Incorporation of 3-dimensional lycopodium with hydrophobic nature and interconnected nano-channels into polyvinylidene fluoride membranes for desalination applications by vacuum membrane distillation

In the present research,for the first time,lycopodium as a novel nanofiller was incorporated into a polyvinylidene fluoride matrix to fabricate lycopodium/polyvinylidene fluoride flat-sheet membrane for desalination applications by vacuum membrane distillation process.The prepared lycopodium/polyvinylidene fluoride membranes and lycopodium were characterized by field emission scanning electron microscopy,X-ray diffraction,Fourier transform infrared,energy dispersive X-ray,and mapping analyses.Water contact angle and liquid entry pressure measurements were also performed.Response surface methodology was applied to optimize membrane structure and performance.The optimized lycopodium/polyvinylidene fluoride membrane exhibits superior performance compared to the neat polyvinylidene fluoride membrane in terms of flux,salt rejection,water contact angle,and hydrophobicity.In vacuum membrane distillation experiments,using a 15000 ppm NaCl solution as a feed at 70℃,the neat polyvinylidene fluoride membrane,optimum membrane,and agglomerated membrane(with high lycopodium loading)demonstrated 3.80,25.20,and 14.83 LMH flux and 63.30%,99.99%,99.96%salt rejection,respectively.This improvement in flux and salt rejection of the optimized membrane was related to the presence of lycopodium with hydrophobic nature and interconnected nano-channels in membrane structure.It was found that lycopodium,as the most hydrophobic material,effectively influences the membrane performance and structure for membrane distillation applications.

Structure and Magnetic Properties of Ni Nanowires Array Fabricated by Direct Current Electro-deposition in Anodic Alumina Membrane

Ordered nanostructure arrays of Ni-Al 2O 3 were synthesized by direct current electro-deposition in anodic alumina membranes (AAM). The investigation with a n electron microscope,an X-ray diffractmeter and a vibration sample magnetomete r indicates that the Ni nanowires, growing in the pores of AAM with about 45nm i n diameter, are monocrystalline and have a definite preferred crystallizing orie ntation. The magnetic behavior of the arrays and their mechanism were discussed.

Fabrication of novel thin-film composite membrane based on ultrathin metal-organic framework interlayer for enhancing forward osmosis performance

To improve operation efficiency,an interlayered thin-film composite forward osmosis(iTFC-FO)membrane was designed by introducing an ultrathin and porous interlayer based on aluminum tetra-(4-carboxyphenyl)porphyrin(a stable metal-organic framework nanosheet,Al-MOF).Surface characterization results revealed that Al-MoF spread evenly in the macro-porous substrate,and provided a flat and smooth reaction interface with moderate hydrophilicity and uniform small aperture.The resultant polyamide(PA)layer had a thin base(without intrusion into substrate)and crumpled surface(with abundant leaves).The leaves size and cross-linking degree of PA layer firstly increased and then decreased with the Al-MOF loading.Compared to the original membrane,the iTFC-FO showed an enhanced water permeability and a reduced reverse sodium flux in both modes of active layer facing feed solution(ALFS)and active layer facing draw solution(AL-DS).To be specific,the specific reverse sodium flux(reverse sodium flux/pure water flux)decreased from 0.27 g/L to 0.04 g/L in the AL-FS mode,while from 1.36 g/L to 0.23 g/L in the AL-DS mode with 2 mol/L NaCl as DS.Moreover,the iTFC-FO maintained high stability and high permeability under high-salinity and contaminated environment.This study offers a new possibility for the rational fabrication of high-performance TFC-FO membranes.