STUDY OF REACTIVE MEDIUM FOR PERMEABLE REACTIVE BARRIERS (PRB): LABORATORY EXPERIMENTS

Abstract

This study presents results of laboratory studies to evaluate the assessment of zeolites as a reactive medium of Permeable Reactive Barriers (BRPs) in 3 particle size ranges (4.0x10^-4 a 1.0x10^-3 m, 1.0x10^-3 a 2.0x10^-3 m e 1.0x10^-3 a 3.0x10^-3 m). Studies were developed through physical, chemical, mineralogical, permeability and sorption characterization. The characterized zeolite is Clinoptilolite species, with specific weight of the solids of 22.87 kN/m³, Si/Al ratio of 6.8 and cation exchange capacity of 180 cmolc/kg. The different volumetric arrangements of the particles generated values ​​of dry bulk density ranging from 10.01 to 11.00 kN/m³ and saturated hydraulic conductivities from 1x10^-5 to 3x10^-4 m/s, which result in arrangements compatible with different geological media. In terms of sorption, Langmuir isotherm adjust with r² of 0.997 and for the adsorption kinetics, the behavior occurs through the sharing of electrons between zeolite and solute, with first order reaction coefficients ranging from 0.06 to 0.4 h^-1 depending on the time of percolation. The results show that the zeolites in the studied particle size ranges are suitable for use as a reactive BRP medium in economically viable thicknesses for contaminated areas inserted in geological materials related to the Botucatu Formation.