Antonio Carlos Saraiva da Costa

Lixiviação de íons após a aplicação de resíduos orgânicos de uma indústria farmoquímica

In the last decades, increasing amounts of industrial residues have been deposited in the soil in either a planned way, or accidentally. The objective of this work is to evaluate the impact of the application of a high dose of organic residues (Biossolid - Bs and Sludge - Sd) produced by a pharmochemical industry on the contamination of spring waters. Therefore, an experiment was set up in PVC columns of 20 x 120 cm (diameter x height) in a factorial design 2 x 2 x 2+ 2 with, 2 soils (NVdf and PVd), 2 residues (Bs and Sd), 2 forms of application of 1 million L ha-1 (incorporated and on surface), and a control for each soil. In each column, ten water applications were performed corresponding to 120% of the water column holding capacity; the leached water was collected to evaluate its chemical attributes. EC of the leached water presented a decrease from 1st to the 2nd water application, and the pH increased until the fourth water application. The appraised ions presented different behaviors; those that form outer sphere complex (NO3-, Cl-, Ca2+, Mg2+ and Na+) had fast leaching. The nutrients that form inner sphere complex behaved differently, and PO43- presented low leaching, while K+ leached less than the control and SO42- leached more after the 3rd water application.

Relações entre a substituição isomórfica de Fe por Al e as características químicas e mineralógicas de hematitas sintéticas

Hematites were synthesized with different degrees of isomorphic substitution (IS) of Fe for Al to a maximum of 16Almol%.The minerals were characterized by X-ray diffraction, total chemical analysis, extraction of iron and aluminum soluble in ammonium acid oxalate (Feo+Alo), determination of the anion exchange capacity (AEC) and specific surface area (SSA).The results showed that the synthesis methods resulted in a minimum amount of impurities and that, in a general way, the foreseen values of isomorphic substitution were achieved.The SSA values were relatively low for the hematites with up to 10% of Al, and elevated for the hematites with 13 and 16% of Al of isomorphic substitution. A good correlation was observed between the SSA and the AEC with the amounts of Fe and Al, soluble in ammonium acid oxalate (Feo+Alo).