Caracterização e aplicação do lodo secundário de esgoto sanitário como material adsorvente para remoção do corante preto reativo 5 em coluna de leito fixo

Abstract

The dyes are pollutants in aquatic ecosystem who has a removal complexity, because their stability against hear, light and oxidative agents. The removal of this pollutant is very important, since in aquatic environments they cause imbalance of fauna and flora. Because this aggravating factor and the growth of textile sector (3,5% in 2016), the study and application of economically viable ways to remove this compound are important. Therefore, the use of adsorbent process is efficient, since those techniques is easy to apply, in addition, the activated carbon can be made from waste, reducing two environmental liabilities using only one removal technique. In this work there the objective evaluates the use of ETE sludge as an alternative adsorbent in adsorption of Black Reactive 5 dye from Sigma-Aldrich in aqueous solution. The sludge used as column filled, on bench scale, in the pyrolysis (SP) and functionalized (SF) forms. Physicochemical and textural characterization of SP and SF samples were did by determination of moisture content, specific mass, pHpcz, volatile and ash content, functional groups by infrared spectroscopy with Fourier transform (FTIR), acid functional groups by Boehm method, mass variation as a functional of temperature by thermogravimetric analysis and the specific area by adsorption/desorption analysis of N2.In fixed-bed column the essays were conduct for PS pH 3,5 e 42,64 ºC, and FS pH 5,4 e 51,28 ºC. Optimal conditions previously reported by Freitas (2019). In these tests the influence of adsorbent mass, affluent flow and initial concentration of the adsorbate on the efficiency of dye removal in the column was evaluated. The models of Thomas and Yoon-Nelson were adjusted to the experimental data. From the results, it was verified that kinetic data were well adjusted in both kinetic models with R2 higher than 0,98. It was observed from the results obtained in the kinetic models, that the adsorption process was more efficient using the adsorbent sludge functionalized as a fixed bed filling. Fixed bed adsorption was favored for lower flow rates and higher adsorbent. With the statically study it was found that the flow variable had a negative effect on the adsorption process and the variable mass had a positive effect. Thus, it was possible to conclude that the higher dye removal efficiencies in fixed bed tests occurs at lower flow rates and higher bed heights for both adsorbents.