Potential of the hydrothermal carbonization process for the degradation of organic pollutants.

The degree of degradation of 12 organic compounds from various classes, comprising of pharmaceuticals, pesticides, and industrial chemicals, was analyzed after hydrothermal treatment at 200°C for 4 or 16h, or 255°C for 16h. The reactions were conducted in water, aqueous H2SO4, or sucrose solution in aqueous H2SO4 as a representative matrix of hydrothermal carbonization (HTC) of wet biomasses. The impact of the sucrose-matrix, which formed during the HTC reaction as a solid hydrochar material and a complex pattern of dissolved organic matter in the aqueous phase, was found to be insignificant for the degree of conversion of most compounds. On the contrary, the degree of degradation of 2,6-dinitrotoluene, 2-chloronaphthalene and 3-chlorobiphenyl was enhanced when biomass was present. At high temperatures most of the pollutants were converted except for ibuprofen and chlorinated aromatics. Hydrothermal treatment of ß-hexachlorocyclohexane and 4,4'-dichlorodiphenyltrichloroethane led to the formation of stable chlorinated aromatic intermediates.

Spatial structure of peptides determined by residual dipolar couplings analysis.

The gated decoupled (13)C NMR spectra of a dipeptide (Glu-Trp) and a tetrapeptide (NAc-Ser-Phe-Val-Gly-OMe) were recorded in D(2)O and in a lyotropic alignment medium (pentaethylene glycol monododecyl ether/n-hexanol). The residual dipolar couplings were extracted as the differences between the observed couplings for the magnetic nuclei dissolved in the latter and former media. Using a computational optimization, the spatial structures of the compounds were calculated starting from their respective low energy conformations obtained on a semiempirical basis. The uniformity of each conformation was confirmed by the solid-state (13)C NMR spectra of powder samples. Differences between the starting structures and final ones, optimized when employing residual dipolar couplings, are discussed.