Removal of Copper (II) and Nickel (II) Ions from Aqueous Solutions by a Composite Chitosan Biosorbent

Abstract

A composite chitosan biosorbent (CCB) was prepared by coating chitosan on to ceramic alumina. The adsorption characteristics of the sorbent for copper and nickel ions were studied under batch equilibrium and dynamic flow conditions at pH 4.0. The equilibrium adsorption data were correlated with Langmuir, Freundlich, and Redlich‐Peterson models. The ultimate monolayer capacities, obtained from Langmuir isotherm, were 86.2 and 78.1 mg/g of chitosan for Cu(II) and Ni(II), respectively. In addition, dynamic column adsorption studies were conducted to obtain breakthrough curves. After the column was saturated with metal ions, it was regenerated with 0.1 M sodium hydroxide. The regenerated column was used for a second adsorption cycle.     

Separation of Nickel(II) and Cadmium(II) with Ion-Exchange Process

Separation of nickel(II) and cadmium(II) ions from sulphate solution has been studied. The solutions of Ni(II) and Cd(II) have been treated with different exchange resins: Lewatit OC-1026, Lewatit TP-207, and Lewatit MonoPlus SP 112. Data obtained from the ion-exchange process was compared with data from the supported liquid membrane experiment. It was shown that the use of the supported liquid membrane process enables separation of investigated ions. In this process the highest recovery factor was obtained. The best separation of metal ions was obtained for the ion-exchange process with Lewatit OC 1026.     

Comparison of Biosorption of Nickel (II) and Copper (II) Ions from Aqueous Solution by Sphaeroplea Algae and Acid Treated Sphaeroplea Algae

Abstract

Biosorption of nickel (II) and copper (II) ions from aqueous solution by dead sphaeroplea algae in natural and acid treated forms were studied as a function of concentration, pH, and adsorbent dose. The optimum pH for nickel (II) and copper (II) biosorption was found to be 6.0 and 4.0 respectively. The metal ion uptake increased with initial metal ion concentration studied up to 500 mg/L. Both the Freundlich and Langmuir adsorption models could fit the equilibrium data. The adsorption reasonably fitted the Lagergren kinetic model. Further the biomass was characterized by FTIR spectra. Surface area values are measured to be 0.9 and 2.1 m²/g for natural and acid treated forms respectively. The maximum adsorption capacity was found to be 3.40, 4.15 mmol/g for nickel (II) and 2.21, 3.41 mmol/g for copper (II) in natural and acid treated forms respectively.     

Free Cholesterol Affects the Function and Localization of Human Na+/Taurocholate Cotransporting Polypeptide (NTCP) and Organic Cation Transporter 1 (OCT1)

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are associated with obesity. They are accompanied by increased levels of free cholesterol in the liver. Most free cholesterol resides within the plasma membrane. We assessed the impact of adding or removing free cholesterol on the function and localization of two hepatocellular uptake transporters: the Na⁺/taurocholate cotransporting polypeptide (NTCP) and the organic cation transporter 1 (OCT1). We used a cholesterol–MCD complex (cholesterol) to add cholesterol and methyl-β-cyclodextrin (MCD) to remove cholesterol. Our results demonstrate that adding cholesterol decreases NTCP capacity from 132 ± 20 to 69 ± 37 µL/mg/min and OCT1 capacity from 209 ± 66 to 125 ± 26 µL/mg/min. Removing cholesterol increased NTCP and OCT1 capacity to 224 ± 65 and 279 ± 20 µL/mg/min, respectively. In addition, adding cholesterol increased the localization of NTCP within lipid rafts, while adding or removing cholesterol increased OCT1 localization in lipid rafts. These results demonstrate that increased cholesterol levels can impair NTCP and OCT1 function, suggesting that the free cholesterol content of the liver can alter bile acid and drug uptake into the liver. This could explain the increased plasma bile acid levels in NAFLD and NASH patients and potentially lead to altered drug disposition.     

Protein Biochemistry and Molecular Modeling of the Intra-Melanosomal Domain of Human Recombinant Tyrp2 Protein and OCA8-Related Mutant Variants

Tyrosinase-related protein 2 (Tyrp2) is involved in the melanogenesis pathway, catalyzing the tautomerization of dopachrome to 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Recently, a new type of albinism was discovered with disease-causing mutations in the TYRP2 gene. Here, for the first time, we characterized the intra-melanosomal protein domain of Tyrp2 (residues 1-474) and missense variants C40S and C61W, which mimic the alterations found in genetic studies. Recombinant proteins were produced in the Trichoplusia Ni (Ti. Ni) larvae, purified by a combination of immobilized metal affinity (IMAC) and gel-filtration (GF) chromatography, and biochemically characterized. The mutants showed the protein expression in the lysates such as the wild type; however, undetectable protein yield after two steps of purification exhibited their misfolding and instability. In addition, the misfolding effect of the mutations was confirmed computationally using homology modeling and molecular docking. Together, experiments in vitro and computer simulations indicated the critical role of the Cys-rich domain in the Tyrp2 protein stability. The results are consistent with molecular modeling, global computational mutagenesis, and clinical data, proving the significance of genetic alterations in cysteine residues, which could cause oculocutaneous albinism type 8.     

