We investigated effects of ozone treatment on solubility of cellulose and chemical composition in cellulose extracted from palm fiber. The initial holocellulose, α-cellulose, and lignin contents of the extracted cellulose were 88.0, 81.9, and 8.75%, respectively. The extracted cellulose was treated with ozone and NaOH solution. Ozone treatment for 5 hr at 40 C using 3% citric acid decreased the lignin content from 8.75 to 2.71%. Under these conditions, the degree of polymerization (DP) of the cellulose decreased to 29 from 160 and the carboxyl content increased to 2.05 mmol/g. When the solid phase was treated with NaOH after ozone treatment, the mass of the solid phase decreased as the ozone treatment time increased. The lowest mass was 0.43 g. Additionally, the mass of cellulose regenerated from the liquid phase increased with increasing treatment time. The highest mass of regenerated cellulose was 0.54 g. The masses of the solid phase and regenerated cellulose obtained without ozone treatment under the same conditions were 0.76 and 0.18 g, respectively. These results suggest that ozone treatment improves the solubility of cellulose by converting hydroxyl groups in the cellulose to carboxyl groups and reducing the DP.

Carboxymethyl cellulose (CMC) was prepared using cellulose extracted from palm fiber (CPF). The effect of ozone pretreatment on the CMC properties [degree of substitution (DS) and viscosity] was investigated. After treatment of CPF with ozone, CMC was prepared by alkalization followed by etherification using sodium hydroxide (NaOH) and sodium monochloroacetic acid (NaMCA) in an alcoholic medium. The DS of CMC increased with increased ozone pretreatment time and with increased amounts of NaOH and NaMCA reagents. The CMC solubility increased with increasing DS. Therefore, the solubility increased with ozone pretreatment time. The favored treatment conditions were ozone pretreatment for 3 h, followed by the addition of 10 mL of 30% NaOH and 4.5 g of NaMCA. Under these conditions, the DS, purity, and solubility were 1.05, 79.6%, and 94.6%, respectively. The viscosity of CMC prepared using cellulose treated with ozone decreased with increasing ozone pretreatment time, which was caused by the reduced degree of polymerization. Therefore, use of ozone pretreatment for CMC preparation is an effective method for controlling CMC properties.

Carboxymethyl cellulose (CMC) was prepared using cellulose extracted from palm fiber (CPF). The effect of ozone pretreatment on the CMC properties degree of substitution (DS) and viscosity was investigated. After treatment of CPF with ozone, CMC was prepared by alkalization followed by etherification using sodium hydroxide (NaOH) and sodium monochloroacetic acid (NaMCA) in an alcoholic medium. The DS of CMC increased with increased ozone pretreatment time and with increased amounts of NaOH and NaMCA reagents. The CMC solubility increased with increasing DS. Therefore, the solubility increased with ozone pretreatment time. The favored treatment conditions were ozone pretreatment for 3 h, followed by the addition of 10 mL of 30% NaOH and 38.6 mM of NaMCA. Under these conditions, the DS, purity, and solubility were 1.05, 79.6%, and 94.6%, respectively. The viscosity of CMC prepared using cellulose treated with ozone decreased with increasing ozone pretreatment time, which was caused by the reduced degree of polymerization. Therefore, use of ozone pretreatment for CMC preparation is an effective method for controlling CMC properties.