
Author(s):  
Andre Baldermann ◽  
Andrea Cäcilia Grießbacher ◽  
Claudia Baldermann ◽  
Bettina Purgstaller ◽  
Ilse Letofsky-Papst ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Physical Adsorption ◽  
Ion Concentration ◽  
Pseudo First Order Reaction ◽  
Uptake Mechanism ◽  
Nano Structure ◽  
Metal Ion Removal ◽  
Ion Removal ◽  
Transmission Electron

The capacity and the mechanism of the adsorption of aqueous barium (Ba), cobalt (Co), strontium (Sr) and zinc (Zn) by Ecuadorian (NatAllo) and synthetic (SynAllo-1 and SynAllo-2) allophanes were studied as a function of contact time, pH and metal ion concentration using kinetic and equilibrium experiments. The mineralogy, nano-structure and chemical composition of the allophanes were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and specific surface area analyses. The evolution of adsorption fitted to a pseudo-first-order reaction kinetics, where equilibrium between aqueous metal ions and allophane was reached within &lt; 10&thinsp;min. The metal ion removal efficiencies varied from 0.7 to 99.7 % at pH 4.0 to 8.5. At equilibrium, the adsorption behavior is better described by the Langmuir model than by the Dubinin-Radushkevich model, yielding sorption capacities of 10.6, 17.2 and 38.6 mg/g for Ba^(2+), 12.4, 19.3 and 29.0 mg/g for HCoO_2^-, 7.2, 15.9 and 34.4 mg/g for Sr^(2+) and 20.9, 26.9 and 36.9 mg/g for Zn^(2+), respectively, by NatAllo, SynAllo-2 and SynAllo-1. The uptake mechanism is based on a physical adsorption process. Allophane holds great potential to remove aqueous metal ions and could be used instead of zeolites, montmorillonite, carbonates and phosphates for wastewater treatment.

scholarly journals Effective removal of heavy metal ions from aqueous solutions using a new chelating resin poly [2,5-(1,3,4-thiadiazole)-benzalimine]: kinetic and thermodynamic study

2015 ◽  
Vol 6 (2) ◽  
pp. 310-324 ◽  
Author(s):  
Selvaraj Dinesh Kirupha ◽  
Selvaraj Kalaivani ◽  
Thangaraj Vidhyadevi ◽  
Periyaraman Premkumar ◽  
Palanithamy Baskaralingam ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ph Value ◽  
Thermo Gravimetric Analysis ◽  
Kinetic Studies ◽  
Ion Concentration ◽  
Chelating Resin ◽  
Gravimetric Analysis ◽  
Equilibrium Data ◽  
Experimental Values

A novel poly [2,5-(1,3,4-thiadiazole)-benzalimine] abbreviated as TDPI adsorbent was synthesized using simple polycondensation technique. The synthetic route involves the preparation of 2,5-diamino-1,3,4-thiadiazole from 2,5-dithiourea and subsequent condensation with terephthalaldehyde. The resin was chemically characterized using Fourier transform infrared (FT-IR), 1H-NMR, and 13C-NMR spectroscopic analysis. Surface morphology and thermal stability were analyzed using scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA). The effect of the pH value of solution, contact time, adsorbent dose, and initial metal ion concentration were investigated by batch equilibrium adsorption experiments. Kinetic studies show that the adsorption of metal ions onto the resin proceeds according to the pseudo-second-order model and the equilibrium data were best interpreted by the Redlich–Peterson isotherm. The experimental values of the adsorption capacities of Pb2+, Cu2+, Ni2+, and Cd2+ on to TDPI could reach up to 437.2, 491.6, 493.7, and 481.9 mg.g−1 respectively. The exothermic nature of the process, the affinity of the adsorbent towards the metal ions and the feasibility of the process are explained in the thermodynamic parameters. The resin stability and re-usability studies suggest that the resin is chemically stable (0.3 N HCl and H2SO4) and could be regenerated without any serious decline in performance.

Removal of Pb(II) and Cd(II) From Aqueous Solution by Adsorption Using Agrowaste-Modified Kaolinite Clay

2021 ◽  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Metal Ion ◽  
Low Cost ◽  
Ion Concentration ◽  
Kaolinite Clay ◽  
Adsorbent Surface ◽  
Initial Adsorption ◽  
Adsorption Rates

This study showed that kaolinite clay modified with Moringa oleifera pods is a promising low cost adsorbent for the removal of metals from aqueous solution because the resultant composite has higher adsorption capacities, and hence a better metal ions removal efficiency. The efficiencies of these adsorbents for the removal of Pb (II) and Cd (II) ions from aqueous solutions were studied as a function of pH, time, adsorbate concentration and adsorbent dose. Adsorption results showed that pH did significantly affect removal of heavy metal ions between pH 3 and 6. Increasing contact time and initial metal ion concentration increased the sorption capacity of the adsorbent for the metal ions. Adsorbent dosage indicated mainly surface phenomena involving sharing of electrons between the adsorbent surface and the metal ion species. The adsorption of metal ions from aqueous solutions of both metal ions at different initial metal ion concentrations reduced the initial adsorption rates of the adsorption of Pb (II) and Cd (II) by unmodified and modified kaolinite clay.

