Kulit tebal daripada limau bali yang tidak bernilai digunakan untuk menghasilkan karbon teraktif dengan kawasan permukaan tinggi dan sesuai untuk penjerapan pewarna yang tidak terurai. Oleh itu, objektif utama kajian ini adalah untuk menyediakan karbon teraktif terbaik daripada kulit limau bali melalui pengaktifan kimia menggunakan kalium hidroksida. Pada mulanya, kulit dikisar sampai 0.355 mm dan seterusnya menjalani proses pengkarbonan pada suhu 700˚C selama sejam di bawah aliran nitrogen 150 sm3/min. Arang terhasil dijerap isi dengan kalium hidroksida pada nisbah yang berbeza (1, 2, dan 3). Arang ini diaktifkan pada pelbagai suhu (600˚C, 700˚C, dan 800˚C) selama sejam. Karbon teraktif terbaik, AC800 (3) dihasilkan pada suhu 800˚C dan nisbah 3. Walaupun hasil AC800 (3) daripada arang hanya 42.17%, tetapi AC800 (3) mempunyai kawasan permukaan yang tinggi iaitu 1223.55 m2/g. Karbon teraktif ini seterusnya dijalani kajian penjerapan metilena biru untuk mendapatkan kapasiti penjerapan. Kajian penjerapan secara kelompok dijalani dengan menggunakan kepekatan awal yang berbeza (300-700 mg/L). Keseimbangan penjerapan meningkat dengan peningkatan kepekatan awal. Kapasiti penjerapan maksimum AC800(3) bagi metilena biru adalah paling tinggi (666.67 mg/g). Data eksperimen penjerapan berpadanan dengan model Langmuir dengan nilai R2 sebanyak 0.9995. Kajian kinetik mematuhi model kinetik pseudo tertib kedua. Keputusan kajian menunjukkan bahawa penjerapan karbon teraktif daripada kulit limau bali sesuai untuk penjerapan metilena biru daripada larutan akuas.
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The bulky skin of pomelo which has low market value can be used to produce activated carbon with high surface area which is suitable for adsorption of dye which is non-degradable. Hence, the main objective of this research is to prepare optimum activated carbon from pomelo skin via two-step chemical activation using potassium hydroxide. The skin was first grinded to 0.355 mm and then carbonized at 700˚C for 1 hour under nitrogen flow at 150 cm3/min. The char produced was then impregnated with potassium hydroxide at different ratio (1, 2, and 3). The char was then activated at various activation temperature (600˚C, 700˚C, and 800˚C) for 1 hour under nitrogen flow. The best activated carbon, AC800(3) was produced at activation temperature of 800˚C and impregnation ratio 3. Although the yield of AC800(3) from char was only 42.17%, it was observed that AC800(3) had high surface area which was 1223.55 m2/g. This prepared activated carbon was used to perform adsorption study with methylene blue to determine the adsorption capacity. The batch adsorption study was carried out using different initial concentration (300 to 700 mg/L). The adsorption equilibrium increased with the increase of initial concentration. The maximum adsorption capacity for methylene blue of AC800(3) was the highest with the value of 666.67 mg/g. The experimental data of adsorption fitted well to Langmuir isotherm with R2 of 0.9995. The kinetic study obeyed pseudo-second-order model. The results of adsorption study showed that activated carbon from pomelo skin is suitable for methylene blue removal from aqueous solution.
Preparation of activated carbon from pomelo skin via chemical activation / Leong Ann Tsun