Abstract
This paper concerns the improvement method that can increase the separation performance of commercial RO/NF membranes having low separation performance by model calculations. We assumed three cases; (1) a lot of defects absolutely, (2) low ζ potential in the defects, (3) coexistence both rp = 1 nm and rp > 1 nm defects. We concluded that (1) this calculation estimated the required improvement ratios from each value of σ pre-treatment to certain values of σ post–treatment, so this procedure could be a guideline for improving treatment was, (2) the lower ζ potential in the defects was, the higher increasing effect of separation performance by improving treatment, (3) in the membranes that had low ratio of a normal section, the separation performance decreased although the improving treatment was applied because of the existence of defects impossible to improve.
