The Effect of Ozonation, Ultrasonic, and Hybrid Ozonation-Ultrasonic Pretreatment Methods on the Delignification of Oil Palm Mesocarp Fibers

Abstract

Oil palm mesocarp fiberis a by-product of the palm oil pressing process, which has great potential if used as a second-generation biofuel raw material. The main components of oil palm mesocarp fiber are cellulose, hemicellulose, and lignin commonly called lignocellulose. Cellulose is the most valuable component to be utilized in the bioenergy sector. However, the oil palm mesocarp fibers lignin layer, which binds cellulose and restricts cellulose accessibility, makes it difficult to use. Ozone pretreatment is considered to be an alternative and effective method of lignin breakdown. This study compares the ozonation, ultrasonic, and hybrid ozonation-ultrasonicmethods used to degrade lignin in oil palm mesocarp fibers. The operating conditions were set at pH (3, 4, 5, 6, 7, 8, 9, 10, 11), flow rate (1, 2, 3, 4, 5) L min-1, for (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100) minutes, at 29±1 oC. The research indicates that using ozonation-ultrasonic hybridization results in a more significant degradation of lignin than using ozonation and ultrasonics individually. In this investigation, the hybrid ozonation-ultrasonic treatment gives the best lignin degradation results and the highest quantities of cellulose, reaching 91.99% after 60 minutes at a temperature of 29±1 oC, a pH of 9, and a flow rate of 2 L.min-1. Meanwhile, the degradation of lignin using ozone treatment is 72.75%, and ultrasound only 47.70%. Cellulose with the highest purity is 89.71%.

Effect of ultrasound-advanced oxidation processes for pretreatment of oil palm mesocarp fiber for cellulose extraction

“…The pretreatment process aimed at obtaining cellulose was significantly influenced by the solution pH, which had to be adjusted to facilitate effective lignin degradation. Based on previous research conducted by Anggoro (2022), utilizing Ultrasound-Advanced Oxidation Processes on palm oil fibers, the optimum time was found to be 60 minutes, at a pH of 9-10. However, in this study, it was carried out at pH 4, 5, and 6 with a duration of 70, 80, and 90 minutes, respectively.…”

“…Subsequently, ultrasonic ozonation was conducted with an ozone flow rate of 2 L/min at 30°C for durations of 70, 80, and 90 minutes under solution pH conditions of 4, 5, and 6, adjusted by adding either 0.1 M NaOH or 0.1 M H2SO4 to the solution. Following treatment, the residue was filtered, washed with distilled water, and dried in an oven at 100°C (Anggoro et al, 2022).…”

The Effects of Ozonolysis on Oil Palm Fruit Mesocarp Delignification

“…Therefore, ozone reacted more easily with OPFM to break lignin bonds, as observed in a previous study on Furthermore, lignin degradation increases as the amount of ozone reacted increases due to the powerful oxidizing properties of ozone. This is because a higher flowrate can provide a more consistent and intense exposure of ozone to the lignin, leading to a higher rate of radical formation and subsequent lignin degradation (Baig et al, 2015;Anggoro et al, 2022). When lignin comes into contact with ozone, it can be degraded rapidly, leading to the break of aromatic rings and the generation of carboxyl groups .…”