금속성 응집제와 모노클로라민의 상호작용이 Polyamide 계 RO막 성능에 미치는 영향

Abstract

The bench-scale chlorine exposure study was performed to investigate the effect of pretreatment by free chlorine and monochloramine (NH2Cl) on the performance of RO membranes made of polyamide (PA). Feed monochloramination at 2 mg/L did not cause significant productivity loss compared to free chlorine. However, metal coagulants reacted with monochloramine, the PA membrane suffered from a gradual loss of membrane integrity by chlorine oxidation, which was characterized as a decrease in salt rejection. Especially, RO membranes exposed to alum coagulants with monochloramine revealed the salt rejection lower than those exposed to iron coagulants. XPS membrane surface analysis demonstrated that the chlorine uptake on the membrane surface increased and carbon peaks were shifted significantly when exposed to alum coagulants with monochloramine.