Frontiers in Chemistry
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2023
·
IF 5.5
Li Shaofeng,Zhang Meilin,Sun Jian,Sun Jianping,Wang Ying
Polyvinylidene fluoride (PVDF) membranes are favored for their excellent properties. However, the inherent strong hydrophobicity of PVDF membranes limits their development in the field of water treatment. The objective of this study was to improve the performance of PVDF membranes using the self-polymerization, strong adhesion properties, and biocompatible effects of dopamine (DA). The PVDF/DA membrane modification conditions were simulated and optimized using response surface methodology (RSM), and the experimental design was used to investigate three main parameters. The results showed that the DA solution concentration of 1.65 g/L, the coating time of 4.5 h, the post-treatment temperature of 25°C, the contact angle decreased from 69° to 33.9°, and the pure water flux on the PVDF/DA membrane was higher than that on the original membrane. The absolute value of the relative error between the actual and predicted values is only 3.36 %. In the MBR parallel comparison test, compared with the PVDF/DA membrane, the total amount of extracellular polymers (EPS) of the PVDF membrane increased by 1.46 times and the polysaccharide increased by 1.56 times, which further showed that the PVDF/DA modified membrane had the excellent anti-pollution ability. Through Alpha diversity analysis, the biodiversity detected on PVDF/DA membranes was higher than that of PVDF membranes, which further proved its good bio-adhesion ability. These findings could offer a reference for the hydrophilicity, antifouling, and stability of PVDF/DA membranes, which would establish the foundation for the comprehensive applications in MBR.
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高影响因子
Membranes
·
2023
·Vol. 13
·期 2
·225
·
IF 4.2
Yubo Xu,Long-Fei Ren,Jun Li,Chengyi Wang,Yangbo Qiu,Jiahui Shao,Yiliang He
Membrane distillation (MD) is attractive for water reclamation due to the fact of its unique characteristics. However, membrane wetting becomes an obstacle to its further application. In this paper, a novel hydrophobic polyvinylidene fluoride/poly(vinyl pyrrolidone) (PVDF/PVP) membrane was fabricated by electrospinning and solvothermal treatment. The electrospun membranes prepared by electrospinning showed a multilevel interconnected nanofibrous structure. Then, a solvothermal treatment introduced the micro/nanostructure to the membrane with high roughness (Ra= 598 nm), thereby the water contact angle of the membrane increased to 158.3 ± 2.2°. Owing to the superior hydrophobicity, the membrane presented high resistance to wetting in both NaCl and SDS solutions. Compared to the pristine PVDF membrane, which showed wetting with a flux decline (120 min for 0.05 mM surfactant solution treatment), the prepared membrane showed outstanding stability over 600 min, even in 0.2 mM surfactant solutions. These results confirm a simple method for anti-wetting hydrophobic membrane preparation, which presented universal significance to direct contact membrane distillation (DCMD) for industrial application.Keywords:membrane distillation;membrane wetting;electrospinning;solvothermal treatment
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高影响因子
Membranes
·
2022
·Vol. 13
·期 1
·14
·
IF 4.562
Jingjun Peng,Bhaskar Jyoti Deka,Shaodi Wu,Zhongyuan Luo,Jehad A. Kharraz,Wei Jia
Water pollution caused by oil spills or sewage discharges has become a serious ecological environmental issue. Despite the membrane separation technique having a promising application in wastewater purification, the membrane fabrication method and separation robustness have remained unsatisfactory until now. Herein, we developed a novel strategy, spacer-assisted sequential phase conversion, to create a patterned polyvinylidene fluoride@polypropylene (P-PVDF@PP) substrate membrane with a multiscale roughened surface. Based on that surface structure, the underwater oil resistance behavior of the P-PVDF@PP membrane was improved. Moreover, owing to the abundant active sites on the P-PVDF@PP surface, the polydopamine/P-PVDF@PP (PDA/P-PVDF@PP) Janus membrane could be readily fabricated via wet chemical modification, which exhibited excellent switchable oil–water separation performance. Regarding surfactant-stabilized oil-water emulsion, the as-prepared PDA/P-PVDF@PP Janus membrane also had robust separation efficiency (as high as 99% in the n-hexane/water, chloroform/water, and toluene/water emulsion separation cases) and desirable reusability. Finally, the underlying mechanism of emulsion separation in the PDA/P-PVDF@PP Janus membrane was specified. The as-designed PDA/P-PVDF@PP Janus membrane with high-efficiency oil–water separation shows potential application in oily wastewater treatment, and the developed fabrication method has implications for the fabrication of advanced separation membranes.Keywords:emulsion separation;Janus membrane;patterned interface;switchable wettability
