Membrane fouling is the key problem that occurs in membrane process for water treatment. However, how membrane microstructure influences the fouling behavior is still not clear. In this study, fouling behavior caused ...Membrane fouling is the key problem that occurs in membrane process for water treatment. However, how membrane microstructure influences the fouling behavior is still not clear. In this study, fouling behavior caused by dextran was deeply and systematically investigated by employing four poly（vinylidene fluoride） （PVDF） membranes with different pore sizes, ranging from 24 to 94 nm. The extent of fouling by dextran was accurately characterized by pore reduction, flux decline, and the change of critical flux. The result shows that membrane with the smallest pore size of 24 nm experienced the smallest fouling rate and the lowest fouling extent. As the membrane pore size increased, the critical flux ranges were 105-114, 63-73, 38-44 and 34- 43 L. m 2. h t, respectively. The critical flux and fouling resistances indicated that the fouling propensity in- creases with the increase of membrane pore size. Two pilot membrane modules with mean pore size of 25 nm and 60 nm were applied in membrane filtration of surface water treatment. The results showed that serious ir- reversible membrane fouling occurred on the membrane with pore size of 60 nm at the permeate flux of 40.5 L.m 2.h 1. On the other hand, membrane with pore size of 25 nm exhibited much better anti-fouling per- formance when permeate flux was set to 40.5, 48 and 60 L-m 2-h- 1.展开更多
Mefunidone （MFD）, a pirfenidone analogue, has been suggested as a novel anti-fibrotic agent in preclinical research stage. In this work, we developed a sensitive and specified HPLC-UV method and validated it for the...Mefunidone （MFD）, a pirfenidone analogue, has been suggested as a novel anti-fibrotic agent in preclinical research stage. In this work, we developed a sensitive and specified HPLC-UV method and validated it for the determination of MFD in rat plasma. A cost-effective protein precipitation method using methanol was used to process the plasma samples, and pirfenidone was employed as the internal standard （IS）. Chromatographic separation was performed on an Agilent ZORBAX SB-Aq column （4.6 mm 250 mm, 5 μm） with a mobile phase consisting of 10 mM ammonium formate solution （pH 3.0, adjusted by 1.5%o formic acid）-acetonitrile-methanol （60：23：17, v/v/v） at a flow rate of 1.0 mL/min, and the samples were monitored at an ultraviolet wavelength of 245 nm. The retention times of MFD and IS were 5.5 and 7.8 min, respectively. The calibration curve was linear （r2 = 0.9997） between 0.1 and 20 pg/mL. The intra- and inter-day precisions were within 8.6%, and the bias of intra- and inter-accuracies of the method was between -4.2% and 6.5%. The method was successfully applied to pharmacokinetic study of MFD after i.g. and i.v. administration in rats. The elimination half-life was （3.41±0.81） h for i.g. administration and （2.26±0.87） h for i.v. administration. The absolute bioavailability of MFD in rat was 79.1%.展开更多
基金Supported by the National Natural Science Foundation of China(2160060639)the Natural Science Foundation of Jiangsu Province(BK20160984)the Scientific Research Foundation for Returned Overseas Chinese Scholars,State Education Ministry(ZX15511310002)
文摘Membrane fouling is the key problem that occurs in membrane process for water treatment. However, how membrane microstructure influences the fouling behavior is still not clear. In this study, fouling behavior caused by dextran was deeply and systematically investigated by employing four poly（vinylidene fluoride） （PVDF） membranes with different pore sizes, ranging from 24 to 94 nm. The extent of fouling by dextran was accurately characterized by pore reduction, flux decline, and the change of critical flux. The result shows that membrane with the smallest pore size of 24 nm experienced the smallest fouling rate and the lowest fouling extent. As the membrane pore size increased, the critical flux ranges were 105-114, 63-73, 38-44 and 34- 43 L. m 2. h t, respectively. The critical flux and fouling resistances indicated that the fouling propensity in- creases with the increase of membrane pore size. Two pilot membrane modules with mean pore size of 25 nm and 60 nm were applied in membrane filtration of surface water treatment. The results showed that serious ir- reversible membrane fouling occurred on the membrane with pore size of 60 nm at the permeate flux of 40.5 L.m 2.h 1. On the other hand, membrane with pore size of 25 nm exhibited much better anti-fouling per- formance when permeate flux was set to 40.5, 48 and 60 L-m 2-h- 1.
基金National Natural Science Foundation of China(Grant No.81573498)supported by Nanxin Pharmaceutical Co.,Ltd.(Guangdong,China)
文摘Mefunidone （MFD）, a pirfenidone analogue, has been suggested as a novel anti-fibrotic agent in preclinical research stage. In this work, we developed a sensitive and specified HPLC-UV method and validated it for the determination of MFD in rat plasma. A cost-effective protein precipitation method using methanol was used to process the plasma samples, and pirfenidone was employed as the internal standard （IS）. Chromatographic separation was performed on an Agilent ZORBAX SB-Aq column （4.6 mm 250 mm, 5 μm） with a mobile phase consisting of 10 mM ammonium formate solution （pH 3.0, adjusted by 1.5%o formic acid）-acetonitrile-methanol （60：23：17, v/v/v） at a flow rate of 1.0 mL/min, and the samples were monitored at an ultraviolet wavelength of 245 nm. The retention times of MFD and IS were 5.5 and 7.8 min, respectively. The calibration curve was linear （r2 = 0.9997） between 0.1 and 20 pg/mL. The intra- and inter-day precisions were within 8.6%, and the bias of intra- and inter-accuracies of the method was between -4.2% and 6.5%. The method was successfully applied to pharmacokinetic study of MFD after i.g. and i.v. administration in rats. The elimination half-life was （3.41±0.81） h for i.g. administration and （2.26±0.87） h for i.v. administration. The absolute bioavailability of MFD in rat was 79.1%.
