SYNTHETIC CHARACTERIZATION OF ORGANIC NANOMATERIALS AND POTENTIAL APPLICATION IN WATER PURIFICATION

Abstract

The poor quality of drinking water and increase in water borne diseases have been of great concern which necessitates continued research for water purification. The use of organic materials for purifying water has been attempted locally in various forms without due cognizance to scientific potency of the materials. Cellulose and nanocellulose were obtained from Moringa oleifera seeds and Cocos nucifera endocarps organic materials using acid hydrolysis. The isolated cellulose and nanocellulose were characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The XRD pattern shows that the crystal structure of the isolated cellulose from Cocos nucifera endocarps and Moringa oleifera seeds are cellulose I with allomorph cellulose Iβ (monoclinic). The isolated cellulose from Cocos nucifera endocarps and Moringa oleifera seeds revealed prominent characteristics peaks at 21.89° and 22.47° respectively. The major crystalline peaks of nanocellulose from Cocos nucifera endocarps and Moringa oleifera seeds were observed at 22.05° and 22.53° respectively. The values of crystallinity index (𝐶𝐼𝑟 ) from the XRD pattern of the isolated cellulose were 51% for Cocos nucifera endocarps and 62.6% for Moringa oleifera seeds. Crystallinity index values of the nanocellulose were 60.8% for Cocos nucifera endocarps and 65.4% for Moringa oleifera seeds. The values of total crystalline index (TCI), lateral order index (LOI) and hydrogen bond intensity (HBI) of the nanocellulose for Cocos nucifera endocarps were 0.91, 1.38 and 0.96 while the values of the nanocellulose for Moringa oleifera seeds were 0.93, 1.17 and 0.94. These values indicate high degree of crystallinity and more ordered cellulose structure. Nanocellulose is more crystalline than the isolated cellulose, then the tendency of its capability in water purification is high. The surface morphology of the isolated cellulose from Cocos nucifera endocarps have rod-like feature and the nanocellulose are predominantly rod-like with conical feature while the particles of the isolated cellulose from Moringa oleifera seeds are predominantly conical with needle-like feature and the nanocellulose have rod-like feature. The isolated cellulose from Cocos nucifera endocarps has an average length of 56.90 𝜇𝑚 and diameter of 20.00 𝜇𝑚 while the isolated cellulose from Moringa oleifera seeds has an average length of 46.20 𝜇𝑚 and diameter of 88.90 𝜇𝑚. For the nanocellulose, the average length of Cocos nucifera endocarps is 26.07 𝑛𝑚 and the diameter is 61.84𝑛𝑚 while the average length of Moringa oleifera seeds is 14.30 𝑛𝑚 and the diameter is 36.33 𝑛𝑚. Reduction of cellulose to nanosize and large capability of occupying large surface area increases the ability of purifying water. The FTIR shows the presence of hydroxyl, carbonyl, carboxyl, C=C stretching and C-H stretching functional groups. The negative charges of the hydroxyl, carbonyl and carboxyl functional groups in nanocellulose react with impurities in water that carry positive charges. Additionally, the positive charges of the functional groups react with the impurities that carry negative charges and bind the impurities in water. After binding the impurities in water, they stick together and precipitate. These characteristics are indicative of the potential application of nanocellulose isolated from Cocos nucifera endocarps and Moringa oleifera seeds.