Remoção de corante por biossorvente em coluna de leito fixo: modelagem e simulação

Abstract

In the textile industry large volumes of water are consumed, resulting in wastewater rich in dyes. Adsorption is widely used to dye removal. However, it requires big amounts of adsorbent and it need to be economically viable to be used in industrial scale. The main objective of this study was to investigate Neolan Black WA textile dye biosorption onto malt bagasse and propose a fixed-bed column's mathematical model. First of all, the malt bagasse was dried at 60°C during 24 hours, crushed and sieved. The biosorbent characterization was done by ash, humidity, volatile matter and fixed carbon content, scanning electron microscopy (SEM), N2 adsorption/desorption (BET/BJH) and isotherms infrared spectroscopy (FTIR). The optimal conditions of biosorption set at pH=8 and particle size 48-60 mesh. In the equilibrium isotherm, the Langmuir model adjusted the experimental results with a best correlation coefficient and a maximum adsorbed quantity of 64,34 mg/g. The pseudo-second order model adjusted the experimental results with a best correlation coefficient and a equilibrium time of 25 hours. The mathematical model was obtained by differential balances in liquid phase (wastewater) and solid phase (biosorbent), using Langmuir and Freundlich Isotherms to describe the quantity adsorbed in the solid phase. Experimental data was obtained by biosorption in a 10 cm fixed-bed column and biosorbent saturation was achieved in 6 hours. Finally, it was concluded that the mathematical model whose use Langmuir Isotherm to describe the quantity of Neolan Black WA adsorbed in the solid phase, as well as axial dispersion, report the best experimental fitting data and a maximum adsorbed quantity of 527,36 mg/g.