Remoção de chumbo de efluente sintético e tratamento do resíduo sólido perigoso gerado utilizando a estabilização por solidificação.

Abstract

Lead is a heavy metal strongly toxic to human beings and environment. The adsorption has been used to remove lead from industrial effluents; while the stabilization by solidification has been efficient to convert and retain heavy metals that can be finding in solid waste. The proposal of this research was to study the removal of heavy metals from wastewater contaminated by lead, using national gray clay as the solid adsorbent, and treat the solid waste that was developed by the process of removal of lead by adsorption. The research was done into three stages. In the first one, the gray clay was characterized by X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDS), Scanning Electron Microscopy (SEM) and Differential Thermal Analysis and Thermogravimetric Analysis (ATD / ATG). In the second step, the finite bath tests, or adsorption tests, were used to determine the percentage and capacity removal of lead by gray clay. In the third step, the stabilization by solidification of harmful solid waste, generated by the previous stage, was done to convert the residue from class I (harmful) to class II A (not harmful). The results of the characterizations identified the gray clay as a mixture of clay minerals from mica and kaolinite group. The finite bath tests proved the great affinity of gray clay for the metal lead (Pb2+), reaching 100% removal in conditions of pH equal to 5, independent of concentration and agitation speed. The hazardous waste treated by stabilization by solidification had good integrity. The leaching and solubilization tests showed that after treatment, the solid residue of adsorption increased from class I (hazardous) to class II - non-inert (not dangerous) and process efficiency in all tests was higher than 99%, reaching 99,92% for the one that used 10% of solid residue of adsorption.