Yes, reaction rate is T dependent, but control of microbial activity during P sorption studies is critical, and becomes increasingly important the longer the duration of reaction. So one likely explanation of the observations is that the rate of microbial growth, and consequently the rate of P sequestration, may increase from 25 to 35 degrees and decline at higher T.

Very helpful. Thank you Paul Milham

A few other things:

1. Toluene and choroform are weak microbial suppressants. Hg and azide are effective, but objectionable on health grounds

2. pasteurisation at 80 degrees C is said to help control the microbial activity but I'm still inclined to use something like toluene for insurance

3. the suspensions must be aerobic so they need continuous mixing and a head pace at least 30% the volume of the suspension

4. end-over-end mixing is too energetic and rotation on the long axis is recommended at ~10 rpm

I've tried 3 times to attach some refs but each time have lost this text :)

Files below