ナノろ過膜による微量化学物質の除去性に関する研究

抄録

Nanofiltration (NF) has been focused as advanced drinking water treatment process for removing trace chemicals (e.g. pesticides, endocrine disrupting chemicals) and disinfection by-products precursors. The removal profiles and mechanism, however, have been unknown yet, because NF shows different performance according to the characteristics of chemicals as well as the materials of membranes. It is important to estimate the removal performance for the optimum application to drinking water treatment systems.
The objective of this study is to estimate the applicability of NF membrane in terms of removing trace chemicals. Experiments were carried out in a semi-batch filtration system. Four commercially membranes, with the same salt rejection (approximately 50-60%), were used, and pesticides, phenol compounds and phthalic acid esters were employed as target chemicals. Results showed that several types of trace chemicals were adsorbed onto membrane separate layer, therefore the values of observed rejection were high at initial filtration stage. Depending on the adsorption features, rejection was gradually decreased due to membrane adsorption sites coming to equilibrium. It was found that rejection of several types of trace chemicals depended on the function of molecular width. Negative rejection values were also observed in four membranes, depending on simple molecular structure on target chemicals.