Chemical characterization of bamboo leaves (Gigantochloa albociliata and Dracaena surculosa) by sodium hydroxide treatment

Abstract

Background: Dracaena surculosa and Gigantochloa albociliata leaves are different in morphology and appearance. Sodium hydroxide (NaOH) is widely used in pulping of wood for making paper or regenerated fibers. NaOH is used to separate lignin from cellulose fibers, and this treatment is needed to identify the characteristics of leaves.  This study was conducted in order to investigate the characteristics of D. surculosa and G.albociliata species under NaOH treatment.   Methods: NaOH was applied to the leaves for 8 hours.  Treated and untreated bamboo leaves were analysed using FTIR analysis, in order to identify the presence of functional groups in the leaves. Results: It was observed that these two species not only differ physically, but also chemically. The presence of OH, CH and alkynes functional groups in the leaf sample indicates that the species share similar properties but have a slight difference in the molecular bonds. From the morphological observation of D. surculosa and G. albociliata leaves, they are slightly different in terms of leaf appearance and characteristics. G. albociliata have thicker leaves compared to D. surculosa , and NaOH treatment shows that D. surculosa leaves are harder to dissolve into the solvent. Scanning electron microscope (SEM) analysis of these two species shows the initial structure of fibres in the leaves are intact but after NaOH treatment, the fibres are ruptured and appear in non-uniform shapes. Conclusions: The initial morphology of G. albociliata and D.surculosa is different in color and appearance. However after NaOH treatment, the color becomes almost the same. Regarding SEM analysis, after NaOH treatment the morphology of the bamboo leaves completely changes. Therefore, it can be concluded that the process of hemicellulose removal had occurred during treatment. The results show that lignin has been removed by NaOH treatment to enhance the characteristics of the bamboo leaves from different species.