Characterisation of in-situ modified bacterial cellulose using 2-acetyl-1-pyrroline
Loading...
Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Teknologi Malaysia
Abstract
Bacterial cellulose (BC) is a biopolymer with high purity of cellulose and excellent mechanical properties. Increased interest in the use of natural polymer makes BC as an excellent alternative for plant cellulose. Furthermore, the morphology and properties of BC can be easily altered by incorporation with additives that are not specifically required for the growth of the bacteria in fermentation media. This unique property of BC opens a new gate for development of new cellulose composites with desired properties by incorporation of selective suitable materials. In this research, bacterial cellulose-pyrroline (BC-P) composites were developed where BC was modified using in-situ technique. 2-acetyl-1- pyrroline from Pandanus amaryllifolius (pandan) was added into the fermentation medium of BC at five different concentrations. The impact on the characteristics of BC-P composites produced and their performance in hexavalent chromium (Cr (VI)) removal from aqueous solution of Cr (VI) were studied. The results showed that the increase of 2-acetyl-1-pyrroline concentration from 0 to 13 mg/L in the medium resulted in the increase of wet weight from 18.41 g to 45.85 g and dry weight from 1.31 g to 4.75 g. The physicochemical properties of BC-P composites produced were studied. For microstructure study using field emission scanning electron microscopy analysis, all composites showed similar interwoven organized fibrils network. Small particles of pyrroline could be seen on the fibrils surface where the particles number increased with the increase of 2-acetyl-1-pyrroline concentration. Mechanical testing revealed that high concentration of 2-acetyl-1-pyrroline gave better tensile strength of BC-P up to 48.20 MPa with crystanillity of 85.27%. Adsorption experiments with aqueous solution of Cr (VI) were carried out where the results showed proportional removal of Cr (VI) from 58.65% to 83.06% with increase of 2-acetyl-1-pyrroline concentration. Several factors were studied to obtain suitable parameter for the adsoption process. In comparison to native BC, BC-P composites had succesfully achieved up to 87% removal of Cr (VI) from aqueous solution of Cr (VI). The most suitable conditions for the adsorption using BC-P composites were at 180 min contact time with adsorbent dosage of 0.25 g, initial Cr (VI) concentration of 75 g/ml and pH 3. Mathematical modelling for adsorption kinetics and isotherm were well correlated with the pseudo second-order (R2>0.96) and the Freundlich isotherm model (R2> 0.99), respectively. In conclusion, addition of 2-acetyl-1-pyrroline using in-situ technique was successfully proven to be able to modify the characteristic of BC for producing new BC-P composites. Furthermore, the ability of BC-P composites as a biosorbent were proven by successfully achieved up to 87% efficiency of Cr (VI) ions removal from aqueous solution of Cr (VI) Characterisation of in-situ modified bacterial cellulose using 2-acetyl-1-pyrroline
Description
Thesis (PhD. (Bioprocess Engineering))
Keywords
Cellulose—Analysis, Cellulose—Biotechnology, Chemistry, Technical—Research