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
·
IF 5.2
Guoxu He,Menghui Wan,Zhihua Wang,Yanbao Zhao,Lei Sun
Due to its minute droplet size and stability, separation of the emulsion is a non-negligible challenge. In this paper, polyvinylidene fluoride (PVDF) nanofibrous membranes were prepared via the electrospinning method. The nanofibrous membranes were subsequently surface-modified by ZnO nanoparticles , tannic acid (TA), and n-dodecyl mercaptan (DT), in order to reduce the nanofiber membranes' surface energy while increasing their surface roughness . Thus, superhydrophobic and antibacterial nanofibrous membranes have been fabricated for oil-water emulsion separation. The as-fabricated nanofibrous membranes have a water contact angle of 156.5°. The product has a porosity of up to 73.3% due to the high porosity of the electrospinning nanofibrous membranes. In addition, the tensile strength of the PVDF@ZnO@TA@DT nanofibrous membrane is up to 69.25 MPa. Due to these properties, oil droplets can pass through the membrane during the oil-water separation, while the water phase is blocked by the membrane. This results in a good selective permeability of the membrane. As a result, the separation efficiency of the PVDF@ZnO@TA@DT nanofibrous membranes reaches more than 99%, and the flow flux is 1008.88 L·m −2 ·h −1 . At the same time, antimicrobial testing demonstrates that the nanofibrous membranes have a bacteriostatic rate of over 98%. Combined with these properties, PVDF@ZnO@TA@DT electrospun nanofibrous membranes have great potential for efficient emulsion separation and deep purification of wastewater.
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Nanomaterials
·
2023
·Vol. 13
·期 1
·211
·
IF 5.3
Juanjuan Zhou,Wenying Zhou,Mengxue Yuan,Xinbo Dong,Jiebing Zhang,Xuejiao Zhang,Yanqing Zhang,Xiaolong Chen,Yanrong Chen,Xiangrong Liu
An insulating shell on the surface of conductive particles is vital for restraining the dielectric loss and leakage current of polymer composites. So as to inhibit the enormous loss and conductivity of pristine nickel (Ni)/poly(vinylidene fluoride)(PVDF) composites but still harvest a high dielectric permittivity (εr) when filler loading approaches or exceeds the percolation threshold (fc), pristine Ni particles were covered by a layer of titanium dioxide (TiO2) shell via a sol–gel approach, and then they were composited with PVDF. The impacts of the TiO2coating on the dielectric performances of the Ni/PVDF composites were explored as a function of the filler concentration, the shell thickness and frequency. In addition, the dielectric performances were fitted using the Havriliak–Negami (H–N) equation in order to further understand the TiO2shell’s effect on polarization mechanism in the composites. The Ni@TiO2/PVDF composites exhibit highεrand enhanced breakdown strength (Eb) but remarkably suppressed loss and conductivity when compared with pristine Ni/PVDF because the TiO2shell can efficiently stop the direct contact between Ni particles thereby suppressing the long–range electron transportation. Further, the dielectric performances can be effectively tuned through finely adjusting the TiO2shell’ thickness. The resulting Ni@TiO2/PVDF composites with highεrandEbbut low loss show appealing applications in microelectronics and electrical fields.Keywords:dielectric properties;metal;core–shell structure;polymer composites
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Jian Xu,Jiuyun Cui,Haotian Sun,Yuting Wu,Changguo Xue,Atian Xie,Chengcai Li
Facile preparation of hydrophilic membranes is essential for achieving efficient separation of oil-water emulsion. In this paper, a hydrophilic PVDF@TP membrane was prepared by very simple direct modification using green tea (The main extract is tea polyphenols, TP). The PVDF@TP membrane exhibits good hydrophobicity in air and underwater superoleophilicity. The oil-water separation potential of this membrane was studied using several model oil-in-water emulsions. The resulting membrane exhibitd high separation efficiency (above 99 %) and separation fluxes (955–1672 L m −2 h −1 bar −1 ) for various oil-in-water emulsions. Additionally, separation efficiency of PVDF@TP membrane was still above 98 % even after 10 times continuous separation, demonstrating its good antifouling ability and stability. In addition, bending, ultrasonic and stirring treatments showed that the membrane has good mechanical durability. In view of the advantages of facile preparation, economy and high-performance, the hydrophilic PVDF@TP membrane has a very broad application potential in industrial oily wastewater and oil spill treatment.
