Effect of different additives on the physical and chemical CO2 absorption in polyetherimide hollow fiber membrane contactor system

Preparation and characterization of PVDF/CaCO3 composite membranes etched by hydrochloric acid

This study aimed to improve the pore size, porosity, and hydrophobicity of polyvinylidene fluoride (PVDF) membranes for desalination by vacuum membrane distillation (VMD). New membranes were prepared via etching PVDF/calcium carbonate (CaCO₃) composite membranes using hydrochloric acid (HCl), depending on the chemical reaction of CaCO₃ and HCl. Etched membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), contact angle (CA), atomic force microscope (AFM), and scanning electron microscopy (SEM). The results showed that CaCO₃ of composite membranes was completely reacted by 1.5 mol/L HCl after composite membranes had been etched 90 min. The crystallinity of etched membranes was the same as that of PVDF/CaCO₃ composite membranes, and no new functional groups appeared in etched membranes, which indicated that etched membranes had good chemical stability. The surface roughness increased and led to the increase of contact angle, which means the hydrophobicity of etched membranes was enhanced. As a result, the increment of permeation flux had been improved in a VMD process. It was found that the maximum flux of etched membrane was enhanced and up to 1.65 times of composite membrane when the concentration of sodium chloride (NaCl) solution was 5.0 wt%, and the maximum flux reached up to 30.9 kg m^-2 h^-1.

Preparation and characterization of poly(ether sulfone)/fluorinated silica organic–inorganic composite membrane for sulfur dioxide desulfurization

The highly hydrophobic poly(ether sulfone)/fluorinated silica (PES/fSiO2) organic–inorganic composite membrane for sulfur dioxide (SO2) desulfurization was prepared by incorporating the fSiO2 particles on the PES membrane via sol–gel process and fluorination. The formation of PES/fSiO2 organic–inorganic composite membrane was examined by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis, field-emission scanning electron microscopy, and water contact angle. The experimental results showed that the fSiO2 inorganic layer was tightly bonded to the PES membrane surface through silane chemical reactions. The incorporation of the fSiO2 inorganic layer on the PES membrane surface increases the surface roughness and reduces the surface free energy because of the hydrophobic dodecafluoroheptyl-propyl-trimethoxysilane. The hydrophobicity of the PES/fSiO2 composite membrane was dramatically enhanced from 78.0° of PES membrane to 128.2° of PES/fSiO2 membrane. Compared with PES membrane, the desulfurization performance of PES/fSiO2 membrane was investigated. PES/fSiO2 organic–inorganic composite membrane indicated a reasonably stable SO2 absorption flux of 7.69E-4 mol/m2 s during the 240-min-long time operation.

Polyvinylidene fluoride hollow fiber mixed matrix membrane contactor incorporating modified ZSM-5 zeolite for carbon dioxide absorption

PVDF/ ZSM-5 hollow fiber mixed matrix membrane.

Highly effective CO2 capture using super-fine PVDF hollow fiber membranes with sub-layer large cavities

This work reports a noticeable advancement in CO₂ capture using gas–liquid membrane contactors (GLMC) composed of super-fine poly(vinylidene fluoride) hollow fiber membranes (PVDF HFMs) incorporated with sub-layer large cavities.

Effect of air-gap length on carbon dioxide stripping performance of a surface modified polysulfone hollow fiber membrane contactor

Surface Modifying Macromolecule (SMM) blended PSf hollow fibers were spun at different air-gaps to evaluate CO₂ stripping from aqueous DEA solution and water.