I have a TGA curve which showed that my UiO-66 is completely converted to ZrO2 at around 530 degrees, I just need to know how to calculate the weight loss ratio.
Weight loss at a given temperature is calculated a s a ratio of the remaining mass at that temperature to the mass at the start of the experiment. For example, the weight loss ratio at the start of the experiment is 100%.
Hi Islam,
You need just calculate the mass loss form thermogravimetric curve as the difference between starting mass and the minimum of your TG curve. The weight loss ratio is like starting mass to final mass proportion. But if you need calculate mass loss that strictly corresponds to H2O content (OH group decomposition in UiO-66), you should draw DTG curve – this is just the first derivative of TG curve over time and in that way you are able to find the boundary between thermal events, that you observed, and in this range you should determine mass loss. If you used coupled thermal analysis for evolved gas, the issue is simple, just determine the onset and offset temperature of H2O release and the mass loss that corresponds to this temperature. If you don’t have access to software dedicated your thermogravimetry, excel is the best tool for this calculations. Good luck!
The discussion in the following link may be useful.
https://www.researchgate.net/post/kindly_explain_by_calculation_how_one_can_determine_the_weight_loss_of_molecules_from_the_TGA_curves_State_with_illustration_in_a_stepwise_order
Vianney Andrew Yiga Can you explain why weight loss at a given temperature should be calculated a s a ratio of the remaining mass at that temperature to the mass at the start of the experiment?
It is a loss. Therefore mass at the strat of the experiment minus residual mass that is the remaining mass should refer to weight loss. To calculate in percentage, the difference should be divided by initial mass and then multiply by 100. In your example, the weight loss ratio at the start of the experiment is 0%. It can be 100% when residual weight is 0 that is total weight is lost.
Md. Abu Bin Hasan Susan you are right. The ratio you state provides exactly the same answer as what i state.
For drawing a TG graph, mass loss is referred to as being a decrease from 100% to the least mass ratio. That is why at the start of the experiment, mass loss is 100%.
Vianney Andrew Yiga TG graph can be presnted as mass plotted against temperature or mass loss plotted agaainst temperature. If you plot mass vs. temperature, it starts from 100%. It, in fact, presents residual mass plotted against temperature. But if you really mean, mass loss, it should start from 0%. Please check my previous answer again carefully.
- Badges
- Science topic
- Similar topics
- Methodology
- Research Methodology
- Research Papers