Bismuth Oxide Carbonate Structures Synthesized by Microwave—Assisted Solvothermal Approach and Its Use as Catalyst for the Degradation of Azo Dye in a Solution

Because the textile industry wastewater is polluted with azo dyes, and in order to improve a process of wastewater remediation, the synthesized sample was evaluated in the photocatalysis of methylene blue and compared with commercial Bi2O3 and anatase TiO2. Structures of bismuth oxide carbonate (Bi2O2CO3) were successfully synthesized using a solution at 0.03 M concentration of sodium bismuthate as precursor and ethylene glycol as dissolvent by solvothermal microwave-assisted approach. The semiconductor catalyst samples were characterized by X-ray diffraction (XDR), scanning electron microscope (SEM) and Brunauer-Emmett-Teller analysis (BET). The application of the synthesized sample as catalyst, obtained a 68% of degradation. This result is better than the commercial Bi2O3 and close to the anatase TiO2 degradation. This sample shows a variation in the formula (with the presence of carbonates) but also shows an acceptable degradation percentage according to TiO2 results, making Bi2O2CO3 a possible substitute of TiO2.

Europium recovery process by means of polymeric nanoparticles functionalized with acrylic acid,curcumin and fumaramide

Polymeric nanoparticles of poly(methyl methacrylate)were obtained by emulsion polymerization techniques in a proce ss of two stages.The particles were functionalized with acrylic acid,curcumin,and fumaramide and three series of polymeric particles were obtained.The incorporation of functional groups was confirmed by Fourier transform-infrared spectrosocopy(FT-IR)and ultraviolet-visible(UV-Vis)methods.The spherical morphology of particles with an average diameter of 100 nm was observed by scartning electron microscopy(SEM).The polymeric materials were used for recovery of[Eu]from synthetic solutions.The nanoparticles show excellent chelation capacity to trap rare-earth ions,because they recover more than 85%of[Eu]at pH of 2.The images of SEM after extraction process show arrays between particles with larger average particle sizes to 1.5 um.In addition,the particles have a good stripping capacity,exceeding 50%of it,maintaining their homogeneity in morphology and good stability in dispersion for the recovery and stripping processes.A pseudo-second model order is obtained for the extraction and stripping processes while the best results of stripping process are obtained at pH of 6.

Synthesis of advanced ceramics by hydrothermal crystallization and modified related methods

The present article aims to give a brief overview about the advantages of the hydrothermal crystallization method for the synthesis of advanced ceramics.Emphasis is given,not only on the conventional hydrothermal crystallization,but also on some of its variants;such as ultrasound-assisted,electrochemical-assisted,microwave-assisted and surfactant-assisted hydrothermal methods which open up new opportunities for the synthesis of ceramic materials with novel properties demanded for advanced applications.In the current work the synthesis of barium titanate(BaTiO3),lithium metasilicate(Li2SiO3)and sodium-potassium niobate(Na,K)NbO3 powders are reported as cases of study.

Mixed-conducting ceramic–carbonate membranes exhibiting high CO2/O2 permeation flux and stability at high temperatures

This investigation demonstrates the feasibility to fabricate high quality ceramic–carbonate membranes based on mixed-conducting ceramics.Specifically,it is reported the simultaneous CO2/O2 permeation and stability properties of membranes constituted by a combination of ceramic and carbonate phases,wherein the microstructure of the ceramic part is composed,in turn,of a mixture of fluorite and perovskite phases.These ceramics showed ionic and electronic conduction,and at the operation temperature,the carbonate phase of the membranes is in liquid state,which allows the transport of CO32-and O2–species via different mechanisms.To fabricate the membranes,the ceramic powders were uniaxially pressed in a disk shape.Then,an incipient sintering treatment was carried out in such a way that a highly porous ceramic was obtained.Afterwards,the piece is densified by the infiltration of molten carbonate.Characterization of the membranes was accomplished by SEM,XRD,and gas permeation techniques among others.Thermal and chemical stability under an atmosphere rich in CO2 was evaluated.CO2/O2 permeation and long-term stability measurements were conducted between 850 and 940℃.The best permeation–separation performance of membranes of about 1 mm thickness,showed a maximum permeance flux of about 4.46×10^–7 mol·m^–2·s^–1·Pa^–1 for CO2 and 2.18×10^–7 mol·m^–2·s^–1·Pa^–1 for O2 at 940℃.Membranes exhibited separation factor values of 150–991 and 49–511 for CO2/N2 and O2/N2 respectively in the studied temperature range.Despite long-term stability test showed certain microstructural changes in the membranes,no significant detriment on the permeation properties was observed along 100 h of continuous operation.