Synthesis and characterization of Carboxymethyl Cellulose (CMC) from waste tea

Abstract

Carboxymethyl cellulose (CMC) was synthesized by using extracted cellulose from waste tea. Cellulose was extracted from waste tea by using alkaline and bleaching treatments to remove non cellulosic components such as lignin and hemicellulose. The extracted cellulose was characterized by using Fourier Transform Infrared (FTIR) spectroscopy, the two peak at 1745.18 cm-1 and 1249.73 cm-1 which represent the C=O stretching and C–O stretching, respectively disappeared in the spectra after the alkaline and bleaching treatments indicated that hemicellulose and lignin were almost removed from the waste tea after chemical treatment. The extracted cellulose then was converted to carboxymethyl cellulose (CMC) by etherification process using chloroacetic acid and sodium hydroxide. There are two reaction occur simultaneously during carboxymethylation that are the primary reaction which produces pure carboxymethyl cellulose (CMC) and side reaction that produces undesired sodium glycolate. The carboxymethylation reaction was evaluated by varying the effect of sodium hydroxide concentration (10-40) %, chloroacetic dosage (0.05 - 0.5) g and reaction time (0.5 - 4.0) h. The best conditions to prepare carboxymethyl cellulose (CMC) are at 20% sodium hydroxide concentration, 0.3 g chloroacetic acid dosage and 1.5 hour reaction time. The maximum degree of substitution, DS obtained is 0.60 and the maximum percentage carboxymethyl content is 18.02 %. The differences spectrum can be observed in prepared carboxymethyl cellulose (CMC) at peaks 1031.89 cm-1, 1424.44 cm-1 and 1607.18 cm-1 are represent to –O– , –CH2– and –COO–, respectively this is due to the carboxyl and its salts groups, which is confirmed substitution of carboxymethyl groups in cellulose structure.