Disolución

Se habla de una disolución acuosa (aq o ac) siempre que el disolvente (o el disolvente mayoritario, en el caso de una mezcla de disolventes) es agua. El agua como disolvente es muy polar y forma puentes de hidrógeno muy fuertes.

Las disoluciones acuosas tienen una gran importancia en la biología, desde los laboratorios de ciencia básica hasta la química de la vida, pasando por la química industrial. Por la vasta cantidad y variedad de sustancias que son solubles en agua, esta se denomina a veces disolvente del milenio.

Los compuestos iónicos como el cloruro de sodio, son los más solubles en agua, mientras que los compuestos covalentes suelen ser tan poco solubles como los metales insolubles.

Abstract

The lignin is a macromolecule of vegetable origin, formed by units of phenilpropane. The pulp process for the

production of paper modifies the lignin structure generating different types of pollutant residues. Some

technologies and methodologies have been used for avoiding formation or to eliminate, but without good

results, this work proposed the use of Advanced Oxidation Processes (PAO). Different conditions of

oxidation were used as: UV/H2O2, UV/O3 and UV/H2O2/O3, to modify the lignin using a photoreactor type

batch with capacity of a liter and equipped with a lamp UV of 1000 W. Used two concentrations of lignin

(0.025 % and 0.05 %). Analized the value of the chemical oxygen demand (DQO), before and after the

treatment. For the system light UV/H2O2 with lignin to 0.025 %, the DQO diminished of 323 mg l

-1

to 144

mg/l during the hour of treatment and with lignin to 0.05 % the DQO diminished 870 mg l

-1

to 175 mg l

-1

in

three hours of treatment. For the system light UV/H2O2/O3 with lignin to 0.025 %, the DQO diminished of

323 mg l

-1

to 127 mg l

-1

in an hour. For the concentration of 0.05 % the DQO diminished from 870 mg l

-1

to

52 mg l

-1

in three hours. For the system light UV/O3 with lignin to 0.025 %, the DQO diminished of 323 mg

l

-1

163 mg l

-1

in two hours. With these results we conclude that the system of oxidation used modified the

lignin in all the experiments. For that, the best conditions to transform the lignin was that of the system

UV/H2O2/O3 followed of UV/H2O2 and the system light UV/O3 had less efficiency, for this needing more time

to obtain approximately the same quantity of transformation of this compound. These results open the

possibility of using this system to eliminate lignin or by-products in the paper industry.

Key words: Advanced Oxidation Processes, photooxidation, lignin, macromolecule.

Resumen

La lignina es una macromolécula de

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