The modelling of non isothermal

Non-isothermal temperature-programmed calcination studies were carried out to obtain the air-solid sample interaction profile and the appropriate calcination temperature for the dried catalysts. Fig. 2 and Fig. 3 illustrate the weight loss and derivative weight profile of the 3 wt% La-promoted catalyst respectively. It can be observed that T0901317 when the solid samples were heated, weight reductions were recorded symptomatic of the gas–solid interaction within a certain temperature region. Moreover, in the temperature region of 298–410 K, an average percentage weight loss of 13.0 wt% was recorded. This weight loss was most likely due to the removal of the physisorbed water and bulk water that were initially present in the sample. The second weigh loss occurred within the temperature range of 430 to about 580 K (15.0 wt% loss). According to Estellé et al. [19], subspecies weight loss can be attributed to the elimination of chemically bound water from nickel nitrate hexahydrate (Ni(NO3)2·6H2O) as in Eq. (8) as well as lanthanum nitrate hexahydrate (La(NO3)3·6H2O) as shown in Eq. (9). In addition, the Eqs. (10) and (11) may occur to release the water.equation(8)Ni(NO3)2·6H2O → Ni(NO3)2·2H2O + 4H2Oequation(9)La(NO3)2·6H2O → La(NO3)3 + 6H2Oequation(10)AlO·nH2O → AlO(OH) + nH2Oequation(11)2AlO(OH) → Al2O3 + H2O