Abstract
The membrane separation properties for pesticides included in the standard and the guideline for potable water were examined with 4 kinds of nanofiltration membranes: nominal NaCl rejection ranging from 92% to 15%. Pesticides were analyzed at sub ppb level by HPLC direct injection method with a ODS column. The highest desalting membrane rejected all pesticides at more than 92% and at more than 99.9% for 8 pesticides. Isoxathion, CNP, EPN, and bebsulide were rejected at more than 98% by the lowest desalting membrane, although the rejection for the other pesticides decreased with decrease in salt rejection of the membranes.
From the relationship between rejection and molecular width for the highest desalting membrane, the molecular sieving effect was indicated as an important factor for solute separation. In addition, it was pointed out that the pesticides highly rejected by all membranes are strongly hydrophobic and include a phenyl group.
