Investigation of thermal degradation kinetics and catalytic pyrolysis of industrial sludge produced from textile and leather industrial wastewater

Abstract

This paper elucidates catalytic and non-catalytic pyrolysis characteristics of sludge obtained from the biological treatment of textile and leather industrial wastewater. Iso-conversional model-free methods, such as Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Friedman, were employed to evaluate the kinetic and thermodynamic parameters. The E-a (activation energy) values of non-catalytic and catalytic pyrolysis with y-zeolite and activated alumina (Al2O3) were determined via KAS method to be in the range of 84.66-291.18, 73.12-197.17 and 84.66-217.44 kJ/mol, respectively, whereas similar trends were observed when the other two methods were used. Gas chromatography/mass spectrometer (GC/MS) analyses showed that the oil obtained from the non-catalytic procedure was rich in fatty acids, steroidal compounds and N-compounds. Activated alumina was effective in removing nitrogen-containing compounds from the oil while y-zeolite promoted deoxygenation and deacidification reactions and, as a result, the oil became rich in alkanes and alkenes which improved its quality as a fuel.