Solar photocatalytic degradation of polyethylene terephthalate nanoplastics: Evaluation of the applicability of the TiO2/MIL-100(Fe) composite material

For the first time, TiO2/MIL-100(Fe) photocatalysts supported on perlite mineral particles prepared by the solvothermal/microwave methods and post-annealing technique were tested in the degradation of polyethylene terephthalate nanoplastics (PET NPs). Powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, N2 physisorption, photoluminescence emission spectroscopy, photocurrent response, and electrochemical impedance spectroscopy were used to characterize the as-prepared materials. The response surface methodology approach was used to study the effects: pH of the NPs suspension and incorporated amount of MIL-100(Fe) on the TiO2/MIL-100(Fe) catalyst to optimize the photocatalytic degradation of the PET NPs under simulated solar light. The degradation of the PET NPs was evaluated by measuring turbidity and carbonyl index (FTIR) changes. The total organic carbon (TOC) in the solution during the degradation of the PET NPs was assessed to measure NPs oxidation into water-soluble degradation by-products. The active species involved in the photocatalytic degradation of PET NPs by the TiO2/MIL-100(Fe) composite was further examined based on trapping experiments. The use of 12.5 wt% TiO2/MIL-100(Fe) catalyst showed improved photocatalytic efficacy in the oxidation of PET NPs at pH 3 under simulated sunlight compared to bare TiO2. The increase in the carbonyl index (CI = 0.99), the reduction in the turbidity ratio (0.454), and the increase in the content of TOC released (3.00 mg/L) were possible with 12.5 wt% TiO2/MIL-100(Fe) material. In contrast, the PET NPs were slowly degraded by TiO2-based photocatalysis (CI = 0.96, turbidity ratio = 0.539, released TOC = 2.12 mg/L). The mesoporous TiO2/MIL-100(Fe) composites with high specific surface area, capacity to absorb visible light, and effective separation of photogenerated electron-hole charges clearly demonstrated the enhancement of the photocatalytic performance in the PET NPs degradation under simulated solar light

[Futbolistas asturianos XXIV] [Material gráfico]

Contiene fotografías pertenecientes al archivo fotográfico del diario "Región", publicadas hacia 1964Algunas fotos no indican autoría; el resto firmadas por Foto E. Gar (Oviedo), Foto Arsenio (Trubia, Oviedo), Foto Sierra (Oviedo), Foto Longoria (Grado), Antonio Rodríguez Fernández (Carbayín, Siero

Enzymatic oligomerization and polymerization of arylamines: state of the art and perspectives

The literature concerning the oxidative oligomerization and polymerization of various arylamines, e.g., aniline, substituted anilines, aminonaphthalene and its derivatives, catalyzed by oxidoreductases, such as laccases and peroxidases, in aqueous, organic, and mixed aqueous organic monophasic or biphasic media, is reviewed. An overview of template-free as well as template-assisted enzymatic syntheses of oligomers and polymers of arylamines is given. Special attention is paid to mechanistic aspects of these biocatalytic processes. Because of the nontoxicity of oxidoreductases and their high catalytic efficiency, as well as high selectivity of enzymatic oligomerizations/polymerizations under mild conditions-using mainly water as a solvent and often resulting in minimal byproduct formation-enzymatic oligomerizations and polymerizations of arylamines are environmentally friendly and significantly contribute to a "green'' chemistry of conducting and redox-active oligomers and polymers. Current and potential future applications of enzymatic polymerization processes and enzymatically synthesized oligo/polyarylamines are discussed

Estudio electroquímico de la reacción de litio con fases tipo Aurivillius y Sillen

Algunas fases tipo Aurivillius y Sillen han sido probadas como electrodos positivos para baterías secundarias a través de un estudio electroquímico. Se ha llevado a cabo un estudio electroquímico y estructural de la reacción con litio de las fases más representativas de los sistemas Bi2O3-WO3, Bi2O3- MoO3 y Bi2O3-Nb2O5. Aunque la cantidad de litio incorporado en todos lo casos fue grande, debido a la transformación irreversible de la matriz de la fase anfitrión, la capacidad específica de las celdas se perdió abruptamente después del primer ciclo. Con base en los datos de difracción de rayos-X in situ de las fases litiadas, se propone un mecanismo de reacción. Some Aurivillius and Sillen phases have been tested as positive electrode materials for secondary lithium batteries through an electrochemical study. We have carried out an electrochemical and structural study of the lithium reaction with some of the most representative phases of the Bi2O3-WO3, Bi2O3- MoO3, and Bi2O3-Nb2O5 systems. Although the amount of lithium atoms incorporated in all cases was large, due to irreversible structural transformations in the matrix of the host, specific capacity of the cells was dramatically lost after the first cycle. On the basis of in situ X-ray diffraction data of lithiated phases, we propose a reaction mechanism