ISOLATION AND MODIFICATION OF CELLULOSE FROM COCONUT COIR FOR APPLICATION IN METHYLENE BLUE ADSORPTION

• Main Author: Laurentia Tandinata, Gracella
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/65246
• Institution: Institut Teknologi Bandung

In the present time, there are a lot of industries, that dispose of their waste products which can result in water pollution. There are several ways to reduce water pollution, one of those is using adsorption technique. In this study, cellulose as a natural polymer was used. Cellulose has hydroxyl groups which can be chemically modified to increase the adsorption capacity of cellulose for application in water pollutant adsorption. Methylene blue was used as an adsorbate in this study. Methylene blue is a cationic azo dye, difficult to be biodegraded and mostly used in textile, plastic, and pharmaceutical industry. Methylene blue in waste water will accumulate over time which can cause disruption to the ecosystem of water bodies. This research was divided into four steps. They were cellulose isolation from coconut coir, modification of cellulose, characterization of cellulose and its modified product, and adsorption study. Cellulose isolation from coconut coir was carried out with pre-wash step, alkaline treatment with sodium hydroxide, and delignification. Modification of cellulose was conducted via graft copolymerization using itaconic acid as a monomer and cerium ammonium nitrate (CAN) as an initiator to synthesize cellulose-g-poly(itaconic acid). Graft copolymerization was carried out with a theoretical DPn of 60. Cellulose and cellulose-g- poly(itaconic acid) were characterized using FTIR spectroscopy and X-ray diffraction (XRD). Adsorption study was conducted with 60 minutes as the optimum contact time and 12 as the optimum pH. Adsorption of methylene blue with cellulose and cellulose-g-poly(itaconic acid) followed the Freundlich isotherm model with Kf value of 5.7393 (mg.g-1) (L .mg-1)1/n and 8.3015 (mg.g-1) (L .mg-1)1/n respectively. The 1/n constant for cellulose and cellulose-g- poly(itaconic acid) were 0.7836 and 0.6787 resepectively. Kinetic study showed that the adsorption methylene blue using cellulose and cellulose-g-poly(itaconic acid) followed the pseudo second order model. Thermodynamic study showed that adsorption of methylene blue using cellulose and cellulose-g-poly(itaconic acid) was a physical adsorption. ?????° and ?????° values for adsorption using cellulose were 23.073 kJ.mol-1 and 0.3426 kJ.mol-1K-1, which showed that the adsorption was an endothermic process and with an increase in disorder. ?????° and ?????° values for adsorption using cellulose-g-poly(itaconic acid) were 0.2234 kJ.mol-1 and -0.2392 kJ.mol-1K-1, which showed that the adsorption was an endothermic process and with a decrease in disorder. The efficiency of adsorption using cellulose was 71.96%, while cellulose-g-poly(itaconic acid) was 69.36%. This indicated that the presence of poly(itaconic acid) as the side chains in cellulose could not yet improve the adsorption capacity of cellulose.