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11.
In this work, the influence of CCl4 on the sonochemical decolorization of anthraquinonic dye Acid Blue 25 (AB25) in aqueous medium was investigated using high frequency ultrasound (1700 kHz). This frequency, reputed ineffective, was tested in order to introduce the ultrasound waves with high frequency in the field of degradation or removal of dyes from wastewater, due to its limited use in this field, and to increase the application of high frequency ultrasound wave in the field of environmental protection. The effects of various parameters such as the concentration of CCl4, frequency (22.5 and 1700 kHz), solution pH, temperature and tert-butyl alcohol adding on the decolorization rate of AB25 was studied. The obtained results clearly demonstrated the significant intensification of AB25 decolorization in the presence of CCl4. The enhancement effect of CCl4 increased by decreasing temperature and by increasing the CCl4 concentration. The pH has a significant influence on the bleaching of dye both in the absence and presence of CCl4. The three investigated dosimeter methods (KI oxidation, Fricke reaction and H2O2 production) well corroborate the improvement of the sonochemical effects in the presence of CCl4. The best sonochemical decolorization rate of AB25 in aqueous solution both in the absence and presence of CCl4 is observed to occur at 1700 kHz compared to 22.5 kHz. The sonochemical oxidation of CCl4 generates oxidizing species in the liquid phase that are highly beneficial for oxidation of hydrophilic and non-volatile pollutant, such as dyes, because they are less susceptible to free radical attack due to lower stability of the generated free radicals. 相似文献
12.
Samia Benmansour Fatima Setifi Smaïl Triki Franck Thétiot Jean Sala-Pala Carlos J. Gómez-García Enrique Colacio 《Polyhedron》2009
Reactions of CuCl2 with different CN complexes in presence of a neutral ancillary ligand lead to two novel mixed-valence Cu complexes [CuII(bpy)CuI(CN)3]n, 1 (bpy = 2,2′-bipyridine) and {[CuII(tn)2][CuI4(CN)6]}n2 (tn = 1,3-diaminopropane). For compound 1, the asymmetric unit involves two Cu ions Cu1 and Cu2 (CuI and CuII centres, respectively) which strongly differ in their environments. The Cu1 ion presents a CuC4 pseudo-tetrahedral geometry, while the Cu2 ion presents a CuN5 slightly distorted square-pyramidal geometry. The extended structure of 1 is generated by three cyano ligands which differ in their coordination modes. One CN group has a μ3 coordination mode and bridges two CuI and one CuII ion, while the two other CN groups act as μ2 bridges leading to a sophisticated 3-D structure. As for 1, the asymmetric unit of 2 involves three crystallographically different Cu ions (Cu1A and Cu1B, presumably CuI centres, and Cu2 presumably CuII centres). The Cu2 ion presents centrosymmetric CuN4 coordination environments involving four nitrogen atoms from two bidentate tn ligands; while the Cu1A and Cu1B ions are three coordinated to cyano groups. The structure can be described as formed by 18-membered “[CuI(CN)]6” planar metallocycles that are connected to their six neighbors to generate 2-D sheets; these sheets stack forming infinite hexagonal channels in which the [Cu(tn)2]2+ units are located. Magnetic measurements show an unexpected weak ferromagnetic coupling (θ = 0.239(1) K) of the CuII ions through the long and “a priori diamagnetic” –NC–CuI–CN– bridges in compound 1 and an essentially paramagnetic behavior in compound 2. 相似文献
13.
Hind A. Maouel Vronique Alonzo Thierry Roisnel Houria Rebbah Eric Le Fur 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(7):i36-i38
The title synthesized hypophosphite has the formula V(H2PO2)3. Its structure is based on VO6 octahedra and (H2PO2)− pseudo‐tetrahedra. The asymmetric unit contains two crystallographically distinct V atoms and six independent (H2PO2)− groups. The connection of the polyhedra generates [VPO6H2]6− chains extended along a, b and c, leading to the first three‐dimensional network of an anhydrous transition metal hypophosphite. 相似文献
14.
Laurent Cario Houria Kabbour Catherine Guillot‐Deudon Alain Meerschaut 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):i55-i56
Dilanthanum triniobium disulfide octaoxide, La2Nb3S2O8, crystallizes in the orthorhombic space group Pnnm and is isostructural with the Ln2Ta3X2O8 (Ln = La, Ce, Pr and Nd, and X = S and Se) family of tantalum compounds. Nb4+ and Nb5+ ions co‐exist in the structure and occupy different crystallographic sites. While the Nb4+ ions are found in mixed oxygen and sulfur octahedra, the Nb5+ ions are found in oxygen‐only octahedra. 相似文献
15.
