Search results for "SORBENT"
showing 10 items of 635 documents
Mapping of the high molecular weight kininogen binding site of prekallikrein. Evidence for a discontinuous epitope formed by distinct segments of the…
1993
Prekallikrein, a glycoprotein involved in contact phase activation, circulates in plasma in the form of a binary complex with high molecular weight kininogen (H-kininogen). The binding to H-kininogen is mediated by the prekallikrein heavy chain consisting of four repetitive domains, A1-A4. To define more precisely the region(s) involved in kininogen binding, we have employed an affinity cross-linking strategy with a synthetic peptide of 31 residues which mimics the prekallikrein binding site of H-kininogen. Cross-linking of the radiolabeled peptide to (pre)kallikrein revealed a binding segment in the NH2-terminal portion of the prekallikrein heavy chain; another binding segment was located …
Human kininogens interact with M protein, a bacterial surface protein and virulence determinant.
1995
Streptococcus pyogenes, the most significant streptococcal species in clinical medicine, expresses surface proteins with affinity for several human plasma proteins. Here we report that kininogens, the precursors to the vasoactive kinins, bind to the surface of S. pyogenes. M protein, a surface molecule and a major virulence factor-in these bacteria, occurs in > 80 different serotypes. Among 49 strains of S. pyogenes, all of different M serotypes, 41 bound radiolabelled kininogens, whereas 6 M protein-negative mutant strains showed no affinity. M protein of most serotypes bind fibrinogen, and among the 55 strains tested, binding of kininogens was closely correlated to fibrinogen bindi…
Mercury(II) removal from aqueous solution by sorption onto alginate, pectate and polygalacturonate calcium gel beads. A kinetic and speciation based …
2013
Abstract Gel beads of calcium alginate, pectate and polygalacturonate salts have been tested as sorbent materials for mercury(II) removal from aqueous solutions. Physico-chemical properties of gel beads, defined by SEM–EDX, TGA and texture and density analysis, were correlated with gel beads sorption capacity towards Hg 2+ ion. A speciation study in aqueous solution was carried out to define the strength of interaction of mercury ion with the polymers investigated and to assess the more suitable experimental conditions to achieve the best effectiveness of Hg 2+ sorption by gel beads. On the basis of the speciation study, pH values in the 3–5.5 pH range were considered appropriated for mercu…
The effect of montmorillonite clay in alginate gel beads for polychlorinated biphenyl adsorption: Isothermal and kinetic studies
2014
Beads of alginate montmorillonite have been used as sorbent for polychlorinated biphenyls from aqueous solutions.The structure and the differences between the different beads were established by IR spectroscopy (FT-IR). The adsorption at 25 °C has been studied in a batch system, following its kinetics and assessing adsorbent dose, initial PCB concentrations, and pH effects. The results show that increasing the initial concentration of the PCBs and the adsorption time favored the adsorption. Adsorption isotherm data were modeled using Chapman, Freundlich and Langmuir adsorption isotherms and the appropriate parameters were calculated.Adsorption of trichlorobiphenyls on alginate–montmorilloni…
Effect of EDTA on divalent metal adsorption onto grape stalk and exhausted coffee wastes
2007
In the present work, two industrial vegetable wastes, grape stalk, coming from a wine producer, and exhausted coffee, coming from a soluble coffee manufacturer, have been investigated for the removal of Cu(II) and Ni(II) from aqueous solutions in presence and in absence of the strongly complexing agent EDTA. Effects of pH and metal-EDTA molar ratio, kinetics as a function of sorbent concentration, and sorption equilibrium for both metals onto both sorbents were evaluated in batch experiments. Metal uptake was dependent of pH, reaching a maximum from pH around 5.5. EDTA was found to dramatically reduce metal adsorption, reaching total uptake inhibition for both metals onto both sorbents at e…
Succinate-bonded pullulan: An efficient and reusable super-sorbent for cadmium-uptake from spiked high-hardness groundwater.
2015
Abstract Chemically modified pullulan was evaluated for its sorption efficiency and selectivity to remove cadmium (Cd) from spiked high-hardness groundwater (GW). Pullulan esterified with succinic anhydride using dimethylaminopyridine showed a fairly high degree of substitution value as confirmed by 1 H NMR spectroscopy. Pullulan succinate (Pull-Suc) was converted into the sodium salt (Pull-Suc-Na). The effect of contact time (5–200 min) and pH (2–8) on Cd-uptake by the sorbent (Pull-Suc-Na) was investigated. The sorbent showed more than 90% Cd-removal in first 15 min from distilled water (DW) and GW solution, respectively. Comparison of Pull-Suc-Na with other polysaccharidal sorbents sugge…
The removal of sulphate from mine water by precipitation as ettringite and the utilisation of the precipitate as a sorbent for arsenate removal.
2016
Abstract The aim of this research was to investigate sulphate removal from mine water by precipitation as ettringite (Ca6Al2(SO4)3(OH)12·26H2O) and the utilisation of the precipitate as a sorbent for arsenate removal. The mine water sulphate concentration was reduced by 85–90% from the initial 1400 mg/L during ettringite precipitation depending on the treatment method. The precipitation conditions were also simulated with MINEQL + software, and the computational results were compared with the experimental results. The precipitated solids were characterised with X-ray diffraction and a scanning electron microscope. The precipitated solids were tested as sorbents for arsenate removal from the…
On mathematical modelling of the solid-liquid mixtures transport in porous axial-symmetrical container with Henry and Langmuir sorption kinetics
2018
In this paper we study diffusion and convection filtration problem of one substance through the pores of a porous material which may absorb and immobilize some of the diffusing substances. As an example we consider round cylinder with filtration process in the axial direction. The cylinder is filled with sorbent i.e. absorbent material that passed through dirty water or liquid solutions. We can derive the system of two partial differential equations (PDEs), one expressing the rate of change of concentration of water in the pores of the sorbent and the other - the rate of change of concentration in the sorbent or kinetical equation for absorption. The approximation of corresponding initial b…
Development of iron oxide/activated carbon nanoparticle composite for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution
2018
Iron oxide (Fe3O4) and iron oxide/activated carbon (Fe3O4/AC) were fabricated by co-precipitation method for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution in batch mode. These nanoparticles were characterized by BET, FTIR, XRD, SEM/TEM and VSM. The optimum conditions for the removal of ions were pH = 2 for Cr(VI) and 6 for Cu(II) and Cd(II), initial metal ion concentration = 50 mg L−1, nanoparticle dose = 50 mg/10 mL, temperature = 25 ± 1 °C, shaking speed = 180 rpm and contact time = 3 h. The equilibrium data of ions sorption were well described by Langmuir, Freundlich, Redlich-Peterson and Intraparticle Diffusion model. The R2 values obtained by Langmuir model were h…
Immunochemical method for penthiopyrad detection through thermodynamic and kinetic characterization of monoclonal antibodies.
2021
Immunoassays are nowadays being employed for rapid contaminant analysis in clinical, environmental, and agrochemical samples. A thorough characterization of the antibody‒antigen interaction can bring light to the immunoreagent selection process in order to develop sensitive and robust tests. Thus, determination of equilibrium and reaction rate constants is usually recommendable. However, this can be quite tricky for low molecular weight compounds, and competitive strategies are commonly followed to estimate apparent affinity values. In the present study, a collection of monoclonal antibodies to penthiopyrad was raised for the first time, and apparent equilibrium constants were assessed by t…