Nanoarchitectonics of carbon molecular sieve membranes with graphene oxide and polyimide for hydrogen purification

Abstract

Hydrogen is an important energy carrier for the transition to a carbon-neutral society, the CMS membrane exhibited ultrahigh H2/N2 selectivity (117) and H2 permeability, which have bright prospects for hydrogen purification.

Thin-Film-Composite Carbon Molecular Sieve Membranes for Efficient Helium and Hydrogen Separation

“…46 As the carbonization temperature increases, peak G becomes narrower with increasing peak strength I(G), which corresponds to the formation of an ordered graphitic carbon structure in the CMS membrane at high temperatures. As reported many times in the literature, 43,47,48 a more ordered carbon structure normally leads to a sharper micropore size distribution, consequently higher gas selectivity but lower gas permeability/permeance. FTIR spectroscopy was also used to analyze the chemical bond changes of the membrane materials before and after carbonization (Figure 1c).…”

“…In the later stages of carbonization, the remaining carbon chains transform into stiff aromatic carbon chains and assemble into carbon “plates”. In other words, as the carbonization temperature increases, more ordered carbon structures were formed, leading to a sharper pore size distribution at higher carbonization conditions. , …”

“…55 In this section, the effects of carbonization on CMS membrane's H 2 and He separation performances were investigated, and results are shown in Figure 6. Similar to many CMS membranes, 45,48,56,57 the gases permeance of the CMS membranes first increases and then decreases when the carbonization temperature changes from 450 to 600 °C. This is potentially due to the removal of oxygen and hydrogen atoms from the TB polymer chains at the early stage of carbonization, which leads to an increase in free volume elements and the formation of a relatively disordered and loose carbon structure inside the CMS film at 550 °C.…”

“…58 In the later stages of carbonization, the remaining carbon chains transform into stiff aromatic carbon chains and assemble into carbon "plates". In other words, as the carbonization temperature increases, more ordered carbon structures were formed, 48 leading to a sharper pore size distribution at higher carbonization conditions. 23,59 The permeance test showed that both H 2 and He permeances and their selectivity of the prepared TFC CMS membrane were greatly improved after carbonization.…”

Diethylenetriamine-functionalized reduced graphene oxide having more amino groups for methylene blue removal

“…The products or composites possessed excellent properties. These compounds might include 1-aminopropyl-3methylimidazolium chloride, 7 1,4-phenylenediamine or 2,3,5,6-tetramethyl-1,4-phenylenediamine, 8,9 amino-modied MXene (3-trimethoxysilylpropan-1-amine modied MXene), 10 ethylenediamine, [11][12][13] 4,4 ′ -diaminodiphenylmethane, 14 and amino acids (e.g., alanine, tyrosine, and cysteine). 15 The epoxide of GO can also react with an amino group that is also attached directly or indirectly to the graphene sheet.…”