The intercalation of organic anions, namely acrylate, methacrylate, 2-acrylamido-2-me thyl-1-propanesulfonate (AMPS), 4-vinylbenzoate, and 4,4’-azobis(4-cyanopentanoate) into Mg-Al and Zn-Al layered double hydroxides (LDHs) was studied. The coprecipitated Mg-Al-NO 3 and Zn-Al-NO 3 hydrotalcite-like compounds with M II /Al molar ratio of 2 were used as precursors. The anion exchange and rehydration of calcined LDH precursors were applied for the intercalation. The anion exchange appeared to be the most effective method; all examined organicanions were intercalated successfully by this way both in Mg-Al and Zn-Al host structur es. The intercalated LDHs were us ed as comonomer and initiator for preparation o f LDH/polymethacrylate nanocomposites: mixture of monomer and LDHs intercalated with organic anions were dispersed in aqueous phase and then the emulsion polym erization was performed in the presence of inorganic (nano)particles to obtain polybutylmethacrylate hybrid latexes. Na nostructured hybrid materials containing a low amount (1 - 3 wt%) of inorganic nanofiller were prepared. Particles with size of 60 - 100 nm were detected by dynamic light scattering and small-angle X-ray scattering methods. Furthermore, a hydrophobization of LDH nanof illers with dodecylsulfate (DS) was tested in order to facilitate their dispersion in the polymer matrix. A minor part of AMPS anions was incorporated into Mg-Al-DS LDH during anion exchange in the aqueous solution containing AMPS. Us ing Mg-Al-DS LDH modified w ith AMPS, the nanocomposites were obtained by emulsion polymerization and also by the solution polymer ization in 1-methyl-2-pyrolidone., František Kovanda, Eva Jindová, Barbora Doušová, David Koloušek, Josef Pleštil and Zdeňka Sedláková., and Obsahuje bibliografické odkazy
Arsenic, antimony and selenium belong to toxic contaminants with high environmental risk. In contrast to metal cationic contaminants (Be, Zn, Cd, Hg Pb, etc.) the metalloids and nonmetals of groups 5 and 6 of periodic system generally form the oxyanions in two oxidizing states (i.e. arsenates and arsenites, antimonates and antimonites, as well as selenates and selenites) in dependence on redox potential and pH value. It is well known that above mentioned oxyanions have a strong adsorption affinity to hydrated oxides and/or oxides hydroxides of Fe, Al and Mn, preferably Fe forming stable surface complexes. In fact, commercially produced Fe oxides-based sorbents are too expensive for strongly contaminated aqueous systems. Aluminosilicates have opened new possibilities in sorption technology due to favourable surface properties, availability, environmental and economical reasons, but they are not selective sorbents of anionic contaminants thanks to a low pHZPC. A simple Fe/Al/Mn pre-treatment of raw aluminosilicates can significantly improve their sorption affinity to oxyanionic contaminants, including arsenites and arsenates, selenites and selenates and antimonites and antimonates, respectively. Different types of natural and/or second-rate clays (metakaolines with the large content of Fe, raw bentonites and natural clinoptilolite-rich tuff, ) from Central European localities were used for FeII, FeIII, AlIII and MnII pre-treatment., Barbora Doušová, Lucie Fuitová, Lenka Herzogová, Tomáš Grygar, David Koloušek and Vladimír Machovič., and Obsahuje bibliografii