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무기염을 이용한 다공성 PVDF 고분자막의 친수화를 통한 초저압용 나노여과막 제조 연구 KCI 등재
Studies on the Preparation of Nanofiltration Membrane for Ultra-low Pressure Application through Hydrophilization of Porous PVDF Membrane Using Inorganic Salts
초저압용 나노여과 중공사 복합막을 제조하기 위하여 poly(vinylidene fluoride) (PVDF) 소수성 중공사막 표면에무기염인 K2Cr2OH와 KMnO4 수용액으로 친수화 처리를 하였으며, 처리된 막 표면 위에 piperazine (PIP)과 trimesoyl chlor-ide (TMC)로 계면 중합하여 복합막을 제조하였다. NaCl, CaSO4, MgCl2 100 ppm 용액 및 300 ppm의 NaCl과 CaSO4 혼합용액을 이용하여 코팅물질의 농도, 코팅시간 및 건조시간에 따른 복합막의 투과특성을 알아보았다. 실험 결과 친수화 물질로는K2Cr2OH을 사용하였을 때 더 높은 배제율을 보였으며, 친수화 시간이 길어질수록 투과도는 향상되고 배제율은 감소하는 경향을 나타내었다. 또한 촉매인 triethyl amine (TEA)과 sodium lauryl sulfate (SLS)의 농도가 높을수록 투과도는 감소하고, 염제거율은 증가하였다. 최적 조건으로는 K2Cr2OH으로 10분 동안 친수화 시킨 PVDF 중공사막 위에 PIP 2 wt% 용액(PIP 함량 대비 Triethyl amine (TEA) 7 wt%, SLS 20 wt% 혼합용액)과 TMC 0.1 wt%를 이용하여 계면중합한 것으로 공급액 NaCl100 ppm에 대해서는 투과도 40 LMH, 제거율 50%이었고, CaSO4 100 ppm에 대해서는 투과도 48 LMH, 제거율 55%를 나타내었다.
To prepare the hollow fiber nanofiltration composite membranes, the poly(vinylidene fluoride) (PVDF) mem-brane was hydrophilized with K2Cr2OH and KMnO4 aqueous solutions. And then the composite membrane was synthesized on that membrane surfaces using interfacial polymerization with piperazine (PIP) and trimesoyl chloride (TMC). The result-ing membranes were characterized in terms of the rejection and flux for NaCl, CaSO4, MgCl2 100 ppm solution and 300 ppm of NaCl and CaSO4 mixed solution by varying the coating time, drying time, and the concentration of the coating materials. As a result, the higher rejections were shown for K2Cr2OH solutionas a hydrophilization material, and the flux was enhanced while the rejection reduced as the hydrophilization time is longer. Also, the rejection increased and the flux reduced as the concentrations of triethyl amine (TEA) and sodium lauryl sulfate (SLS) were higher. Typically, the rejection 50% and flux 40 LMH for NaCl 100 ppm solution, and the rejection 55% and flux 48 LMH for CaSO4 100 ppm solution were obtained for the PVDF hollow fiber composite membrane prepared with the conditions of PIP 2 wt% (Triethyl amine (TEA) 7 wt%, SLS 20 wt% mixed solution against PIP concentration) and TMC 0.1 wt%.
