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Products of the reaction between dialdehyde starch and Y-NH2 compounds (e.g. semicarbazide or hydrazine) are effective ligands for metal ions. The usefulness of these derivatives was tested in the experiment, both in terms of the immobilization of heavy metal ions in soil and the potential application in phytoextraction processes. The experimental model comprised maize and the ions of such metals as: Zn(II), Pb(II), Cu(II), Cd(II), and Ni(II). The amount of maize yield, as well as heavy metal content and uptake by the aboveground parts and roots of maize, were studied during a three-year pot experiment. The results of the study indicate the significant impact of heavy metals on reduced yield and increased heavy metal content in maize. Soil-applied dialdehyde starch derivatives resulted in lower yields, particularly disemicarbazone (DASS), but in heavy metal-contaminated soils they largely limited the negative impact of these metals both on yielding and heavy metal content in plants, particularly dihydrazone (DASH). It was demonstrated that the application of dihydrazone (DASH) to a soil polluted with heavy metals boosted the uptake of Zn, Pb, Cu, and Cd from the soil, hence there is a possibility to use this compound in the phytoextraction of these metals from the soil. Decreased Ni uptake was also determined, hence the possibility of using this compound in the immobilization of this metal. The study showed that dialdehyde starch disemicarbazone was ineffective in the discussed processes.

Environmentally friendly method of the preparation of dialdehyde starch (DAS) based composites containing nanosilver (DAS/Ag) and nanogold (DAS/Au) as reducing and protecting agents was developed. UV-vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed formation of about 10nm ball shaped Ag and Au nanoparticles situated within the polysaccharide template. Thermal properties of the composites were characterized involving differential scanning calorimetry (DSC), whereas molecular weights of polysaccharide chains of the matrix were estimated with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Formation of nanosilver and nanogold containing composites led to induction of the polymerization and/or crosslinking reactions of DAS molecules, resulting in a significant rise of molecular weight of polysaccharide chains constituting DAS/Ag and DAS/Au composite templates., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

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Abstract: Prior to the oxidation with iodate(VII), potato starch was 24h illuminated with linearly polarized visible light. The illumination provided starch dialdehyde of higher aqueous solubility and much higher susceptibility to enzymatic hydrolysis with glucoamylase. It could be rationalized in terms of the effect of illumination on the macrostructure of starch granules as shown with scanning electron microscope (SEM) and X-ray powder diffraction (XRD) studies. [Copyright &y& Elsevier]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Dialdehyde starch (DAS) of degree of oxidation (DO) of 1.5% (DAS1-5), 5% (DAS5), 15% (DAS15) and 25% (DAS25) was prepared from potato starch in the periodate oxidation reaction with electrochemical recovery of the oxidant. Molecular weights (M w) and radii of gyration (R g) of polysaccharide chains of native and oxidized starches were measured by means of a high-performance size exclusion chromatography coupled with multiangle laser light scattering and refractive index detectors. The weight average molecular weight (M w) and radius of gyration (R g), calculated for the whole complicated peak of the eluate of native starch were 30.0×106 and 119.6nm, respectively. The oxidation induced instant degradation of starch polysaccharide chains. M w value of the chains of the polysaccharide molecules eluted from the sample of DO 1.5% (DAS1-5, 2.2×106) was by one order lower than the average molecular weight of native starch molecules (30×106). Even more significant decrease in molecular weight up to 6.4×104 was observed for the DAS5 sample. The chain length distribution of amylopectin structural units of native and DAS was characterized by the hydrolysis with isoamylase followed by treatment with β-amylase. Chain distribution profiles of completely debranched samples were available from a high-pressure size exclusion chromatography with multiangle laser light scattering and refractometric index detectors. The oxidation slightly changed the average molecular weight (M w) of the A-type chains although it evoked changes in the mass ratio of the A-type chains. The weight average molecular weight M w and mass ratio of B-type chains significantly differed depending on DO of the sample. X-ray diffraction patterns indicated that crystallinity of DAS1-5 and DAS5 decreased in relation to native starch. Oxidised starches of the highest DO were fully amorphous. [Copyright &y& Elsevier]

Dialdehyde starch (30%) from periodate-oxidized potato starch was converted into its dioxime (DASOX). The dioxime was coordinated to the Ca, Cd, Co (II), Cu (II), Fe (II), Mg, Mn (II), Ni (II), Pb (II), and Zn ions. Particular metal ions were chelated to a different extent. In the complexes, one mole of a metal ion was coordinated on from 9 to 80 moles of the DASOX units. Similarly as pure DASOX, the metal complexes decomposed thermally in four steps. The coordination to all metal ions except Fe (II) increased temperature of the thermal decomposition and, except Cu (II), they also increased the rate of the first decomposition stage. After coordination the ligand decomposed more profoundly than in the free stage. Computational simulations pointed to the nitrogen atoms of the dioxime C&z.dbnd6;N moiety and the oxygen atom of the former pyranose ring as the coordination sites. [Copyright &y& Elsevier]

The Ca, Cd, Co (II), Cu (II), Fe (II), Mg, Mn (II), Ni (II), Pb (II), and Zn complexes of starch dialdehyde dithiosemicarbazone (DASTSC) of 14% oxidation were prepared and characterised. Based on the measured magnetic susceptibility for the Co (II) complex the low-spin character is ascribed to these complexes. The nitrogen atoms of the C&z.dbnd6;N moiety as well as the sulphur atoms of the C&z.dbnd6;S moiety are accepted as the coordination sites for the central metal atoms. Thermal analysis pointed two thermal effects on heating DASTSC up to its decomposition. The thermograms of DASTSC complexes contained three thermal effects in the same temperature region. One mole of a metal ion could coordinate with 1.1–65.4 mole of the ligand. [Copyright &y& Elsevier]

Abstract: Dialdehyde starch obtained by periodate oxidation from potato starch was converted into its disemicarbazone (DSC), dithiosemicarbazone (DTSC), dihydrazone (DHZ) and dioxime (DOX). The Cu(II) complexes of these compounds were prepared and characterized by Raman and EPR spectra, as well as by the measurements of magnetic susceptibility. EPR investigations showed that two types of complexes with different surroundings of copper centres existed in each starch derivative. Besides nitrogen atoms of the Cand sulphur atoms of the C also oxygen atoms from starch hydroxyl groups and/or water molecule were proposed as the coordination sites for the central copper ions. [Copyright &y& Elsevier]