Non-isothermal kinetic analysis of thermal dehydration of La2(CO3)3·3.4H2O in air

Abstract The single phase La 2 (CO 3 ) 3 ·3.4H 2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La 2 (CO 3 ) 3 ·3.4H 2 O from 30 to 1000 °C were characterized by XRD, FTIR and DTA–TG. The kinetics of dehydration of La 2 (CO 3 ) 3 ·3.4H 2 O in the temperature range of 30–366 °C was investigated under non-isothermal conditions. Flynn–Wall–Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La 2 (CO 3 ) 3 ·3.4H 2 O is a kind of three-step competitive reaction, and controlled by an n -order initial reaction followed by n -order competitive reaction ( F n F n F n model). The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG–DTG curves very well.