i want to investigate microplastics removal efficiency through coagulation and flocculation process . i need to know the initial dose of the three mentioned inorganic salts dose for my lab based experiment. what should be the concentration of stock solution and what should be the initial dose during jar test. Thanks
Both ferric chloride and sulphate form good and large flocs which may work to sediment / precipitate micro / nano plastics. Titration is the only way you are going to achieve success with varying concentrations. Both are inexpensive flocculents. The most important factor however is the starting pH. It is perhaps best to start off with a buffered pH of 9 using calcium to raise the pH. That will also help with the formation of large flocs. Ferric is very acid so expect a finished pH of around 5.5 or even lower.
microplastics may or may not carry a charge. the chemicals you mention are all targeting negatively charged colloids. You may need to also look at some polyelectrolyte options, cationic, anionic and non-ionic. I do recommend Jorg's suggestion of DAF though.
Prepare stock solution of 1 gpl each. Use dosage from 30 mg/l. There should be sufficient alkalinity to produce good floc. FeCl2, FeSO4 work better at pH above 9.0.
In my experience it is not possible to calculate or predict the optimum dose of coagulants and flocculants. Set up a jar test to evaluate the concentrations and combinations. Your chemical suppliers will do this for you, however, you will be better served to purchase the equipment and train one of your operators to do this.