Flocculation as Method for Optimizing Crossflow Microfiltration

Student thesis: Master thesis (including HD thesis)

  • Pernille Malthe Rosenkjær
4. term, Chemistry, Master (Scient) (Master Programme)
This master's thesis intends to find a strategy for flocculation as pretreatment to optimize crossflow microfiltration of polystyrene particles suspended in demineralized water. This is done by evaluating some properties of flocculants. The investigated properties include structure, molecular weight, and charge density. The evaluation is done by using three different polymers as flocculant under crossflow microfiltration on a model scale laboratory system. The polymers in question are Zetag 7631 (linear, high molecular weight), polyDADMAC (linear, low molecular weight), and Zetag 7867FS40 (Cross-linked).

The polymer dosage used for the experiments is based on the charge ratio (CR). Three different charge ratios are used for each of the polymers; CR0.5, CR1 and CR2. The critical permeate flux is used as the evaluating factor because it represents the highest flux for which no fouling occurs.

It is concluded that the critical flux increases as the charge ratio increases. Further, using a high molecular weight linear polymer as flocculant gives the best filtration results and highest critical flux.
Publication date15 Dec 2010
Number of pages84
ID: 42369946