Flocculation as Method for Optimizing Crossflow Microfiltration
Translated title
Author
Term
4. term
Education
Publication year
2010
Submitted on
2010-12-15
Pages
84
Abstract
Denne kandidatafhandling søger at finde en strategi for flokkulering som forbehandling til optimere af tværstrøms-mikrofiltrering af polystyren partikler suspenderet i demineraliseret vand. Dette gøres ved at evaluere nogle egenskaber for flokkuleringsmidler. De undersøgte egenskaber omfatter struktur, molekylevægt og ladningstæthed. Evalueringen sker ved at bruge tre forskellige polymerer som flokkuleringsmiddel under tværstrøms-mikrofiltrering på et modelskala-laboratorie-system. De anvendte polymerer er Zetag 7631 (lineær, høj molekylærvægt), polyDADMAC (lineær, lav molekylærvægt) og Zetag 7867FS40 (tværbundet). Den anvendte dosering af polymeren i forsøgene er baseret på ladningsforholdet (CR). Tre forskellige ladningsforhold bliver brugt for hver af de tre polymerer; CR0.5, CR1 and CR2. Den kritiske permeat flux anvendes som evalueringsparameter, fordi den repræsenterer de højeste flux, hvor der ikke sker nogen fouling. Det konkluderes, at den kritiske permeat flux stiger med et stigende ladningsforhold, og at en lineær polymer med høj molekylvægt som flokkuleringsmiddel giver de bedste filtreringsresultater med den højeste kritiske permeat flux.
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.
Documents