Separation of Ni(II) and Cd(II) Ions with Supported Liquid Membranes (SLM) using D2EHPA as a Carrier

Separation of nickel(II) and cadmium(II) ions from sulphate solution with use of supported liquid membranes (SLM) has been studied. Di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in kerosene was used as the ion carrier. Obtained data were compared with data from polymer inclusion membranes (PIM) experiments. It was shown that use of SLM membranes enables separation of Ni(II) and Cd(II) ions. Experimental results data show that faster transport and higher recovery factor values were obtained for supported liquid membranes.     

Modelling Individual and Competitive Adsorption of Cadmium(II) and Zinc(II) Metal Ions from Aqueous Solution onto Bagasse Fly Ash

Abstract

The present study deals with the competitive adsorption of cadmium (Cd(II)) and zinc (Zn(II)) ions onto bagasse fly ash (BFA) from binary systems. BFA is a waste obtained from the bagasse‐fired boilers of sugar mills. The initial pH≈6.0 is found to be the optimum for the individual removal of Cd(II) and Zn(II) ions by BFA. The equilibrium adsorption data were obtained at different initial concentrations (C ₀ = 10–100 mg/l), 5 h contact time, 30°C temperature, BFA dosage of 10 mg/l at pH ₀ = 6. The Redlich–Peterson (R–P) and the Freundlich models represent the single ion equilibrium adsorption data better than the Langmuir model. The adsorption capacities in the binary‐metal mixtures are in the order Zn(II)>Cd(II) and is in agreement with the single‐component adsorption data. The equilibrium metal removal decreases with increasing concentrations of the other metal ion and the combined action of Cd(II) and Zn(II) ions on BFA is found to be antagonistic. Equilibrium isotherms for the binary adsorption of Cd(II) and Zn(II) ions on BFA have been analyzed by non‐modified Langmuir, modified Langmuir, extended‐Langmuir, Sheindorf–Rebuhn–Sheintuch (SRS), non‐modified R–P and modified R–P adsorption models. The isotherm model fitting has been done by minimizing the Marquardt's percent standard deviation (MPSD) error function using MS Excel. The SRS model satisfactory fits for most of the adsorption equilibrium data of Cd(II) and Zn(II) ions onto BFA.     

室温固相法合成2-吡啶甲酸钴、镍配合物

利用乙酸钴(Ⅱ)、氯化镍(Ⅱ)和2-吡啶甲酸为原料,采用室温固相法合成了2-吡啶甲酸钴(Ⅱ)、镍(Ⅱ)配合物M(C5H4NCOO)2.xH2O(M=Co,Ni;x=6,3),用EDTA配位滴定、元素分析、X射线粉末衍射、红外光谱和热分析等方法对产物进行组成和结构表征。结果表明,2-吡啶甲酸中的羧基氧原子和杂环氮原子及水分子参与配位,其热分解包括失水、配体的氧化分解过程,最后完全形成金属氧化物。     

室温固相法合成2-吡啶甲酸钴、镍配合物

利用乙酸钴(II)、氯化镍(II)和2-吡啶甲酸为原料,采用室温固相法合成了2-吡啶甲酸钴(II)、镍(II)配合物M(C5H4NCOO)2?xH2O,用EDTA配位滴定、元素分析、X射线粉末衍射、红外光谱和热分析等方法对产物进行组成和结构表征。结果表明,2-吡啶甲酸中的羧基氧原子和杂环氮原子及水分子参与配位,其热分解包括失水、配体的氧化分解过程,最后完全形成金属氧化物。     

Highly Efficient Nickel(II) Chloride/Bis(tricyclohexylphosphine)nickel(II) Chloride‐Cocatalyzed Hydrodefluorination of Fluoroarenes and Trifluorotoluenes with Superhydride

A simple and highly efficient approach for the hydrodefluorination of both fluoroarenes and trifluorotoluenes in the presence of lithium triethylborohydride using a catalytic amount of nickel(II) chloride (NiCl₂, 2 mol%) combined with a catalytic amount of bis(tricyclohexylphosphine)nickel(II) chloride [NiCl₂(PCy₃)₂, 2 mol%] as cocatalyst has been developed.     

