Grafting of amino groups onto carbon fibers by bromination followed by ammonolysis

Because of the low content of chelating groups onto carbon fibers (CFs), their adsorptive parameters are poor, and this has negative effects on their applications as lightweight sorbents. In this work, we established a modification method to incorporate amine groups into carbon fiber surfaces by bromination followed by ammonolysis to create an interfacial layer which can adsorb heavy metal ions from solutions. The changed chemical composition, surface morphology, and thermal stability were investigated. Thermoprogrammed desorption mass-spectrometry and thermal analysis showed thermal transformation and interplay between forms of the grafted bromine groups of 0.5 mmol/g and the resulting amino groups of 0.44–0.56 mmol/g. After grafting, the surface chemistry parameters were improved due to the covalent bonding and grafting of the amine groups as interface modifier. Scanning electron microscopy observation also confirmed that the surface morphology maintains the same, without impairment of fiber properties. This work is therefore a beneficial approach towards enhancing the adsorption parameters by controlling the interface layer of CFs

Chemical grafting of sulfo groups onto carbon fibers

We proposed the brominated carbon cloth that made of polyacrylonitrile-based activated carbon fibers (PAN-ACFs) as a precursor to chemically and uniformly graft SO3H groups to prepare the solid acid catalyst. The thermal and catalytic properties of the sulfonated PAN-ACFs were examined by IR controlled catalytic measurements and thermal analysis. The catalytic test results showed that the sulfonated surface remarkably improved the operating efficiency in isopropanol dehydration by decreasing the reaction temperature. All PAN-ACFs with grafted SO3H groups prepared through brominated precursors can converse 100% of isopropanol into propylene at moderate temperature. They showed the highest catalytic activity compared to PAN-ACFs sulfonated with oleum and chlorosulfonic acid, which conversed only 40% and 70% of isopropanol into propylene and deactivated at the higher temperatures in the reaction medium

Catalytic efficiency of activated carbon functionalized with phosphorus-containing groups in 2-propanol dehydration

The functionalization of activated carbon (AC) by P-containing groups was conducted, and their thermal desorption was studied. Depending on the used method, the functionalized AC contains 0.5–1.45 mmol/g of acidic groups acting in catalytic 2-propanol dehydration. All catalysts showed 100% conversion of 2-propanol to propylene. The catalytic activity does not change with time under isothermal conditions and during their repeated use in catalysis, for 3 cycles of heating-cooling. In fact, the yield of propylene remains stable; it does not decrease with each cycle. Preliminary oxidation with nitric acid causes a small increase in the catalytic activity

Additional file 1 of Surface Response of Brominated Carbon Media on Laser and Thermal Excitation: Optical and Thermal Analysis Study

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