• 폴리머
• /
• 제24권5호
• /
• pp.621-628
• /
• 2000

폴리프로필렌 다공성 분리막은 산, 알칼리에 대한 내화학성이 좋고, 기계적 성질이 우수하며 높은 열적 안정성을 가지고 있으나, 막의 소수성 때문에 일부 영역에만 사용이 제한되고 있다. 따라서 본 연구에서는 소수성 막의 성능을 향상시키기 위해서 방사선 조사에 의한 그라프트 중합법을 사용하여, 친수성 작용기 (-COOH, -OH)를 갖는 acrylic acid (AAc)와 2-hydroxyethyl methacrylate (MEMA)를 도입하였다. 이때 반응시간, 반응온도, 조사량, 간의 첨가 효과, 팽윤현상에 의한 그라프트율의 변화를 조사하였다. 분리막의 기공크기를 분석하는 방법으로 행한 가스투과 실험에서 단량체의 종류와 관계없이 그라프트가 증가함에 따라 가스 투과속도가 감소함을 보였고, 오일 에멀젼 투과실험에서 미개질 폴리프로필렌 막의 오염현상은 크게 발생하였으나, 그라프트 중합 후, 높은 투과속도를 유지하여 막의 친수화 효과가 큰 것으로 나타났다.

• Membrane and Water Treatment
• /
• 제10권2호
• /
• pp.155-163
• /
• 2019

The roles of polypropylene (PP) beads and pH on membrane fouling and treatment efficiency were investigated in a hybrid advanced water treatment process of tubular carbon fiber membranes (ultrafiltration (UF) or microfiltration (MF)) and PP beads. The synthetic feed including humic acid and kaolin flowed inside the membrane, and the permeated contacted the PP beads fluidized in the space between the membrane and the module with UV irradiation and periodic water back-flushing. In the hybrid process of UF ($0.05{\mu}m$) and PP beads, final resistance of membrane fouling ($R_f$) after 180 min increased as PP beads increased. The turbidity treatment efficiency was the maximum at 30 g/L; however, that of dissolved organic matters (DOM) showed the highest at PP beads 50 g/L. The $R_f$ strengthened as pH of feed increased. It means that the membrane fouling could be inhibited at low alkali condition. The treatment efficiency of turbidity was almost constant independent of pH; however, that of DOM showed the maximum at pH 5. For MF ($0.1{\mu}m$), the final $R_f$ was the minimum at PP beads 40 g/L. The treatment efficiencies of turbidity and DOM were the maximum at PP beads 10 g/L.

• Membrane and Water Treatment
• /
• 제4권2호
• /
• pp.143-155
• /
• 2013

Four membranes were used to separate Chlorella sp. from their culture medium in cross-flow microfiltration (MF) experiments: cellulose acetate (CA), cellulose nitrate (CN), polypropylene (PP) and polyvinylidenefluoride (PVDF). It was found that the hydrophilic CA and CN membranes with a pore size of 1.2 ${\mu}m$ exhibited the best performances among all the membranes in terms of permeation flux. The hydrophobicity of each membrane material was determined by measuring the angle between the water (liquid) and membrane (solid). Contact angle measurements showed that deionized (DI) water had almost adsorbed onto the surfaces of the CA and CN membranes, which gave $0.00^{\circ}$ contact angle values. The PP and PVDF membranes were more hydrophobic, giving contact angle values of $95.97^{\circ}$ and $126.63^{\circ}$, respectively. Although the pure water flux increased with increasing pore diameter (0.8 < 1.2 < 3.0 ${\mu}m$) in hydrophilic CA and CN membranes, the best performance in term of filtration rate for filtering a microalgae suspension was attained by membranes with a pore size of 1.2 ${\mu}m$. The fouled membrane pore sizes and pore blocking were inspected using a scanning electron microscope (SEM). MF with large pore diameters was more sensitive to fouling that contributed to intermediate blocking, where the size of the membrane pores is almost equivalent to that of cells.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2003년도 춘계 총회 및 학술발표회
• /
• pp.31-38
• /
• 2003

A pilot scale biofilter pretreatment-microfiltration system (BF-MF) was operated to investigate the effect of biofilter treatment in fouling reduction of microfiltration. Biofiltration was expected to reduce the membrane fouling by removal of turbidity and metal oxides. The hollow-fiber MF module with a nominal pore size of 0.1$\mu$m and a surface area of 8m$^2$ was submerged in a filtration tank and microfiltration was operated at a constant flux of 0.5 m/d. Biofiltration using polypropylene pellets was performed at a high filtration velocity of 320 m/d. Two experimental setups composed of MF and BF/MF, i.e., without and with biofilter pretreatment, were compared. Throughout the experimental period of 9 months, biofilter pretreatment was effective to reduce the membrane fouling, which was proved by the result of time variations of trans-membrane pressure and backwash conditions. The turbidity removal rate by biofiltration varied between 40% to 80% due to the periodic washing for biofilter contactor and raw water turbidity. In addition to turbidity, metals, especially Mn, Fe and Al were removed effectively with average removal rates of 89.2%, 67.8% and 64.9%, respectively. Further analysis of foulants on the used membranes revealed that turbidity and metal removal by biofiltration was the major effect of biofiltration pretreatment against microfiltration fouling.

• 공업화학
• /
• 제10권6호
• /
• pp.954-959
• /
• 1999

본 연구에서는 소수특성의 PP 정밀여과막에 방사선을 조사하여 친수성 모노머인 2-hydroxyethyl methacrylate(HEMA), acrylic acid(AAc) 및 methacrylic acid(MAAc)를 그라프트 중합하였다. 3가지 모노머에 대한 그라프트 중합반응에서 물/메탄올 혼합용매의 조성에 따라 그라프트율에 미치는 효과를 조사하였으며, 이에 대한 각 모노머의 농도에 따른 영향을 고찰하였다. 가장 높은 그라프트율을 얻는 용매조건은 AAc는 순수한 물에서, MAAc는 물/메탄올 혼합비가 50/50 vol %에서, 그리고 HEMA는 25/75 vol %이었다. 그라프트된 PP 다공성 분리막의 모노머 도입여부와 표면특성변화는 FTIR-ATR 및 SEM을 이용하여 관찰하였다. 또한 인장강도와 연신율을 측정하여 그라프트율에 따른 막의 기계적 특성을 평가하였다. 그라프트된 PP막은 본래의 PP막보다 물 투과속도가 증가하였으며, 물 투과에 적당한 모노머로 HEMA임을 알았고 99%의 그라프트율에서 가장 좋은 물 투과속도를 보였다. 또한 AAc가 그라프트된 PP막 및 MAAc가 그라프트된 PP막의 물 투과속도는 pH나 $Cu^{2+}$에 의해 크게 좌우되나 HEMA는 pH나 $Cu^{2+}$에 영향이 거의 없었다.