Remediação e monitoramento de contaminantes ambientais utilizando resíduo da indústria de cerâmica vermelha

Abstract

This work describes the use of tile fragments (CAT), a waste material from the red ceramic industry in Monte Carmelo, Minas Gerais, Brazil, provided by the Laboratório de Ensaios Cerâmicos (LEMC), and evaluated as an adsorbent material for the removal of Brilliant Blue Coomassie G-250 (CBB) dye in aqueous medium in the first chapter. UV-Vis spectroscopy and a digital image analysis method were used to quantify the dye. The UV-Vis spectrum of the dye was obtained with pH ranging from 1.0 to 13.0, with the maximum wavelength selected being 558.5 nm, at pH ranging from 5.0 to 9.0. The CAT was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), infrared spectroscopy (IR), and zero point of charge pH (pHPCZ), indicating a pHPCZ of 5.0. The pH of the medium, particle size, and mass of CAT, as well as adsorption kinetics and isotherms, were evaluated in batch mode. The highest removal (%) values were at pH = 5.0, 8 mg L−1, and an average particle size of 0.111 mm. Under optimized conditions, 20 minutes of contact provided a constant and maximum adsorption capacity with a qmax of 7.1 mg g−1. For the digital image analysis method: LD = 0.59 mg L−1, LQ = 1.79 mg L−1, R2 = 0.9986. For UV-Vis: LD = 0.14 mg L−1, LQ = 0.42 mg L−1, R2 = 0.9935. The digital image analysis method was applied as a substitute for UV-Vis molecular absorption spectroscopy for the study of CBB removal by CAT. In the second chapter, a square wave voltammetry method by anodic redissolution was developed using graphite/acrylonitrile-butadiene-styrene (G/ABS) electrodes modified with CAT for the determination of Pb2+. Optimal conditions were 0.1 mol L−1 acetate buffer at pH 4.8 and an electrode modified with 1% CAT (m/m). Optimized parameters for the technique were 120 mV pulse amplitude, 15 Hz pulse frequency, and 6 mV potential increment. Calibration curves showed R2 values of 0.994 (external standard) and 0.940 (standard addition). The average recovery of Pb2+ was 134% with low relative standard deviations (2.39% to 5.39%), indicating method precision. The methodology demonstrates sensitivity and potential for the sustainable use of waste in the analysis of lead- contaminated samples. The tile manufacturing waste can be applied in the remediation of contaminated waters.