Preparation and characterization of carboxymethylcellulose obtained from groundnut shell (Arachis hypogae)

Background: Carboxymethylcellulose (CMC) is a vital constituent in pharmaceuticals, foods, cosmetics and other various sectors. Cellulose is a natural biodegradable polysaccharide component found in the cell wall of plants. This study presents the preparation and characterization of carboxymethyl cellulose derived from the shell of Arachis hypogaea which is an agricultural waste product.

Method: Groundnut shell α-cellulose was first isolated from the powder using standard method. Groundnut shell CMC was synthesized from the α-cellulose by mercerization using sodium hydroxide which promotes hydroxyl group activation and then followed by etherification with monochloroacetic acid to modify the cellulose structure. Various characterization such as FTIR spectroscopy, X-ray diffraction and SEM imaging were done to determine the physical and structural characteristics of the resulting CMC. Groundnut shell CMC (GS-CMC) was examined for its physiochemical and micromeritic properties.

Result: The extraction yield of GS- CMC was about 72% with a swelling index of 46.7%. GS- CMC exhibited excellent flow with an angle of repose of 28.07° and Carr’s index of 9.03%. The degree of Substitution (DS) obtained for GS-CMC is 2.2 which is indicative of high degree of substitution of carboxymethyl cellulose. The FTIR spectroscopy analysis of Groundnut shell CMC showed robust absorption band at 1587 cm which serves as confirmation for the presence of the COO group, signifying the successful Carboxymethylation process.

Conclusion: Carboxymethyl cellulose was successfully derivatized from α-cellulose obtained from groundnut shell powder. GS-CMC could possibly be explored further for its potential applications in the pharmaceutical industry.