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高影响因子
Membranes
·
2023
·Vol. 13
·期 9
·773
·
IF 4.2
Jun Xiang,Sitong Wang,Nailin Chen,Xintao Wen,Guiying Tian,Lei Zhang,Penggao Cheng,Jianping Zhang,Na Tang
In order to enhance the separation performance and reduce the heat loss of transmembrane for membrane distillation, the thermal efficiency and hydrophobicity of the membrane distillation need to be simultaneously enhanced. In this work, a polyvinylidene difluoride/polyethylene glycol terephthalate (PVDF/PET) hydrophobic/hydrophilic membrane has been prepared by non-solvent phase induction method. Nanosized silica aerogel (SiAG) with high porosity has been added to the composite membranes. The modifying effects and operating conditions on permeate flux and thermal efficiency in direct contact membrane distillation (DCMD) are investigated. Furthermore, the latent heat of vaporization and the heat transfer across the membranes have been compared for SiAG addition, which indicates that the composite PVDF@SiAG/PET membranes demonstrate a great potential for distillation-separation application due to their high heat efficiency.Keywords:non-solvent induce phase separation;hydrophobic/hydrophilic membrane;silica aerogel;low thermal-conductivity;membranes distillation
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高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
Linlin Zhou,Tao Yang,Chunyu Guo,Kang Wang,Enhui Wang,Laipan Zhu,Hailong Wang,Sheng Cao,Kuo-Chih Chou,Xinmei Hou
Piezoelectric silicon carbide (SiC) has been quite attractive due to its superior chemical and physical properties as well as wide potential applications. However, the inherent brittleness and unsatisfactory piezoelectric response of piezoelectric semiconductors remain the major obstacles to their diversified applications. Here, flexible multifunctional PVDF/6H-SiC composite fiber films are fabricated and utilized to assemble both piezoelectric nanogenerators (PENGs) and stress/temperature/light sensors. The open circuit voltage ( V oc ) and the density of short circuit current ( I sc ) of the PENG based on the PVDF/5 wt% 6H-SiC composite fiber films reach 28.94 V and 0.24 µA cm –2 , showing a significant improvement of 240% and 300% compared with that based on the pure PVDF films. The effect of 6H-SiC nanoparticles (NPs) on inducing interfacial polarization and stress concentration in composite fiber films is proved by first-principles calculation and finite element analysis. The stress/temperature/light sensors based on the composite fiber film also show high sensitivity to the corresponding stimuli. This study shows that the PVDF/6H-SiC composite fiber film is a promising candidate for assembling high-performance energy harvesters and diverse sensors.
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Journal of Water Process Engineering
·
2023
·
IF 7
Mengmeng Liu,Jianqiang Wang,Yajie Ding,Yong Zhou,Fu Liu
Viscous oil separation and its highly efficient recovery is a great challenge in oil/water separation applications. Membrane separation was considered as a prospective strategy for oil/water separation, but membrane contamination caused by the oil droplets restricted its applications significantly. We here propose a nondispersive solvent extraction strategy to efficiently recover viscous lubricant oil from emulsions via a polydopamine modified PVDF Janus membrane . The incorporated thin polydopamine layer facilitates the adsorption and diffusion of surfactant stabilized oil droplets through the membrane. We studied the influence of polydopamine coating time, the flow rate on both feed and extraction sides, the weight content of lubricant oil on the recovery of oil. The optimized membrane exhibited a 10 h accumulative flux (1595 g·m −2 ) for viscous lubricant oil in water emulsion, which was 70 % higher than the contrast PVDF membrane. The current study might significantly advance application of this novel method for highly efficient separation and recovery of viscous oils from oil/water mixtures.
