Estudo da retenção de cromo em alumina, gibbsita e aluminossilicatos e avaliação dos processos de lixiviação

Abstract

There are descriptions of various processes which can promote the elimination of the heavy metal ions present on aqueous waste. Most of those processes relays on the use of precipitating agents, such as hydroxides or sulfides. However these methods are open tocriticism since they generated by themselves more solid wastes and there is no such thing as a totally insoluble salt. Other methods employ solid phases that can retain the ions trough adsorption or ion exchange mechanisms. There are, for instance, various reports describingthe use of zeolites, aluminosilicates etc., on those retention processes with very significant results. Herein we report the study of the retention of the ion chrome by alumina, gibbsite, a commercial molecular sieves and kaolinite, an aluminosilicate found on the nature, using different conditions of concentration chromium in solution, temperature and contact time, complemented with studies on the discharge of the ion from these materials. Though the inner nature of the retention processes needs further experiments to be clarified, molecular sieves and gibbsite proved to be the most successful phase for the retention of the ion chrome due the almost absolutely ratio of the retention theirselves andtheir high resistance against leaching processes.