Satu tumbuhan akuatik, karbon teraktif kiambang itik, untuk menyingkirkan metilena biru (MB) daripada larutan akuas telah dinilai melalui kumpulan ujian penjerapan. Karbon teraktif kiambang itik dihancurkan dan disaring ke dalam tiga saiz yang berbeza iaitu 63, 150 dan 250 μm. Sebelum pirolisis, tumbuhan ini dikeringkan di bawah sinaran cahaya matahari dan dikisar menjadi kepingan kecil untuk dipeletkan. Kesan daripada kepekatan awal pewarna (100 hingga 500 mg/L), masa sentuh, suhu larutan (30 dan 60° C) dan pH larutan (2 hingga 10) telah disiasat. Antara saiz yang berbeza karbon teraktif kiambang itik, saiz 63 dan 125 μm menunjukkan kapasiti penjerapan yang paling tinggi diikuti oleh saiz 250 μm. Saiz zarah yang kecil memberikan kawasan permukaan yang lebih besar untuk pemindahan jisim, maka lebih banyak kawasan aktif bagi proses penjerapan. Penjerapan sesuhu pewarna MB pada karbon teraktif kiambang itik sesuai dipadankan oleh garis sesuhu Langmuir dengan penjerapan kapasiti maksima sebanyak 221.516 mg/g. Kajian kinetik termasuk pseudo tertib pertama dan pseudo tertib kedua telah dipilih untuk mengikuti proses penjerapan MB. Penjerapan MB ke karbon teraktif kiambang sesuai dipadankan oleh model kinetik pseudo tertib pertama. Selain daripada itu, parameter termodinamik ΔG °, ΔH °, ΔS ° dan Ea juga ditentukan.
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An aquatic plant, duckweed based activated carbon, to remove methylene blue (MB) from aqueous solution was evaluated through batch adsorption test. The duckweed activated carbon was crushed and sieved into three different sizes which are 63, 150 and 250 μm. Prior to pyrolysis, the plant was sun dried and ground into small pieces for pelletization. The effect of initial dye concentration (100 to 500 mg/L), contact time, solution temperature (30 and 60°C) and solution pH (2 to 10) were investigated. Among different sizes of duckweed activated carbon sizes, 63 and 125 μm sizes provided the highest adsorption capacity followed by 250 μm sizes. Smaller particles size gave larger surface area for mass transfer, hence more active sites for adsorption process. Adsorption isotherm of MB dye onto duckweed activated carbon well fitted to the Langmuir isotherm with maximum monolayer adsorption capacity of 221.52 mg/g. Kinetic studies including pseudo-first-order and pseudo-second-order equation were choose to follow the MB adsorption processes. Adsorption of MB onto duckweed activated carbon was best fitted by pseudo-first-order kinetic model. Other than that, thermodynamic parameters ΔG°, ΔH°, ΔS° and Ea were also determined.
Adsorption of synthetic dye using activated carbon from duckweed algae (Lemna minor L.) / Nur Athirah Md. Akhir