Novel water-soluble polymers, N-(g-propanoyl-valin)-chitosan and N-(g-propanoyl-aspartic acid)-chitosan, were synthesized by reaction of low molecular weight chitosan with N a -(3-bromopropanoyl)-valine and N a -(3-bromopropanoyl)-aspartic acid, respectively, under mild conditions. Prior to reaction with chitosan, the peptide substituents have been prepared by standard peptide chemistry methods from 3-bromopropanoic acid and the relevant a-amino acid tert-butyl esters. The chemical structure and physical properties of the novel chitosan derivatives were characterized by 1 H NMR and IR spectroscopy. The polymers are highly soluble in a wide pH range, which opens new perspectives for the applications of chitosan-based materials. q

Water-soluble peptide-chitosans were obtained by reaction of low-molecular-weight chitosan, having a low degree of acetylation, with peptide substituents under mild conditions. These peptide substituents were prepared by standard peptide chemistry from 3bromopropanoic acid and tert-butyl esters of the a-amino acids glycine and phenylalanine. The structure of the new peptide-chitosan polymers was confirmed by proton nuclear magnetic resonance and infrared spectroscopy. The thermotropic and morphological properties of both the new peptide-chitosans and two other analogues, derived from valine and aspartic acid [synthesis reported in

In the present study, a novel porous carbon obtained by K 2 CO 3 activation of potato peel waste under optimized conditions was applied for the first time as liquid-phase adsorbent of sodium diclofenac in parallel with a commercial activated carbon. The biomass-activated carbon presented an apparent surface area of 866 m 2 g -1 and well-developed microporous structure with a large amount of ultramicropores. The obtained carbon presented leaching and ecotoxicological properties compatible with its safe application to aqueous medium. Kinetic data of laboratorymade and commercial sample were best fitted by the pseudo-second-order model. The commercial carbon presented higher uptake of diclofenac, but the biomass carbon presented the higher adsorption rate which was associated with its higher hydrophilic nature which favoured external mass transfer. Both adsorbents presented adsorption isotherms that were best fitted by Langmuir model. The biomass carbon and the commercial carbon presented adsorption monolayer capacities of 69 and 146 mg g -1 , and Langmuir constants of 0.38 and 1.02 L mg -1 , respectively. The better performance of the commercial sample was related to its slightly higher micropore volume, but the most remarkable effect was the competition of water molecules in the biomass carbon.