Interest in phosphorus recovery from urine diverted from faeces has been growing recently. Phosphorus in urine can be precipitated out as struvite (MgNH₄PO₄·6H₂O) with addition of magnesium salt under alkaline conditions. Struvite formation, however, should be more well understood for its practical application. We predicted the struvite formation with a development of a new equilibrium model. The model considered the formation of eight different kinds of precipitates, including struvite, with effects of ionic strength and temperature.

In addition, experiments on struvite formation in urine were conducted for the model validation. The model prediction of struvite formation had good agreement with the experimental results. The optimum pH to form struvite was predicted to be 9.4-9.7. In order to precipitate 99% of phosphate in urine with 1.5 fold Mg concentration to PO₄-P, the pH value was necessary to be more than 8.1 based on the model prediction.

Assignments to be completed by Tuesday:

• Redox Reaction Worksheet

• Ionisation Energy assignment correction

There is also a chemistry test on Atomic Structure on Thursday.

VA4 was not very well done as I lost a lot of marks on things such as significant figure and there is also some mistakes in my graph.

I shall avoid all those mistakes in my next practical. :)

The pace of the Chemistry lesson so far is fine. It is neither too fast nor too slow.

We had the retest for mole concept around last week. Hope that I will did better than the first one. :)

Chem Assignments to be completed:

• Assignment 3B
• Mole Concept correction
• Microsoft Excel I.E. activity
• DIscuss VA3 error on MI Link

Till Then.....

For today Chemistry lesson, we touched on Ionisation Energy and all about the graph and the factors that affect the Ionisation Energy.

Ionisation Energy: is the minimum amount of energy required to remove the most loosely held electron from one mole of gaseous atoms to produce 1 mole of gaseous ions each with a charge of 1+.

Other than that, we also learn about NUCLEAR CHARGE and SCREENING EFFECT.

*The more or the higher repulsion, the smaller the ionisation energy.
*The more or the higher attraction, the bigger the ionisation energy.