Reduction of disinfection by-products precursors by nanofiltration process.

This research is dedicated to determine the rejection ratios of disinfection by-products (DBPs) precursors including resorcinol, phloroglucinol, 3-hydroxybenzoic acid, and tannic acid solution in the presence of calcium by nanofiltration with NF70 membrane. The rejections of these model compounds also were studied at various compositions of a feed solution by changing pH and concentrations of model compounds. It was found that the model compound rejection and membrane permeability increase with pH due to the conformational transformation of ionizable molecules and electric interaction between the model compounds and NF70 membrane. The interactions of model compounds with calcium have no significant effect on model compounds retentions. Because of the complexation of calcium with model compounds, calcium rejection rises with the presence of model compounds and with an increase of pH.