Environmental Friendly Natural Polymer and Its Polylactic Acid Modified Composite Synthesized from Thais Coronata Shell for Urea Uptake from Waste Water by Equilibration

Abstract

: CHITOSAN was extracted from Thais Coronata shell and modified with poly-lactic acid by gelation method to derive its poly-lactic chitosan nano-composite. Both the chitosan and the polylactic acid modified composite where analyzed using FT-IR and SEM for changes in functional group and surface morphology. A spectrum of unmodified chitosan with absorption bands ranging from 3533 cm -1 to 3942 cm -1 , all attributed to O-H stretching vibrations, and a cluster of bands attributed to N-H stretching vibrations of primary and secondary amine at 3417 cm -1 , 3317 cm -1 , 3286 cm -1 , and 3217cm -1 . The -NH 2 stretching is approximated matched by the high and deep adsorption peak at 1496cm -1 corresponding to Amide II, which is a characteristic band of N-acetylation. SEM images of unmodified and poly-lactic acid modified chitosan composites at 500 and 1500x magnification reveals a rough surface with significant pores, typified and notable irregularities that are ideal for adsorption. The morphology of the poly-lactic acid modified chitosan has changed significantly in relation to its weak surface properties, with a smoother surface domain and reduced pore structure. The degree of ionic activity between chitosan and the poly lactic acid grafted onto the polymer chain is linked to morphological variability. The samples where investigated as potential bio-sorbents for urea uptake from waste water by equilibration. Adsorption experiments were conducted on 20100mg/L urea wastewater and the effect of contact time, concentration, temperature and pH on urea removal efficiency was studied. At temperature of 30°C and pH of 2.5, maximum removal efficiency of 50.16 and 54.33% were obtained for the modified and un-modified chitosan respectively. Results from adsorption studies revealed that the modification with poly-lactic acid did not enhance adsorption capacity of chitosan, although its solubility and resistance to acidic degradation was improved. The development of chitosan materials with better adsorption capacity in the light of urea uptake is therefore very feasible.