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ANALYSIS OF CHELATING CAPACITY OF LIGNIN FROM SUGARCANE STRAW
Engineering School of Lorena, University of São Paulo, Lorena - USP

Marcondes, W. F.; Gonçalves, A. R. e-mail: [e-mail]

ABSTRACT
Although 70% of the surface of our planet is covered with water, less than 3% is freshwater, that 65% is suitable for human direct consumption. The shortage of this precious liquid is real in several regions of the world. In recent years, the chelating agents have been extensively investigated due to their behavior as sequestrant agent of metal ions present in aqueous solutions. Among the substances that have a high chelating capacity, lignin highlights because of the presence in its structure of coordinating atoms with metal ions.

OBJECTIVE
The objective of the present work was to study the interaction between the sugarcane straw lignin and ion Cu2+ atoms in ammonia hydroxide medium

-Equation that represents variation of the concentration of ammonium hydroxide (2 to 5% v / v) in 0.01 M solution of copper sulphate Abs. = 0,01153 [hydroxide] + 0,53695 -Equation that represents variation of the concentration of copper sulphate (0.004 to 0.01M) in a solution 3% v / v ammonium hydroxide. Abs. = 53,98754 x [Cu] + 0,00534 -Equation that represents variation of the concentration of copper sulphate (0.004 to 0.01M) in a solution 3% v / v ammonium hydroxide and lignin 0,004 g / L. Abs. = 55,05113 x [Cu] + 0,00101 -Equation that represents variation of the concentration of copper sulphate (0.004 to 0.01M) in a solution 3% v / v ammonium hydroxide lignin and 0.02 g / L. Abs. = 54,70262 x [Cu] + 0,00998 Tests were carried out varying the concentration of ammonium hydroxide, while maintaining fixed concentration of lignin, and there are no significant difference in absorbance reading.

METHODOLOGY
- Obtaining lignin Sugarcane straw Alkaline/AQ pulping NaOH 4 % (w/v) solid/liquid rate1:7,5 (w/v) e antraquinone 0,15 % (w/v), 1 h 100°C. concentrated sulfuric