REMOÇÃO DE ALPRAZOLAM EM ÁGUAS UTILIZANDO MATERIAIS RESIDUAIS ALTERNATIVOS

Abstract

Alprazolam (ALP) is an emerging contaminant and belongs to a group of substances called benzodiazepines. Due to the current environmental concern with emerging contaminants, and with improperly discarded residues, this work shows the use of two waste material for the removal of ALP in water. One of them is the s boiler shell residue, in Portuguese translated to Resíduo de casca de caldeira (RCC); and the other is a mixture of pulverized activated carbon of pinus with diatomaceous earth, in Portuguese translated to carvão ativado pulverizado de pinus com terra diatomácea (CAPP / TD). The adsorbent materials were characterized as to their physical-chemical properties (ash, moisture, apparent density, pH, iodine number, pHpzc, particle size, surface area and Scanning Electron Microscopy, in Portuguese translated to Microscopia Eletrônica de Varredura - MEV). In the sequence batch and fixed bed studies were carried out. In the batch studies the equilibration times and the behavior with the mass variation of each residue analyzed were evaluated. In the fixed bed column study, the influence of variables such as flow, temperature and pH on ALP removal was evaluated through an experimental design. The saturation times of the columns were evaluated, and a study of interferences was also carried out. The CAPP / TD surface area was 217.4 m2/g and for RCC was 349.54 m2/g, both presented pHpzc above 8, and basic pH. The CAPP / TD presented higher particle sizes, lower iodine number and higher amount of ashes when compared to RCC. The batch studies showed ALP removal of 69% in 60 min and 85% in 90 min for RCC and CAPP / TD respectively. The sorption isotherms show to be in agreement with a classification of Giles. The best conditions for ALP removal in fixed bed were pH = 6; T = 30 °C; V = 1.3 mL min-1 for RCC and pH = 4; T = 25 °C; V = 0.56 mL min-1 for CAPP / TD. The saturation times for RCC and CAPP / TD occurred after 85 and 105 min, respectively. For both residues, no matrix interference was observed. The study demonstrated that both adsorbents were efficient for removal of ALP, and can be applied in environmental samples.