INORGANIC COLLOIDS AT PH 3 WITH ORGANICS

To understand the effect of organics on the primary particles, another set of experiments far from surface water conditions (pH 3 with no electrolyte solution) was carried out. 

In the presence of 5 mgL (as organic carbon) HA, rejection of colloids was higher and flux decline lower than in the absence of organics. Results are shown in Table 5.3 (No 4) and Table 5.4. Organic rejection increased compared to filtration in the absence of colloids (compare Table 5.2). 

These effects can be attributed to the adsorption of organics on the colloids, which increases negative colloid charge and depletes organics in the permeate to some extent, as well as the low solubility of HA at this pH and thus the filtration of the aggregates or the precipitate. 

Colloid Membrane DOC Rejection r%l Fe Rejection p/o] DOC Deposit [%Doq Fe Deposit p/o Pel Flux Decline P/ol 

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