Search results for "aqueous solution"
showing 10 items of 1610 documents
Efficient removal of bisphenol A from wastewaters: Catalytic wet air oxidation with Pt catalysts supported on Ce and Ce–Ti mixed oxides
2019
Catalytic wet air oxidation (CWAO) of an aqueous solution of bisphenol A (BPA) was investigated at 160 ℃ and 2.0 MPa of air in a batch reactor. Activity of supported platinum catalysts (2.5 wt%), prepared by wet impregnation, was compared with pure cerium and cerium–titanium oxide catalysts. Supported platinum catalysts showed higher activities in the removal of BPA than pure CeO2, Ce0.8Ti0.2O2 and Ce0.2Ti0.8O2. The oxidation reaction was followed the pseudo-first order rate law and the highest BPA removal, 97% and 95%, was achieved with Pt/CeO2 and Pt/Ce0.8Ti0.2O2 catalysts respectively. The CWAO of BPA aqueous solution was not a surface area specific reaction but the more important factor…
Improvement of boehmite nanoparticles' aqueous dispersability by controlling their size, shape and crystallinity
2014
In this work, results on the control of size, shape, crystallinity and aqueous dispersability of boehmite prepared by a hydrothermal process are reported. The two step synthetic procedure entailed the precipitation of a xerogel by adding NaOH until pH 10 to a solution of aluminum nitrate at 100 °C without or with additives such as tartaric acid and maltitol, and a subsequent hydrothermal treatment at 150 and 200 °C for different periods of time. The final materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and elemental analysis. The stability and other characteristics of the boehmite nanoparticle aqueous dispersions were determined by measuring t…
Naphthalene-containing polyamines supported in nanosized boehmite particles
2007
Boehmite nanoparticles with covalently linked polyamine chains functionalized with naphthalene fluorophores have been prepared and characterized. The characterization of the materials by elemental microanalysis, X-ray powder diffraction, MAS 29Si NMR and electron microscopy unambiguously prove that the covalent anchorage had occurred. Steady-state fluorescence emission studies show that the luminescent properties of the modified nanoparticles are sensitive to changes in concentration of hydrogen ions, metal ions and anionic nucleotides such as ATP. The behaviour of the attached materials in aqueous solution is parallel to the behaviour of the single fluorophoric polyamines. Comparisons are …
Influence of metal ions on the structures of Keggin polyoxometalate-based solids: Hydrothermal syntheses, crystal structures and magnetic properties
2006
Abstract Three new Keggin polyoxometalate (POM)-based compounds linked to 3d metal complexes have been synthesized under hydrothermal conditions: [Cu(phen)2]2{[Cu(phen)]2 [SiMo12O40(VO)2]} (1), {[Zn(phen)2]2[GeMo12O40(VO)2]}{[Zn(phen)2(H2O)]2 [GeMo12O40(VO)2]}·3H2O (2) and {[Co(phen)2]2[PMo12O40(VO)2]}{[Co(phen)2(OH)]2 [PMo12O40(VO)2]}·2.5H2O (3) (phen=1,10-phenanthroline). These three compounds present, as building blocks, the bicapped Keggin anions [XMo12O40(VO)2] (X=Si, Ge and P). Compound 1 consists of a bicapped Keggin anion [SiMo12O40(VO)2]2− linked to two [Cu(phen)]+ complexes with two [Cu(phen)2]+ countercations. Compound 2 contains two bicapped Keggin anions [GeMo12O40(VO)2]4−, one…
Synthesis and coordinating ability of an anionic cobaltabisdicarbollide ligand geometrically analogous to BINAP.
2004
The anionic chelating ligand [1,1'-(PPh 2 ) 2 -3,3'-Co(1,2-C 2 B 9 H 1 0 ) 2 ] - has been synthesized from [3,3'-Co(1,2-C 2 B 4 H 1 1 ) 2 ] - in very good yield in a one-pot process with an easy work-up procedure. The coordinating ability of this ligand has been studied with Group 11 metal ions (Ag, Au) and with transition-metal ions (Pd, Rh). The two dicarbollide halves of the [1,1'-(PPh 2 ) 2 -3,3'-Co(1,2-C 2 B 9 H 1 0 ) 2 ] - ligand can swing about one axis in a manner analogous to the constituent parts of BINAP and ferrocenyl phosphine derivatives. All these ligands function as hinges, with the most important property in relation to the coordination requirements of the metal being the P…
Increasing the nuclearity and spin ground state in a new family of ferromagnetically-coupled {Ni10} disk-like complexes bearing exclusively end-on br…
2018
The synthesis of a new family of ferromagnetically-coupled {Ni10} clusters counterbalanced by various [Ln(NO3)5]2− ions is herein described. The resulting compounds are organic chelate-free and the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology reminiscent of the structure of the brucite mineral.
Combination of ozonation and photocatalysis for purification of aqueous effluents containing formic acid as probe pollutant and bromide ion
2014
The treatment by advanced oxidation processes (AOPs) of waters contaminated by organic pollutants and containing also innocuous bromide ions may generate bromate ions as a co-product. In the present work heterogeneous photocatalysis and ozonation have individually been applied and in combination (integrated process) to degrade the organic compounds in water containing also bromide anions. The results show that: i) the sole photocatalysis does not produce bromate ions and in the case of its presence, it is able to reduce bromate to innocuous bromide ions; ii) the integration of photocatalysis and ozonation synergistically enhances the oxidation capabilities; and iii) in the integrated proces…
A unique microstructure of the fiber networks deposited from foam-fiber suspensions
2015
Abstract Fiber networks can be formed using aqueous foam as the suspending medium. The mean bubble size of the foam affects the resulting pore-size distribution of the fiber network. The foam–fiber interactions cause in particular an increase in the proportion of large micropores of the network, in comparison with the fiber networks that result from traditional water forming at a similar material density. Experiments were carried out for two different types of cellulose fiber, and characterization of the resulting pore structure was based on X-ray microtomography of the resulting fiber networks. The unique pore structure obtained with foam forming was reflected in various macroscopic proper…
A multifuctional nanoplatform for drug targeted delivery based on radiation-engineered nanogels
2020
Abstract Under a rational design, combining biologically active molecules, ligands to specific cell receptors and fluorescent, radioactive or paramagnetic labels into a single nano-object can bridge the unique properties of the individual components and improve conventional sensing, imaging and therapeutic efficacies. The validation of these functional nano-objects requires careful testing both in terms of physico-chemical properties and biological behaviour in vitro and in vivo, prior to translation into the clinic. Ionising radiation of aqueous polymer solutions is a viable strategy to produce multifunctional nanogels from aqueous solutions of hydrophilic polymers. By proper selection of …
Influence of metal ions on thermal aggregation of bovine serum albumin: aggregation kinetics and structural changes
2009
Metal ions are implicated in protein aggregation processes of several neurodegenerative pathologies. In this work the effects of Cu(II) and Zn(II) ions on heat-induced structural modifications of bovine serum albumin (BSA) were studied, with the aim of delineating the role of these ions in the early stages of proteins aggregation kinetics. A joint application of different techniques was used. The aggregate growth was followed by dynamic light scattering measurements, whereas the conformational changes occurring in the protein structure were monitored by Raman and IR spectroscopy. Both in absence and in presence of metal ions, heating treatment gave rise to b-structures to the detriment of a…