Characterization of Activated Carbon Using Chemical Activation via Microwave Ultrasonic System

Abstract

Higher adsorption capacities of activated carbon (AC) can be evaluate according to pore volume, porosity and surface area. AC with higher pore volume, porosity and surface area desired in the present study in order to enhance the properties of AC supercapacitor. Thus, the present studies focus on the chemical activation process to increase the characterization of AC. The study was using bamboo waste as a precursor and the activation process was conducted using microwave ultrasonic system. The chemical agent used during the process was KOH and H 2 SO 4 . Microwave activation was conducted at intensity 100 W and 300 W for 30 min and sonication frequency was constantly set at 200 Hz for 60 min. The sample was carbonized at temperature of 400 ºC and 800 ºC using furnace for 2 hours. Then, AC was characterized for surface area using BET analysis and functioning group using FTIR analysis. The results shown the carboxyl, aliphatic, aromatic and phenolic hydroxyl group are present on raw bamboo while new functional group such as alkyl halide and some of some weak bands appeared which analogous with out of plane bending mode of the C-H or O-H group occur for AC. Active surface area and total pore volume of AC supercapacitor in 5M of concentration for H 2 SO 4 and KOH corresponded to 1167 m 2 /g, 0.724 cm 3 /g, 740.10 m 2 /g, 0.462 cm 3 /g, respectively.Keywords: supercapacitor, microwave-ultrasonic, activation, chemical, carbonization Abstrak Kapasiti penjerapan yang tinggi pada karbon teraktif boleh dinilai mengikut isipadu liang, keliangan dan luas permukaan. Keaktifan karbon dengan isi padu liang yang tinggi, tahap keliangan yang besar dan luas permukaan yang tinggi amat dikehendaki di dalam kajian ini bagi meningkatkan sifat-sifat keaktifan karbon superkapasitor. Oleh itu, kajian ini memberi tumpuan kepada proses pengaktifan kimia untuk meningkatkan pencirian yang diperlukan dalam karbon aktif. Kajian ini telah menggunakan sisa buluh sebagai pelopor dan proses pengaktifan telah dijalankan menggunakan sistem ultrasonik-gelombang mikro. Agen kimia yang digunakan semasa proses pengaktifan adalah KOH dan H 2 SO 4 . Pengaktifan gelombang ketuhar telah digunakan pada intensiti 100 W dan 300 W selama 30 min dan kekerapan sonikasi telah ditetapkan pada 200 Hz selama 60 min. Sampel telah dikarbonisasi pada suhu 400 ºC dan 800 ºC mengunakan relau selama 2 jam. Kemudian, karbon aktif dikelaskan bagi mendapatkan luas permukaan dengan menggunakan analisis BET dan kumpulan berfungsi pula menggunakan analisis FTIR. Keputusan menunjukkan karboksil aliphatik, aromatik dan kumpulan fenolik hidrosil hadir pada bahan asas buluh manakala kumpulan berfungsi baharu seperti alkil halida dan beberapa kumpulan yang lemah muncul dimana serupa dengan lenturan mod bagi C-H atau O-H yang terhasil pada karbon aktif. Kawasan permukaan yang aktif dan jumlah isipadu liang

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