Authors:Edson C. da Silva Filho, Pedro D. R. Monteiro, Kaline S. Sousa, and Claudio Airoldi
In this work Chitosan (Ch) was chemically modified with ethylenesulfide (Es) under solvent-free conditions to give (ChEs), displaying a high content of thiol groups due to opening of the three member cyclic reagent. ChEs was used in studies of lead and cadmium adsorption from aqueous solution, using the batchwise method and calorimetric studies were accomplished to those interactions, through the calorimetric titration technique. The obtained results show that the modified Ch, ChEs is a material, that besides presenting the advantages of being a biopolymer, it showed a good adsorption capacity of the lead and cadmium cation metallic, that are extremely poisonous and harmful to the environment. The results of the calorimetric titration showed that the related thermodynamic parameters to those adsorptions shown favorable thermodynamic data.
Authors:Edson da Silva Filho, Sirlane Santana, Júlio Melo, Fernando Oliveira, and Claudio Airoldi
Cellulose was chemically modified with SOCl2 to obtain chlorodeoxycellulose, followed by a reaction that gave bonded ethylene-1,2-diamine (en), producing 6-(2′-aminoethylamino)-6-deoxycellulose.
The reactions were carried out without the presence of solvent, in water or in N,N′-dimethylformamide, in which the highest amount of amino compound was incorporated onto the biopolymer backbone. The X-ray
diffraction patterns for the chlorodeoxycellulose indicate new crystallinities that result from hydrogen bonds established
through bonded chorine atoms and the remaining hydroxyl groups, while all the aminodeoxycelluloses were amorphous compounds.
Thermal stabilities, for all aminated celluloses gave lower final mass losses than for the chlorinated biopolymer, whose value
is lower than unmodified cellulose.