Purification of Unrefined Nickel(II) Sulfate Solution by a Continuous Countercurrent Multistage Extraction with bis(2-Ethylhexyl)phosphinic Acid

Separation of cobalt(II) and nickel(II) using bis(2-ethylhexyl)phosphinic acid as an extractant has been investigated by a liquid–liquid and a continuous countercurrent extraction. For comparison, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester has also been used, and the results are discussed in terms of cobalt–nickel selectivity. Based on the results, a highly selective procedure using 20% bis(2-ethylhexyl)phosphinic acid in heptane has been proposed to separate zinc(II), copper(II), manganese(II), cadmium(II), magnesium(II) and cobalt(II) from nickel(II). The separation method has been successfully applied to purification of unrefined nickel(II) sulfate solutions. © 1997 SCI.     

The Role of the ATP-Binding Cassette A1 (ABCA1) in Human Disease

Cholesterol homeostasis is essential in normal physiology of all cells. One of several proteins involved in cholesterol homeostasis is the ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein widely expressed in many tissues. One of its main functions is the efflux of intracellular free cholesterol and phospholipids across the plasma membrane to combine with apolipoproteins, mainly apolipoprotein A-I (Apo A-I), forming nascent high-density lipoprotein-cholesterol (HDL-C) particles, the first step of reverse cholesterol transport (RCT). In addition, ABCA1 regulates cholesterol and phospholipid content in the plasma membrane affecting lipid rafts, microparticle (MP) formation and cell signaling. Thus, it is not surprising that impaired ABCA1 function and altered cholesterol homeostasis may affect many different organs and is involved in the pathophysiology of a broad array of diseases. This review describes evidence obtained from animal models, human studies and genetic variation explaining how ABCA1 is involved in dyslipidemia, coronary heart disease (CHD), type 2 diabetes (T2D), thrombosis, neurological disorders, age-related macular degeneration (AMD), glaucoma, viral infections and in cancer progression.     

1-(2,3,5-三氮唑偶氮)-2-萘酚的合成及其与镍的显色反应研究

合成了 1 - ( 2 ,3,5 -三氮唑偶氮 ) - 2 -萘酚 (简称 TZAN) ,研究了它与镍的显色反应。结果表明 :在 p H7.0～ 8.0的水溶液中镍与 TZAN形成一种稳定的红色配合物 ,其最大吸收波长位于5 2 8.8nm处 ,表观摩尔吸光系数ε=3.40× 1 0 4 L /mol· cm,配合物的组成 Ni2 + ∶ TZAN=1∶ 2。镍浓度在 0～ 1 .2 mg/L范围内服从比尔定律。在氟化铵和硫脲的存在下 ,可直接测定合金中的微量镍     

新显色剂7-(苯并噻唑-2-偶氮)-8-羟基喹啉-5-磺酸的分析性能及其与锌显色反应的研究

报道了新显色剂７－（苯并噻唑－２－偶氮）－８－羟基喹啉－５－磺酸（简称ＢＴＨＱＳＡ）的离解常数的测定，同时研究了该显色剂对锌离子光度分析的条件，摩尔吸光系数ε＝５．１×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，锌离子浓度在０～６．５μｇ／２５ｍＬ符合比尔定律，并对人发中的微量锌进行测定。     

Thermal, Spectroscopic, Cyclic Voltammetric, and Biological Activity Studies of Cobalt(II), Nickel(II), and Copper(II) Complexes of Dicarboxylic Amino Acids and 8-Hydroxyquinoline

Mixed ligand complexes of Co^II, Ni^II and Cu^II with dicarboxylic amino acids (aspartic, glutamic or H₂ADA) as primary ligands and 8-hydroxyquinoline as a secondary ligand were prepared and characterized by elemental analysis, conductivity measurements, thermal analysis, cyclic voltammetry, and electronic and infrared (IR) spectroscopy. Cyclic voltammetry reveals a reversibility of the Cu^II/Cu^I couple, while the reactions of the Co^II and Ni^II complexes are irreversible. All complexes have a metal-to-ligand ratios of 1:1:1 and octahedral structures are suggested to be attained by interactions among both of the amino acids and 8-hydroxyquinoline anions with the metal ions. The reaction orders and activation energies have been computed by means of the Coats–Redfern and Horowitz–Metzger equations. The biological activity of selected complexes as anti-fungal agents has been tested.     

