resumo
Kinetic parameters for three anion exchange reactions - Zn-LDH-NO3 -> Zn-LDH-Cl, Zn-LDH-NO3 -> Zn-LDH-SO(4)and Zn-LDH-NO3 -> Zn-LDH-VOx- were obtained byin situsynchrotron study. The first and the second ones are two-stage reactions; the first stage is characterized by the two-dimensional diffusion-controlled reaction following deceleratory nucleation and the second stage is a one-dimensional diffusion-controlled reaction also with a decelerator nucleation effect. In the case of exchange NO3--> Cl(-)host anions are completely released, while in the case of NO3--> SO(4)(2-)the reaction ends without complete release of nitrate anions. The exchange of Zn-LDH-NO3 -> Zn-LDH-VO(x)is a one-stage reaction and goes much slower than the previous two cases. The latter is characterized by a one stage two-dimensional reaction with an instantaneous nucleation. As a result, at the end of this process there are two crystalline phases with different polyvanadate species, presumably V(4)O(12)(4-)and V2O74-, nitrate anions were not completely released. The rate of replacing NO(3)(-)anions by guest ones can be represented as Cl-> SO42-> VOxy-.
palavras-chave
LAYERED DOUBLE HYDROXIDES; CRYSTAL-STRUCTURE; PHASE-CHANGE; HYDROTALCITE; ANIONS; RESISTANCE; CONVERSION; NANOSHEETS; CATALYSTS; KINETICS
categoria
Chemistry; Physics
autores
Iuzviuk, MH; Bouali, AC; Serdechnova, M; Yasakau, KA; Wieland, DCF; Dovzhenko, G; Mikhailau, A; Blawert, C; Zobkalo, IA; Ferreira, MGS; Zheludkevich, ML
nossos autores
Aliaksandr Mikhailau
Estudante de doutoramento
Kiryl Yasakau
Investigador Auxiliar
Mário Guerreiro Silva Ferreira
Professor(a) Jubilado(a)agradecimentos
We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at PETRA III under the proposal number I-20170366. We would like to thank Dr Sergey Volkov for assistance in using the diffractometer in P08 high-resolution diffraction beamline. M. H. I. and A. C. B. are grateful for the financial support of the German-Russian Interdisciplinary Science Center (G-RISC) in form of a travel grant (T-2018b-1 and T-2018a-3 respectively) that enables them to perform a scientific exchange and complete this work. K. Y. thanks financial support of a researcher grant (IF/01284/2015) and both K. Y. and M. G. S. F. thank the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. M. S. and M. L. Z. are thankful to I2B fond for financial support of this work in frame of MUFfin project as well as the ACTICOAT project (Era.Net RUS Plus Call 2017, Project 477).