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The intercalation of amphoteric amino acid tyrosine (Tyr) into LDH by co-precipitation method was systematically studied. The influence of initial molar ratios (R) of LDH to Tyr has also been examined. Powder X-ray diffraction, Fourier transform infrared spectroscopy, specific surface areas and pore size distributions, and thermal analysis have been employed for the characterization of the nanocomposites. The nanohybrids were found to have an expanded layered structure except the samples prepared with low R values, indicating that the biomolecules were intercalated into the gallery as anions. The intercalation of amino acids resulted in the increase of the surface areas and pore volumes, and the value of surface areas and pore volumes increased with enhancement of biomolecules intercalated. TEM analysis revealed that with increasing biomolecules into the gallery, the nanohybrids were changed from hexagonal particles to spherical ones. Moreover, the configuration of Tyr anions was varied under different R values, changed from monolayer to bilayers with more biomolecules intercalating into the gallery.

A series of mixed MgAl-HTlc, Mg 12x Al x -NO 3 -HTlc (where X 5 M(III)/(M(III)1 M(II)) 5 1/3 in the starting solution) were prepared following the coprecipitation method at a constant pH under different synthesis temperatures. Their structural, textual and rheological properties were examined respectively. It is found from the results that the increase of the synthesis temperature will increase the interlayer spacing of the layered compounds, but under the room temperature, the sample shows the best crystallinity. Nitrogen adsorption isotherms were used to determine the surface areas and pore structure of these compounds, and the effect of the synthesis temperature on the surface characteristics is discussed. It is thought that the microporosity was related to the treatment temperature, and most of the samples contain large amount of micropores about 1.5 nm. The results of the hydrated diameters showed that all the samples are polydispersity, but flocculation occurred in the samples, which were prepared under higher temperatures. The flow curve of the suspension showed that the samples, which were prepared under relatively low temperatures, behaved as Newton-like behavior with a slight shear -thickening, whereas the flow curves of the other samples, which were prepared under higher temperatures, are shear-thinning, typical behavior of the flocculated system. The result of the rheology is accordant with the results of the hydrated diameters, the coagulation suspension showed the non-Newton flow behavior, whereas the other suspensions showed the Newton-like flow.Keywords Hydrotalcite-like compounds, temperature effect INTRODUCTIONHydrotalcite-like compounds (HTlc) belong to a large class of anionic and basic clays, also known as layered double hydroxide. They are composed of positively charged brucite-like [Mg(OH) 2 ] layers with trivalent cations substituting for divalent cations at the centers of octahedral sites of hydroxide sheets whose vertexes contain hydroxide ions, and each OH 2 group is shared by three octahedral cations and points toward the interlayer regions. [1] The excess positive charges of HTlcs are compensated by interlamellar anions. Although, in principle, any anion could be placed in the interlamellar space, carbonates are the anions commonly found in naturally occurring materials. They can be represented by the general formula [M II