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RSC Advances
·
2023
·Vol. 13
·期 28
·19002-19010
·
IF 3.9
Han Runlin,Wang Chaoyue,Bi Congcong,Wang Hanli
Polyvinylidene fluoride (PVDF) has been widely studied and applied in separation membranes due to its high thermal and chemical stability and mechanical strength. However, PVDF has strong hydrophobicity, resulting in easy contamination of the membrane surface and fast flux attenuation, so it is necessary to modify the membrane surface to improve its separation selectivity and service life. In this paper, PVDF microporous membrane was used as the matrix material and graphene oxide (GO) as the separation layer material. The GO/Mn3O4/PVDF composite membrane was prepared by layer self-assembly of GO nanosheets, and the functional layer spacing was adjusted by nanometer Mn3O4 intercalation. The prepared composite membrane showed high flux and separation selectivity in the filtration of organic compounds. The results showed that the rejection of methylene blue increased from 34% to 99.5%, and the flux decreased from 3000 L m−2 h−1 to 95 L m−2 h−1 when GO nanosheets covered the PVDF supporting membrane. After the introduction of Mn3O4 nanowires in the GO interlayer, the dye rejection reached 99.9% and the flux reached 612 L m−2 h−1. Compared with the unintercalated composite membranes, the flux of the prepared composite membranes showed good stability in the treatment of methylene blue, and the rejection remained unchanged.
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高影响因子
Micromachines
·
2022
·Vol. 13
·期 10
·1747
·
IF 3.523
Yantao Zheng,Qifei Liu,Xingyu Guan,Yuan Liu,Shengqiang Nie,Yi Wang
A new synthetic strategy has been developed for the facile fabrication of a N-doped porous carbon (NC-800) material via a facile carbonization of functionalized poly(vinylidene fluoride) (PVDF). The prepared NC-800 exhibits good specific capacitance of 205 F/g at 1 A/g and cycle stability (95.2% retention after 5000 cycles at 1 A/g). The adsorption capacity of NC-800 on methylene blue and methyl orange was 780 mg/g and 800 mg/g, respectively. The facile and economical method and good performance (supercapacitor and adsorption) suggest that the NC-800 is a promising material for energy storage and adsorption.Keywords:supercapacitor;carbon;different content nitrogen self-doping;adsorption
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Jinjuan Xue,Jin Li,Jiamin Gao,Mingxin Wang,Shuaishuai Ma
Effective synchronous removal of water-immiscible oils and water-miscible refractory aromatic pollutants from wastewater is of great significance for water remediation. In this work, a low-cost and easy-prepared composite membrane was fabricated by vacuum assisted assembling of CoFe 2 O 4 and tannic acid on polyvinylidene fluoride (PVDF) substrate. The CoFe 2 O 4 functionalized PVDF membrane (CoFe 2 O 4 @PVDF) exhibited in-air superamphiphilic and underwater superoleophobic surface wettability. The resultant membrane displayed relatively favorable permeation flux (811.5 to 1837.5 Lm −2 h −1 ) and high separation efficiency (above 99 %) in the separation of a series of emulsified oils ranged from nanoscale to microscale from water. Meanwhile, the as-fabricated CoFe 2 O 4 @PVDF membrane coupled with peroxymonosulfate (PMS) exhibited an extensive oxidizing capacity and high degradation efficiency towards aromatic contaminants with desired mineralization ability. More importantly, considering that the fabricated CoFe 2 O 4 @PVDF membrane possessed special super-wettability as well as PMS activation-based catalytic ability, it also applied in the treatment of simulated complex wastewater. The process achieved effectively synchronous oil/water separation and PMS activation toward pollutants degradation. Besides, in five cyclic continuous “degradation-separation” tests, the recovered CoFe 2 O 4 @PVDF membrane after PMS-based degradation in each cycle could separate oil/water emulsions as usual. It exhibited almost complete oil rejection and flux recovery property under multicycle filtration, demonstrating its excellent durability and stability. This flexible integration of PMS-based AOP catalytic capability and super-wettability into a composite membrane can provide inspiration for effective complicated wastewater rehabilitation.
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