Anjan Biswas Houria TrikiT. Hayat Omar M. Aldossary 《Applied mathematics and computation》2011,217(24):10289-10294
The generalized Burgers equation with generalized evolution is studied in this paper. The soliton ansatz is used to carry out the integration of this generalized Burgers equation. This study is then extended to 1+2 dimensions, even with full nonlinearity. 相似文献
16.
Yang Chunyu Zhou Qin Triki Houria Mirzazadeh Mohammad Ekici Mehmet Liu Wen-Jun Biswas Anjan Belic Milivoj 《Nonlinear dynamics》2019,95(2):983-994
Nonlinear Dynamics - Interactions of bright solitons in the Heisenberg ferromagnetic spin chain, governed by a $$(2+1)$$ -dimensional nonlinear Schrödinger equation with variable coefficients,... 相似文献
17.
18.
Chahlae Atmani Fatima El Hajj Samia Benmansour Mathieu Marchivie Smail Triki Françoise Conan Véronique Patinec Henri Handel Gaelle Dupouy Carlos J. Gómez-García 《Coordination chemistry reviews》2010,254(13-14):1559-1569
This review focuses on new families of spin crossover (SCO) complexes based on polynitrile anions as new anionic ligands or on polyazamacrocycles as neutral macrocyclic ligands. We have shown that the structural and electronic characteristics (original coordination modes and high electronic delocalization) of the polynitrile anions can be tuned by slight chemical modifications such as substitution of functional groups or variation of the negative charge to design new discrete or polymeric SCO systems.In our ongoing work on the design of new molecular systems based on new ligands that can be fine-tuned via chemical modifications, another promising way which has been recently developed in our group concerns the use of new neutral polydentate ligands which are able to tune the ligand field energy around the metal centre. Here we report some recent original Fe(II) SCO complexes based on such polydentate ligands. 相似文献
19.
Samia Benmansour Chahlae Atmani Fatima Setifi Smaïl Triki Mathieu Marchivie Carlos J. Gómez-García 《Coordination chemistry reviews》2010,254(13-14):1468-1478
The use of polynitrile anions as ligands (L) either alone or in combination with neutral co-ligands (L′) is a very promising and appealing strategy to get molecular architectures with different topologies and dimensionalities thanks to their ability to coordinate and bridge metal ions in many different ways. The presence of several potentially coordinating nitrile groups (or even other donor groups as –OH, –SH or –NH2), their rigidity and their electronic delocalization allow the synthesis of original magnetic high dimensional coordination polymers with transition metals ions. Furthermore, these ligands have shown coordinating and bridging capabilities in novel discrete and polymeric bistable materials (materials showing original magnetic behaviours or spin crossover (SCO) transitions). Here we report an overview of the results obtained with some of these modified polynitrile ligands, showing their rich coordination chemistry and their crucial role in new molecular materials exhibiting unusual magnetic transitions. 相似文献
20.
Hèla Hassairi Latifa Bousselmi Ezzeddine Triki 《Journal of Solid State Electrochemistry》2010,14(3):393-401
The purpose of this study is to establish reliable procedure reproducing the degradation processes that occurred on the archaeological artefacts before their excavation. Two simulating soil media are chosen, the first one (FJ) is made from archaeological soil filtrate and the second is a chloride- and/or sulphate-containing solution (CSJ) taken at the same soil amounts of aggressive ions. According to stationary studies, corrosion mechanism in CSJ medium is catalysed by the presence of chloride at the surface of tin bronze electrode, but sulphate products tend to stabilise the surface of bronze sample immersed in soil filtrate. In FJ, the trend of impedance spectra remains unchanged during the immersion period. Adjusted impedance parameters prove that passivation and depassivation can occur simultaneously on bronze surface with different expansion. In CSJ, impedance data evolve according to the immersion time. The evolution of adjusted parameters according to the immersion time describes well the surface state of the bronze sample. The corrosion process is more difficult while the metallic surface is covered with a bronze corrosion layer “patina” which explain the capacitance decreasing and the resistance increasing (after 50 days). Scanning electron microscopy observations coupled with energy-dispersive X-ray spectrometry analysis approve our electrochemical results. 相似文献