COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2015
·
IF 2.752
Tingting Li,Zhiming Zhang,Wei Li,Ce Liu,Jianfei Wang,Libao An
Nanofibrous membranes of H 4 SiW 12 O 40 /polymethylmethacrylate (PMMA)/polyvinyl alcohol (PVA) were prepared by electrospinning technique. The sandwich structure and element composition of the membranes were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transformation infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The characterization indicated that H 4 SiW 12 O 40 has been successfully loaded into the upper and bottom layers of the sandwich nanofibrous membrane, while the Keggin structure of H 4 SiW 12 O 40 was preserved. The as-prepared H 4 SiW 12 O 40 /PMMA/PVA sandwich nanofibrous membranes exhibited greatly enhanced photocatalytic efficiency (≥94.0%) in the degradation of methyl orange (MO) under ultraviolet irradiation, outperforming H 4 SiW 12 O 40 powder (4.6%) and H 4 SiW 12 O 40 /PMMA composite nanofibrous membrane (13.8%). Notably, the sandwich nanofibrous membrane could be easily separated from aqueous MO solution and the photocatalytic efficiency of the membrane had little change after three photocatalytic cycles. The great performance of the as-prepared membrane may be attributed to the water tolerance of the sandwich nanofibrous membrane and the stability of H 4 SiW 12 O 40 in the membrane. The photocatalytic mechanism of the sandwich nanofibrous membrane was also discussed.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 98
·96237-96244
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IF 3.289
Xiangxu Cui,Tingting Li,Shaowei Yao,Libao An,Yuqing Li,Zhi Zhou,Mengchao Guo,Zhiming Zhang
For comprehensive treatment of wastewater, an electrospun H4SiW12O40 (SiW12)/chitosan (CS)/polycaprolactam (PA6) sandwich nanofibrous membrane (SNM) with dual-functions of adsorption and photocatalysis was prepared to remove Cr(VI) and methyl orange (MO) from aqueous solution. The three layers of the SNM had good compatibility and thus no visible stratification phenomenon was observed in the SNM. Taking advantage of the merits of high porosity, good hydrophilicity, robust mechanical strength and superior water tolerance, the obtained SNM presented an excellent comprehensive performance with high adsorption capacity toward Cr(VI) (78.5 mg g−1), high photodegradation efficiency toward MO (96.7%) and good reusability. Based on the images of the SNM after Cr(VI) adsorption, the SiW12/PA6 layer (upper and bottom layer) was not affected in the adsorption process, which was consistent with our initial design. XPS analysis was carried out to investigate the mechanism of adsorption and photocatalysis. In the adsorption process, Cr(VI) was initially adsorbed on the CS/PA6 layer (intermediate layer), followed by the reduction of Cr(VI) to Cr(III) by the –NH2 of CS. The photocatalytic process was driven by the reductive pathway with faster degradation rate due to the electron donation from PA6 to SiW12. Although Cr(III) at the layer boundary was involved in the photocatalytic process, the photocatalytic activity of the SiW12/PA6 layer was almost not influenced. This work may provide a new and effective strategy to construct multifunctional nanofibrous membranes for the comprehensive treatment of wastewater.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 15
·12491-12496
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IF 3.289
Wei Li,Tingting Li,Xuegang Ma,Yuanliang Li,Libao An,Zhiming Zhang
H4SiW12O40/polycaprolactam (PA6) composite nanofibrous membranes with a minimum average diameter of ∼70 nm were prepared by an electrospinning technique. Characterization with Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) indicated that H4SiW12O40 has been successfully loaded into the PA6 membrane and its Keggin structure was intact. The as-prepared H4SiW12O40/PA6 membranes exhibited greatly enhanced photocatalytic efficiency (≥96.0%) and excellent reusability in the degradation of methyl orange (MO) under ultraviolet irradiation, which may be attributed to the synergistic effect of PA6 and H4SiW12O40. The photocatalytic process was likely to be driven by the reductive pathway with a much faster degradation rate due to the electron donation from PA6 to H4SiW12O40. The hydrogen bonds between H4SiW12O40 and PA6 could enhance the stability of H4SiW12O40 in the membrane, so that there was nearly no loss of photocatalytic activity of the catalyst after three cycles of reactions. In view of this, H4SiW12O40/PA6 composite nanofibrous membranes exhibit potential for practical applications to eliminate organic pollutants from wastewater.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
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2017
·
IF 4.811
Wei Li,Tingting Li,Guangtao Li,Libao An,Fan Li,Zhiming Zhang
H 4 SiW 12 O 40 (SiW 12 )/cellulose acetate (CA) composite nanofibrous membrane was prepared by electrospinning in which CA was employed as the support of SiW 12 . Characterization with Fourier transformation infrared spectroscopy (FT-IR), Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) indicated that SiW 12 has been successfully loaded into the CA membrane and its Keggin structure remained intact. The as-prepared composite membrane exhibited enhanced photocatalytic activity in the decomposition of tetracycline (TC) and methyl orange (MO) compared with pure SiW 12 under ultraviolet irradiation. The optimal mass ratio of SiW 12 to CA was 1:4, and the corresponding degradation efficiency for TC and MO was 63.8% and 94.6%, respectively. It is noteworthy that the degradation rate of MO increased more evidently than that of TC under the same conditions, which may be attributed to the different role that CA nanofibrous membrane played in the TC and MO photodegradation process. Besides providing more contact area between SiW 12 and the pollutant in TC photodegradation, CA membrane played an additional role that donated electron to SiW 12 in the MO degradation process, leading to a different photocatalytic mechanism with greatly enhanced degradation rate. Moreover, the composite membrane presented an excellent reusability, which was mainly ascribed to the water-insolubility of CA and the hydrogen bonds between CA and SiW 12 . This work will be useful for the design of biopolymer-based membrane photocatalysts applied to antibiotics and dyes wastewater treatment.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2015
·Vol. 133
·期 11
·
IF 1.768
Tingting Li,Zhiming Zhang,Wei Li,Ce Liu,Haoyu Zhou,Libao An
Silicotungstic acid (H 4 SiW 12 O 40 )/poly(vinyl alcohol) (PVA)/poly(methyl methacrylate) (PMMA) composite nanofiber membranes were prepared by an electrospinning technique. A PMMA emulsion was mixed with PVA and H 4 SiW 12 O 40 evenly in water (electrospinning solvent). The configuration and elemental composition of the membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results indicate that H 4 SiW 12 O 40 with an intact Keggin structure existed in the composite membrane. The as-prepared H 4 SiW 12 O 40 /PVA/PMMA membranes exhibited enhanced photocatalytic efficiency (>84%) in the degradation of methyl orange (MO); it outperformed H 4 SiW 12 O 40 powder (4.6%) and the H 4 SiW 12 O 40 /PVA nanofiber membrane (75.2%) under UV irradiation. More importantly, the H 4 SiW 12 O 40 /PVA/PMMA membranes could be easily separated from the aqueous MO solution, and the photocatalytic efficiency of the membranes decreased inappreciably after three photocatalytic cycles. This may have been due to the enhanced water tolerance of the membranes and the stability of H 4 SiW 12 O 40 in the membranes. The photocatalytic process was driven by the reductive pathway with a much faster degradation rate because of the presence of PVA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43193.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）