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Abstrak :
Currently the world’s second largest palm oil producer Malaysia produces a large amount of oil palm biomass each year. Although some oil palm parts and derivatives like empty fruit bunch and fibre have been commercialized as fuel, less attention has been given to oil palm fronds (OPF). Initial feasibility and characterization studies of OPF showed that it is highly feasible as fuel for gasification to produce high value gaseous fuel or syngas. This paper discusses the experimental gasification attempt carried out on OPF using a 50 kW lab scale downdraft gasifier and its results. The conducted study focused on the temperature distributions within the reactor and the characteristics of the dynamic temperature profile for each temperature zones during operation. An average pyrolysis zone temperature of 324oC and an average oxidation zone temperature of 796oC were obtained over a total gasification period of 74 minutes. A maximum oxidation zone temperature of 952oC was obtained at 486 lpm inlet air flow rate and 10 kg/hr feedstock consumption rate. Stable bluish flare was produced for more than 70% of the total gasification time. Similar temperature profile was obtained comparing the results from OPF gasification with that of woody biomass. Furthermore, the successful ignition of the syngas produced from OPF gasification ascertained that OPF indeed has a higher potential as gasification feedstock. Hence, more detailed studies need to be done for better understanding in exploiting the biomass as a high prospect alternative energy solution. In addition, a study of the effect of initial moisture content of OPF feedstock on the temperature distribution profile along the gasifier bed showed that initial moisture content of feedstock in the range of 15% gives a satisfactory result, while experiments with feedstock having higher moisture content resulted in lower zone temperature values.

Abstrak :
Melimpahnya limbah plastik di lingkungan berpotensi menimbulkan bahaya pencemaran karena adanya degradasi plastik menjadi mikroplastik. Beredarnya pencemaran oleh mikroplastik ini mendukung dimulainya penelitian terkait pendeteksian mikroplastik di lingkungan. Salah satu metode deteksi mikroplastik tersebut adalah pemanfaatan sifat fluoresensi dari carbon quantum dots (CQDs). Pada penelitian ini, CQDs akan diproduksi melalui metode hidrotermal menggunakan bahan baku pelepah kelapa sawit sebagai sumber karbon karena mengandung kadar lignin sebanyak 15-26%. Untuk memperoleh karbon tersebut, pelepah kelapa sawit dihancurkan lalu diubah menjadi biochar melalui proses pirolisis. Biochar digunakan sebagai prekursor pembuatan CQDs yang diproduksi melalui metode hidrotermal pada variasi suhu 180°C, 190°C, 200°C. Pada penelitian ini, dihasilkan CQDs dengan peak 291 nm pada rentang panjang gelombang UV yang menunjukkan adanya pita serapan π-π* pada struktur karbon CQDs. Munculnya gugus C=C, O-H dan C=O yang dominan pada pengujian FTIR juga membuktikan keberhasilan produksi CQDs melalui metode hidrotermal ini. CQDs yang dihasilkan pada ketiga variasi suhu tersebut berukuran kurang dari 10 nm serta memiliki intensitas fluoresensi paling tinggi pada variasi 200℃ ketika dieksitasi pada 405 nm. Akan tetapi, quenching pada CQDs setelah berinteraksi dengan mikroplastik polietilen (PE) dan polietilen tereftalat (PET) belum dapat disimpulkan. Oleh karena itu, perlu dilakukan penelitian lebih lanjut untuk mengetahui interaksi antara CQDs dan mikroplastik, terutama PE dan PET. ......The abundance of plastic waste in the environment has the potential to cause pollution hazards due to the degradation of plastic into microplastics. The circulation of pollution by microplastics supports the start of research related to detecting microplastics in the environment. One method for detecting microplastics is utilizing the fluorescence properties of carbon quantum dots (CQDs). In this research, CQDs will be produced via the hydrothermal method using palm frond raw materials as a carbon source because they contain lignin levels of 15-26%. To obtain this carbon, palm fronds are crushed and then converted into biochar through a pyrolysis process. Biochar is used as a precursor for making CQDs which are produced via the hydrothermal method at varying temperatures of 180°C, 190°C, 200°C. In this research, CQDs were produced with a peak of 291 nm in the UV wavelength range, indicating the existence of a π-π* absorption band in the CQDs carbon structure. The appearance of dominant C=C, O-H and C=O groups in FTIR testing also proves the success of CQDs production via this hydrothermal method. The CQDs produced at the three temperature variations were less than 10 nm in size and had the highest fluorescence intensity at the 200℃ variation when excited at 405 nm. However, the quenching of CQDs after interacting with polyethylene (PE) and polyethylene terephthalate (PET) microplastics cannot be concluded. Therefore, further research needs to be carried out to determine the interaction between CQDs and microplastics, especially PE and PET.

Abstrak :

Pelepah Kelapa Sawit (OPF) merupakan salah satu limbah pertanian Indonesia yang melimpah dengan berbagai potensi yang menjanjikan. Kandungan holoselulosa yang tinggi pada minyak pelepah sawit dapat dimanfaatkan untuk memproduksi gula pereduksi dan bahan kimia platform. Gula pereduksi diperoleh melalui pretreatment (delignifikasi) dan hidrolisis enzimatik. Makalah ini melaporkan pretreatment pelepah kelapa sawit menggunakan pretreatment hidrotermal dengan beberapa jenis larutan buffer asam (fosfat, asetat, dan sitrat) untuk meningkatkan produksi glukosa dan xilosa. Studi dilakukan dengan membandingkan kinerja pelarut hidrotermal menggunakan air dan larutan penyangga asam terhadap degradasi lignin dan OPF yang dihidrolisis secara enzimatis pada kondisi operasi yang stabil. Kondisi operasi pretreatment yang optimal ditentukan dengan memvariasikan waktu tinggal dan suhu pretreatment. Larutan penyangga sitrat menunjukkan kemampuan degradasi lignin terbaik pada suhu 150^OC dan waktu tinggal 40 menit. Hasil recovery glukosa dan xilosa yang diperoleh adalah 24,76 g/g dan 3,93 g/g. Penggunaan larutan buffer asam menunjukkan peningkatan hasil recovery glukosa sebesar 88,31% dibandingkan pretreatment hidrotermal konvensional, namun hasil recovery xilosa mengalami penurunan sebesar 17,29%. ......Oil Palm Fronds (OPF) are one of Indonesia's abundant agricultural wastes, with many promising potentials. The high holocellulose content in the oil palm frond can be used to reduce sugars and platform chemicals. Reducing sugar is obtained through pretreatment (delignification) and enzymatic hydrolysis. This paper reports on oil palm frond pretreatment using hydrothermal pretreatment with several types of acid buffer solutions (phosphoric, acetic, and citric) to increase the production of glucose and xylose. The study was conducted by comparing the performance of hydrothermal solvents using water and acid buffers against lignin degradation and enzymatically hydrolyzed OPF under stable operating conditions. The optimal pretreatment operating conditions were determined by comparing the residence time and pretreatment temperature. Buffer Citrate showed the best lignin degradation ability at temperature 150^OC and residence time 40 minute. The yields recovery of glucose and xylose obtained were 24.76 g/g and 3.93 g/g. Using an acid buffer solution showed an increase in glucose yield recovery of 88.31% compared to conventional hydrothermal pretreatment, but the yield recovery of xylose decreased by 17.29%.