This powerpoint presentation begins by presenting the problem statement concerning nanofiltration:
nanofiltration (NF) has an attractive capability of rejecting
multivalent ions at a much lower pressure than that used for
reverse osmosis (RO);
NF productivity is generally hampered by multicomponent fouling
caused by colloidal materials, dissolved organics, inorganic
precipitates, and microorganisms accumulating on the membrane
surface; and,
foulant-foulant interactions cause much more complex fouling
behaviors than those of individual fouling phenomena.
The research goal was to develop an integrated model that has the ability to:
describe combined fouling due to three different foulants;
unify two-component fouling models such as cake-enhanced osmotic
pressure and bi-dispersed colloidal fouling; and, include all the single-component fouling scenarios. The theory is presented and is broken down into singlet fouling, doublet fouling, triplet fouling, and equivalent flux. Presentation conclusions indicate the following: a novel theory was developed on the basis of the Happel's cell model to
analyze the combined fouling of colloids, macromolecules, and solute
ions;
resistance of the combined fouling is much greater than each
fouling of colloids-alone and macromolecules-alone cases; at the beginning of dead-end filtration, BSA gel layer undergoes
remarkable structural compression with increasing volume fraction,
while alginate and dextran do not;
colloids and BSAs are not well mixed during the early stage of the
filtration, causing theoretical under-prediction of the permeate
flux; and,
theoretical
flux of combined fouling and the equivalent
flux of the
weak form provide the lower and upper bounds of the experimental
flux of the triplet fouling; therefore, using measurement of individual
fouling phenomena of colloids-alone and macromolecules-alone cases,
the permeate
flux of triplet fouling can be well estimated. Includes figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 13 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 24 |
| Published : | 11/01/2009 |
