Surface modification of cellulose isolated from Sesamun indicum underutilized seed: A means of enhancing cellulose hydrophobicity

Cellulose (SC) isolated from sesame seed (SS) was surface modified with the introduction of an ester functional group via a simple reaction to produce the modified product (SA). SS, SC and SA were characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), particle size distribution (PSD), zeta potential and scanning electron microscopy (SEM). SC and SA were evaluated for their water holding capacity (WC), oil holding capacity (OC), swelling capacity (SW) and their ability to adsorb heavy metals. The FTIR revealed peaks corresponding to the formation of the ester functional group at the surface of SA. The crystallinity of SC was 28.02% but after the modification, it increased to 77.03% in SA. The PSD of SC and SA was both monomodal with sizes of 10.1305 μm in SC and 10.2511 μm in SA. The adsorption capacity of SC towards Pb (II) and Cu (II) ions was higher than that of SA. However, SA was unable to adsorb Cu (II) ions. SA exhibited the lower WC and SW values as compared to SC which suggested an improved hydrophobicity after the modification. This study has shown that hydrophobicity can be improved in cellulose via surface modification.