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

Abstract

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.