Determination of cobalt(II), nickel(II) and palladium(II) Ions via fabric phase sorptive extraction in combination with high-performance liquid chromatography-UV detection

A method for the determination of Co(II), Ni(II) and Pd(II) in aqueous samples by fabric phase sorptive extraction-high-performance liquid chromatography-UV detection (FPSE-HPLC-UV) is developed. A preconcentration step was necessary due to the trace level concentrations of these elements in aqueous samples. Sol-gel polytetrahydrofuran nanocomposite was selected as the sorbent. All major FPSE parameters were optimized. The limit of detection for Co(II), Ni(II) and Pd(II) morpholino dithiocarbamate complexes were found at much lower concentration level compared with earlier reported data with excellent reproducibility. The new FPSE-HPLC-UV method can be used for routine determination of these metal species in various aqueous environmental samples and in different alloys.     

Flotation of Cesium Coprecipitated with Nickel Hexacyanoferrate(II) from Aqueous Solutions and Radioactive Waste Simulants

Abstract

The coprecipitate flotation of ¹³⁷Cs from dilute aqueous solutions and simulated radioactive wastes using nickel hexacyanoferrate(II) as a coprecipitant and sodium lauryl sulfate, cetyltrimethylammonium bromide, or dodecyl amine as a collector was extensively investigated to establish the best conditions for cesium removal. Under the optimal conditions, removals exceeding 99% and decontamination factors higher than 110 could be achieved for the radioactive waste simulants. The results are compared with those obtained by conventional removal methods and are discussed in terms of the collector properties and the electrical state of the coprecipitate.     

2-（4-咪唑基苯乙烯基）-8-羟基喹啉锌的合成与光致发光特性

合成了一种新型的2-（4-咪唑基苯乙烯基）-8-羟基喹啉配体以及其金属锌配合物,用红外光谱（IR）、紫外光谱（UV）、元素分析（EA）、核磁共振氢谱（1H NMR）等确认了化合物的结构,通过荧光光谱测定了配合物的荧光性质,证实其具有良好的光致发光性能,最大发射波长为576 nm;热重分析实验也表明了金属锌配合物有很好的热稳定性。     

A Holistic Evolutionary and 3D Pharmacophore Modelling Study Provides Insights into the Metabolism,Function, and Substrate Selectivity of the Human Monocarboxylate Transporter 4 (hMCT4)

Monocarboxylate transporters (MCTs) are of great research interest for their role in cancer cell metabolism and their potential ability to transport pharmacologically relevant compounds across the membrane. Each member of the MCT family could potentially provide novel therapeutic approaches to various diseases. The major differences among MCTs are related to each of their specific metabolic roles, their relative substrate and inhibitor affinities, the regulation of their expression, their intracellular localization, and their tissue distribution. MCT4 is the main mediator for the efflux of L-lactate produced in the cell. Thus, MCT4 maintains the glycolytic phenotype of the cancer cell by supplying the molecular resources for tumor cell proliferation and promotes the acidification of the extracellular microenvironment from the co-transport of protons. A promising therapeutic strategy in anti-cancer drug design is the selective inhibition of MCT4 for the glycolytic suppression of solid tumors. A small number of studies indicate molecules for dual inhibition of MCT1 and MCT4; however, no selective inhibitor with high-affinity for MCT4 has been identified. In this study, we attempt to approach the structural characteristics of MCT4 through an in silico pipeline for molecular modelling and pharmacophore elucidation towards the identification of specific inhibitors as a novel anti-cancer strategy.     

Bisphenol A Inhibits the Transporter Function of the Blood-Brain Barrier by Directly Interacting with the ABC Transporter Breast Cancer Resistance Protein (BCRP)

The breast cancer resistance protein (BCRP) is an important efflux transporter in the blood-brain barrier (BBB), protecting the brain from a wide range of substances. In this study, we investigated if BCRP function is affected by bisphenol A (BPA), a high production volume chemical used in common consumer products, as well as by bisphenol F (BPF) and bisphenol S (BPS), which are used to substitute BPA. We employed a transwell-based in vitro cell model of iPSC-derived brain microvascular endothelial cells, where BCRP function was assessed by measuring the intracellular accumulation of its substrate Hoechst 33342. Additionally, we used in silico modelling to predict if the bisphenols could directly interact with BCRP. Our results showed that BPA significantly inhibits the transport function of BCRP. Additionally, BPA was predicted to bind to the cavity that is targeted by known BCRP inhibitors. Taken together, our findings demonstrate that BPA inhibits BCRP function in vitro, probably by direct interaction with the transporter. This effect might contribute to BPA’s known impact on neurodevelopment.