摘要：

Cellulose and sugarcane bagasse were used in the preparation of new chelating materials for adsorption of heavy metals. Physical and chemical modifications were accomplished in those biopolymers aiming the preparation of materials able to adsorb heavy metals as lead, cadmium, copper and chromium. Those modifications include the non-mercerization of cellulose and sugarcane bagasse and the treatment of mercerized and mercerized materials with succinic anhydride for the introduction of carboxylic acid functions. Then, those acid functions were modified with triethylenetetramine, as a polydentate ligand, to anchor amine groups to the materials. Those amine groups were quaternized using methyl-iodide to obtain quaternary ammonium groups.Mercerization effects were evaluated by x-ray diffraction, FTIR and TGA-DTA. The materials obtained by chemical modifications were characterized by FTIR, TGA-DTA and elemental analysis of C, H and N. Mass gains and the concentrations of introduced acid and basic functions were calculated.Compared to succinylated non-mercerized cellulose and sugarcane bagasse, succinylated mercerized cellulose and sugarcane bagasse showed an increase of 7.1 and 12.1% in the mass gain and 0.4 and 0.2 mmol/g in the concentration of carboxylic acid functions respectively.Compared to succinylated non-mercerized cellulose and sugarcane bagasse modified with triethylenetetramine, succinylated mercerized cellulose and sugarcane bagasse modified with triethylenetetramine showed an increase of 13.7 and 5.1% in the mass gain and 0.8 and 0.3 mmol/g in the concentration of amine functions respectively.One of the materials containing amine groups was quaternized in order to prepare a material containing quaternary ammonium groups capable of accomplishing anionic exchange.The chelating materials obtained were used in studies of adsorption and their maximum adsorption capacities were evaluated by Langmuir model and compared.Compared to succinylated non-mercerized cellulose and sugarcane bagasse, succinylated mercerized cellulose and sugarcane bagasse showed an increase in adsorption capacity of 32.6 and 83.3 mg/g of Pb2+, 16.3 and 43.6 mg/g of Cd2+, 17.5 and zero mg/g of Cu2+, respectively. Thus, it is proven the efficiency of mercerization in the preparation of materials with greater power of adsorption.

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