SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Sha Yu,Yitian Qin,Qi Zhao,Mei Li,Haijun Yu,Guodong Kang,Yiming Cao
Nafion-PTFE hollow fiber composite membranes were applied in the ammonia removal and recovery with a novel aqueous-organic membrane contactor (AOMC) process, in which an aqueous solution and an organic solution were separated by the composite membrane. A kerosene-diluted di-(2-ethylhexyl) phosphoric acid (D2EHPA) solution was used to receive the ammonia, which could be recycled and reused after regeneration by the stripping agent (a dilute solution of H 2 SO 4 , HNO 3 , or H 3 PO 4 ). The new-type membrane contactor can avoid the accompanying water transport in conventional membrane contactors. The effects of experimental factors including the pH, the velocity and the initial ammonia concentration of the feed on the overall mass transfer of the ammonia were investigated. Meanwhile, how the regeneration experiment parameters influenced the stripping ratio was also studied. The results showed that the AOMC process was more favorable to treat ammonia feed with low ammonia concentrations. The ammonia removal could be over 99% under certain conditions. Additionally, the ammonia was concentrated 26.4 times after four cycles. It was found that the accompanying water transport was non-negligible in the traditional aqueous-aqueous membrane contactor (AAMC) process when treating ammonia feed of low concentrations, with the maximum water flux two orders of magnitude higher than ammonia.
研究领域:
环境工程
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Shixue Liu,Zhuo Jiao,Chengcai Li,Tong Xu,Guojin Liu,Hailin Zhu,Yuhai Guo,Xueliang Jiang,Jiuming Li,Xiang Yin
Combining membrane separation with advanced oxidation technology can make the membrane self-cleaning, extending its service life. However, the preparation of composite membranes with excellent catalytic ability, self-cleaning performance, and stability remains a key research direction. In this study, a PTFE composite membrane with peroxymonosulfate activation self-cleaning ability was successfully prepared by in-situ growth of CoOOH and ZIF-67 on the surface of a l -DOPA/PEI modified PTFE membrane. The as-prepared membrane is superhydrophilic and has significant superoleophobic surfaces underwater, the separation efficiency of the as-prepared membrane for multiple oil-water emulsions exceeded 98.4 %. Meanwhile, the effective degradation of several organic dyes under visible light was simulated, with still high degradation efficiency (>99 %) after 10 cycles. Overall, this study puts forward a approach towards self-cleaning membranes based on PTFE material; the resulting composite membrane's high separation efficiency, stability under repeated use conditions as well as its self-cleaning ability position it as an attractive candidate for long-term wastewater purification applications.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Sha Yu,Guodong Kang,Zhihao Zhu,Meiqing Zhou,Haijun Yu,Yiming Cao
Nafion-PTFE hollow fiber composite membranes were fabricated and applied in vacuum membrane distillation (VMD) process to improve the anti-fouling and anti-wetting performance in the presence of oil and surfactant . The composite membrane exhibited an underwater super-oilphobic property according to the contact angle test. The VMD performance when treating saline feed containing 3.5 wt% NaCl and 1000 ppm mineral oil for the composite membrane behaved a stable flux for 40 h. In construct, an immediate and sharply-declined flux was observed for the pristine PTFE , indicating the significant improvement in the anti-fouling property. Meanwhile, the composite membrane also alleviated the wetting phenomena caused by the surfactant comparing with the pristine PTFE membrane, and the Nafion-PTFE composite membrane behaves a stable flux and high salt rejection higher than 99.99% for 60 h treating saline feed containing O/W emulsions. The pressure depression effect of the Nafion layer on the mass transfer was analyzed. It was found that the depression could be reduced with the increasing of the feed temperature and the enhancement of the corresponding effective pore diameter of the Nafion layer, that the pressure depression factor decreased from 0.23 to 0.04 with the feed temperature increasing from 60 °C to 75 °C.
研究领域:
环境工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Membranes
·
2021
·Vol. 11
·期 6
·420
·
IF 4.106
Tianshu Liu,Xiaoji Zhou,Yizhuo Sun,Renbi Bai
In this study, PVDF/PTFE composite membranes were prepared by adding a PTFE nanoemulsion to a PVDF solution and casting it through the conventional non-solvent-induced phase separation method. The objective was to explore the effectiveness of using a simple and economical method to modify PVDF membranes with PTFE to enhance their anticorrosion performance, especially under highly acidic or alkaline conditions. PTFE nanoparticles (of around 200 nm in size) in nanoemulsion form were blended with PVDF at a mass ratio of PTFE:PVDF in the range of 0–0.3:1. The obtained membranes were examined to determine the effect of the added PTFE nanoparticles on the structure of the modified PVDF membranes as well as on their mechanical strength and surface characteristics. The membranes were then immersed in various concentrations of acidic or alkaline solutions for varied durations ranging from a few days up to as long as 180 days (6 months). The impacts of by the corrosive solutions on the tensile strength, surface roughness, and water flux of the membranes with different exposure times were quantified. The results showed that although a certain extent of change may occur with extended immersion times, greatly enhanced anticorrosion performance was obtained with the prepared PVDF/PTFE membranes compared with the unmodified PVDF membrane. For example, after being immersed in 5 mol-H+··L−1H2SO4, HCl, and HNO3solutions for 6 months, the tensile strength at breaking point remained at up to 69.70, 74.07, and 71.38%, respectively, of the initial strength for the PVDF/PTFE (M30) membrane. This was in contrast to values of only 55.77, 70.43, and 61.78% for the unmodified PVDF membrane (M0). Although the water flux and surface roughness showed a change trends to the tensile strength, the PVDF/PTFE (M30) membrane had much higher stability than the PVDF (M0) membrane. In a continuous filtration experiment containing H2SO4at 0.01 mol-H+·L−1for 336 h (14 days), the PVDF/PTFE membrane showed a maximum flux change of less than 30%. This was in comparison with a change of up to 50% for the PVDF membrane. However, the PVDF/PTFE membranes did not seem to have a greatly enhanced anticorrosion performance in the alkaline solution environment tested.Keywords:PVDF/PTFE composite membrane;PTFE nanoparticle;polymer blending;non-solvent induced phase separation method;anticorrosive performance
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）