Metal Ion Release after Hip and Knee Arthroplasty – Causes, Biological Effects and Diagnostics

2019 ◽  
Vol 158 (04) ◽  
pp. 369-382 ◽  
Author(s):  
Jörg Lützner ◽  
Klaus-Peter Günther ◽  
Anne Postler ◽  
Michael Morlock
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Biological Effects ◽  
Ion Concentration ◽  
Blood Levels ◽  
Ceramic Head ◽  
Ion Release ◽  
Imaging Results ◽  
Metal Ion Release ◽  
Metal Metal

AbstractAll metal implants in human bodies corrode which results in metal ions release. This is not necessarily a problem and represents for most patients no hazard. However, if a critical metal ion concentration is exceeded, local or rarely systemic problems can occur. This article summarizes the mechanisms of metal ion release and its clinical consequences. Several situations can result in increased metal ion release: metal-on-metal hip arthroplasties with increased wear, increased micromotion at taper interfaces, direct metal-metal contact (polyethylene wear, impingement), erroneously used metal heads after ceramic head fracture. Possible problems are in most cases located close to the concerned joint. Furthermore, there are reports about toxic damage to several organs. Most of these reports refer to erroneously used metal heads in revisions after a broken ceramic head. There is currently no evidence of carcinogenic or teratogenic effects of implants but data is not sufficient to exclude possible effects. Cobalt and chromium blood levels (favorably in whole blood) should be measured in patients with suspected elevated metal ions. According to current knowledge levels below 2 µg/l seem to be uncritical, levels between 2 and 7 µg/l are considered borderline with unknown biological consequences and levels above 7 µg/l indicate a local problem which should be further diagnosed. Metal ion levels always need to be interpreted together with clinical symptoms and imaging results.

scholarly journals Trace Metal Detection in Aqueous Reservoirs Using Stilbene Intercalated Layered Rare-Earth Hydroxide Tablets

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Solomon Omwoma
Keyword(s):  
Trace Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Aqueous Media ◽  
Mitigation Measures ◽  
Metal Ion Analysis ◽  
Gradual Process ◽  
Metal Detection ◽  
Trace Metal Detection ◽  
High Concentrations

Contamination of aquatic reservoirs with metal ions is a slow gradual process that is not easy to detect. Consequences of the metal ions, especially the ones with high atomic numbers (heavy metals) at high concentrations, are severe and irreversible in aquatic reservoirs. As such, early detection mechanisms, especially at trace concentration, are essential for mitigation measures. In this work, a new, robust, and effective tool for trace metal detection and monitoring in aqueous solutions has been developed. Tablets (1 mm thick and similar to medicinal tablets) were manufactured from a powder comprising stilbene intercalated into gallery spaces of lanthanide-containing layered double hydroxides. The tablets were placed in a water column having different concentrations of Pb2+ and Cu2+ ions, and the water was allowed to flow for 45 minutes at a flow rate of 100 ml/s. Thereafter, the tablets were dried and made to powder, and their phosphorescence was measured. The gradual stilbene phosphorescence turnoff in the tablets from various concentrations of metal ions was correlated with sorption amounts. The tablets were able to detect effectively metal ions (up to Pb2+ 1.0 mmol/L and Cu2+ 5.0 mmol/L) in the aqueous media. As such, the concentrations of Pb2+ and Cu2+ ions at trace levels were determined in the test solutions. This method provides a real-time metal ion analysis and does not involve sampling of water samples for analysis in the laboratory.

scholarly journals Insights into the Recent Use of Modified Adsorbents in Removing Heavy Metal Ions from Aqueous Solution

2021 ◽  
Vol 12 (2) ◽  
pp. 1884-1898
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Metal Removal ◽  
Low Cost ◽  
Ion Concentration ◽  
Future Research ◽  
Batch Tests

Natural water gets contaminated with heavy metal ions because of industrial effluents' discharge into the aquatic environment. As these heavy metal ions cause various health hazards, they should be removed from the aqueous solution. Heavy metal ion concentration in the aqueous solution is very less, so conventional metal removal and recovery processes cannot be applied here. The adsorption method is a great alternative to all these processes as it is a cost-effective and easy method. The use of natural, low-cost materials as adsorbents is eco-friendly also. However, metal uptake capacity of low-cost materials is very less. So, modification is required for low-cost materials to increase their efficiency. In the present review, different modification procedures adopted by different researchers have been discussed. Different low-cost materials used are sawdust, fruit and vegetable wastes, soil, minerals, etc. The modifying agents are heat, acids, bases, and other chemicals. Nevertheless, most of the studies are limited to batch tests only. Future research should be carried out on the extension of batch tests to column study for the large-scale treatment of contaminated water, and the cost of modification procedures and their impact on the environment should also be assessed.

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